EP1276979B1 - Method and device for controlling a drive unit of a vehicle - Google Patents

Description

State of the art

The invention relates to a method and a device for controlling a drive unit of a vehicle according to the preambles of the independent claims.

A method and such a device for controlling a drive unit of a vehicle is known, for example, from DE 195 34 633. In the method described there and the device described therein, torque changes of the engine are delayed by low-pass filtering of the driver's specification. Furthermore, a pulse-shaped course of the injection quantity is proposed in order to achieve a soft application of the engine, after which the injected fuel quantity is released for acceleration without delay.

Due to the low-pass filtering, the spontaneity of the driving behavior is impaired. In addition, in modern drivetrain concepts, an interaction between engine movement and drivetrain is observed, so that the impact load can still increase.

To avoid such problems, a method and a device according to the independent claims is provided.

By using a filter in which at least two high-pass and one low-pass are connected in parallel, state changes between thrust and train can be carried out very quickly. Due to the rapid change of state, a spontaneous vehicle reaction to the driver's specification can be realized. The damping of the shock when hitting the new plant position causes a significant reduction in the noise during the load change process, a reduction in the load impact during load changes as a result of small changes in driver specification and a reduced excitation of the drive train to bucking.

Characterized in that the signals of the high and the low pass filter are connected in parallel, and that their temporal phase angle is adapted applicatively to the motor drive train combination, the driving behavior can be designed largely independent of the impact load damping.

With slow changes of the driver specification, a comfortable state transition is possible even without acceleration and deceleration of the masses. With such suggestions, no intervention of the Lastschlagdämpfers.

Due to the special combination of filters, the masses of the drive train are accelerated by at least one momentum and delayed again before hitting the new plant position, the position of this pulse relative to the time of the quantity change request and the position of the pulses to each other is variable or applicable.

drawing

The invention will be explained below with reference to the embodiments shown in the drawing. FIG. 1 shows an overview block diagram of a device for implementation 2 shows a detailed representation as a block diagram of the device according to the invention, and FIG. 3 shows different signals plotted over time.

Description of the embodiments

FIG. 1 shows an overview block circuit diagram of a device for controlling the drive unit of a vehicle, in which the procedure according to the invention can be used. There, the procedure according to the invention is described using the example of a diesel internal combustion engine. However, the procedure according to the invention can also be used in other types of internal combustion engines, in particular in spark-ignited internal combustion engines.

With 100 an internal combustion engine is referred to, which is connected, inter alia, with a controller 110. The controller 110 processes signals from various sensors 115 as well as a signal QKF provided by a filter means 120. The filter means 120, the signal QK is fed as input. The filter means further processes the output signals of various sensors 125. The signal QK is provided by a setpoint 130. The quantity specification is applied by an accelerator pedal position sensor 140, various sensors 135 with signals.

Based on the position of the accelerator pedal, the accelerator pedal position sensor generates a signal FP with respect to the accelerator pedal position. The accelerator pedal position sensor can be designed, for example, as a rotary potentiometer. In this case, a resistance value and / or the voltage drop at the potentiometer is used as a signal.

Based on the output signal of the accelerator pedal position sensor 140 and the output signals of the various sensors 135, the quantity set point 130 calculates the signal QK, which represents a measure of the power desired by the internal combustion engine. The specification of the amount of fuel QK takes place, for example, as a function of sensors 135 which detect different temperature values, pressure values and other operating states.

In a diesel internal combustion engine, this is preferably the amount of fuel to be injected. In a spark-ignited internal combustion engine, this is preferably a signal that indicates the throttle position or the ignition timing.

In order to avoid the impact of the load, the injection quantity in a diesel internal combustion engine may not be released suddenly. It is sufficient to filter the injection quantity only in the amount range in which the internal combustion engine moves relative to the body. This filtering of the fuel quantity signal is carried out by the filter means 120, wherein the filtering takes place as a function of different state variables which characterize the state of the internal combustion engine and / or of the driven vehicle. The filtering preferably takes place as a function of the rotational speed, which is detected by means of a rotational speed sensor 125. The transmission behavior of the filter means 120 is shown in FIG. 2. The filtered quantity signal QKF is supplied to the controller 110.

The actuator 110 is, for example, a fuel metering device defining the amount of fuel to be injected. This may be, for example, a solenoid valve. Depending on the filtered fuel quantity signal QKF and the output signals of other sensors 115, the actuator 110 measures the corresponding fuel quantity of the internal combustion engine 100.

The procedure according to the invention is not restricted to the application in diesel internal combustion engines. It can also be used in other internal combustion engines. Further, it is not limited to the application in the fuel injection. It can also be used in other power output determining quantities, such as the throttle position or the ignition angle

The filter means 120 is shown in more detail in FIG. Already described in Figure 1 elements are marked with corresponding reference numerals. The quantity request signal QK reaches a first dead-time element 200, a second dead-time element 220 and a third dead-time element 250. The output signal of the first dead-time element 200 is applied to a low-pass filter 210. At the output of the low-pass filter 210 is the signal QKF0, with which a first node 215 is applied.

The output signal of the second deadtime element 220 passes through a first input limit 230 to a first high pass 240. At the output of the first high pass is the output QKF1, with which the first node 215 is acted upon.

