Title of Invention

METHOD AND APPARATUS TO PROVIDE NECESSARY OUTPUT TORQUE RESERVE BY SELECTION OF HYBRID RANGE STATE AND INPUT SPEED FOR A HYBRID POWERTRAIN SYSTEM

Abstract A method for controlling a powertrain system includes determining a current transmission operating range state and engine state, determining at least one potential transmission operating range state and engine state, providing at least one operator torque request, determining preferability factors associated with the current transmission operating range state and engine state, and potential transmission operating range states and engine states, wherein determining preferability factors associated with potential transmission operating range states includes assigning biasing costs to operator torque requests which reside within a pre-determined range of possible operator torque requests for at least two of the potential transmission operating range states, preferentially weighting the preferability factors for the current transmission operating range state and engine state, and selectively commanding changing the transmission operating range state and engine state based upon stheaid preferability factors and the operator torque request.
Full Text METHOD AND APPARATUS TO PROVIDE NECESSARY OUTPUT
TORQUE RESERVE BY SELECTION OF HYBRID RANGE STATE AND
INPUT SPEED FOR A HYBRID POWERTRAIN SYSTEM
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Application
No. 60/985,232 filed on 11/4/2007, which is hereby incorporated herein by
reference.
TECHNICAL FIELD
[0002] This disclosure relates generally to control systems for electro-
mechanical transmissions.
BACKGROUND
[0003] The statements in this section merely provide background
information related to the present disclosure and may not constitute prior art.
[0004] Known powertrain architectures include torque-generative devices,
including internal combustion engines and electric machines, which transmit
torque through a transmission device to an output member. One exemplary
powertrain includes a two-mode, compound-split, electro-mechanical
transmission which utilizes an input member for receiving motive torque from
a prime mover power source, preferably an internal combustion engine, and an
output member. The output member can be operatively connected to a
driveline for a motor vehicle for transmitting tractive torque thereto. Electric
machines, operative as motors or generators, generate a torque input to the

transmission, independently of a torque input from the internal combustion
engine. The electric machines may transform vehicle kinetic energy,
transmitted through the vehicle driveline, to electrical energy that is storable in
an electrical energy storage device. A control system monitors various inputs
from the vehicle and the operator and provides operational control of the
powertrain, including controlling transmission operating state and gear
shifting, controlling the torque-generative devices, and regulating the electrical
power interchange among the electrical energy storage device and the electric
machines to manage outputs of the transmission, including torque and
rotational speed.
SUMMARY
[0005] A powertrain system in a motorized vehicle has an accelerator pedal
and includes an engine coupled to an electro-mechanical transmission
selectively operative in one of a plurality of transmission operating range
states and one of a plurality of engine states. A method for controlling the
powertrain system includes determining a current transmission operating range
state and engine state, determining at least one potential transmission
operating range state and engine state, providing at least one operator torque
request, determining preferability factors associated with the current
transmission operating range state and engine state, and potential transmission
operating range states and engine states, wherein determining preferability
factors associated with potential transmission operating range states includes
assigning biasing costs to operator torque requests which reside within a pre-
determined range of possible operator torque requests for at least two of the

potential transmission operating range states, preferentially weighting the
preferability factors for the current transmission operating range state and
engine state, and selectively commanding changing the transmission operating
range state and engine state based upon stheaid preferability factors and the
operator torque request.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] One or more embodiments will now be described, by way of
example, with reference to the accompanying drawings, in which:
[0007] FIG. 1 is a schematic diagram of an exemplary powertrain, in
accordance with the present disclosure;
[0008] FIG. 2 is a schematic diagram of an exemplary architecture for a
control system and powertrain, in accordance with the present disclosure;
[0009] FIG. 3 shows an arrangement of a first plurality of preferability
factors relating to a method, in accordance with the present disclosure;
[0010] FIG. 4 illustrates a combination of a plurality of preferability factors
in accordance with the present disclosure;
[0011] FIG. 5 A provides a graphical representation of a stabilization of
changes of operating range of an electro-mechanical hybrid transmission, in
accordance with the present disclosure;
[0012] FIG. 5B shows an alternate graphical representation of a stabilization
of changes of operating range of an electro-mechanical hybrid transmission, in
accordance with the present disclosure;

[0013] FIG. 6 depicts an architecture useful in carrying out execution of a
change of operating range of an electro-mechanical hybrid transmission, in
accordance with the present disclosure;
[0014] FIG. 7 shows a path taken by the transmission input speed over the
course of a change from one potential transmission operating range state to
another, in accordance with the present disclosure;
[0015] FIG. 8 illustrates variation in transmission input speed values as a
function of time for various potential operating range states of an electro-
mechanical hybrid transmission, in accordance with the present disclosure;
[0016] FIG. 9 shows differences in rpm values between different
transmission input speed values at a selected point in time between various
potential operating range states of an electro-mechanical hybrid transmission,
in accordance with the present disclosure;
[0017] FIG. 10 shows a profile of how input speeds for an electro-
mechanical hybrid transmission vary at a change in mode during resetting of a
filter, in accordance with the present disclosure;
[0018] FIG. 11 illustrates one biasing cost function useful in biasing the
preferability of a potential transmission operating range state for a given
operator torque request, in accordance with the present disclosure;
[0019] FIG. 12 is one embodiment of a representation of the difference over
time between an operator torque request and a desirable transmission torque
output for an exemplary transmission operating range state, in accordance with
the present disclosure;

[0020] FIG. 13 is a graphical definition of the space in which a search engine
selects values for evaluation of torque outputs for continuously variable
transmission modes, in accordance with the present disclosure;
[0021] FIG. 14 diagrammatically illustrates the utility of a switch in
permitting selection of either a first Torque Reserve range size, a second
Torque Reserve range size, and a Torque Reserve of zero, in accordance with
the present disclosure;
[0022] FIGS 15 and 16 collectively illustrate a comparison of the size of
ranges of operator torque requests over which the biasing cost function which
establishes the Torque Reserve for different operating modes of a motorized
vehicle equipped with a transmission, in accordance with the present
disclosure; and
[0023] FIG. 17 shows a biasing cost function in the absence of a Torque
Reserve, in accordance with the present disclosure.
DETAILED DESCRIPTION
[0024] Referring now to the drawings, wherein the showings are for the
purpose of illustrating certain exemplary embodiments only and not for the
purpose of limiting the same, FIG. 1 shows an exemplary electro-mechanical
hybrid powertrain. The exemplary electro-mechanical hybrid powertrain
shown in FIG. 1 comprises a two-mode, compound-split, electro-mechanical
hybrid transmission 10 operatively connected to an engine 14, and first and
second electric machines ('MG-A') 56 and ('MG-B') 72. The engine 14 and
first and second electric machines 56 and 72 each generate power which can
be transmitted to the transmission 10. The power generated by the engine 14

and the first and second electric machines 56 and 72 and transmitted to the
transmission 10 is described in terms of input torques, referred to herein as T1
TA, and TB respectively, and speed, referred to herein as N1; NA,and NB,
respectively.
[0025] In one embodiment, the exemplary engine 14 comprises a multi-
cylinder internal combustion engine which is selectively operative in several
states to transmit torque to the transmission 10 via an input shaft 12, and can
be either a spark-ignition or a compression-ignition engine. The engine 14
includes a crankshaft (not shown) operatively coupled to the input shaft 12 of
the transmission 10. A rotational speed sensor 11 is preferably present to
monitor rotational speed of the input shaft 12. Power output from the engine
14, comprising rotational speed and output torque, can differ from the input
speed, N1, and the input torque, T1, to the transmission 10 due to torque-
consuming components being present on or in operative mechanical contact
with the input shaft 12 between the engine 14 and the transmission 10, e.g., a
hydraulic pump (not shown) and/or a torque management device (not shown).
[0026] In one embodiment the exemplary transmission 10 comprises three
planetary-gear sets 24, 26 and 28, and four selectively-engageable torque-
transmitting devices, i.e., clutches C1 70, C2 62, C3 73, and C4 75. As used
herein, clutches refer to any type of friction torque transfer device including
single or compound plate clutches or packs, band clutches, and brakes, for
example. A hydraulic control circuit 42, preferably controlled by a
transmission control module (hereafter 'TCM') 17, is operative to control
clutch states. In one embodiment, clutches C2 62 and C4 75 preferably
comprise hydraulically-applied rotating friction clutches. In one embodiment,

clutches C1 70 and C3 73 preferably comprise hydraulically-controlled
stationary devices that can be selectively grounded to a transmission case 68.
In a preferred embodiment, each of the clutches C1 70, C2 62, C3 73, and C4
75 is preferably hydraulically applied, selectively receiving pressurized
hydraulic fluid via the hydraulic control circuit 42.
[0027] In one embodiment, the first and second electric machines 56 and 72
preferably comprise three-phase AC machines, each including a stator (not
shown) and a rotor (not shown), and respective resolvers 80 and 82. The
motor stator for each machine is grounded to an outer portion of the
transmission case 68, and includes a stator core with electrical windings
extending therefrom. The rotor for the first electric machine 56 is supported
on a hub plate gear that is operatively attached to shaft 60 via the second
planetary gear set 26. The rotor for the second electric machine 72 is fixedly
attached to a sleeve shaft hub 66.
[0028] Each of the resolvers 80 and 82 preferably comprises a variable
reluctance device including a resolver stator (not shown) and a resolver rotor
(not shown). The resolvers 80 and 82 are appropriately positioned and
assembled on respective ones of the first and second electric machines 56 and
72. Stators of respective ones of the resolvers 80 and 82 are operatively
connected to one of the stators for the first and second electric machines 56
and 72. The resolver rotors are operatively connected to the rotor for the
corresponding first and second electric machines 56 and 72. Each of the
resolvers 80 and 82 is signally and operatively connected to a transmission
power inverter control module (hereafter 'TPIM') 19, and each senses and
monitors rotational position of the resolver rotor relative to the resolver stator,

