Title of Invention

METHOD AND DEVICE FOR CONTROLLING A DRIVE UNIT OF A VEHICLE

Abstract

ABSTRACT (IN/PCT/2001/01755/ CHE) "METHOD AND DEVICE FOR CONTROLLING A DRIVE UNIT OF A VEHICLE" A method for controlling a drive unit of a vehicle, with a control element for influencing the power output, it being possible to set a power-determining signal on the basis of the position of an operating element, and the control element being activated as a function of a filtered power-determining signal, characterized in that the signal is filtered by a filter, which has at least two high-passes and a low-pass, which are connected in parallel.

Full Text

The invention relates to a method and a device for controlling a drive unit of a vehicle. A method and such a device for controlling a drive unit of a vehicle are disclosed, for example, by DE 195 34 633. In the method and the device described therein, variations in the engine torque are delayed by low-pass filtering of the driver input. A pulsed rate of injection is furthermore proposed, in order to achieve a gentle take-up by the engine, the injected fuel quantity thereafter being delivered without delay for the purpose of acceleration. The low-pass filtering has an adverse effect on the spontaneity of the engine pick-up behaviour. Furthermore, with modern drivetrain concepts an interaction between engine motion and drivetrain is observable, so that the load shock may even be intensified. The fact that a filter is used, in which at least a high-pass and a low-pass are connected in parallel, makes it possible to change very rapidly between overrun and traction conditions. The capacity for rapid change in operating condition facilitates a spontaneous vehicle response to the driver input. Damping of the shock when encountering the new take-up 'position results in a significant reduction of the noise during the load transition, a reduction of the load shock when varying the load as a consequence of minor variations of the driver input, and less incitement of the drivetrain to bucking. The fact that the signals of the high-pass filter and the low-pass filter are connected in parallel, and that the timing of their phase position is applicatively adjusted to the engine drivetrain combination, means that the pick-up behaviour can be designed to a large extent independently of the load shock damping. In the event of slow variations in the driver input, a comfortable transitional state is also possible without acceleration and deceleration of the masses. Such stimuli do not interfere with the load shock damper. Due to the special combination of filters, the masses of the drivetrain are accelerated by at least a torque pulse and decelerated again before encountering the new take-up position, the position of the said pulse relative to the timing of the desired change in fuel quantity and position of the pulses in relation to one another being variable or applicable. Drawing The invention will be explained below with reference to the embodiments represented in the drawing. Figure 1 shows a general block circuit diagram of a device for performing the method according to the invention, Figure 2 shows a detailed representation, in the form of a block diagram, of the device according to the invention, and Figure 3 shows various signals plotted over time. DESCRIPTION OF EXEMPLARY EMBODIMENTS Figure 1 shows a general block circuit diagram of a device for controlling the drive unit of a vehicle, in which the method according to the invention may be used. The method according to the invention is described there with reference to the example of a diesel internal combustion engine. The method according to the invention may also be used, however, in other types of internal combustion engines, particularly in internal combustion engines with spark ignition. 100 denotes an internal combustion engine, which is connected, among other things, to a control element 110. The control element 110 processes signals from various sensors 115 and a signal QKF, which is provided by a filter device 120. The signal QK is delivered to the filter device 120 as input variable. The filter device also processes the output signals from various sensors 125. The signal QK is provided by a fuel quantity setting 130. The fuel quantity setting is influenced by signals from an accelerator pedal position sensor 140, of various sensors 135. Starting from the position of the accelerator pedal, the accelerator pedal position sensor generates a signal FP relating to the accelerator pedal position. The accelerator pedal position sensor may take the form of a rotary potentiometer, for example. In this case a resistance value and/or the voltage drop at the potentiometer is used as signal. From the output signal of the accelerator pedal position sensor 140 and the output signals of the various sensors 135, the fuel quantity setting 130 calculates the signal QK, which represents a measure of the power output required by the internal combustion engine. The fuel quantity QK is set, for example, as a function of sensors 135 that register various temperature values, pressure values and other operating conditions. In the case of a diesel internal combustion engine this preferably relates to the quantity of fuel to be injected. In the case of an internal combustion engine with spark ignition this preferably relates to a signal indicating the throttle position or the ignition point. In order to avoid the load shock, the fuel injection quantity in a diesel internal