DE102008054781A1 - Method for operating drive motor of engine system with speed limit, involves performing integration function for integrating speed difference between predetermined maximum speed and momentary speed of drive motor - Google Patents

Abstract

The method involves performing an integration function for integrating a speed difference between a predetermined maximum speed of a drive motor (2) and a momentary speed of the drive motor over the time for providing the integrator value. The integrator value of the integration function is limited on a limit value when the modulus of the integrator value exceeds the modulus of the limit value. Independent claims are also included for the following: (1) a device for operating a drive motor of an engine system with a speed limit; and (2) a computer program with a program code.

Description

Technical area

The The invention relates to drive motors, in particular internal combustion engines, whose maximum speed is limited by means of an end speed controller becomes.

State of the art

Motor control units for drive motors such as B. Internal combustion engines usually have final speed controller to limit the maximum speed. This allows functions, the z. B. ensure protection against overspeed, a top speed limit a driven with the drive motor vehicle and a gear z. B. protect in a switching process can be realized. Usually are used as final speed controllers PI or PID controllers (PI: proportional-integral controller, PID: proportional-integral-derivative-controller) used.

Of the Integrator share of final speed controllers is usually limited, even when reaching the setting limit (minimum or maximum Engine torque) to achieve an acceptable control behavior. To the limit the Integratoranteils of such Enddrehzahlreglers are different Known method. in principle can be limited to fixed or variable limit values. at however, there is a limit to fixed limit values the disadvantage that an increase in the integral share over the potential Setting range can not be safely prevented if the limit value over the current Setting limits is. If the limit value is below the setting limits on the other hand, the available one Adjustment area not used.

in the In the case of variable limit values, a method is also known, the limit depends from the currently available Make parking limits. However, this has the disadvantage of a limited control dynamics, in particular with a strong reduction of the manipulated variable or the actuating torque and a subsequent sudden increase the manipulated variable or the actuating torque to a strong delay of implementing the driver specification to lead can.

It It is an object of the present invention to provide a method of operation a final speed controller or a final speed controller to provide in which the Integratoranteil the Enddrehzahlreglers, in particular in control at the approach to the final speed, the total available control intervention allowed and still near the final speed, a fast response across from has a specification of a control value.

Disclosure of the invention

These The object is achieved by the method for operating a drive motor an engine system with a speed limitation according to claim 1 and by the device according to the independent claim solved.

Further advantageous embodiments of the invention are specified in the dependent claims.

• – Durchführen einer Integrationsfunktion zum Integrieren einer Drehzahlabweichung zwischen einer vorgegebenen maximalen Drehzahl des Antriebsmotors und einer momentanen Drehzahl des Antriebsmotors über der Zeit, um den Integratorwert bereitzustellen;
• – Begrenzen des Integratorwerts der Integrationsfunktion auf einen Begrenzungswert, wenn der Betrag des Integratorwerts den Betrag des Begrenzungswert überschreitet, wobei der Begrenzungswert von der variablen Vorgabegröße und von einer Integratorgrenzgröße abhängt, so dass der Begrenzungswert bei einem Unterschreiten des Betrags der Integratorgrenzgröße durch den Betrag der Vorgabegröße auf die Integratorgrenzgröße festgelegt wird und andernfalls auf die Vorgabegröße festgelegt wird.

According to a first aspect, a method for operating a drive motor of a motor system with a speed limitation is provided, wherein the drive motor is operated with a manipulated variable, wherein the manipulated variable is limited to a limiting value dependent on an integrator value, if a variable, in particular filtered default variable for driving the Drive motor exceeds the limit size. The method comprises the following steps:

• - performing an integration function for integrating a speed deviation between a predetermined maximum speed of the drive motor and a current speed of the drive motor over time to provide the integrator value;
• Limiting the integrator value of the integration function to a limiting value when the magnitude of the integrator value exceeds the magnitude of the limiting value, wherein the limiting value depends on the variable default quantity and on an integrator limit quantity, such that the limiting value falls below the magnitude of the default quantity if the magnitude of the integrator limit value is undershot is set to the integrator limit size and otherwise set to the default size.

A The idea of the above method is to calculate the integrator value of the Limit the integration function to a variable limit, wherein the limiting value at a high default size z. B. the default size or one of them dependent Value corresponds and at a low default size, i. H. a default size below the integrator limit, the Integrator value limited only to the Integratorgrenzgröße. This will do the full reset prevents the integrator when the default size for the drive motor as far as possible withdrawn becomes. This can be done after a withdrawal the default size and a subsequent one fast increase the default size guaranteed be that the speed limit, the maximum speed on the should be limited, if possible quickly reached again.

