Indian Patents. 255163:A METHOD OF AND A SYSTEM FOR REGULATING A THROTTLE OPENING OF AN ENGINE IN A HYBRID ELECTRIC VEHICLE

Title of Invention	A METHOD OF AND A SYSTEM FOR REGULATING A THROTTLE OPENING OF AN ENGINE IN A HYBRID ELECTRIC VEHICLE
Abstract	A method of regulating a throttle opening of an engine in a hybrid electric vehicle system includes initiating a fuel-cut off operating mode of the engine, monitoring an engine speed during said fuel cut-off operating mode and regulating the throttle opening based on the engine speed during the fuel-cut off mode to maintain a manifold absolute pressure (MAP) of the engine above a threshold MAP.

Full Text	FUEL-CUT MANIFOLD ABSOLUTE PRESSURE CONTROL CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Application No. 60/840,389, filed on August 25, 2006, the disclosure of which is expressly incorporated herein by reference. FIELD [0002] The present disclosure relates to hybrid vehicles, and more particularly to regulating the engine of a hybrid vehicle in a fuel cut-off mode such as during deceleration fuel cut-off (DFCO) or electric motoring of the engine. BACKGROUND [0003] Hybrid vehicles are driven by multiple powerplants including, but not limited to an internal combustion engine and an electric machine. The electric machine functions as a motor/generator. In a generator mode, the electric machine is driven by the engine to generate electrical energy used to power electrical loads or charge batteries. In a motor mode, the electric machine supplements the engine, providing drive torque to drive the vehicle drivetrain. [0004] In some instances, the fuel is cut-off to the engine during deceleration (referred to as deceleration fuel cut-off (DFCO)) or electric motoring of the engine. During these events, the engine is back driven, which induces reciprocal movement of the cylinders within the engine. As a result of the back 1 driving of the engine, the manifold absolute pressure (MAP) of an intake manifold of the engine is significantly reduced, resulting in reduced efficiency and other losses. More specifically, reduced MAP results in low pressure in the intake ports and in the combustion chamber (i.e., within the cylinder in the space above the piston). [0005] If the pressure is too low, the oil can be drawn out of the engine crankcase through the piston rings, the valve guides disposed within the inlet ports, as well as through other paths. The piston rings can also flutter or vibrate depending on dynamic pressure differences between the crank case and the combustion chamber, which can be detrimental to the engine and may be perceptible by vehicle occupants. SUMMARY [0006] Accordingly, the present disclosure provides a method of regulating a throttle opening of an engine in a hybrid electric vehicle system. The method includes initiating a fuel-cut off operating mode of the engine, monitoring an engine speed during the fuel cut-off operating mode and regulating the throttle opening based on the engine speed during the fuel-cut off mode to maintain a manifold absolute pressure (MAP) of the engine above a threshold MAP. By maintaining the MAP above the threshold MAP, the above-described low pressure conditions are avoided. More specifically, the pressure is maintained sufficiently high to inhibit drawing out of the engine oil from the engine crankcase and to prevent flutter or vibration of the piston rings. 2 [0007] Further areas of applicability of the present disclosure will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the disclosure, are intended for purposes of illustration only and are not intended to limit the scope of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS [0008] The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein: [0009] Figure 1 is a schematic illustration of an exemplary hybrid vehicle system; [0010] Figure 2 is a graph illustrating exemplary manifold absolute pressure (MAP) traces based on the MAP control of the present disclosure; [0011] Figure 3 is a flowchart illustrating exemplary steps executed by the MAP control of the present disclosure; and [0012] Figure 4 is a functional block diagram of exemplary modules that execute the MAP control of the present disclosure. DETAILED DESCRIPTION [0013] The following description of the preferred embodiment is merely exemplary in nature and is in no way intended to limit the disclosure, its application, or uses. For purposes of clarity, the same reference numbers will be used in the drawings to identify similar elements. As used herein, the term 3 module refers to an application specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and memory that execute one or more software or firmware programs, a combinational logic circuit, or other suitable components that provide the described functionality. [0014] As used herein, a fuel cut-off operating (FCO) mode refers to operation during which fuel is cut off to the engine such as during deceleration fuel cut-off (DFCO), electric motoring of the engine or other FCO modes. [0015] Referring now to Figure 1, an exemplary hybrid vehicle 10 includes an engine 12 and an electric machine 14, which drive a transmission 16. More specifically, the electric machine 14 supplements the engine 12 to produce drive torque to drive the transmission 16. In this manner, fuel efficiency is increased and emissions are reduced. The engine 12 and electric machine 14 are coupled via a belt-alternator-starter (BAS) system 18. More specifically, the