combustion engine must not be released in a surge. It is sufficient here to filter the fuel injection quantity solely within the quantity range in which the internal combustion engine moves in relation to the vehicle body. This filtering of the fuel quantity signal is performed by the filter device 120, the filtering being performed as a function of the engine speed registered by means of a speed sensor 125. The transient response of the filter device 120 is represented in Figure 2. The filtered quantity signal QKF is fed to the control element 110. The control element 110 is, for example, a fuel metering device determining the quantity of fuel to be injected. This may be a solenoid valve, for example. As a function of the filtered fuel quantity signal QKF and the output signals from other sensors 115, the control element 110 meters the corresponding fuel quantity for the internal combustion engine 100. The method according to the invention is not confined to use in diesel internal combustion engines. It may also be used in other internal combustion engines. Nor is it confined to use in fuel injection. It may also be used with other variables determining the power output, such as the throttle position or the ignition advance angle, for example. The filter device 120 is represented in more detail in Figure 2. Elements already described in Figures 1 are shown with corresponding reference numbers. The fuel quantity requirement signal QK passes to a first delay element 200, to a second delay element 220 and to a third delay element 250. The output signal from the first delay element 200 is applied to a low-pass 210. The signal QKFO, which is applied to a first switching point 215, is delivered at the output of the low-pass 210. The output signal from the second delay element 220 passes by way of a first input limiter 230 to a first high-pass 240. The output signal QKFl, which is applied to the first switching point 215, is delivered at the output of the first high-pass. The output signal from the third delay element 250 passes by way of a second input limiter 260 to a second high-pass 270. The output signal from the second high-pass 270 passes to a second switching point 280, at the second input of which the output signal from the first switching point 215 is delivered. The output signal from the switching point 280 passes by way of an output limiter 290 as filtered fuel quantity requirement QKF to the control element 110. A PTDl element is preferably used as low-pass 210. According to the invention, however, other filters with low-pass response may also be used. Filters with DTI response are preferably used as first and second high-pass. However, other filters with high-pass response may also be used. In a simplified embodiment it is possible to omit the third delay element 250, the second input limiter 260 and/or the second high-pass 270. The arrangement of the delay elements 200, 220 and 250 is chosen merely as an example. These delay elements may also be arranged on the output side of the input limiter or on the output side of the low-pass or on the output side of the high-passes. Special low-passes and high-passes containing higher order elements may also be used instead of the delay elements. Furthermore it is possible to omit the input limiters 230, 260 and/or the output limiter 290 depending on the design. The low-pass 210 determines the static transient response of the filter. In the same way this transmission element essentially determines the behaviour in responding to the driver's requirement. In the event of a change in the input variable QK, a fuel quantity pulse is needed, which ensures the acceleration and deceleration of the masses. This fuel quantity pulse is provided by the high-pass filters 240 and 270. The delay elements 220 and 250 ensure that the signals from the filters 210, 240 and/or 270 are phase-offset in relation to one another. This guarantees the chronological sequence of pulses and hence the desired characteristic of the output signal. Through suitable choice and/or dimensioning of the delay elements, it is possible to apply the position of this pulse in relation to the timing of the required change in fuel quantity and the position of the pulses in relation to one another. It is particularly advantageous if the delay elements and hence the phase-offset are variable as a function of the operating condition of the internal combustion engine and/or the vehicle. Suitable parameters for characterizing the operating condition are the speed of the internal combustion engine, the load of the internal combustion engine, the road speed and/or other variables. High-gain amplifications of the high-passes 240 and 270 permit load shock damping even in the case of minor changes in the fuel quantity setting QK. The input limiters 230 and 260 prevent any excessive intervention in the event of large variations of the signal. It is proposed according to the invention that it be possible to set the input limiters 230 and 260 as a function of the fuel quantity requirement. At medium and high loads the drive train usually sits securely. Variations in the fuel quantity requirement QK in this range do not generally give rise to any transitional state between overrun and traction. As a result no load shock can occur here either. The input limiters 230 and 260 are designed in such a way that deactivation of the load shock damping occurs within these operating points. The output limiter 290 ensures that the maximum admissible quantities