Farther it can be provided that a proportional function is performed, depending on the speed deviation to a proportional value available set, whereby the limiting size depends on the integrator value and depends on the proportional value, in particular depending on the sum provided becomes.

Especially can set the provided limit size to the default size or limit the limit value.

According to one embodiment the integrator limit size can be one correspond to current load torque of the drive motor or depend on this.

Farther can the manipulated variable for driving of the drive motor by a minimum selection of the limit size and the Default size determined become.

• – einen Integratorblock zum Durchführen einer Integrationsfunktion zum Integrieren einer Drehzahlabweichung zwischen einer vorgegebenen maximalen Drehzahl des Antriebsmotors und einer momentanen Drehzahl des Antriebsmotors über der Zeit, um einen Integratorwert bereitzustellen, wobei der Integratorblock ausgebildet ist, um den Integratorwert der Integrationsfunktion auf einen Begrenzungswert zu begrenzen, wenn der Betrag des Integratorwerts den Betrag des Begrenzungswerts überschreitet;
• – eine Einrichtung zum Bereitstellen einer Begrenzungsgröße abhängig von dem Integratorwert;
• – eine Einrichtung zum Bereitstellen einer variablen, insbesondere gefilterten Vorgabegröße zum Betreiben des Antriebsmotors;
• – eine Einrichtung zum Ansteuern des Antriebsmotors mit einer Stellgröße, die der auf die Begrenzungsgröße begrenzten Vorgabegröße entspricht, wenn die variable Vorgabegröße die Begrenzungsgröße überschreitet;
• – eine Einrichtung zum Vorgeben des Begrenzungswerts abhängig von der variablen Vorgabegröße und von einer Integratorgrenzgröße, so dass der Begrenzungswert bei einem Unterschreiten des Betrags der Integratorgrenzgröße durch den Betrag der Vorgabegröße auf die Integratorgrenzgröße festgelegt wird und andernfalls auf die Vorgabegröße festgelegt wird.

According to a further aspect, an apparatus for operating a drive motor of an engine system with a speed limitation is provided. The device comprises:

• An integrator block for performing an integration function for integrating a speed deviation between a predetermined maximum speed of the drive motor and a current speed of the drive motor over time to provide an integrator value, wherein the integrator block is configured to limit the integrator value of the integration function to a limiting value, when the amount of the integrator value exceeds the limit value;
• A means for providing a limiting quantity dependent on the integrator value;
• - means for providing a variable, in particular filtered default size for operating the drive motor;
• - A device for driving the drive motor with a manipulated variable, which corresponds to the limiting variable limited default size, when the variable default size exceeds the limiting amount;
• A means for specifying the clipping value in dependence on the variable preselected quantity and on an integrator clipping quantity such that the clipping value is set to the integrator clipping size if the magnitude of the integrator clipping size is less than the integrator clipping size and is otherwise set to the default size.

According to one Another aspect is a computer program is provided, the program code contains which, when executed on a data processing unit, performs the above method.

Brief description of the drawings

embodiments The invention will be explained in more detail with reference to the accompanying drawings. It demonstrate:

1 a schematic representation of an engine system with a final speed controller;

2 a functional representation of a final speed control as in the final speed controller, the in 1 is shown is shown;

3a and 3b the control behavior of the final speed controller of 2 with a short return of the given driver request torque at a conventional final speed controller and at a final speed controller, as in 2 is shown.

Description of embodiments

In 1 is schematically an engine system 1 with a drive motor 2 , in particular an internal combustion engine, and with an engine control unit 3 shown that the drive motor 2 controls. The engine control unit 3 controls the drive motor 2 with the aid of drive signals AS, which in the engine control unit by means of motor sizes MG, the drive of the motor 2 or from there arranged sensors the engine control unit 3 to be provided. As a further engine size is using a speed sensor 4 a speed n of the drive motor 2 recorded and the engine control unit 3 provided. The engine control unit 3 generates the drive signals AS depending on a speed n of the drive motor 2 specific operating point of the drive motor 2 ,

In the case described here corresponds to the drive motor 2 an internal combustion engine, wherein the drive signals AS correspond to signals that supply the air supply z. B. set using a throttle, determine the injection quantity and the injection timing of fuel, set the ignition point, etc. The control signals AS are still dependent on a the engine control unit 3 or in the engine control unit 3 predetermined adjusting torque M _Stell generated, so that the drive signals AS the internal combustion engine 2 be provided so that the internal combustion engine 2 the torque required by the setting torque M _Stell provides.