electric machine 14 operates as a starter (i.e., motor) and an alternator (i.e., generator) and is coupled to the engine 12 through a belt and pulley system. The engine 12 and the electric machine 14 include pulleys 20, 22, respectively, that are coupled for rotation by a belt 24. The pulley 20 is coupled for rotation with a crankshaft 26 of the engine 12. [0016] In one mode, the engine 12 drives the electric machine 14 to generate power used to recharge an energy storage device (ESD) 28. In another mode, the electric machine 14 drives the engine 12 using energy from the ESD 28. The ESD 28 can include, but is not limited to, a battery or a super-capacitor. Alternatively, the BAS system 18 can be replaced with a flywheel-alternator- 4 starter (FAS) system (not shown), which includes an electric machine operably disposed between the engine and the transmission or a chain or gear system that is implemented between the electric machine 14 and the crankshaft 26. [0017] The transmission 16 can include, but is not limited to, a manual transmission, an automatic transmission, a continuously variable transmission (CVT) and an automated manual transmission (AMT). Drive torque is transferred from the engine crankshaft 26 to the transmission 16 through a coupling device 30. The coupling device 30 can include, but is not limited to, a friction clutch or a torque converter depending upon the type of transmission implemented. The transmission 16 multiplies the drive torque through one of a plurality of gear ratios to drive a driveshaft 32. [0018] A control module 34 regulates operation of the vehicle 10. The control module 34 controls fuel injection and spark to selectively activate and deactivate cylinders of the engine 12. More specifically, when the vehicle 10 is at rest, none of the cylinders of the engine 12 are firing (i.e., are deactivated) and the engine 12 is stopped. During vehicle launch (i.e., acceleration from rest), the electric machine 14 drives the crankshaft to spin-up the engine 12 to an idle RPM and to initiate vehicle acceleration. During periods where low drive torque is needed to drive the vehicle (i.e., a hybrid engine off (HEOff) mode), drive torque is provided by the electric machine 14. When in the HEOff mode, fuel and spark are cut-off to the cylinders of the engine. Further, opening and closing cycles of the intake and exhaust valves can be prevented to inhibit air flow processing within the cylinders. 5 [0019] An accelerator pedal 36 is provided. A pedal position sensor 36 is sensitive to a position of the accelerator pedal 36 and generates a pedal position signal based thereon. A brake pedal 40 is provided. A brake pedal position sensor 42 is sensitive to a position of the brake pedal 40 and generates a pedal position signal based thereon. The control module 34 operates a brake system 43 based on the brake pedal position signal to adjust a pressure within the brake system, which in turn regulates a braking force of brakes (not shown). A speed sensor 44 is responsive to the rotational speed (RPMEM) of the electric machine 44. The speed sensor 44 generates a speed signal. The control module 34 operates the vehicle 10 based on the pedal position signals generated by the pedal position sensors 38, 42 and the speed signal generated by the speed sensor 44, as described in further detail below. The engine speed (RPMENG) can be determined based on the speed signal. More specifically, RPMEM can be multiplied by the known pulley ratio to provide RPMENG [0020] The manifold absolute pressure (MAP) control of the present disclosure regulates the position of the throttle while the engine is being operated in a fuel cut-off (FCO) mode. More specifically, during deceleration fuel and spark are cut-off, preferably on a cylinder by cylinder basis, and the electric machine 14 regeneratively brakes the vehicle to charge the ESD 28. The MAP control of the present disclosure monitors RPMENG and adjusts the throttle position to maintain the MAP above a threshold level. Fuel cut-off may also occur during electric motoring of the engine. 6 [0021] With particular reference to Figure 2, if the engine is operating in the FCO mode, MAP is monitored and is maintained above a threshold MAP (MAPTHR). More specifically, the MAP control regulates the throttle area (AIHR) based on engine RPM. A target or minimum MAP value is determined from a look-up table based on engine RPM. ATHR is determined from the minimum MAP value. More specifically, the MAP value is processed through a MAP-based torque model to calculate a desired torque (TDES)- In a toque-based system, TDES can be used for engine control, wherein the torque model accounts for fuel cut scenarios. For airflow-based systems, a desired air per cylinder (APC) is determined based on the MAP value by solving for APC using an inverse APC torque model. By dividing the desired APC by an intake period, a minimum mass air flow (MAF) needed to satisfy the desired MAP is determined. ATHR is then determined based on the minimum MAF. [0022] Referring now to Figure 3, exemplary steps executed by the MAP control will be described in detail. In step 300, control determines whether the engine is being operated in the FCO mode. If the engine is not being operated in the FCO mode, control ends. If the engine is operating in the FCO mode, control monitors RPMENG in step 302. In step 304, control determines ATHR based on RPMENG. Control regulates the throttle based on ATHR in step 308 and loops