thus monitoring rotational position of respective ones of first and second
electric machines 56 and 72. Additionally, the signals output from the
resolvers 80 and 82 are interpreted to provide the rotational speeds for first
and second electric machines 56 and 72, i.e., NAand NB, respectively.
[0029] The transmission 10 includes an output member 64, e.g. a shaft,
which is operably connected to a driveline 90 for a vehicle (not shown), to
provide output power, e.g., to vehicle wheels 93, one of which is shown in
FIG. 1. The output power is characterized in terms of an output rotational
speed, No and an output torque, To- A transmission output speed sensor 84
monitors rotational speed and rotational direction of the output member 64.
Each of the vehicle wheels 93, is preferably equipped with a sensor 94 adapted
to monitor wheel speed, VSS-WHL, the output of which is monitored by a
control module of a distributed control module system described with respect
to FIG. 2, to determine vehicle speed, and absolute and relative wheel speeds
for braking control, traction control, and vehicle acceleration management.
[0030] The input torques from the engine 14 and the first and second electric
machines 56 and 72 (T1, TA, and TB respectively) are generated as a result of
energy conversion from fuel or electrical potential stored in an electrical
energy storage device (hereafter 'ESD') 74. ESD 74 is high voltage DC-
coupled to the TPIM 19 via DC transfer conductors 27. The transfer
conductors 27 include a contactor switch 38. When the contactor switch 38 is
closed, under normal operation, electric current can flow between the ESD 74
and the TPIM 19. When the contactor switch 38 is opened electric current
flow between the ESD 74 and the TPIM 19 is interrupted. The TPIM 19
transmits electrical power to and from the first electric machine 56 by transfer

conductors 29, and the TPIM 19 similarly transmits electrical power to and
from the second electric machine 72 by transfer conductors 31, in response to
torque commands for the first and second electric machines 56 and 72 to
achieve the input torques TA and TB- Electrical current is transmitted to and
from the ESD 74 in accordance with commands provided to the TPIM which
derive from such factors as including operator torque requests, current
operating conditions and states, and such commands determine whether the
ESD 74 is being charged, discharged or is in stasis at any given instant.
[0031] The TPIM 19 includes the pair of power inverters (not shown) and
respective motor control modules (not shown) configured to receive the torque
commands and control inverter states therefrom for providing motor drive or
regeneration functionality to achieve the input torques TA and TB. The power
inverters comprise known complementary three-phase power electronics
devices, and each includes a plurality of insulated gate bipolar transistors (not
shown) for converting DC power from the ESD 74 to AC power for powering
respective ones of the first and second electric machines 56 and 72, by
switching at high frequencies. The insulated gate bipolar transistors form a
switch mode power supply configured to receive control commands. There is
typically one pair of insulated gate bipolar transistors for each phase of each of
the three-phase electric machines. States of the insulated gate bipolar
transistors are controlled to provide motor drive mechanical power generation
or electric power regeneration functionality. The three-phase inverters receive
or supply DC electric power via DC transfer conductors 27 and transform it to
or from three-phase AC power, which is conducted to or from the first and
second electric machines 56 and 72 for operation as motors or generators via

transfer conductors 29 and 31, depending on commands received which are
typically based on factors which include current operating state and operator
torque demand.
[0032] FIG. 2 is a schematic block diagram of the distributed control module
system. The elements described hereinafter comprise a subset of an overall
vehicle control architecture, and provide coordinated system control of the
exemplary hybrid powertrain described in FIG. 1. The distributed control
module system synthesizes pertinent information and inputs, and executes
algorithms to control various actuators to achieve control objectives, including
objectives related to fuel economy, emissions, performance, drivability, and
protection of hardware, including batteries of ESD 74 and the first and second
electric machines 56 and 72. The distributed control module system includes
an engine control module (hereafter 'ECM') 23, the TCM 17, a battery pack
control module (hereafter 'BPCM') 21, and the TPIM 19. A hybrid control
module (hereafter 'HCP') 5 provides supervisory control and coordination of
the ECM 23, the TCM 17, the BPCM 21, and the TPIM 19. A user interface
('UI') 13 is operatively connected to a plurality of devices through which a
vehicle operator may selectively control or direct operation of the electro-
mechanical hybrid powertrain. The devices present in UI 13 typically include
an accelerator pedal 113 ('AP') from which an operator torque request is
determined, an operator brake pedal 112 ('BP'), a transmission gear selector
114 ('PRNDL'), and a vehicle speed cruise control (not shown). The
transmission gear selector 114 may have a discrete number of operator-
selectable positions, including the rotational direction of the output member 64
to enable one of a forward and a reverse direction.


[0033] The aforementioned control modules communicate with other control
modules, sensors, and actuators via a local area network (hereafter 'LAN') bus
6. The LAN bus 6 allows for structured communication of states of operating
parameters and actuator command signals between the various control
modules. The specific communication protocol utilized is application-specific.
The LAN bus 6 and appropriate protocols provide for robust messaging and
multi-control module interfacing between the aforementioned control
modules, and other control modules providing functionality such as antilock
braking, traction control, and vehicle stability. Multiple communications
buses may be used to improve communications speed and provide some level
of signal redundancy and integrity. Communication between individual
control modules can also be effected using a direct link, e.g., a serial
peripheral interface ('SPI') bus (not shown).
[0034] The HCP 5 provides supervisory control of the powertrain, serving to
coordinate operation of the ECM 23, TCM 17, TPIM 19, and BPCM 21.
Based upon various input signals from the user interface 13 and the
powertrain, including the ESD 74, the HCP 5 generates various commands,
including: the operator torque request ('TO_REQ'), a commanded output torque
('TCMD') to the driveline 90, an engine input torque command, clutch torques
for the torque-transfer clutches C1 70, C2 62, C3 73, C4 75 of the
transmission 10; and the torque commands for the first and second electric
machines 56 and 72, respectively. The TCM 17 is operatively connected to the
hydraulic control circuit 42 and provides various functions including
monitoring various pressure sensing devices (not shown) and generating and
communicating control signals to various solenoids (not shown) thereby


controlling pressure switches and control valves contained within the
hydraulic control circuit 42.
[0035] The ECM 23 is operatively connected to the engine 14, and functions
to acquire data from sensors and control actuators of the engine 14 over a
plurality of discrete lines, shown for simplicity as an aggregate bi-directional
interface cable 35. The ECM 23 receives the engine input torque command
from the HCP 5. The ECM 23 determines the actual engine input torque, T1,
provided to the transmission 10 at that point in time based upon monitored
engine speed and load, which is communicated to the HCP 5. The ECM 23
monitors input from the rotational speed sensor 11 to determine the engine
input speed to the input shaft 12, which translates to the transmission input
speed, N1. The ECM 23 monitors inputs from sensors (not shown) to
determine states of other engine operating parameters which may include
without limitation: a manifold pressure, engine coolant temperature, throttle
position, ambient air temperature, and ambient pressure. The engine load can
be determined, for example, from the manifold pressure, or alternatively, from
monitoring operator input to the accelerator pedal 113. The ECM 23
generates and communicates command signals to control engine actuators,
which may include without limitation actuators such as: fuel injectors, ignition
modules, and throttle control modules, none of which are shown.
[0036] The TCM 17 is operatively connected to the transmission 10 and
monitors inputs from sensors (not shown) to determine states of transmission
operating parameters. The TCM 17 generates and communicates command
signals to control the transmission 10, including controlling the hydraulic
circuit 42. Inputs from the TCM 17 to the HCP 5 include estimated clutch


torques for each of the clutches, i.e., C1 70, C2 62, C3 73, and C4 75, and
rotational output speed, NO, of the output member 64. Other actuators and
sensors may be used to provide additional information from the TCM 17 to the
HCP 5 for control purposes. The TCM 17 monitors inputs from pressure
switches (not shown) and selectively actuates pressure control solenoids (not
shown) and shift solenoids (not shown) of the hydraulic circuit 42 to
selectively actuate the various clutches C1 70, C2 62, C3 73, and C4 75 to
achieve various transmission operating range states, as described hereinbelow.
[0037] The BPCM 21 is signally connected to sensors (not shown) to
monitor the ESD 74, including states of electrical current and voltage
parameters, to provide information indicative of parametric states of the
batteries of the ESD 74 to the HCP 5. The parametric states of the batteries
preferably include battery state-of-charge, battery voltage, battery temperature,
and available battery power, referred to as a range PBAT_MIN to PBAT_MAX-
[0038] Each of the control modules ECM 23, TCM 17, TPIM 19 and BPCM
21 is preferably a general-purpose digital computer comprising a
microprocessor or central processing unit, storage mediums comprising read
only memory ('ROM'), random access memory ('RAM'), electrically
programmable read only memory ('EPROM'), a high speed clock, analog to
digital ('A/D') and digital to analog ('D/A') circuitry, and input/output
circuitry and devices ('I/O') and appropriate signal conditioning and buffer
circuitry. Each of the control modules has a set of control algorithms,
comprising resident program instructions and calibrations stored in one of the
storage mediums and executed to provide the respective functions of each
computer. Information transfer between the control modules is preferably

accomplished using the LAN bus 6 and serial peripheral interface buses. The
control algorithms are executed during preset loop cycles such that each
algorithm is executed at least once each loop cycle. Algorithms stored in the
non-volatile memory devices are executed by one of the central processing
units to monitor inputs from the sensing devices and execute control and
diagnostic routines to control operation of the actuators, using preset
calibrations. Loop cycles are preferably executed at regular intervals, for
example at each 3.125, 6.25, 12.5, 25 and 100 milliseconds during ongoing
operation of the powertrain. However, any interval between about 2
milliseconds and about 300 milliseconds may be selected. Alternatively,
algorithms may be executed in response to the occurrence of any selected
event.
[0039] The exemplary powertrain shown in reference to FIG. 1 is capable of
selectively operating in any of several operating range states that can be
described in terms of an engine state comprising one of an engine on state
('ON') and an engine off state ('OFF'), and a transmission state comprising a
plurality of fixed gears and continuously variable operating modes, described
with reference to Table 1, below.