The output signal of the third dead-time element 250 passes through a second input limit 260 to a second high-pass filter 270. The output signal of the second high-pass filter 270 reaches a second connection point 280, at whose second input the output signal of the first connection point 215 is present. The output signal of the node 280 passes through an output limit 290 as a filtered quantity request QKF to the actuator 110th

As low-pass filter 210, a PTD1 element is preferably used. According to the invention, however, other filters with low-pass behavior can also be used. As the first and second high pass filters are preferably used with DT1 behavior. But there are also other filters with high passability usable.

In a simplified embodiment, it is possible for the third deadtime element 250, the second input limit 260 and / or the second high-pass 270 to be omitted. The arrangement of the deadtime elements 200, 220 and 250 is chosen only as an example. These dead-time elements can also be arranged after the input limit or after the low pass or after the high passes. Instead of dead-time elements, it is also possible to use special low-passes or high-passes which contain higher order terms. Furthermore, it is possible that, depending on the embodiment, the input limits 230, 260, and the output limit 290 are omitted.

The low-pass filter 210 determines the static transmission behavior of the filter. Likewise, this transmission element essentially determines the response to the driver's request.

If the input quantity QK is changed, a fuel quantity pulse is required which ensures the acceleration and deceleration of the masses. This fuel quantity pulse is provided by the high pass filters 240 and 270. By the deadtime elements 220 and 250, the signals of the filters 210,240 and / or 270 are phase-shifted from each other in time. As a result, the temporal sequence of the pulses and thus the desired course of the output signal is ensured. By suitable choice and / or dimensioning of the deadtime elements is the location of this pulse relative to the time of quantity change request and the position of the pulses is applied to each other. It is particularly advantageous if the dead time elements and thus the phase shift can be specified variably as a function of the operating state of the internal combustion engine and / or of the vehicle. Suitable parameters for characterizing the operating state are the rotational speed of the internal combustion engine, the load of the internal combustion engine, the driving speed and / or other variables.

High gains of the high passes 240 and 270 enable the load impact damping even with small changes in the quantity specification QK. The input buffers 230 and 260 prevent too much interference with large changes in the signal QK.

It is preferably provided that the input limits 230 and 260 can be specified as a function of the desired quantity QK. For medium and high loads, the drive train is usually safe. Changes in the quantity request QC in this area usually do not cause a state transition between push and pull. As a result, no load impact can occur here. The input limits 230 and 260 are designed such that a deactivation of the load impact damping takes place in these operating points.

The output limit 290 ensures that the maximum permissible quantity values are not exceeded. By suitable choice of the deadtime elements, the input limit, the transmission behavior of the high passes, the low pass and the output limit, the behavior of the filter can be optimally adapted to any vehicle.

In Figure 3, the temporal behavior of the various signals is exemplified. At time T1 changes the quantity request to an increased amount. At time T3, the quantity request returns to its original value. This is plotted in part 3a. In subfigure 3b, the output signal of the low-pass filter 210 is shown. From time T1, the signal QKF0 approaches its new final value preferably according to an exponential function. After the time T3, the signal QF0 does not go back directly, but the transition to its original output value takes place only after a certain delay time from the time T4. This delay between the time T3 and the time T4 is caused by the first deadtime element 200.

In subfigure 3c, the output signal QKF1 of the first high pass is plotted. Preferably, this filter generates a positive pulse at time T1 and a negative pulse at time T3. That the first high-pass generates a positive mass and a negative mass during transition to an increased amount of fuel.

In subfigure 3d, the output signal QKF2 of the second high pass 270 is plotted. The second high pass produces a negative mass impulse when moving to higher amounts and a positive mass impulse when moving to lower, lower levels. Furthermore, the dead time element 250 delays the respective quantity pulse by a certain delay time. That the negative pulse does not occur at time T1 but at time T2 and the positive pulse does not occur at time T3 but at time T4.

In the exemplary embodiment illustrated, a first high-pass filter generates a positive or negative quantity pulse in each case during the transition to higher or lower quantities. The second high-pass produces a time-delayed one inverse Quantity pulse. The low pass connected in parallel immediately forwards the corresponding quantity request with a given course. By adding these three filtered signals, the output signal QKF of the filter means 120 shown in subfigure 3e results.

In the transition to a changed quantity request, preferably two corresponding quantity pulses occur. That In the transition to an increased amount, first a positive and then a negative volume pulse occurs, and at the transition to smaller amounts first a negative and then a positive volume pulse. This ensures that no load shock occurs.

The procedure according to the invention is not limited to the described embodiment. It can also be used corresponding digital filter, which have a corresponding behavior. It is essential that the filtering takes place in such a way that when there is a transition to a changed signal, the filtered signal has at least one corresponding pulse. This means that when there is a transition to an increased value, a positive pulse takes place, and a transition to a lower value results in a negative pulse.

So far, the procedure of the invention has been demonstrated using the example of fuel quantities. However, the procedure according to the invention is also applicable to torque signals or other quantities corresponding to the fuel quantity.

Preferably, the desired quantity, with which the actuator is acted upon, filtered accordingly. However, it can also be provided that the output signal of the sensor 140 or another size corresponding to the driver's request is filtered accordingly.

Claims (3)

1. 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.
2. Method according to Claim 1, characterized in that 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. Device 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, the filter having at least a high-pass and a low-pass, which are connected in parallel.

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