JPH11200937A - Setting element control method and device - Google Patents

Abstract

(57) Abstract: The present invention compensates for the influence of a change in a supply voltage on a control circuit. When a setting element for regulating the air supply to an internal combustion engine is controlled, the setting element is controlled within a control circuit, wherein a control stage is provided, the control stage comprising a target value and a target value. The manipulated variable for the setting element is formed as a function of the actual value. This manipulated variable is adjusted as a function of the supply voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for controlling a setting element for adjusting the amount of air supplied to an internal combustion engine.

[0002]

BACKGROUND OF THE INVENTION Such a method and such a device are described in DE-A-3510173 (U.S. Pat. No. 4,603,603).
No. 675). There, a setting element for adjusting the air supply to the internal combustion engine is set as a function of the target value and the actual value within the control range. In the described embodiment, the setting element is an electrically operated throttle valve of an internal combustion engine, which throttle valve is controlled within a position control circuit. In this case, the target value of the position control circuit is derived from the position of the operating element that can be operated by the driver, in particular, the position of the accelerator pedal. The actual value representing the position of the setting element is measured by a suitable measuring device. The voltage supply for this device is provided by a battery. Therefore, if the battery voltage or the supply voltage is
It is a factor that adjusts the described control circuit.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a measure for compensating the influence of such fluctuations in the supply voltage on such control circuits.

[0004]

An object of the present invention is to provide a method of controlling a setting element for adjusting an air supply amount to an internal combustion engine,
The internal combustion engine, wherein the setting element is operated as a function of a target value and an actual value within a control circuit, in which case a control stage is provided, said control stage generating an operation amount as a function of the target value and the actual value. In the method for controlling the setting element for adjusting the air supply amount, the supply voltage is measured, and the operation amount is adjusted based on the deviation of the supply voltage from the reference voltage.

[0005] The above object is also achieved by a control device for a setting element for regulating the air supply to an internal combustion engine, comprising a control stage for forming a manipulated variable for the setting element as a function of a target value and an actual value. And a means for adjusting the manipulated variable as a function of the supply voltage.

The characteristics of the control circuit are completely independent of changes in the supply voltage due to compensation as a function of the supply voltage. Thereby, the control characteristics are significantly improved. In particular, a change in the circuit amplification of the control circuit, and thus a stability margin, due to a change in the supply voltage is avoided. Therefore, the compensation of the supply voltage change allows the stability margin to be determined more accurately, and the tuning of the control circuit can be improved in consideration of the stability and its dynamic characteristics. It is particularly important that the dynamics of the control circuit be unaffected by changes in the supply voltage.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.

FIG. 1 shows a control unit 10, which comprises at least one input circuit 12, at least one microcomputer 14, and at least one output circuit 16. These elements are interconnected via a communication system 18 for data exchange between them. At least one output line 20 from the output circuit 16 of the control unit 10 is connected to an electrically operated setting element 22.
Leads to. This setting element 22 consists essentially of an electric servomotor 24 which is provided via a mechanical connection 26 in the actual setting element 30, namely in the intake system 28 of the internal combustion engine, not shown. Associated with the throttle valve. Furthermore, a measuring device 36 is provided in the area of the setting element 22, the measuring device 36 being connected via line 38 to the control unit 10 and, in fact, its input circuit 1.
2 is supplied with a signal wdkba, which represents the actual position of the setting element, in particular the actual position of the throttle flap 30. Further, an input line 40 is supplied to the input circuit 12, and a signal w is output from the measuring device 42 via the input line 40.
ped is transmitted. This signal represents the position of an operating element operable by the driver, in particular the position of the accelerator pedal.
In addition, input lines 44 to 48 are provided, which are used to control the internal combustion engine from the measuring devices 50 to 54, such as engine temperature, engine speed, supplied air. Supply mass flow rate etc. Another input line 56 carries a signal representing the supply voltage Ubat of the control device from the corresponding measuring device 58.
The supply voltage here refers to the battery voltage, for example, which is supplied to the setting element and the components controlling the setting element.

In a preferred embodiment, the setting element 2
2 is set within the range of the closed loop position control circuit. In this case, the desired value is formed from the accelerator pedal position wped, possibly taking into account other operating variables such as the air mass flow supplied and the engine speed. This goal is
The actual value is compared to determine a deviation between the target value and the actual value. As a function of this deviation, the control stage forms an operating signal according to its given control strategy (eg PID), which is output via line 20 for operating the setting element 22. In this case, the actual value wdkba approaches the target value. Such a control circuit has a predetermined circuit amplification degree,
That is, it has an amplification between the output signal of the control stage and the manipulated variable that is a function of the supply voltage. This means that the supply voltage indicates the amount of disturbance to the control circuit. Since the circuit amplification affects the stability of the control circuit, instability may occur due to the influence of the supply voltage on the circuit amplification. In order to prevent this, a correspondingly large stability margin of the control circuit must be taken into account in the design of the control circuit, and this stability margin can negatively influence the dynamics of the control circuit in some cases. In order to improve the control characteristics, the circuit amplification is determined as a function of the supply voltage. This compensates for variations in the supply voltage.