[0040] Each of the transmission operating range states is described in the
table and indicates which of the specific clutches C1 70, C2 62, C3 73, and C4
75 are applied for each of the operating range states. As an example, a first
continuously variable mode, i.e., EVT Mode 1, or Ml, is selected by applying
clutch C1 70 only in order to "ground" the outer gear member of the third
planetary gear set 28. The engine state can be one of ON ('M1_Eng_On') or
OFF ('M1_Eng_Off). A second continuously variable mode, i.e., EVT Mode
2, or M2, is selected by applying clutch C2 62 only to connect the shaft 60 to
the carrier of the third planetary gear set 28. The engine state can be one of
ON ('M2_Eng_On') or OFF ('M2_Eng_Off'). For purposes of this
description, when the engine state is OFF, the engine input speed is equal to
zero revolutions per minute ('RPM'), i.e., the engine crankshaft is not rotating.
A fixed gear operation provides a fixed ratio operation of input-to-output
speed of the transmission 10, i.e., N1/NO, is achieved. For example, a first
fixed gear operation ('G1') is selected by applying clutches C1 70 and C4 75.

A second fixed gear operation ('G2') is selected by applying clutches C1 70
and C2 62. A third fixed gear operation ('G3') is selected by applying
clutches C2 62 and C4 75. A fourth fixed gear operation ('G4') is selected by
applying clutches C2 62 and C3 73. The fixed ratio operation of input-to-
output speed increases with increased fixed gear operation due to decreased
gear ratios in the planetary gears 24, 26, and 28. The rotational speeds of the
first and second electric machines 56 and 72, NAand NB respectively, are
dependent on internal rotation of the mechanism as defined by the clutching
and are proportional to the input speed measured at the input shaft 12.
[0041] In response to operator input via the accelerator pedal 113 and brake
pedal 112 as captured by the user interface 13, the HCP 5 and one or more of
the other control modules determine the commanded output torque, TCMD,
intended to meet the operator torque request, To_REQ, to be executed at the
output member 64 and transmitted to the driveline 90. Resultant vehicle
acceleration is affected by other factors including, e.g., road load, road grade,
and vehicle mass. The operating range state is determined for the transmission
10 based upon inputs which include a variety of operating characteristics of
the powertrain. These include the operator torque request communicated
through the accelerator pedal 113 and brake pedal 112 to the user interface 13
[0042] In some embodiments, the operating range state may be predicated on
a powertrain torque demand caused by a command to operate the first and
second electric machines 56 and 72 in an electrical energy generating mode or
in a torque generating mode. In some embodiments, the operating range state
can be determined by an optimization algorithm or routine which determines a
preferential selection of the operating range state based upon inputs which


may include: operator demand for power; battery state-of-charge; and
operating efficiencies of the engine 14 and the first and second electric
machines 56, 72. The control system manages torque inputs from the engine
14 and the first and second electric machines 56 and 72 based upon pre-
selected outcome criteria embedded in the executed selection routine, and
system operation is controlled thereby to effectively manage resources
commensurate with desired levels of ESD state-of-charge and fuel delivery.
Moreover, operation can be determined, including over-riding of any desired
feature(s), based upon detection of a fault in one or more components or sub-
systems. The HCP 5 monitors the torque-generative devices, and determines
the power output from the transmission 10 required to achieve the output
torque necessary to meet the operator torque request. The ESD 74 and the
first and second electric machines 56 and 72 are electrically-operatively
coupled for power flow therebetween. Furthermore, the engine 14, the first
and second electric machines 56 and 72, and the electro-mechanical
transmission 10 are mechanically-operatively coupled to transmit power
therebetween to generate a power flow to the output member 64.
[0043] Given various operating conditions possible for a motorized vehicle
equipped with an electro-mechanical hybrid transmission, which include
varied environmental and road conditions such as road grade and operator
torque demands, it is generally possible for an electro-mechanical hybrid
transmission to be usefully operatively engaged potentially in more than one
transmission operating range state, including such range states specified in
Table I, at a given time during its operation. Moreover, it may be true that for
every change in road grade, throttle opening, and brake pedal depression that a


motorized vehicle comprising an electro-mechanical hybrid transmission
experiences during the course of its typical travel, differing transmission
operating range state and engine states of the engine may at any time be
viewed as being advantageous in consideration of an overall balance between
such factors including fuel economy, required torque output of the
transmission, and state-of-charge of the ESD 74. At any one instant in time, a
particular transmission operating range state and engine state may be
desirable, advantageous or preferred, while at subsequent instants in time other
transmission operating range state and engine states may be desirable,
advantageous or preferred, with the result being that over even a relatively
short time span of operation such as, for example, five minutes, conditions
making dozens or more desirable, advantageous, or preferred transmission
operating range state and engine states exist during such time span. However,
this disclosure provides that altering the transmission operating range state and
engine state in response to each and every single change in operating
conditions encountered is not necessarily desirable in a motorized vehicle
having an electro-mechanical hybrid transmission.
[0044] According to one embodiment of this disclosure, FIG. 3 shows a first
plurality of numerical values, each of which represents a preferability factor
for each of the potential operating range states of an electro-mechanical hybrid
transmission, and potential engine states for the engine, including the
operating range states and engine states specified in Table I. In FIG. 3, the
designations M1 and M2 refer to mode 1 and mode 2 of the electro-
mechanical hybrid transmission. The designations G1, G2, G3, and G4 refer
to gear 1, gear 2, gear 3, and gear 4, respectively, and HEOff refers to the


engine state, which engine state is either engine-on or engine-off. In one
embodiment of this disclosure, any one or more such preferability factors may
be arbitrarily assigned. In another embodiment, any one or more of such
preferability factors may comprise an output generated as a result of any
algorithmic or other data processing method which has as an input or basis any
information provided by any one or more sensors disposed at any location on a
motorized vehicle equipped with such an electro-mechanical hybrid
transmission, or disposed on, at, or near any portion of its drive train where
data may be acquired. Such sensors may include without limitation: a wheel
speed sensor 94, an output speed sensor 84, and a rotational speed sensor 11.
[0045] It is desired that the preferability factors provided for each of the
transmission operating range states and engine state shown in FIG. 3 are
maintained in association with their respective transmission operating range
state and engine state, and according to one embodiment of this disclosure
such preferability factors are set forth in an array, as shown in FIG. 3. This
arrangement is not a strict requirement, but is of convenience when
performing a method according to this disclosure, as shown and described in
relation to FIG. 4.
[0046] This disclosure also provides a plurality of numerical values, each of
which is associated with one of the possible operating range states and engine
states of an electro-mechanical hybrid transmission at any selected point in
time while in service in a motorized vehicle, such as during operation while a
vehicle is traveling on a road surface, which plurality may be referred to as
current operating range state values. Preferred embodiments include a
numerical value associated with the engine state. This second plurality of


numerical values are shown arranged in an array in FIG. 4 labeled as "current
operating range factors" which includes numerical values for both the
transmission operating range state and the engine state.
[0047] FIG. 4 illustrates how the numerical values of the first plurality of
preferability factors from FIG. 3 may be combined with the second plurality of
preferability factors from the current operating range state and engine state. In
one embodiment, the combination is made by summing the numerical values
from each corresponding operating range state and engine state in each array,
to arrive at a third array that comprises preferability factors for each possible
transmission operating range state and engine state, which is labeled "new
desired operating range factors". As used herein, a desired operating range
state refers to a transmission operating range state or engine state that is, for
one reason or another, generally relating to drivability, but may relate to
engine economy, emissions or battery life, more desirable than the current
transmission operating range state and/or engine state. The numerical values
present in the third array may be compared to one another, and in one
embodiment the lowest numerical value present in the third array represents
the transmission operating range state or engine state which is to be selected or
evaluated for selection as a basis upon which to make a change in operating
state of the electro-mechanical hybrid transmission while a motorized vehicle
containing same is in operation. For example, in the third array in FIG. 4, the
lowest numerical value is 7, corresponding to mode 1 operation of the electro-
mechanical hybrid transmission, whereas the current operating range state for
the transmission is mode 2, evidenced by the zero in the current operating
range array being the lowest numerical value. In one illustrative, non-limiting


exemplary embodiment, a signal would be sent to a shift execution module
embedded in the TCM 17, suggesting a change of transmission operating
range state from mode 2 to mode 1, which may be effected by the TCM. In
alternate embodiments, the TCM may be provided with additional decision-
making data and algorithms to either accept and execute a suggested command
change resulting from a process according to this disclosure, or it may deny
such execution, based on other factors programmed into the TCM 17 which
can be arbitrary in one embodiment, and in other embodiments are based on
the output of one or more algorithms having inputs provided by on-board
vehicle sensors. In one embodiment of the disclosure, the TCM 17 provides
current operating range factors, which may be in the same format that the
numerical values for the second plurality of preferability factors are in. In
other embodiments, the TCM 17 provides current operating range factors in
any format different than that which the numerical values relating to the
second plurality of preferability factors are in.
[0048] In another embodiment, the first plurality of preferability factors
described in reference to FIG. 3 may be combined with an alternative plurality
of preferability factors, which are depicted in the array labeled as the "desired
operating range factors" (which include numerical values for both the
transmission operating range state and the engine state) in FIG. 4, to arrive at a
third array comprising a set of preferability factors which are considered the
"new desired operating range factors." The preferability factors comprising
the desired operating range factors may be an output generated as a result of
any algorithm or other data processing method of information provided by any
one or more sensors disposed at any location on a motorized vehicle equipped


with such an electro-mechanical hybrid transmission, or disposed on, at, or
near any portion of its drive train where data may be acquired. Such sensors
include without limitation: a wheel speed sensor 94, an output speed sensor
84, and a rotational speed sensor 11. In another embodiment, the first plurality
of preferability factors described in reference to FIG. 3 may be combined with
both the preferability factors from the current operating range factors and the
desired operating range factors to arrive at a third array comprising new
desired operating range factors.
[0049] In general, one or more of the preferability factors among the desired
operating range factors will change over time, in response to changing
operating conditions encountered by a motorized vehicle equipped with an
electro-mechanical hybrid transmission, and the value of these factors may
either increase or decrease during vehicle operation. For example, when an
operator makes a torque request upon encountering an uphill grade while
traveling at a low speed, the preferability factor associated with gear 1
operation may be caused to decrease in value in response thereto. Similarly,
when the vehicle operator makes a braking torque request upon encountering
an downhill grade while traveling at a constant speed, the preferability factor
associated with gear 1 operation may be caused to increase substantially in
value so that selection of the gear 1 operating range is essentially precluded.
[0050] In FIG. 4, the numerical values in the arrays comprising the current
operating range factors and the desired operating range factors are identical
only for illustrative purposes, and in practice the numerical values present in
these sets of preferability factors may differ from one another. For
embodiments in which the first plurality of preferability factors from FIG. 3