back to step 300. [0023] Referring now to Figure 4, exemplary modules that execute the MAP control will be described in detail. The exemplary modules include an AIHR determining module 400, an AOFFSET determining module 402, a throttle control 7 module 404 and a FCO module 406. The ATHR determining module 400 determines ATHR and outputs an ATHR value to the throttle control module 404. Similarly, the AOFFSET determining module 400 determines AOFFSET based on RPMENG AND outputs an AOFFSET value to the throttle control module 404. [0024] The FCO module 406 determines whether the engine is operating in the FCO mode and outputs an appropriate signal to the throttle control module 404. The throttle control module 404 regulates the throttle position based on ATHR and AOFFSET More specifically, if the engine is operating in the FCO mode, the throttle control module 404 generates throttle control signals based on ATHR and AOFFSET. If the engine is not operating in the FCO mode, the throttle control module 404 generates throttle control signals based on ATHR [0025] Those skilled in the art can now appreciate from the foregoing description that the broad teachings of the present disclosure can be implemented in a variety of forms. Therefore, while this disclosure has been described in connection with particular examples thereof, the true scope of the disclosure should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the drawings, the specification and the following claims. 8 CLAIMS What is claimed is: 1. A method of regulating a throttle opening of an engine in a hybrid electric vehicle system, comprising: initiating a fuel-cut off operating mode of the engine; monitoring an engine speed; regulating the throttle opening based on said engine speed during said fuel-cut off mode; and maintaining a manifold absolute pressure (MAP) of said engine above a threshold MAP during said fuel-cut off mode. 2. The method of claim 1 further comprising: determining a throttle area offset based on said engine speed; and determining a base throttle area, wherein said regulating of said throttle opening is achieved based on said throttle area offset and said base throttle area. 3. The method of claim 2 wherein said throttle area offset is determined from a look-up table. 4. The method of claim 1 further comprising: determining a minimum MAP based on said engine speed; and determining a base throttle area based on said minimum MAP. 9 5 The method of claim 1 further comprising: determining a minimum MAP based on said engine speed; and determining a desired torque based on said minimum MAP. 10 6. A throttle regulation system of an engine in a hybrid electric vehicle system, comprising: a first module that initiates a fuel-cut off operating mode of the engine; a second module that monitors an engine speed; a third module that regulates a throttle opening based on said engine speed during said fuel-cut off mode, wherein said third module maintains a manifold absolute pressure (MAP) of said engine above a threshold MAP during said fuel-cut off mode. 7. The throttle regulation system of claim 6 further comprising: a fourth module that determines a throttle area offset based on said engine speed, wherein said fourth module determines a base throttle area, and wherein regulating of said throttle opening is achieved based on said throttle area offset and said base throttle area. 8. The throttle regulation system of claim 7 wherein said throttle area offset is determined from a look-up table. 9. The throttle regulation system of claim 6 further comprising: a fourth module that determines a minimum MAP based on said engine speed and that determines a base throttle area based on said minimum MAP. 11 10. The throttle regulation system of claim 9 further comprising: a fourth module that determines a minimum MAP based on said engine speed and that determines a desired torque based on said minimum MAP. 12 11. A method of regulating a throttle of an engine in a hybrid electric vehicle system, comprising: initiating a fuel-cut off operating mode of the engine; determining one of a desired torque and a base throttle area; regulating a throttle opening based on said one of said desired torque and said base throttle area during said fuel-cut off mode; and maintaining a manifold absolute pressure (MAP) of said engine above a threshold MAP during said fuel-cut off mode. 12. The method of claim 11 further comprising: determining a throttle area offset based on said engine speed; and determining said base throttle area, wherein said regulating of said throttle opening is achieved based on said throttle area offset and said base throttle area. 13. The method of claim 12 wherein said throttle area offset is determined from a look-up table. 14. The method of claim 11 further comprising: determining a minimum MAP based on an engine speed; and determining said base throttle area based on said minimum MAP. 13 15 The method of claim 11 further comprising: determining a minimum MAP based on an engine speed; and determining said desired torque based on said minimum MAP. 15 A method of regulating a throttle opening of an engine in a hybrid electric vehicle system includes initiating a fuel-cut off operating mode of the engine, monitoring an engine speed during said fuel cut-off operating mode and regulating the throttle opening based on the engine speed during the fuel-cut off mode to maintain a manifold absolute pressure (MAP) of the engine above a threshold MAP.