are not exceeded. Through suitable choice of the delay elements, the input limiter, the transient response of the high-passes, of the low-pass and of the output limiter, the response of the filter can be optimally adjusted to any vehicles. Examples of the behaviour of the various signals are plotted over time in Figure 3. At time Tl, the fuel quantity requirement changes to an increased quantity. At time T3 the fuel quantity requirement returns to its original value. This is plotted in Figure 3a. The output signal of the low-pass 210 is represented in Figure 3b. From time Tl the signal QKFO approximates to its new final value, preferably according to an exponential function. After time T3, the signal QFO does not start to decrease immediately, the transition to its original output value rather occurring after a certain delay time from time T4 onwards. This delay between time T3 and time T4 is brought about by the first delay element 200. The output signal QKFl of the first high-pass is plotted in Figure 3c. This filter preferably generates a positive pulse at time Tl and a negative pulse at time T3. That is to say the first high-pass generates a positive fuel quantity pulse at the transition to increased fuel quantities and a negative fuel quantity pulse at the transition to lower fuel quantities. The output signal QKF2 from the second high-pass 270 is plotted in Figure 3d. The second high-pass generates a negative fuel quantity pulse at the transition to higher quantities and a positive fuel quantity pulse at the transition to lower, smaller quantities. Furthermore, the delay element 250 delays the respective fuel quantity pulse by a certain delay time. That is to say the negative pulse occurs not at time Tl but at time T2 and the positive fuel quantity pulse not at time T3 but at time T4. In the exemplary embodiment shown a first high-pass generates a positive or a negative fuel quantity pulse at the transition to higher or lower quantities respectively. The second high-pass, with a time delay, generates an inverse fuel quantity pulse in either case. The low-pass connected in parallel immediately relays the corresponding fuel quantity requirement with a predetermined characteristic. Adding these three filtered signals together produces the output signal QKF of the filter device 120 represented in Figure 3e. At the transition to a modified fuel quantity requirement two corresponding fuel quantity pulses preferably occur. That is to say two positive fuel quantity pulses occur at the transition to an increased quantity and two negative fuel quantity pulses at the transition to smaller quantities. This ensures that no load shock occurs. The method according to the invention is not confined to the embodiment described having one low-pass and one high-pass. It can also be implemented using other 'filter devices. In particular, corresponding digital filters can be used, which have a corresponding response. What is essential is that the filtering be performed in such a way that at a transition to a modified signal the filtered signal has at least a corresponding pulse. This means that a positive pulse ensues from a transition to an increased value and a negative pulse ensues from a transition to a lower value. The method according to the invention has hitherto been demonstrated using fuel quantities as an example. However, the method according to the invention is also applicable to torque signals or other variables corresponding to the fuel quantity. The fuel quantity requirement delivered to the control element is preferably filtered accordingly. Provision may also be made, however, for suitable filtering of the output signal from the sensor 140 or another variable corresponding to the driver's requirement. WE CLAIM: 1. A method for controlling a drive unit of a vehicle with a control element for influencing the power output comprising the steps of: setting a power-determining signal on the basis of the position of an operating element; activating the control element as a function of a filtered power-determining signal; and filtering the signal by a filter comprising at least two high-passes and a low-pass connected in parallel. 2. The method as claimed in claim 1, wherein the signals from the first high-pass, the second high-pass and/or the low-pass are phase-offset in relation to one another. 3. A device for controlling a drive unit of a vehicle comprising a control element (110) for influencing the power output, said control element provided to be activated as a function of a filtered power-determining signal; an operating element, whose position enables the setting of the power-determining signal; characterized in that said device comprises a filter (120) for filtering the signal, said filter comprising at least a high-pass (240) and a low-pass (210) connected in parallel.

Documents:

in-pct-2001-1755-che abstract-duplicate.pdf

in-pct-2001-1755-che abstract.pdf

in-pct-2001-1755-che claims-duplicate.pdf

in-pct-2001-1755-che claims.pdf

in-pct-2001-1755-che correspondence-others.pdf

in-pct-2001-1755-che correspondence-po.pdf

in-pct-2001-1755-che description(complete)-duplicate.pdf

in-pct-2001-1755-che description(complete).pdf

in-pct-2001-1755-che drawings-duplicate.pdf

in-pct-2001-1755-che drawings.pdf

in-pct-2001-1755-che form-1.pdf

in-pct-2001-1755-che form-18.pdf

in-pct-2001-1755-che form-26.pdf

in-pct-2001-1755-che form-3.pdf

in-pct-2001-1755-che form-5.pdf

in-pct-2001-1755-che pct.pdf

in-pct-2001-1755-che petition.pdf