are combined with those of the desired operating range factors, a third array
comprising preferability factors for a new desired operating range factors are
provided, at least one of which factors are subsequently provided to a shift
control module which may be embedded in the TCM 17. For instances in
which the shift control module orders the execution of a change in
transmission operating range state, engine state, or both, the preferability
factors comprising the new desired operating range factors are communicated
as an input to a process of this disclosure as the desired operating range factors
in a subsequent iteration of a process as herein described, as it is desirable in
such embodiments to repeatedly perform a method as described herein at any
time interval desired or selected, which may be any interval between about 2
milliseconds and about 300 milliseconds, including all intervals and ranges of
intervals therebetween.
[0051] In preferred combinations of preferability factors according to the
disclosure, it is desirable to only combine preferability factors of like kind
with one another, i.e., preferability factors relating to M1 may only be
combined with other preferability factors which relate to Ml, G2 with G2, and
so forth. Although combination of arrays, each of which comprise a plurality
of preferability factors according to one embodiment of this disclosure has
been shown and described as involving the summation of such arrays, and
selecting the least value present in an array as a value for consideration in
making a change in the operating range of an electro-mechanical hybrid
transmission, the present disclosure also includes embodiments in which the
selection criteria is to choose the largest numerical value. In other
embodiments, the combination of two or more arrays may include subtraction,


division, or multiplication of the numerical values corresponding to each
operating range present in the arrays so combined, to provide that one of the
values emerges as unique or differentiable from the remaining values present
as a result of such combination, each value representing a relative preferability
of the engine state or transmission range state. Selection is then made basis
the highest or lowest numerical value present, or any other differentiable
numerical attribute, in each of such embodiments. For cases where two or
more preferability factors present in a set or array which results from a
combination of preferability factors as provided herein are identical or non-
differentiable from one another, the selection of a transmission operating
range from such non-differentiable values may be arbitrary, or may be set to
any default selection desired.
[0052] In one embodiment of the disclosure, the numerical values of the first
plurality of preferability factors in the array shown in FIG. 3 may be selected
to be of a size sufficient to provide a biasing effect when combined with
numerical values present in either the desired operating range factors or
current operating range factors as described in reference to FIG. 4. For
convenience according to one embodiment, sets of such preferability factors
from FIG. 3 may be provided and arranged in a matrix, as shown in Table II
and Table HI below:



Thus, a plurality of preferability factors for the current operating range factors
may be provided from such matrix. Under such an arrangement, if the current
operating range of the electro-mechanical hybrid transmission is mode 1, then
numerical values from the first row are chosen as the numerical values for the
array to be used in a combination of arrays as described herein. Arrays for the
desired operating range factors may be selected from a matrix such as that
shown in Table III, as representative of preferability factor values associated
with the desired operating range state of the electro-mechanical hybrid
transmission and engine state.


[0053] When combining arrays comprising current operating range factors
and desirable operating range factors described in reference to FIG. 4 with a
plurality of preferability factors as provided in reference to FIG. 3 according
to this disclosure, the net effect is to stabilize the shifting of the transmission
to both the desired operating range and the current operating range by
inclusion of the preferability factors provided according to FIG. 3. Through
judicious selection of the values in Tables II and III above, an unexpected
benefit arises in that it is possible to select values which prohibit specific
changes in operating range states of an electro-mechanical hybrid
transmission. For example, a change in operating range from mode 2 to gear 4
may be permitted, whereas a change in operating range from mode 2 to gear 3
may be forbidden, the choices of which changes to permit or forbid being in
control of the user of a method herein by their judicious selection of numerical
values for the preferability factors. In general, it is desirable to avoid selecting
non-allowed range states, whether based on output speed of the transmission
or any other criteria selected by a user. In one embodiment, different potential
input speeds for mode 1 and mode 2 operation of the transmission are
considered over time in providing corresponding numerical values for these
states in the first plurality of numerical values, independent of the desired
transmission operating range state. According to one embodiment, a selection
process involves consideration only of the input speed associated with the
desired transmission operating state selected. In one preferred embodiment,
the numerical value representative of the current transmission operating range
state has a bias of zero. In other embodiments, the numerical value

representative of the current transmission operating range state has a relatively
small bias, and may be either positive or negative. Although shown as
positive numerical values, a preferability factor according to the disclosure
may be negative, since the net result of a process herein which combines the
different preferability factors for the result specified depends generally on
their relative magnitudes with respect to one another.
[0054] The net effect of the stabilization of shifting events or changes of
operating range of an electro-mechanical hybrid transmission according to this
disclosure is illustrated in FIG. 5A, which uses power loss as its ordinate;
however, other units of ordinate may be employed as desired. In FIG. 5A the
power loss associated with vehicle operation in gear 1 over time of varying
operating conditions is shown by the dotted wavy line. As this power loss
varies along the abscissa of time labeled as mode 1, it may be possible for
other operating range states of the electro-mechanical hybrid transmission to
be employed to advantage with respect to fuel economy, battery state-of-
charge, total torque output, etc. However, given typical wide variance in
torque demands over time by an operator, a plurality of shifting or
transmission mode changes would adversely impact drivability of a vehicle so
equipped. Hence, by the present incorporation of bias, by consideration of the
preferability factors described, the power loss associated with vehicle
operation in gear 1 over time of varying operating conditions may be moved
upwards on the ordinate scale, to the corresponding solid wavy line, the
amount of which bias is represented by the sum of factors A and B from the
first row in Table II and Table III respectively. The result of this with
reference to FIG. 5A is that the transmission operating range remains in mode

1 until the power loss associated with operating in that mode, plus the bias
amount, exceeds the power loss of operating in another operating range state,
in this case gear 1, at which point a change in operating range state is effected,
with the power loss throughout the depicted time interval following the path
marked by solid circles. Accordingly, situations where excessive operating
range state changes of an electro-mechanical hybrid transmission occur, are
maintained at any desirable level, dictated by the preferability factors chosen,
which can mean their minimization, as well as substantial or complete
elimination. This result is also depicted in FIG. 5B, which shows the
transmission desired operating range state as ordinate, depicting the removal
of what would have been deemed as an undesirable operating range state
change for some end-use applications of a vehicle equipped with an electro-
mechanical hybrid transmission according to the disclosure.
[0055] In one embodiment, the matrices, arrays, or other arrangements of
preferability factors as described herein are caused to be present in or
accessible to a microprocessor, in hard or soft memory, and the combinations
described herein are preferably carried out using such a processing device,
which then issues an output to a TCM 17 that itself employs such output as an
input in its own decision-making process. However, any arrangement of the
preferability factors in memory which is convenient for computing purposes
may be employed, in addition to such matrices or arrays as herein described.
Individual preferability factors may relate to, or be based upon any number of
potential variables relating to vehicle operation, and include without limitation
variables relating to energy usage, drivability, fuel economy, tailpipe
emissions, and battery state-of-charge, with information concerning such

variables being provided in one embodiment, by sensors. In other
embodiments, the preferability factors may be derived from or based on losses
in the entire mechanical drive system, including losses due to belts, pulleys,
valves, chains, losses in the electrical system, heat losses, electrical machine
power losses, internal battery power loses, or any other parasitic loss in a
vehicle system, taken either alone, or in combination with any one or more
other loss or losses.
[0056] FIG. 6 depicts an architecture including a microprocessor, which is
capable of carrying out execution of a change of operating range state of an
electro-mechanical hybrid transmission according to one embodiment of the
disclosure. FIG. 6 shows microprocessor MP, having inputs of the current
desired range preferability factors, and the preferability factors described in
reference to FIG. 3. The microprocessor has an output, which is inputted to a
transmission control module, TCM 17, which itself provides feedback to the
microprocessor in the form of a plurality of current operating range state
preferability factors. The TCM 17 is capable of providing a suggested shift
execution command to the transmission 10.
[0057] Operation of a vehicle equipped with an electro-mechanical hybrid
transmission as herein described (including functionally-equivalent devices)
also includes the transmission input speed, N|, which itself is subject to change
as vehicle operating conditions encountered during travel of a motorized
vehicle vary. After undergoing a change in operating conditions, it is true that
in many cases a different transmission operating range state may become more
desirably employed than the present or current transmission operating range
state. In general, the transmission input speed N1 are different for different

transmission operating range states possible when the motorized vehicle is
traveling at the same given speed, when different operating modes or
transmission operating states are contemplated as being employed as alternate
operative modalities for operating at a same given speed. Accordingly, a
change in transmission operating state and/or engine state is desirably
accompanied by a change in transmission input speed N1.
[0058] FIG. 7 illustrates graphically one example of how the transmission
input speed N1 may vary over time when a vehicle equipped with an electro-
mechanical hybrid transmission as herein described undergoes an exemplary
change in operating range state from M14 to M2. The N1 for M1 represents the
current N1 when the current transmission operating range state is M1. G2 N1
and M2 N1 represent the selected (desired) N1 for the corresponding
transmission operating range states. Since a direct change of operating range
state from M1 to M2 is forbidden, the transmission must first pass through G2.
During such a transition, the necessary transmission input speed N1 is seen to
first decrease when going from M1 to G2, then to increase slightly over time
during brief operation in G2, after which a steep increase in N1 is experienced
in achieving M2 operation. Therefore, the path or "trip" that the transmission
input speed N1 is seen to go through is given by:

in which M1 N1 is the transmission input speed for transmission M1 operation;
G2 N1 is the transmission input speed for transmission G2 operation, M2 N1 is
the transmission input speed for transmission M2 operation, and G2 N1 is the

transmission input speed for transmission G2 operation. By weighting the
direction of change of N1, the total "cost" of the trip that the transmission input
speed is seen to go through can be provided by a calculation of the type:

in which the "*" character indicates a multiplication operation, and a and b are
constants in which a is used for negative changes in N1 and in which b is used
for positive changes in N1. In alternate embodiments, a and b are varying
parameters which are a function of the corresponding distance of the N1 trip or
the corresponding desired transmission operating range state. The variable x,
a trip-direction weighting constant, is a subjective value which may be set or
determined by the vehicle engineers. The determination of x takes into
account whether a potential change in transmission operating range state first
requires a shift up followed by a shift down, or whether it first requires a shift
down, followed by a shift up, as shown in FIG. 7. If the required sequence is
shift down, then shift up, then x is set to a subjectively-determined value c. If
the required sequence is shift up then shift down, the x is set to a subjectively-
determined value d. For the case illustrated in FIG. 7, the formula for
determining TC is:

By analogous arithmetic a trip costing factor (TC) may be readily provided for
every potential change in transmission operating range state and engine state

by consideration of the trip that the N1 must pass for a given potential change
in transmission operating range state and engine state at any point in time of
the vehicle travel. Although the changes in N1 shown in FIG. 7 follow a
straight-line path for purposes of illustration, in actual operation the changes in
N1 may also follow curved paths during all or a portion of the transition,
wherein the paths may be either concave-up or concave-down. As shown as
occurring at different points in time in FIG. 7, the calculation of the N1 values
for M1, which in this example is the origin of the trip is that of the monitored
current N1 value, and the calculation of N1 values for G2 and M2 operation,
which represent the intermediate and final destinations of the trip, may be
conducted simultaneously.
[0059] FIG. 8 graphically illustrates how selected values of N1 may vary
over time for each transmission operating range state shown during the
operation of a motorized vehicle equipped with an electro-mechanical hybrid
transmission as herein described. The current N1 profile represents the
monitored current N1 values, which in this example is when the current
transmission operating range state is Ml. In one embodiment, the selected N1
values (which may in alternate embodiments be desired N1 values or required
N1 values) at various points in time are arbitrarily selected to yield the curves
shown. In other embodiments the selected N1 values at various points in time
are based on the output of one or more algorithms having inputs provided by
on-board vehicle sensors, which after manipulation such as by a
microprocessor may provide curves similar or different to those shown in FIG.
8. Importantly, as shown in FIG. 9, for each point in time Tx under
consideration, there is associated with each of such curves a single point,

which may be used as a basis for calculating the differences in rpm, labeled "A
rpm" which differences in rpm are useful in determining a trip costing factor
associated with every potential change in transmission operating range state
for any desired point in time. While rpm is used herein to exemplify one
implementation, other rotational speed metrics are equally applicable. In one
embodiment, the A rpm values may be conveniently set forth in an array as in

wherein the rpm differences associated with M2 involves the rpm difference
M1 to G2 and G2 to M2 as earlier described. The M1 N, value used for the A
rpm calculation is that of the current M1 N1 value and not that of the selected
M1 N1 value. The values for the A rpm in Table IV are exemplary of those
encountered when the transmission is presently in M1 operation, as the value
of the A rpm for M1 is zero, which has a biasing effect that tends to maintain
the transmission operating range state in Ml, thus stabilizing the transmission
operating range state with respect to M1 operation. In one embodiment, the
values for the A rpm associated with each potential change in transmission
operating range state, such as those provided in Table IV, are each next
multiplied by the trip direction weighting constants a, b, c, d (which in
alternate embodiments may be varying parameters which are a function of the
corresponding distance of the trip, A rpm, or corresponding desired range)

from the equation defining TC above for each associated potential change in
transmission operating range state, to arrive at a new array comprising a
plurality of Trips Costing factors (TC) representing preferability factors for
each of the transmission operating range states that are effectively based on
the input speed trip or profile associated with each potential change in
operating range state of the transmission, of which the values in Table V are
provided for exemplary purposes and are non-limiting of this disclosure:

[0060] The preferability factors based on the input speed trip or profile
("transmission input speed trip preferability factors") associated with each
potential operating range state of the transmission as set forth in Table V may
be combined as herein specified with other sets of preferability factors,
including one or more sets of preferability factors shown in and described with
reference to FIG. 4 towards generation of new desired operating range factors.
The selected N1 values at various points in time as shown in FIG. 8 may be
based on the output of one or more algorithms carried out in a microprocessor
having one or more inputs provided by on-board vehicle sensors, including
without limitation sensors mentioned herein. In some embodiments,
transmission input speeds N1 for M1 operation and M2 operation are provided
at selected intervals with regard to the desired operating range state of the
transmission. In one embodiment, the N1 value for M1 is selected by a
microprocessor which searches and selects an N1 value that is associated with

the least power loss, which in this embodiment may serve as, or as a basis for
determining the preferability factor for M1 operation from FIG. 3. At or at
about the same time, the N1 value for M2 operation is selected by a
microprocessor which searches and selects an N1 value that is associated with
the least power loss, which in this embodiment may serve as, or as a basis for
determining the preferability factor for M2 operation from FIG. 3. Slight
changes in operating conditions can substantially alter the preferability factors,
and could result in transmission operation that would attempt to change gears
or modes too frequently, and the biasing or weighting of the preferability
factors as herein described alleviates undesirably frequent shifting. For
embodiments in which N1 values for M1 and M2 are continuously provided at
short time intervals on the order of milliseconds in response to changes in
vehicle operating conditions, given that slight changes in operating conditions
can substantially alter the preferability factors, it occurs that there may be
wide fluctuations in the N1 values for M1 and M2 from one time interval to the
next. Changing operating range state for every instance that a driving
condition changed slightly would result essentially in a transmission which
was nearly constantly attempting to change gears or modes, and the biasing or
weighting of the preferability factors as herein described alleviates undesirably
frequent shifting. Following generation of new desired operating range factors
and selection of the desired operating range, the N1 values for the desired
operating range are evaluated for selection and it is frequently the case that the
N1 values may vary substantially from one interval to the next. It is
accordingly desirable to "filter" the N| values, to remove noise, which noise
comprises values that are very high above or below an average N1 value owing

to instantaneous fluctuation in the N1 values during one or more short time
intervals. In one embodiment, N1 values for both M1 operation, M2 operation
and neutral are filtered, even though the values of only one of M1 or M2 are
actually to be used at a given point in time, i.e., the system continuously
provides N1 values for both M1 and M2 operation. In such embodiment, while
input speeds N1 for M1 or M2 operation are provided continuously or at
selected intervals, only the input speed N1 associated with the desired mode
(either M1 or M2) is used for creating a desired transmission input speed
profile based on current vehicle operating conditions. After selection of a
desired range state is made, the selected N1 values for M1 and M2 are filtered
to reduce noise, while filtering, when the desired range changes reset the filter
of the mode of the desired range that it is transitioning to, in order that the
initial output value is equivalent to the input value, as shown in FIG. 10. The
suggested N1 values depicted therein will eventually be used to create a profile
of desired input speeds based on what range is desired. For example, when
M1 is selected as the desired range, N1 M1 is used as the desired N1 profile, as
soon as M2 becomes desired the profile will switch to suggested N1 M2. This
selective resetting is done so that when the system switches from one profile
to another, the non-filtered suggested N1 is used as the initial value. When
filtering the suggested input speeds for noise reduction, only the suggested
input speed of the desired mode is filtered. This allows the suggested input
speed to reset when its mode is chosen.
[0061] One consideration of operating a motorized vehicle that is equipped
with an electro-mechanical hybrid transmission as described herein, is that the
operator of such a motorized vehicle will at different times make different

torque requests from the drivetrain (such as by depressing the accelerator or
brake pedal). However, in many instances of operator torque requests, the
drivetrain and/or braking system may be incapable of delivering the amount of
torque requested by the operator, i.e., the brake or accelerator pedal may be
depressed beyond the point at which the system capabilities to deliver the
requested torque can be fulfilled.
[0062] For different engine operating points in potential operating range
states of the transmission, given the same operator torque request, the
differences between the operator-requested torque and the drivetrain
capabilities typically differ from one another. In one embodiment of this
disclosure, the difference between the amount of torque requested by the
operator at a given point in time and the torque that is deliverable by the
system when operating at a potential engine operating point is considered for
each of the engine operating points, to generate a plurality of torque difference
values for each of the engine operating points at substantially the time that the
operator makes a torque request. In one embodiment a biasing "cost" value is
assigned to each of the torque difference values in proportion to the magnitude
by which the deliverable torque for a given engine operating point in a
potential transmission operating range state falls short with respect to that of
the operator torque request. Such biasing cost values generally reflect a lower
degree of desirability for engine operating points having higher biasing costs
associated with them for a given operator torque request, when such biasing
costs are compared with one another and used as a basis in evaluating which
engine operating point is most suitable or desirable for a given operator torque
request at a particular point in time of the vehicle operation. In one

embodiment, the sum of all components representing power losses for various
drivetrain components and this bias cost (comprising the total power loss) for
each potential engine operating point at the torque deliverable that is nearest to
that requested by the vehicle operator are compared with one another, with
that potential engine operating point having the least total power loss when
operated at the torque nearest that of the operator request being selected as the
desired engine operating point.
[0063] FIG. 11 shows a cost function useful in providing biasing costs
indicating a component of preferability of a potential engine operating point
and transmission operating range state, which is dependent on the magnitude
of a torque request made by the operator. The exemplary definition of a
biasing cost graph in FIG. 11 is a generally-parabolic cost profile, having as its
abscissa the operator torque request. Such a biasing cost profile may be
determined by any function desired, selected, or created by the vehicle
engineers, and accordingly affords an opportunity to include a subjective
aspect in the determination of preferability of different engine operating points
and potential transmission operating range states. Function types useful in this
regard include without limitation: hyperbolic functions, linear functions,
continuous functions, non-continuous functions, constant functions, smooth-
curved functions, circular functions, ovoid functions, and any combinations
comprising any of the foregoing, either alone or mathematically combined
with one another, over any range of operator torque request values desired or
selected. Thus, in one embodiment, criteria used in the determination of
which engine operating point and transmission operating range state is most
desirable for a given operator torque request at any selected point in time of

the travel of a vehicle having a drivetrain as herein described is not necessarily
bound to the most efficient operation of the motorized vehicle in terms of fuel
economy, power output, drivability, etc.
[0064] For each engine operating point and potential transmission operating
range state, there exists a minimum output torque (To Min) and a maximum
output torque (To Max) that the drivetrain system is capable of delivering.
The maximum output torque is generally applicable towards vehicle
acceleration and includes such components as torque inputted to the
transmission by the engine and torque supplied to the transmission by the
electric machines. The minimum output torque is generally applicable
towards vehicle deceleration, and includes such components as braking torque
provided during regenerative braking, including cases when the charging of a
battery on-board the vehicle is accomplished, more or less, by one or more
electric machines functioning in their capacity as electrical generators.
[0065] With respect to FIG. 11, which represents a single engine operating
point in a potential transmission operating range state, it is clear that for a
substantial range of possible operator torque request values residing between
To Min and To Max, there is no biasing cost associated therewith, i.e., the
value of the function represented by the dotted line is zero. As the operator
torque request approaches or exceeds the To Max value, however, the cost
associated with the operator torque request is given by the ordinate value
along the dotted line curve corresponding to the operator torque request.
Other potential transmission operating range states may have the same,
similarly-shaped, or differently-shaped functions associated with them, as
desired.