Full Text

FUEL-CUT MANIFOLD ABSOLUTE
PRESSURE CONTROL
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 60/840,389, filed on August 25, 2006, the disclosure of which is
expressly incorporated herein by reference.
FIELD
[0002] The present disclosure relates to hybrid vehicles, and more
particularly to regulating the engine of a hybrid vehicle in a fuel cut-off mode such
as during deceleration fuel cut-off (DFCO) or electric motoring of the engine.
BACKGROUND
[0003] Hybrid vehicles are driven by multiple powerplants including, but
not limited to an internal combustion engine and an electric machine. The
electric machine functions as a motor/generator. In a generator mode, the
electric machine is driven by the engine to generate electrical energy used to
power electrical loads or charge batteries. In a motor mode, the electric machine
supplements the engine, providing drive torque to drive the vehicle drivetrain.
[0004] In some instances, the fuel is cut-off to the engine during
deceleration (referred to as deceleration fuel cut-off (DFCO)) or electric motoring
of the engine. During these events, the engine is back driven, which induces
reciprocal movement of the cylinders within the engine. As a result of the back
1

driving of the engine, the manifold absolute pressure (MAP) of an intake manifold
of the engine is significantly reduced, resulting in reduced efficiency and other
losses. More specifically, reduced MAP results in low pressure in the intake
ports and in the combustion chamber (i.e., within the cylinder in the space above
the piston).
[0005] If the pressure is too low, the oil can be drawn out of the engine
crankcase through the piston rings, the valve guides disposed within the inlet
ports, as well as through other paths. The piston rings can also flutter or vibrate
depending on dynamic pressure differences between the crank case and the
combustion chamber, which can be detrimental to the engine and may be
perceptible by vehicle occupants.
SUMMARY
[0006] Accordingly, the present disclosure provides a method of
regulating a throttle opening of an engine in a hybrid electric vehicle system. The
method includes initiating a fuel-cut off operating mode of the engine, monitoring
an engine speed during the fuel cut-off operating mode and regulating the throttle
opening based on the engine speed during the fuel-cut off mode to maintain a
manifold absolute pressure (MAP) of the engine above a threshold MAP. By
maintaining the MAP above the threshold MAP, the above-described low
pressure conditions are avoided. More specifically, the pressure is maintained
sufficiently high to inhibit drawing out of the engine oil from the engine crankcase
and to prevent flutter or vibration of the piston rings.
2

[0007] Further areas of applicability of the present disclosure will
become apparent from the detailed description provided hereinafter. It should be
understood that the detailed description and specific examples, while indicating
the preferred embodiment of the disclosure, are intended for purposes of
illustration only and are not intended to limit the scope of the disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The present disclosure will become more fully understood from
the detailed description and the accompanying drawings, wherein:
[0009] Figure 1 is a schematic illustration of an exemplary hybrid
vehicle system;
[0010] Figure 2 is a graph illustrating exemplary manifold absolute
pressure (MAP) traces based on the MAP control of the present disclosure;
[0011] Figure 3 is a flowchart illustrating exemplary steps executed by
the MAP control of the present disclosure; and
[0012] Figure 4 is a functional block diagram of exemplary modules
that execute the MAP control of the present disclosure.
DETAILED DESCRIPTION
[0013] The following description of the preferred embodiment is merely
exemplary in nature and is in no way intended to limit the disclosure, its
application, or uses. For purposes of clarity, the same reference numbers will be
used in the drawings to identify similar elements. As used herein, the term
3

