EP1309780B1 - Method and device for regulating an operating variable of a drive unit - Google Patents

Abstract

The invention relates to a method and a device for regulating an operating variable of a drive unit. According to the invention, a controller with at least one variable parameter is provided. A switch is made from a first parameter value to a second parameter value in dependence on a switchover signal. At the time of the switchover, a filter is also initialised with a value which corresponds to the size of the change in the output signal of the controller at this time and by which means a constant curve is achieved for the controller output signal at the time of the switchover.

Description

State of the art

The invention relates to a method and a device for controlling an operating variable of a drive unit.

In modern control systems for drive units of motor vehicles are often used control systems, which an operating variable of the drive unit to a predetermined Control setpoint. An example of such control systems are idle speed controllers, by which the speed in the Idling the drive unit to a predetermined setpoint is regulated. Other examples are control systems for regulation the air flow rate through an internal combustion engine, the Exhaust composition, torque, etc. Thus, the DE shows 30 39 435 A1 (US Pat. No. 4,441,471) an idle speed control system, in which to improve the control properties is provided, at least one parameter of the controller variable embody. In the illustrated embodiment is the proportional component of the controller as a function of the size adapted to the control deviation.

Is the adaptation of the at least one controller parameter as Switching between at least two values realized, so creates an inherently unsatisfactory switching pressure, which can affect the control comfort.

Advantages of the invention

By filtering a controller output signal during the switching process at least one controller parameter between at least two values will be a significant improvement of the Regular comfort achieved because a switching pressure effectively avoided becomes.

It is particularly advantageous that the switching torque-neutral runs, d. H. there are no jump-like courses in the torque of the drive unit. A significant improvement the ride comfort is the result. These advantages result in both a proportional and a Differential component of a regulator.

Special advantages with regard to driving comfort are achieved if the filter used when switching with the immediately before the switch over existing controller output signal is initialized.

Particular advantages are shown below in detail Approach in the application in the context of a torque-oriented Motor control structure in which the output of an idle speed controller, the target torque in which Dependence the torque of the drive unit is set is being changed. By using the below described Filters will be a moment-neutral course of the Target torque also when switching the controller parameter reached. These advantages are particularly evident in Internal combustion engines with gasoline direct injection, in which a torque-neutral course of the torque and / or the setpoint torque even with a change of operating mode and the associated switching of the controller parameters is reached.

Further advantages will become apparent from the following description of embodiments or of the dependent Claims.

drawing

The invention will be described below with reference to the drawing illustrated embodiments illustrated. FIG. 1 shows an overview diagram of a controller while in Figure 2 is a flow chart of a controller using the example of a switchable proportional component with filtering shown is. FIG. 3 shows time courses by means of which the Effect of filtering when switching the at least a controller parameter is clarified.

Description of exemplary embodiments

FIG. 1 shows an electronic control unit 10 for control a drive unit in which a controller for regulating is implemented at least one operating size. in the preferred embodiment is in the controller around an idle speed controller. In other embodiments it can be an air flow regulator, a Load controller, a torque controller, a regulator of the exhaust gas composition, etc. act. In Figure 1 is a setpoint images 12, which depends on at least one via input lines 14 to 18 of the control unit 10 supplied operating variable a target value for forms the operating variable to be regulated. In the preferred embodiment an idle speed controller is at the quantities used for setpoint formation around engine temperature, the operating status of secondary consumers, such as For example, an air conditioner, etc. Further, the control unit 10 is supplied via the input line 20 a signal, which is the actual size of the operating variable to be regulated represents. Target and actual size are in the comparator 22 with each other compared. The deviation between nominal and actual size is supplied to the controller 24 as a control deviation Δ. This controller has at least one variable parameter on, in the preferred embodiment, it consists of Proportional, differential and integral parts, whereby proportional and / or differential component are variable.

On the basis of the implemented control strategy forms the Regulator 24 as a function of the control deviation at least one Output signal τ, which from the control unit 10 to control an actuator 26 is output. In the above Example, each share makes a regulator output signal that combined (e.g., added) to form the output signal τ. In the preferred embodiment of an idle control the actuator 26 is an electrically actuable throttle or bypass damper, which the air to a Internal combustion engine adjusted such that the actual value approaches the setpoint. For diesel engines or gasoline direct injection does not become the air, but the force mass set by the output signal, so that actuator Represent adjusting devices for influencing the power supply. In addition, depending on the design, further output signals be generated, for example, for control the ignition angle, which also approximates the actual size contribute to the target size.