[0066] In one embodiment, if the operator torque request is within a range
between To Min and To Max where the biasing cost function represented by
the dashed line curve in FIG. 11 is constant, in this case at zero, there is no
biasing cost assigned for the particular engine operating point in the operating
range state under consideration at levels of operator torque request residing
within this range. When the operator torque request is for a torque that is
greater than To Max, the function determining the biasing costs associated
with the torque request is represented by the dashed line in FIG. 11. This
biasing cost may thus comprise a subjective component in addition to the
objective costs associated with power losses in the determination of the engine
operating point selection and the first plurality of numerical values shown in
FIG. 3. Thus, in one embodiment, an operator torque request which only
slightly exceeds that of To Max, by, for example, 10 Newton-meters, will be
assigned a biasing cost which is less than the biasing cost which would be
assigned to an operator torque request which exceeds that of To Max by more
than 10 Newton-meters.
[0067] Table VI below is exemplary of one way to express costs associated
with the difference between a vehicle operator torque request and the
maximum torque deliverable by the drivetrain system for an exemplary
potential transmission operating range state, wherein Δ N*m is the difference
value in Newton-meters and kW is the cost, expressed in kilowatts in this
example; however any other convenient units, or no units, may be used. Such
an array may be stored in computer memory and accessed by a
microprocessor, on an as-needed basis.
Table VI


[0068] An alternative representation of the biasing cost associated with a
potential transmission operating range state is shown in FIG. 12. In FIG. 12,
the value x represents the difference between the amount of torque requested
by the operator and that torque output which is desirable ("Desirable To") for a
potential transmission operating range state, as but one example. The
Desirable To is that amount of torque that is closest to the operator torque
request that is available based on the output torque limits (To Max and To
Min) of the selected engine operating points and the Torque Reserve for the
particular potential transmission operating range state under consideration.
The quantity x, which is a torque difference value (Δ N*m), varies, depending
on which potential transmission operating state is under consideration, for the
same operator torque request at a same given point in time of the vehicle
operation. Comparison of x values for different potential transmission
operating range states given the same operator torque request enables selection
of that potential transmission operating range state having the least x value, in
one embodiment. In another embodiment, a biasing cost (weighting factor)
may be assigned to the potential transmission operating range state having the
least x value, which is combined with the sum of all components representing
power losses for various drivetrain components, to arrive at a sum total power
loss which may then be used as a criteria for selecting a particular potential
transmission operating range state over others.

[0069] By providing a function having any desired features, including
without limitation those features illustrated by the biasing costs curve in FIG.
11, it is possible to assign a biasing cost to a given operator torque request for
particular instances even when the torque requested in an operator torque
request is below the maximum system torque output. This is illustrated by an
operator torque request having the magnitude at point Q in FIG. 11, which is
below the To Max, yet there is nevertheless a cost assigned for this potential
transmission operating range state and operator torque request. Such a
provision of costing (or biasing) operator torque requests allows establishment
of a Torque Reserve over the range of operator torque requests which reside
between To Max and the operator torque request having the highest magnitude
of torque for which no biasing cost is assigned over a range between To Min
and To Max. The provision of a range of operator torque requests comprising
such a Torque Reserve effectively biases the preferability of the transmission
control system against selecting system actuator operating points and
transmission operating range states having a To Max which is greater than, yet
near to, an operator torque request in an amount that is proportional to the
difference between the operator torque request and the To Max for the
particular engine operating point in a transmission operating range state under
consideration. Instead of biasing to select system actuator operating points
which can produce the highest To Max and lowest To Min, including the
Torque Reserve has the effect of decreasing the bias criteria point To Max to
To Max subtracted by the Torque Reserve. This will not only effect the
operator torque requests which exceed the maximum deliverable output
torque, but also the operator torque requests that are less than and near the

maximum deliverable output torque. This results in improved drivability of
the motorized vehicle by reducing the tendency of the transmission system to
cause multiple shifting events or mode changes when an operator torque
request has a magnitude that is near the maximum deliverable for the
transmission operating range state that is currently selected, i.e., currently
under utilization. In embodiments which follow, no Torque Reserve is
present.
[0070] Moreover, when an operator torque request exceeds To Max (or is
less than To Min) for cases where a method according to this disclosure which
so uses biasing costs is not employed, information relating to the amount by
which an operator torque request exceeds To Max (or is less than To Min) is
lost due to the fact that the total power loss evaluation is based on the
deliverable output torque which is limited by To Max and To Min.
Proceeding in accordance with a method of this disclosure and obtaining a
biasing cost value for an operator torque request which exceeds To Max (or is
less than To Min) provides information relative to the amount by which such a
torque request is in excess of To Max, and this information is incorporated
into the overall selection process concerning which engine operating point and
potential transmission operating state will be selected. In one embodiment,
this information effectively biases a search engine embedded within software
and/or hardware useful for providing the plurality of numerical values shown
in FIG. 3 to locate an engine operating point within each potential
transmission operating range state that biases towards providing the greatest
value of To Max (least value of To Min). In one embodiment, the biasing
costs associated with the operator torque request for each of the potential

operating range states of the transmission substantially at the time an operator
makes a torque request during vehicle operation are but one component used
in determining a first plurality of numerical values as shown in FIG. 3.
[0071] In one embodiment, the calculation of each of the numerical values
present in the first plurality of numerical values shown in FIG. 3 include
components relating to objective power losses such as: engine power loss,
battery power loss, electrical machine power loss, and transmission power
loss. Another embodiment provides additional penalty costs, including costs
for exceeding the battery power limits, engine torque limits, electric machine
torque limits, and other subjective costs desired which may include biasing
costs associated with the output torque request as herein described. Also
included are the components generated as the result of an iterative data
processing method that in one embodiment employs a microprocessor-based
search engine.
[0072] In the case of continuously variable operating mode range states,
search engine suitable for such a method employs, for each potential
transmission operating range state, a space that is defined as shown in FIG. 13
by the region on the coordinate axes bounded by P1 Min, P1 Max, N1 Min, and
N1 Max, wherein P1 represents power inputted to the electro-mechanical hybrid
transmission and N1 is the same transmission input speed. The search engine
selects, either randomly or according to any desired algorithm, an N1 and P1
pair present in the space S and calculates a To Min, To Max, and total power
loss associated with the N1 and P1 pair chosen, based on drivetrain system
component power losses and operating constraints, which constraints are
either inherent in the system, or imposed by vehicle engineers. Repetition of

this method for a large number of different N1 and P1 pairs provides a plurality
of different To Min, To Max, and total power loss values for a given potential
transmission operating range state. The method is repeated for each potential
transmission operating range state and a plurality of To Min, To Max, and
total power loss values are generated in the space S of and for each potential
transmission operating range state and N1 and P1 pairs provided.
[0073] From such plurality of different To Min and To Max values so
generated by a search engine for a given potential transmission operating
range state, the N1 and P1 pair having the highest To Max value associated with
each potential transmission operating range state is biased to be selected as the
preferred N1 and P1, to reduce biasing costs associated with the output torque
request in FIG. 11, which is one of the multiple components in the total power
loss, when an operator torque request is greater than the plurality of different
To Max values generated. For cases in which an operator torque request is
less than the plurality of different To Min generated, the N1 and P1 pair
associated with the lowest To Min value is biased to be selected as the
preferred N1 and P1 to reduce biasing costs associated with the output torque
request in FIG. 11, which is one of the multiple components in the total power
loss for the particular potential transmission operating range state under
consideration. The hybrid Engine-Off state can be considered as continuously
variable modes with the N1 and P1 as being zero; thus, To Min, To Max, and
the total power loss are determined without the need for a search procedure.
[0074] In the case of Fixed Gear range states, a search engine suitable for
such a method employs, for each potential transmission operating range state,
a space that is defined by the region on the coordinate axes bounded by T1