module refers to an application specific integrated circuit (ASIC), an electronic
circuit, a processor (shared, dedicated, or group) and memory that execute one
or more software or firmware programs, a combinational logic circuit, or other
suitable components that provide the described functionality.
[0014] As used herein, a fuel cut-off operating (FCO) mode refers to
operation during which fuel is cut off to the engine such as during deceleration
fuel cut-off (DFCO), electric motoring of the engine or other FCO modes.
[0015] Referring now to Figure 1, an exemplary hybrid vehicle 10
includes an engine 12 and an electric machine 14, which drive a transmission 16.
More specifically, the electric machine 14 supplements the engine 12 to produce
drive torque to drive the transmission 16. In this manner, fuel efficiency is
increased and emissions are reduced. The engine 12 and electric machine 14
are coupled via a belt-alternator-starter (BAS) system 18. More specifically, the
electric machine 14 operates as a starter (i.e., motor) and an alternator (i.e.,
generator) and is coupled to the engine 12 through a belt and pulley system.
The engine 12 and the electric machine 14 include pulleys 20, 22, respectively,
that are coupled for rotation by a belt 24. The pulley 20 is coupled for rotation
with a crankshaft 26 of the engine 12.
[0016] In one mode, the engine 12 drives the electric machine 14 to
generate power used to recharge an energy storage device (ESD) 28. In another
mode, the electric machine 14 drives the engine 12 using energy from the ESD
28. The ESD 28 can include, but is not limited to, a battery or a super-capacitor.
Alternatively, the BAS system 18 can be replaced with a flywheel-alternator-
4

starter (FAS) system (not shown), which includes an electric machine operably
disposed between the engine and the transmission or a chain or gear system
that is implemented between the electric machine 14 and the crankshaft 26.
[0017] The transmission 16 can include, but is not limited to, a manual
transmission, an automatic transmission, a continuously variable transmission
(CVT) and an automated manual transmission (AMT). Drive torque is transferred
from the engine crankshaft 26 to the transmission 16 through a coupling device
30. The coupling device 30 can include, but is not limited to, a friction clutch or a
torque converter depending upon the type of transmission implemented. The
transmission 16 multiplies the drive torque through one of a plurality of gear
ratios to drive a driveshaft 32.
[0018] A control module 34 regulates operation of the vehicle 10. The
control module 34 controls fuel injection and spark to selectively activate and
deactivate cylinders of the engine 12. More specifically, when the vehicle 10 is at
rest, none of the cylinders of the engine 12 are firing (i.e., are deactivated) and
the engine 12 is stopped. During vehicle launch (i.e., acceleration from rest), the
electric machine 14 drives the crankshaft to spin-up the engine 12 to an idle RPM
and to initiate vehicle acceleration. During periods where low drive torque is
needed to drive the vehicle (i.e., a hybrid engine off (HEOff) mode), drive torque
is provided by the electric machine 14. When in the HEOff mode, fuel and spark
are cut-off to the cylinders of the engine. Further, opening and closing cycles of
the intake and exhaust valves can be prevented to inhibit air flow processing
within the cylinders.
5

[0019] An accelerator pedal 36 is provided. A pedal position sensor 36
is sensitive to a position of the accelerator pedal 36 and generates a pedal
position signal based thereon. A brake pedal 40 is provided. A brake pedal
position sensor 42 is sensitive to a position of the brake pedal 40 and generates
a pedal position signal based thereon. The control module 34 operates a brake
system 43 based on the brake pedal position signal to adjust a pressure within
the brake system, which in turn regulates a braking force of brakes (not shown).
A speed sensor 44 is responsive to the rotational speed (RPMEM) of the electric
machine 44. The speed sensor 44 generates a speed signal. The control
module 34 operates the vehicle 10 based on the pedal position signals generated
by the pedal position sensors 38, 42 and the speed signal generated by the
speed sensor 44, as described in further detail below. The engine speed
(RPMENG) can be determined based on the speed signal. More specifically,
RPMEM can be multiplied by the known pulley ratio to provide RPMENG
[0020] The manifold absolute pressure (MAP) control of the present
disclosure regulates the position of the throttle while the engine is being operated
in a fuel cut-off (FCO) mode. More specifically, during deceleration fuel and
spark are cut-off, preferably on a cylinder by cylinder basis, and the electric
machine 14 regeneratively brakes the vehicle to charge the ESD 28. The MAP
control of the present disclosure monitors RPMENG and adjusts the throttle
position to maintain the MAP above a threshold level. Fuel cut-off may also
occur during electric motoring of the engine.
6