The different parts of the controller 24 have parameters, For example, gain factors, whose value can be changed is. In the illustrated example of Figure 1 are two Parameter values or parameter value sets 28 and 30 are provided, which via a switching means 32 to the controller 24 be put. In the preferred embodiment the switchable parameters are the amplification factor the proportional controller and / or the of Differential component. The switching means 32 is switched in the presence of the switching condition formed in 34, the Signal is also provided to the controller 24. In the preferred embodiment of an idle control in Connection with a gasoline direct injection internal combustion engine the switching condition is given when the Operating mode of the internal combustion engine is switched, for example from a homogeneous operation to an unthrottled one Operation or operation with a lean mixture and vice versa. When switching between two modes is then switched from the first to the second parameter of the controller. This is because when changing the operating mode a significant change in the properties of the Controlled system (e.g., dynamic behavior, vibration behavior, etc.) occurs. The parameter values are different Adapted requirements. In addition to the operating mode changeover or alternatively, the parameter switching also triggered depending on other operating states, such a change of the controlled system after itself pull, for example, when a gear on or laid out when the clutch is pressed when powerful Consumers are coupled, etc. Is such a Operating phase change, this leads to the generation of a Switching signal through the unit 34 and the switching of the Parameter.

Switching the parameter (s) changes the output of the regulator leaps and bounds, causing the truck to jerk feel. However, it will be a steady course of the control output aspired to such a noticeable jerk on Prevent vehicle. This applies in particular to tax systems with torque-oriented tax structure, in which the output of the idle controller, among other things for correction one of the control underlying setpoint (Target torque, driver's request) is used.

Depending on the binary switching signal, the appropriate or the appropriate controller parameters are selected. In the preferred Embodiment provide the parameter or parameters gain factors with which the control deviation and / or the temporal change of the speed or the control deviation is multiplied. The output signal of the controller changes when switching over jump, because as a result of the change the size of the gain parameter as part of the multiplication a sudden change in the product occurs. To improve this situation, a filter, preferably a first order low pass filter inserted, which at the time of the occurrence of the switching signal (Edge detection) is initialized. The initialization value of the filter is set to the value which the difference between the controller output value before and after the Switching corresponds. The filter is in the preferred embodiment designed such that its output signal Exponential to zero runs after the occurrence of a changeover. The filter output value will then be from the controller output subtracted, so that the resulting control output signal has a steady time course. These measures are proportional proportions and / or differential proportions applied.

FIG. 2 shows a flow chart illustrating the The procedure described above illustrates. The flowchart represents a realization of the described Measure as a program of the computer of the control unit 10 is and describes the processes in the controller 24 using the example of a Proportional share.

FIG. 2 shows the regulator 24, to which, as already illustrated in FIG. 1, the control deviation Δ is supplied via the switching element 32 to a selected parameter P1, P2 as well as the switching signal B_s. The selected by the switching element 32, in one embodiment, operating variable-dependent (eg on the speed, the deviation, etc.) Proportional (P1, P2) is multiplied in the multiplication 100 with the control deviation Δ to form an output dmllr1. This product shows a jump behavior when switching from one parameter to the other. In the subsequent subtraction point 102, the value formed in the multiplication point 100 is compared with the output value (dmllr1 (z ^-1 )) coming from the preceding computer clock. The latter is buffered in a memory cell 104. The deviation between the new and the old output value is then fed to a filter 106, in particular a low-pass filter. This filter is initialized in the presence of an edge change on the supply line 108. It has the value 0 as input value. The initialization takes place at a change of the switching signal B_s detected in 110. Thus, if a switchover takes place from one parameter to the other or vice versa, the filter is initialized with the value formed in the subtraction point 102. The signal formed in the subtraction point 102 corresponds to the magnitude of the jump when switching in the output signal dmllr1. At the switching time, the filter is thus initialized with the value of the height of the jump. Between two switches, the output of the dmumfil filter exponentially expands from the initialized value to zero. The output signal of the filter is then compared in the subtraction point 112 with the output signal dmllr1 of the multiplication stage 100, in particular subtracted therefrom. This results in a controller output signal dmllr whose course is continuous in the switching phase. This output signal is optionally output, taking into account the output signals of other controller components as drive signal τ.