Min, and T1 Max, wherein T1 represents torque inputted to the electro-
mechanical hybrid transmission where the transmission input speed is
predetermined by the hardware parameter of potential transmission operating
range state. The search engine selects, either randomly or according to any
desired algorithm, a T1 present in the search range and calculates a To Min and
To Max and Total Power Loss associated with the T1 chosen, based on
drivetrain system component power losses and operating constraints, which
constraints are either inherent in the system, or imposed by vehicle engineers.
Repetition of this method for a large number of different T1 provides a
plurality of different To Min and To Max and Total Power Loss values for a
given potential transmission operating range state. The method is repeated for
each potential transmission operating range state and a plurality of To Min and
To Max and Total Power Loss are generated in the search range of and for
each potential transmission operating range state and T1 is provided.
[0075] From such plurality of different To Min and To Max values so
generated by a search engine for a given potential transmission operating
range state, the T1 having the highest To Max value associated with each
potential transmission operating range state is biased to be selected as the
preferred T1 , when an operator torque request is greater than the plurality of
different To Max generated. This reduces biasing costs associated with the
output torque request in FIG. 11, which is one of the components in the total
power loss for the particular potential transmission operating range state under
consideration. For cases in which an operator torque request is less than the
plurality of different To Min generated , the T1 associated with the lowest To
Min value is biased to be selected as the preferred T1 to reduce biasing costs

associated with the output torque request in FIG. 11, which is one of the
components in the total power loss for the particular potential transmission
operating range state under consideration.
[0076] In one embodiment, including when a vehicle operator makes a
request for an acceleration torque that is greater than the maximum deliverable
output torque, following generation of a plurality of engine operating points
(N1 and P1 pairs for continuously variable modes and T1 for fixed gears) for
each potential transmission operating range state, which engine operating
points (N1 and P1 pairs for continuously variable modes and T1 for fixed gears)
each have associated with them a To Min, To Max, and total power loss
values, the desired transmission operating range state is determined by
comparing the points associated with the selected engine operating points (N1
and P1 pairs for continuously variable modes and T1 for fixed gears) from each
potential transmission operating state with one another, and selecting that
operating range state having the least total power loss associated with its point
biased to the highest To Max value, which corresponds to the least value of x
in FIG. 12.
[0077] In another embodiment, including when a vehicle operator makes a
request for a deceleration torque that is less than the minimum deliverable
output torque, following generation of a plurality of engine operating points
(N1, P1 pairs for continuously variable modes and T1 for fixed gears) for each
potential transmission operating range state, which engine operating points
(N1, P1 pairs for continuously variable modes and T1 for fixed gears) each have
associated with them a To Min, To Max, and total power loss values, the
desired transmission operating range state is determined by comparing the

points associated with the selected engine operating points (N1 and P1 pairs for
continuously variable modes and T1 for fixed gears) from each potential
transmission operating state which have the least total power loss with one
another and selecting that operating range state having the least total power
loss associated with its point biased to having the lowest To Min value
(corresponding to the least value of y in FIG. 12).
[0078] In one embodiment, determination of the total power loss associated
with vehicle operation at a point associated with or identified by an engine
operating point (an engine operating point, as used herein, has associated with
it an N1, P1 pair for continuously variable modes, and a T1 value in the case of
fixed gears) in a potential operating range state of the transmission comprises
combining operating costs, in terms of energy usage (kW), which operating
costs are provided based upon factors related to vehicle drivability, fuel
economy, emissions, electrical power consumption and battery life for the
operating range state. Lower operating costs are generally associated with
lower fuel consumption at high conversion efficiencies, lower battery power
usage, and lower emissions for an operating point, and take into account a
current operating range state of the powertrain system.
[0079] Summation of all power losses (total power loss) associated with
operating at a particular point that is associated with an engine operating point
of a potential transmission operating range state provides a preferability factor
(such as those shown in FIG. 3) for operating at that particular point in the
particular potential transmission operating range state under consideration. In
the case when the operator torque request is greater than the torque deliverable
by the driveline system, the point associated with an engine operating point

(N1, P1 pairs for continuously variable modes and T1 for fixed gears) in the
respective search space S or range associated with a potential transmission
operating range state may be selected to be biased to a point at which the
maximum output torque (To Max) of the transmission occurs for that potential
transmission operating range state. Depending on the severity of the bias cost
associated with the operator torque request, the selected point may or may not
be that at which the maximum output torque occurs. Since the point selection
is based on minimizing the total power loss where the bias cost associated
with the output torque request is a component of, the larger the bias costs
associated with the output torque request the more advantage there is to
selecting the point at which the maximum output torque of the transmission
occurs. The search space S or range for each potential transmission operating
range state may be examined, such as by algorithm, and the point associated
with an engine operating point at which the maximum output torque (To Max)
of the transmission is biased to occur identified for each potential transmission
operating range state. The points associated with the engine operating point
at which the maximum output torque (To Max) of the transmission is biased to
occur for each potential transmission operating range state are compared with
one another to identify the potential transmission operating range state having
the lowest power loss that is likely to have the highest To Max, which
potential transmission operating range state is selected as being the preferred
transmission operating range state when a vehicle operator makes a request for
an acceleration torque, which is a torque request that tends to deliver more
torque to the vehicle drive wheel(s) that are in contact with the road surface.

[0080] Similarly, in the case when the operator torque request is less than the
torque deliverable by the driveline system, the point associated with an engine
operating point associated with a potential transmission operating range state
may be selected to be biased to a point at which the minimum output torque
(To Min) of the transmission occurs for that potential transmission operating
range state. Depending on the severity of the bias cost associated with the
operator torque request, the point selected may or may not be that at which the
minimum output torque occurs. Since the point selection is based on
minimizing the total power loss where the bias cost associated with the output
torque request is a component of, the larger the bias costs associated with the
output torque request the more advantage there is to selecting the point at
which the minimum output torque of the transmission occurs. The search
space S, or range for each potential transmission operating range state may be
examined, such as algorithmically using a microprocessor, and the point
associated with an N1 and P1 pair at which the minimum output torque (To
Min) of the transmission is biased to occur identified for each potential
transmission operating range state. The points associated with the engine
operating point at which the minimum output torque (To Min) of the
transmission is biased to occur for each potential transmission operating range
state are compared with one another to identify the potential transmission
operating range state having the lowest total power loss which is likely to have
the lowest To Min, which potential transmission operating range state is
selected as being the preferred transmission operating range state when a
vehicle operator makes a request for an deceleration torque, which is a torque

request that tends to deliver less torque to the vehicle drive wheel(s) that are in
contact with the road surface.
[0081] According to one embodiment of this disclosure, for cases of operator
torque requests which command heavy vehicle acceleration (levels of
acceleration for which the operator torque request is greater than that
deliverable by the driveline system and the pre-determined bias cost associated
with the output torque request is severe enough to overrule all other
components of the total power loss), determining the engine operating point
having the least power loss associated with them automatically results in
determination of the N1 and P1 pair having the To Max, because the engine
operating point having the highest To Max values associated with it, also has
the smallest power losses associated with it. The converse is true for cases of
operator torque requests which command vehicle deceleration.
[0082] Hence, in a method according to an embodiment of the disclosure, an
operator torque request is made during operation of a vehicle equipped with a
system as herein described. A search engine executed by an on-board
microprocessor chooses a first engine operating point from the search space S
or range associated with a potential transmission operating range state. To
Max and To Min values associated with that engine operating point in the
search space S or range are calculated. Then, the power losses associated with
that engine operating point in the respective search space S or range are
calculated. As part of the total power loss calculation, the difference between
the operator torque request and the To Max (or To Min, as may be applicable
for cases where deceleration torque is requested) is assigned a biasing cost.
This process is repeated for each engine operating point in the space S or

range chosen by the search algorithm associated with that potential
transmission operating range state, which results in a cost being associated
with each chosen engine operating point in the respective search space S or
range associated with that potential transmission operating range state. The
points having the lowest biasing costs are inherently inclined to have the
highest To Max and lowest To Min values.
[0083] Thus, a method according to the disclosure is concerned with
balancing selection of a transmission operating range state from a set of
potential transmission operating range states between choosing engine
operating point (N1. P1 pair for continuously variable modes and T1 for fixed
gears, with emphasis on the N1 value, which is used for creating a desired
transmission input profile as earlier described herein) in the respective search
space S or range which have the least power losses of the system associated
with each potential transmission operating range state, which includes a bias
cost that biases the point selection to a point which has the highest To Max,
(or lowest To Min). Preference in some embodiments may be given to those
engine operating point within the respective search space S or range for the
various potential transmission operating range states which have the absolute
least total power losses, which includes large bias costs associated with the
output torque request, which in such instance is more concerned with meeting
an extreme torque request from the operator. In other embodiments,
preference may be given to those engine operating points (N1, P1 pairs for
continuously variable modes and T1 for fixed gears) within the respective
search space S or range for the various potential transmission operating range
states which have the absolute least total power losses, which include none or

small bias costs associated with the output torque request, as this is an instance
wherein it is desired to focus less on attempting to meet the extreme torque
demand of the driver, and more on overall system efficiency. The choice
between whether preference is given to system performance to meet the
operator extreme torque demand as closely as possible, or to maximize the
overall system efficiency is controllable by altering the function which
determines the shape of the biasing costs curve shown in FIG. 11. When the
slope of the curve defined by the function therein is selected to be steeper,
more weight is given to meeting the operator torque request that is higher or
lower than the torque output deliverable by the driveline.
[0084] Once a method of the disclosure has been used to identify which
potential transmission operating range state is to be selected, the transmission
input speed N1 that was the basis for the selection of that particular
transmission operating range state is used as the transmission input speed for
continuously variable modes.
[0085] In a further embodiment, including a Torque Reserve, the range of
operator torque requests over which the biasing cost function which
establishes the Torque Reserve is variable. This is of benefit since increasing
the Torque Reserve reduces the tendency of the transmission system to cause
multiple shifting events and abrupt changes in input speed profiles which
would otherwise occur frequently when the transmission operating point is
near the point where the maximum deliverable output torque can be produced
for the potential transmission operating range state. Decreasing the Torque
Reserve enables the system to operate closer to the point where the maximum
deliverable output torque can be produced for the potential transmission

operating range state when needed. Accordingly, varying the Torque Reserves
for different driving conditions enables the flexibility of weighting the
preference between improving drivability (reducing multiple transmission
shifting events and input speed stabilization), and improving acceleration
performance at high torque requests for each potential transmission operating
range state for different driving conditions. In one embodiment, a change in
the range of operator torque requests over which the biasing costs function that
establishes the Torque Reserve operates is selectable by means of a tow / haul
mode switch, which may be switched manually by the operator, or
automatically by the electronic control module in response to an action of the
operator, or by electronically sensing the position of the accelerator pedal and
appropriately processing the signal information to switch between such
modalities. This is illustrated diagrammatically in FIG. 14, wherein the switch
permits selection of either a first Torque Reserve value (width or span along
the abscissa axis) associated with times in the operation when it is used for
towing / hauling; a second Torque Reserve value associated with normal
vehicle operation which does not involve towing or hauling; or a third Torque
Reserve value of zero, associated with times in operation when the extremely
high accelerator pedal position (for example, about 95% of full pedal range)
indicates that Torque Reserve is not needed to increase performance to meet a
torque request having a relatively high magnitude. In a further embodiment, a
switch algorithm can be pre-set with differing ordering of priorities of which
Torque Reserve to select when multiple criteria are met, the choice of which
exact priorities and criteria are within the selection of the vehicle engineers.