[0021] With particular reference to Figure 2, if the engine is operating in
the FCO mode, MAP is monitored and is maintained above a threshold MAP
(MAPTHR). More specifically, the MAP control regulates the throttle area (AIHR)
based on engine RPM. A target or minimum MAP value is determined from a
look-up table based on engine RPM. ATHR is determined from the minimum MAP
value. More specifically, the MAP value is processed through a MAP-based
torque model to calculate a desired torque (TDES)- In a toque-based system, TDES
can be used for engine control, wherein the torque model accounts for fuel cut
scenarios. For airflow-based systems, a desired air per cylinder (APC) is
determined based on the MAP value by solving for APC using an inverse APC
torque model. By dividing the desired APC by an intake period, a minimum mass
air flow (MAF) needed to satisfy the desired MAP is determined. ATHR is then
determined based on the minimum MAF.
[0022] Referring now to Figure 3, exemplary steps executed by the
MAP control will be described in detail. In step 300, control determines whether
the engine is being operated in the FCO mode. If the engine is not being
operated in the FCO mode, control ends. If the engine is operating in the FCO
mode, control monitors RPMENG in step 302. In step 304, control determines
ATHR based on RPMENG. Control regulates the throttle based on ATHR in step 308
and loops back to step 300.
[0023] Referring now to Figure 4, exemplary modules that execute the
MAP control will be described in detail. The exemplary modules include an AIHR
determining module 400, an AOFFSET determining module 402, a throttle control
7

module 404 and a FCO module 406. The ATHR determining module 400
determines ATHR and outputs an ATHR value to the throttle control module 404.
Similarly, the AOFFSET determining module 400 determines AOFFSET based on
RPMENG AND outputs an AOFFSET value to the throttle control module 404.
[0024] The FCO module 406 determines whether the engine is
operating in the FCO mode and outputs an appropriate signal to the throttle
control module 404. The throttle control module 404 regulates the throttle
position based on ATHR and AOFFSET More specifically, if the engine is operating
in the FCO mode, the throttle control module 404 generates throttle control
signals based on ATHR and AOFFSET. If the engine is not operating in the FCO
mode, the throttle control module 404 generates throttle control signals based on
ATHR
[0025] Those skilled in the art can now appreciate from the foregoing
description that the broad teachings of the present disclosure can be
implemented in a variety of forms. Therefore, while this disclosure has been
described in connection with particular examples thereof, the true scope of the
disclosure should not be so limited since other modifications will become
apparent to the skilled practitioner upon a study of the drawings, the specification
and the following claims.
8

CLAIMS
What is claimed is:
1. A method of regulating a throttle opening of an engine in a hybrid electric
vehicle system, comprising:
initiating a fuel-cut off operating mode of the engine;
monitoring an engine speed;
regulating the throttle opening based on said engine speed during said
fuel-cut off mode; and
maintaining a manifold absolute pressure (MAP) of said engine above a
threshold MAP during said fuel-cut off mode.
2. The method of claim 1 further comprising:
determining a throttle area offset based on said engine speed; and
determining a base throttle area, wherein said regulating of said throttle
opening is achieved based on said throttle area offset and said base throttle
area.
3. The method of claim 2 wherein said throttle area offset is determined from
a look-up table.
4. The method of claim 1 further comprising:
determining a minimum MAP based on said engine speed; and
determining a base throttle area based on said minimum MAP.
9

5 The method of claim 1 further comprising:
determining a minimum MAP based on said engine speed; and
determining a desired torque based on said minimum MAP.
10

6. A throttle regulation system of an engine in a hybrid electric vehicle
system, comprising:
a first module that initiates a fuel-cut off operating mode of the engine;
a second module that monitors an engine speed;
a third module that regulates a throttle opening based on said engine
speed during said fuel-cut off mode, wherein said third module maintains a
manifold absolute pressure (MAP) of said engine above a threshold MAP during
said fuel-cut off mode.
7. The throttle regulation system of claim 6 further comprising:
a fourth module that determines a throttle area offset based on said
engine speed, wherein said fourth module determines a base throttle area, and
wherein regulating of said throttle opening is achieved based on said throttle area
offset and said base throttle area.
8. The throttle regulation system of claim 7 wherein said throttle area offset is
determined from a look-up table.
9. The throttle regulation system of claim 6 further comprising:
a fourth module that determines a minimum MAP based on said engine
speed and that determines a base throttle area based on said minimum MAP.
11