In addition to using this method for the position control described above, other control circuits, such as, for example, rotational speed control, torque control, load control, etc., which regulate the air supply to the internal combustion engine via a setting element. The same advantage can be obtained by using the above.

FIG. 2 shows a process flow diagram in which the circuit amplification as a function of the supply voltage is indicated by the corresponding manipulated variable adjustment. In the preferred embodiment, this is implemented as a program on microcomputer 14.

A target value forming stage 100 is provided, which is supplied from the accelerator pedal position value wped by a characteristic curve, a group of characteristic curves, a table or a calculation step, possibly via lines 44 to 48. The target value wdklr for the position of the set element is determined from other operating variables. This target value wdklr is combined in a combining stage 102 with the actual position wdkba of the setting element. The deviation Δ between the two values is supplied to the control stage 104. The control stage 104 forms an output signal τR as a function of the deviation, which is output as τS via line 20 for operating the set element. In this case, the control stage 104 has a predetermined control strategy, which in the preferred embodiment includes a proportional part, an integral part and a derivative part. The amplification between τR and τS is called circuit amplification in control engineering. The control output signal τR is applied to the multiplication stage 1
06, and in the multiplication stage 106, the control stage 104
Is multiplied by a coefficient k.
In this way, the operation signal τS supplied to the setting element is formed.

The coefficient k is a function of the supply voltage and is determined such that changes in the supply voltage which affect the circuit amplification of the control circuit are compensated.

In a preferred embodiment, the coefficient k is formed as follows. The supply voltage Ubat is measured, and the supply voltage Ubat is supplied to the division stage 108. In the division stage 108, a ratio k * (= Uref / Ubat) between a predetermined reference value Uref of the supply voltage at which the control circuit is tuned and the measured battery voltage Ubat is formed.
The ratio k * is filtered in filter 110 using a PT1 characteristic (a first-order low-pass filter). Filtered ratio k * between reference voltage and actual voltage
Forms a coefficient k, which adjusts the degree of amplification between the control output signal τR and the manipulated variable τS by multiplication.

In addition to forming the ratio at reference numeral 108, in other embodiments, other mathematical operations are performed to determine the deviation between the reference value and the actual value of the supply voltage, for example, a derivative formation. Will be

In yet another embodiment, instead of using a first order low pass filter, a higher order filter or a filter having another transfer function is used, the filter comprising a supply voltage change and a circuit for this change. The time delay to be considered between the effect on the amplification is justified.

[Brief description of the drawings]

FIG. 1 is an overall circuit diagram of a control device for setting elements.

FIG. 2 is a process flow diagram illustrating supply voltage compensation of a control circuit operating a setting element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Control unit 12 Input circuit 14 Microcomputer 16 Output circuit 18 Communication system 22 Electrically operated setting element 24 Electric servo motor 26 Mechanical connection part 28 Intake system 30 Original setting element (throttle valve) 36 Measurement device (throttle valve position) ) 42 Measuring device (accelerator pedal position) 50, 54 Measuring device (other operating variables) 58 Measuring device (supply voltage) 100 Target value forming stage 102 Coupling stage 104 Control stage 106 Multiplication stage 108 Division stage 110 Filter

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02D 41/20 310 F02D 41/20 310B

Claims (8)

[Claims] 1. A method for controlling a setting element for regulating an air supply to an internal combustion engine, said setting element being operated as a function of a target value and an actual value within a control circuit.
In this case, a control stage is provided, wherein the control stage generates a manipulated variable (τS, τR) as a function of a target value and an actual value. Is measured, and the operation amount is adjusted based on the deviation of the supply voltage from the reference voltage. 2. The method according to claim 1, wherein said control circuit is a position control circuit for said setting element. 3. The method according to claim 1, wherein the manipulated variable signal output from the control stage is corrected by multiplication as a function of the supply voltage. 4. The method according to claim 1, wherein a deviation between the supply voltage and the reference voltage is formed, and the amplification between the control output and the manipulated variable is adjusted as a function of the deviation. The method according to any one of the preceding claims. 5. The method as claimed in claim 1, wherein the correction factor is formed by filtering from the deviation between the supply voltage and the reference voltage. 6. The method according to claim 1, wherein the degree of circuit amplification of the control circuit is determined as a function of a supply voltage. 7. The method according to claim 1, wherein the adjustment of the manipulated variable is such that the characteristics of the control circuit are substantially independent of the supply voltage. 8. An operation amount (τS, τR) for a setting element
A control element for regulating the air supply to the internal combustion engine, comprising a control stage for forming the control value as a function of the target value and the actual value, comprising: means for measuring the supply voltage; and Control means for adjusting the setting element.