[0086] The variability of the range of operator torque requests over which
the biasing cost function which establishes the Torque Reserve operates is
illustrated for one embodiment by comparing the range of operator torque
requests over which the biasing cost function which establishes the Torque
Reserve shown in FIG. 15, with that of FIG. 16. In FIG. 15, the range of
operator torque requests over which the biasing cost function which
establishes the Torque Reserve operates is wider than the range of operator
torque requests over which the biasing cost function which establishes the
Torque Reserve operates in FIG. 16. FIG. 17 illustrates a biasing cost function
in which the Torque Reserve value is zero, i.e., there is no Torque Reserve. In
one embodiment, the range of operator torque requests over which the biasing
cost function which establishes the Torque Reserve operates for towing /
hauling service is about 100 Newton-meters. In one embodiment, the range of
operator torque requests over which the biasing cost function which
establishes the Torque Reserve operates for non- towing / hauling service, or
normal vehicle operation, is about 50 Newton-meters. In one embodiment, the
range of operator torque requests over which the biasing cost function which
establishes the Torque Reserve operates for conditions when monitored pedal
position are high, is zero Newton-meters.
[0087] In a further embodiment, the range of operator torque requests over
which the biasing cost function which establishes the Torque Reserve operates
is variable, based on the transmission output speed No, and the function used
to determine the variability may be any function selected by a vehicle
engineer. In one non-limiting embodiment, the function is linear, of the form
y = ax + b.

[0088] In a further embodiment, the range of operator torque requests over
which the biasing cost function which establishes the Torque Reserve operates
is variable, either linear or non-linear, based on the position of the accelerator
pedal.
[0089] In a further embodiment, the range of operator torque requests over
which the biasing cost function which establishes the Torque Reserve operates
is variable, either linear or non-linear, based on the rate of change of position
of the accelerator pedal.
[0090] One or more biasing cost functions may be stored in computer
memory disposed on-board the motorized vehicle. In one embodiment, the
function used for providing the biasing costs associated with operator torque
requests is the same for all potential transmission operating range states. In
another embodiment, the function used for providing the biasing costs
associated with operator torque requests is different for at least two of the
potential transmission operating range states considered in making a selection
between which operating range states are to be considered desirable or
employed at a given time during vehicle operation. In one embodiment of this
disclosure, the function used for providing the biasing costs associated with
operator torque requests in a transmission operating range state is considered
in making a selection of an engine operating point (especially the input speed
selection in continuously variable modes) considered desirable or employed at
a given time during vehicle operation. Calculation of values of biasing costs
based on the biasing cost function(s) and operator torque request(s) is a routine
matter and in one embodiment is carried out in an on-board microprocessor,
the results of the calculations being stored in on-board computer memory.

[0091] It is understood that modifications are allowable within the scope of
the disclosure. The disclosure has been described with specific reference to
the preferred embodiments and modifications thereto. Further modifications
and alterations may occur to others upon reading and understanding the
specification. It is intended to include all such modifications and alterations
insofar as they come within the scope of the disclosure.

CLAIMS
1. Method for controlling a powertrain system in a motorized vehicle
having an accelerator pedal and including an engine coupled to an
electro-mechanical transmission selectively operative in one of a
plurality of transmission operating range states and one of a plurality of
engine states, comprising:
determining a current transmission operating range state and engine
state;
determining at least one potential transmission operating range state and
engine state;
providing at least one operator torque request;
determining preferability factors associated with the current transmission
operating range state and engine state, and potential transmission
operating range states and engine states, wherein determining
preferability factors associated with potential transmission operating
range states includes assigning biasing costs to operator torque
requests which reside within a pre-determined range of possible
operator torque requests for at least two of said potential
transmission operating range states;
preferentially weighting the preferability factors for the current
transmission operating range state and engine state; and
selectively commanding changing the transmission operating range state
and engine state based upon said preferability factors and said
operator torque request.

2. A method according to claim 1 wherein said pre-determined range is
bounded at one of the ends of said range by a torque request value that
corresponds substantially to the maximum torque output possible for a
selected engine operating point at a particular transmission operating
range state under consideration.
3. A method according to claim 1 wherein said pre-determined range is
bounded at one of the ends of said range by a torque request value that
corresponds substantially to the minimum torque output possible for a
selected engine operating point at a particular transmission operating
range state under consideration.
4. A method according to claim 1 wherein the size of the pre-determined
range over which biasing costs are assigned to operator torque requests is
variable.
5. A method according to claim 1 wherein the size of the pre-determined
range over which biasing costs are assigned to operator torque requests is
selectively variable.
6. A method according to claim 4 wherein the size of the pre-determined
range is dependent upon the output speed of said transmission.
7. A method according to claim 4 wherein the size of the pre-determined
range is dependent upon the position of an accelerator pedal.

8. A method according to claim 4 wherein the size of the pre-determined
range is dependent upon the rate of change of the position of an
accelerator pedal.
9. A method according to claim 1 wherein assigning biasing costs to
operator torque requests which reside within a pre-determined range of
possible operator torque requests includes providing a function which
defines the value of the biasing costs associated with different operator
torque requests within said range.
10. A method according to claim 9 wherein said function is linear.
11. A method according to claim 9 wherein said function is non-linear.
12. A method according to claim 9 wherein the size of the pre-determined
range of operator torque requests over which said function operates is
dependent upon the output speed of said transmission.
13. A method according to claim 9 wherein the size of the pre-determined
range of operator torque requests over which said function operates is
dependent upon a position of the accelerator pedal.

14. A method according to claim 9 wherein the size of the pre-determined
range of operator torque requests over which said function operates is
dependent upon a rate of change of a position of the accelerator pedal.
15. A method according to claim 9 wherein said pre-determined range is
bounded at one of the ends of said range by a torque request value for
which no biasing cost value is assigned to said operator torque request.
16. A method for selecting a transmission operating range state from a
plurality of potential transmission operating range states in a powertrain
system including an engine coupled to an electro-mechanical
transmission, comprising:
providing an operator torque request having a magnitude;
providing an on-board microprocessor having a search engine
executed thereby;
selecting a first engine operating point from a search range space
containing possible engine operating points associated with a
potential transmission operating range state;
calculating maximum and minimum output torques that the powertrain
system is capable of delivering (To Max, To Min) associated with
said engine operating point;
assigning a biasing cost to the difference between the magnitude of the
operator torque request, and the torque deliverable by said
transmission less a Torque Reserve, if operating said transmission at

the parameters defined by said first engine operating point over a
pre-determined range of possible operator torque requests;
summing power losses associated with operating said vehicle
transmission at the parameters defined by said first engine operating
point to provide a total power loss;
repeating said selecting, calculating, assigning and summation for a
plurality of engine operating points in said search range space, to
provide a total power loss associated with engine operating points in
said plurality;
selecting at least one engine operating point from said search range space
which has the lowest total power loss;
repeating said selecting, calculating, assigning, summing, repeating and
selecting for at least two potential transmission operating range
states; and
selectively commanding changing the transmission operating range state
based upon as comparison of power losses associated with selected
engine operating points.
17. A method according to claim 16 wherein said engine operating point
used in selectively commanding comprises the transmission input speed
associated with the point having the transmission input speed that was
used as the basis for the selection of the particular transmission operating
range state commanded.

18. A method according to claim 16 wherein biasing costs assigned are
determined by a function which is dependent on said operator torque
request.
19. A method according to claim 16 wherein the size of said pre-determined
range of possible operator torque requests is selectively variable.
20. A method according to claim 16 wherein said pre-determined range is
bounded at one of the ends of said range by a torque request value for
which no biasing cost value is assigned to said operator torque request.
21. A system for controlling a powertrain system including an engine
mechanically coupled to an electro-mechanical transmission selectively
operative in one of a plurality of transmission operating range states and
one of a plurality of engine states, comprising:
a microprocessor configured to receive data and provide an output, said
data including
a first set of preferability factors,
a second set of preferability factors relating to desired operating
range states of said transmission,
a third set of preferability factors relating to current operating range
states of said transmission,
a fourth set of preferability factors, said fourth set of preferability
factors comprising input speed trip preferability factors;

a control module configured to control shifting events in said
transmission, said control module having inputs and outputs, wherein
output from said microprocessor is provided as input to said control
module, said control module being configured to provide said third
set of preferability factors to said microprocessor as an input thereto;
and
an electro-mechanical transmission in effective electrical communication
with output from said control module;
said system configured sufficiently that commanded changes of
transmission operating range state are executed using biasing costs
assigned to potential operating range states of said transmission
based on at least one operator torque request, said costs being
determined by a biasing cost function which provides a torque
reserve operative over a range of operator torque requests, wherein
the size of the range of operator torque requests is selectively
variable.

A method for controlling a powertrain system includes determining
a current transmission operating range state and engine state, determining at
least one potential transmission operating range state and engine state,
providing at least one operator torque request, determining preferability
factors associated with the current transmission operating range state and
engine state, and potential transmission operating range states and engine
states, wherein determining preferability factors associated with potential
transmission operating range states includes assigning biasing costs to
operator torque requests which reside within a pre-determined range of
possible operator torque requests for at least two of the potential transmission
operating range states, preferentially weighting the preferability factors for the
current transmission operating range state and engine state, and selectively
commanding changing the transmission operating range state and engine state
based upon stheaid preferability factors and the operator torque request.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=Y2siFG/z4Al+F3saHCrzIw==&loc=wDBSZCsAt7zoiVrqcFJsRw==


Patent Number 271517
Indian Patent Application Number 1872/KOL/2008
PG Journal Number 09/2016
Publication Date 26-Feb-2016
Grant Date 24-Feb-2016
Date of Filing 03-Nov-2008
Name of Patentee BAYERISCHE MOTOREN WERKE AKTIENGESELLSCHAFT
Applicant Address PETUELRING 130,80788 MUNCHEN
Inventors:
# Inventor's Name Inventor's Address
1 KEE YONG KIM 1699 SCIO RIDGE ROAD ANN ARBOR, MICHIGAN 48103
2 ANTHONY H. HEAP 2969 LESLIE PARK CIRCLE ANN ARBOR, MICHIGAN 48105
PCT International Classification Number B60R16/023
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 60/985232 2007-11-04 U.S.A.