10. The throttle regulation system of claim 9 further comprising:
a fourth module that determines a minimum MAP based on said engine
speed and that determines a desired torque based on said minimum MAP.
12

11. A method of regulating a throttle of an engine in a hybrid electric vehicle
system, comprising:
initiating a fuel-cut off operating mode of the engine;
determining one of a desired torque and a base throttle area;
regulating a throttle opening based on said one of said desired torque and
said base throttle area during said fuel-cut off mode; and
maintaining a manifold absolute pressure (MAP) of said engine above a
threshold MAP during said fuel-cut off mode.
12. The method of claim 11 further comprising:
determining a throttle area offset based on said engine speed; and
determining said base throttle area, wherein said regulating of said throttle
opening is achieved based on said throttle area offset and said base throttle
area.
13. The method of claim 12 wherein said throttle area offset is determined
from a look-up table.
14. The method of claim 11 further comprising:
determining a minimum MAP based on an engine speed; and
determining said base throttle area based on said minimum MAP.
13

15 The method of claim 11 further comprising:
determining a minimum MAP based on an engine speed; and
determining said desired torque based on said minimum MAP.

15

A method of regulating a throttle opening of an engine in a hybrid electric
vehicle system includes initiating a fuel-cut off operating mode of the engine,
monitoring an engine speed during said fuel cut-off operating mode and
regulating the throttle opening based on the engine speed during the fuel-cut off
mode to maintain a manifold absolute pressure (MAP) of the engine above a
threshold MAP.

Documents:

01168-kol-2007-abstract.pdf

01168-kol-2007-claims.pdf

01168-kol-2007-correspondence others 1.1.pdf

01168-kol-2007-correspondence others 1.2.pdf

01168-kol-2007-correspondence others.pdf

01168-kol-2007-description complete.pdf

01168-kol-2007-drawings.pdf

01168-kol-2007-form 1.pdf

01168-kol-2007-form 18.pdf

01168-kol-2007-form 2.pdf

01168-kol-2007-form 3.pdf

01168-kol-2007-form 5.pdf

01168-kol-2007-priority document.pdf

1168-KOL-2007-(24-08-2012)-CORRESPONDENCE.pdf

1168-KOL-2007-ABSTRACT.pdf

1168-KOL-2007-AMANDED CLAIMS.pdf

1168-KOL-2007-CORRESPONDENCE OTHERS 1.3.pdf

1168-KOL-2007-CORRESPONDENCE-1.4.pdf

1168-KOL-2007-DESCRIPTION (COMPLETE).pdf

1168-KOL-2007-DRAWINGS.pdf

1168-KOL-2007-EXAMINATION REPORT REPLY RECIEVED.pdf

1168-KOL-2007-FORM 1.pdf

1168-KOL-2007-FORM 2.pdf

1168-KOL-2007-FORM 3.pdf

1168-KOL-2007-OTHERS.pdf

1168-KOL-2007-PA.pdf

1168-KOL-2007-PETITION UNDER RULE 137-1.1.pdf

1168-KOL-2007-PETITION UNDER RULE 137.pdf

abstract-01168-kol-2007.jpg

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Patent Number

255163

Indian Patent Application Number

1168/KOL/2007

PG Journal Number

05/2013

Publication Date

01-Feb-2013

Grant Date

30-Jan-2013

Date of Filing

24-Aug-2007

Name of Patentee

GM GLOBAL TECHNOLOGY OPERATIONS, INC.

Applicant Address

300 GM RENAISSANCE CENTER DETROIT, MICHIGAN

Inventors:

#	Inventor's Name	Inventor's Address
1	GORO TAMAI	7532 GLASCOTT, WEST BLOOMFIELD, MICHIGAN 48323
2	JAMES L. WORTHING	338 PORT AGE LAKE ROAD, MUNITH, MICHIGAN 49259

PCT International Classification Number

F02D41/04

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	60/840,389	2006-08-25	U.S.A.