Control system for controlling the rotational speed of a drive motor

Abstract

The rotational speed of at least one drive motor of a motor vehicle is controlled by an electronic control system, wherein the differential rotational speed between a specified target rotational speed and an actual rotational speed of the drive motor is considered as a system value for determining the control parameters that influence the rotational speed control process. As an additional system value, the magnitude and direction of the differential rotational speed gradient are considered when determining the control parameters.

Claims

1. An electronic control system for controlling a rotational speed of at least one drive motor of a motor vehicle, comprising: a vehicle-mounted engine controller supplying a predefined target rotational speed and a measured actual rotational speed to a subtractor which forms therefrom a rotational speed difference; a gradient forming device determining a rotational speed difference gradient from the predefined target rotational speed and the measured actual rotational speed, the gradient having a magnitude and a direction of the rotational speed difference; and a processor receiving from the subtractor the rotational speed difference and from the gradient forming device the rotational speed difference gradient as system values and determining therefrom control parameters influencing control of the rotational speed, wherein the engine controller controls the rotational speed of the at least one drive motor based on the control parameters.

2. The control system of claim 1, further comprising a memory storing the control parameters associated with system values or with combinations of the system values.

3. The control system of claim 2, wherein the processor reads out from a parameter map stored in the memory control parameters associated with the system values or the combinations of system values and transmits the control parameters to the engine controller.

4. The control system of claim 1, wherein the motor vehicle is a hybrid vehicle and comprises an internal combustion engine and of an electric motor as drive motors, and wherein engine-specific control parameters associated with each drive motor are used for controlling the rotational speed of the internal combustion engine and of the electric motor.

5. A method for controlling the rotational speed of at least one drive motor of a motor vehicle, comprising: computing with a vehicle-mounted controller a rotational speed difference between a predefined target rotational speed and a measured actual rotational speed of the at least one drive motor as system values; computing with the controller a rotational speed difference gradient from the predefined target rotational speed and the measured actual rotational speed, the gradient having a magnitude and a direction of the rotational speed difference, the gradient being an additional system value; providing the rotational speed difference and the gradient to a processor which determines therefrom control parameters that influence control of the rotational speed; and controlling the rotational speed based on the control parameters.

6. The method of claim 5, further comprising storing in a memory at least one of the system values, the additional system value, the control parameters associated with the system values, or any combination thereof.

7. The method of claim 5, further comprising transmitting the system values and the additional system value to a processor which reads, from a parameter map stored in the memory, control parameters associated with the system values and the additional system values or with combinations of the system values and the additional system values, and transmitting the control parameters to an engine controller of the at least one drive motor.

8. The method of claim 5, and further comprising, using engine-specific control parameters for controlling the rotational speed of each of an internal combustion engine and of an electric motor arranged in a hybrid vehicle as drive motors.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The invention will now be described in more detail with reference to an exemplary embodiment illustrated in the drawing which shows in:

(2) FIG. 1 a block diagram of an electronic control system according to the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(3) FIG. 1 shows a block diagram of an electronic control system according to the invention, which includes an engine controller CPU controlling a drive motor M. The engine controller CPU supplies the actual rotational speed n.sub.ist and the target rotational speed n.sub.soll of the drive motor M to a subtracter 1 and to a device 2, which forms a rotational speed difference gradient Gradn.sub.diff from the difference between n.sub.soll and n.sub.ist and transmits this rotational speed difference gradient Gradn.sub.diff to a processor P. The subtracter 1 transmits to the processor P the rotational speed difference n.sub.diff.

(4) The rotational speed difference n.sub.diff and the rotational speed difference gradient Gradn.sub.diff supplied to the processor P can generally be referred to as system values, which the processor P uses to determine control parameters. In the illustrated exemplary embodiment, the processor P is connected to a parameter map memory PKF in which control parameters associated with all possible combinations of system values are stored in the form of one or more characteristic curve fields.

(5) In the illustrated exemplary embodiment, the target rotational speed n.sub.soll and the actual rotational speed n.sub.ist are transmitted to the processor P as additional system values, so that a parameter mapping can be performed even by taking into account these additional system values. In principle, other system values may also be taken into account to determine the control parameters.

(6) The control parameters determined by the processor P are transmitted to the engine controller CPU so as to enable the engine controller CPU to control the rotational speed of the motor M by using a control program and taking into account these parameters.

(7) The embodiment illustrated in FIG. 1 represents only one possible exemplary embodiment. The control parameters used to control the rotational speed may also be determined in part or completely by a mathematical calculation method which, however, would require a high computing power. Furthermore, the mathematical method would need to be adapted for each engine types, which would be relatively complex. In order to make adjustments to different engine types and different application areas as easily as possible, system-specific control parameters are preferably stored in the parameter map memory PKF. An adaptation to different engine types or application areas is possible by simply exchanging the control parameters in the parameter-map memory.