The described procedure is in one embodiment additionally or alternatively to the differential component of the regulator applied. The integral part is with the described problematic not affected, since he due its function generally a steady output signal waveform having.

The mode of operation of the preferred embodiment shown in FIG Embodiment of the controller is shown in Figure 3 using timing diagrams shown. Figure 3a shows the temporal Course of the switching signal B_s, Figure 3b that of the output signal dmumfil of the filter, Figure 3c the time course of the Output signal dmllr1 the multiplication stage and Figure 3d the time course of the output signal dmllr of the controller or Regulators share.

Until the time t0, the controller with a first parameter Pl operated. At the time t0, the parameter switching takes place, for example, as a result of a change of operating modes. Accordingly, the switching signal B_s becomes according to FIG. 3a is set to the value true. This has the consequence that at time t0 according to Figure 3c a jump-shaped course occurs in the output signal dmllr1. To its compensation becomes according to figure 3b at the time t0 the filter with a Value initializes which of the height of the jump in the output signal the multiplication level corresponds. Corresponding the filter function carries the filter output signal from Time t0 of this value exponential to zero (Fig. 3b). Since the filter output signal from the output of the multiplication stage is subtracted to form the output signal dmllr, then results in accordance with Figure 3d a steady Course of this output signal in the switching phase.

The embodiment of Figure 2 represents a preferred embodiment the general solution by using a filter, which with the value of the height of a jump in one Controller output signal initialized at a parameter changeover is, the resulting jump at the switching time to smooth. Other specific embodiments relating to the concrete installation of the filter function are within the scope of this general solution also conceivable, in particular solutions, where the filter with the output value immediately initialized before switching during the changeover and the control output itself is exponential to the new value, the filter in normal operation outside switching is not active.

Claims (12)

1. Method for controlling an operating variable of a drive unit, a controller being provided which has at least one variable parameter, the controller generating an output signal as a function of a control error taking into consideration the variable parameter, switching over being carried out from a first parameter value to a second parameter value when a switchover signal is present, characterized in that a filter is provided which is activated when switching over occurs from one parameter value to the other parameter value, and is initialized with a value which brings about a continuous profile of the output signal at the switchover time.
2. Method according to Claim 1, characterized in that the switchover signal is formed when a change occurs in the control system, in particular when there is a switchover in the operating mode in an engine with direct gasoline injection, a gear is engaged or disengaged, a clutch is activated or a high-power load is connected into the circuit.
3. Method according to one of the preceding claims, characterized in that the at least one parameter is a gain factor of a proportional controller and/or a constant of a differential controller.
4. Method according to one of the preceding claims, characterized in that, in the proportional controller, the at least one variable parameter is multiplied by the control error in order to form an output signal.
5. Method according to one of the preceding claims, characterized in that a variable is formed which corresponds to the level of the jump in the output signal of the controller when switching over occurs from the first parameter value to the second parameter value.
6. Method according to Claim 4 or 5, characterized in that, when the switchover signal is present, a filter is initialized which is initialized with the signal representing the magnitude of the jump, and the output signal of said filter tends exponentially towards zero starting from this time.
7. Method according to Claim 4, 5 or 6, characterized in that the filter output signal is subtracted from the output signal in order to form a smoothed output signal.
8. Method according to one of the preceding claims, characterized in that the controller is an idling speed controller.
9. Method according to one of the preceding claims, characterized in that the output signal constitutes the output signal of an element of the controller or the entire output signal of the controller.
10. Method according to one of the preceding claims, characterized in that the output signal of the controller is added to a setpoint value in order to control an internal combustion engine, in particular a setpoint torque.
11. Method according to one of the preceding claims, characterized in that, with a differential controller, the time derivative of the rotational speed signal and/or the control error are formed with the constant which can be switched over.
12. Method for controlling an operating variable of a drive unit, having a control unit which comprises at least one controller which generates an output signal for influencing the operating variable, the controller having at least one parameter which can be switched over, having switchover means which switch over from a first parameter value to a second parameter value when at least one switchover signal is present, characterized in that the controller comprises a filter which is initialized when the switchover signal is present, having a value which corresponds to the change in the output signal when the parameter is switched over, and which brings about a continuous profile of the output signal of the controller over the switchover time.

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