The actuating torque M _Stell can be used in internal combustion engines 2 without final speed control to correspond to a driver's desired torque or be dependent on this.

In the in 1 shown motor system is the control torque M _Stell of a final speed controller 5 depending on an indication of a driver command torque FWM and a maximum speed n _max , which is a target speed n _{target of} a final speed controller 5 corresponds to be provided. The final speed controller 5 is in principle designed so that it limits the indication of the driver's desired torque FWM in a suitable manner by its manipulated variable to avoid exceeding the predetermined maximum speed n _max by specifying an excessive driver's desired torque FWM.

In 2 is a functional representation of the final speed controller 5 shown in detail. The final speed controller 5 includes a regulatory block 20 with a proportional block 21 and an integrator block 22 to provide a regulator manipulated variable RSG. This is the proportional block 21 one from a difference unit 23 provided speed deviation .DELTA.n between the target speed n _target , ie the maximum speed n _max , to the internal combustion engine 2 is to be limited, and provided there by multiplication with a proportional factor K _P a corresponding proportional component PA for the controller manipulated variable RSG.

The speed deviation Δn continues to be the integrator block 22 provided that integrates the speed deviation Δn, z. B. by summing the speed deviation .DELTA.n in each calculation step, and an integral component IA provides. The integration in the integrator block 22 takes place with the aid of an integration factor K _I. The proportional factor K _P and the integration factor K _I are specified and applied according to the behavior of the overall system.

The integral component IA is determined by means of a first limiting unit 24 limited and a limited integral IAB is provided. The output of the first limiting block 24 is sent to a reset input of the integrator block 22 is returned, so that the value applied to the output of the first limiting block is written back into the integrator block. Thus, when the limit is reached, the integrator value of the integrator block can also be reached 22 to the limiting value of the first limiting block 24 be limited.

In a summator 26 the limited integral component IAB and the proportional component PA are added and the controller manipulated variable RSG is determined as the sum.

The controller manipulated variable RSG becomes a second limiting block 27 fed, which limits the controller manipulated variable RSG to a limiting torque M _limit .

It is a driver request torque FWM z. B. predetermined by a (not shown) accelerator pedal, the first in a third boundary block 28 to a range of values between 0 and a maximum engine torque M_MotMax, which is the maximum of the internal combustion engine 2 is to be provided drive torque is limited. The limited driver request torque is then in a low-pass filter 29 with a time constant T1 filtered to improve the robustness of the specification of the driver's desired torque (by a gradient limit). At the output of the low-pass filter 29 is a filtered driver request torque FWMF before.

The final speed controller 5 is designed so that at speeds that are relatively far away from the maximum speed, no intervention of the speed control takes place and at specifications of the driver's desired torque (filtered driver request torque FWMF), which exceeds the maximum speed n _max , ie the target speed n _target of Enddrehzahlreglers 5 a restriction would be made. This is done with the help of a minimum block 30 to which the filtered driver request torque FWMF and the limiting torque M _{Limit is} supplied and as actuating torque M _Stell the respectively smaller of the two input variables to the engine control unit 3 is issued.

Since the limiting torque M _limit at a large distance of the instantaneous speed n of the engine 2 From the target speed n _target becomes high, the driver's default of the filtered driver's desired torque is not from the final speed controller 5 affected. Only when the rotational speed n approaches the maximum rotational speed n _max does the limiting torque M _limit decrease, such that, in the case of a driver input torque that is too great, the limiting torque M _{limit of} the control block instead 20 to the engine control unit 3 is issued.

According to a prior art, the limitation in the first limiting block 24 and in the second boundary block 27 the integrator component IA or the controller manipulated variable RSG is limited to the filtered driver desired torque FWMF, so that after a reduction of the driver's desired torque to a small value, the integrator component IA is initially small and only gradually increases due to the rotational speed deviation Δn. For example, it may happen that at a speed n of the internal combustion engine 2 close to the maximum speed n _max and with significant reduction in the indication of the driver's desired torque (accelerator pedal position) to a value z. B. near zero or to zero the integrator in the integration block 22 is reset to this reduced value and at a subsequent increase in the driver's desired torque initially the integration share IA again has to be built. The result of this is that the filtered driver desired torque FWMF is limited to a limiting torque M _Limit , which only permits reaching the maximum rotational speed n _max after the integration component IA has been established.

This behavior is in the diagram 3a shown. One recognizes a short-term collapse of the predetermined driver request torque FWM and, after the driver command torque FWM has risen again, a slow increase of the limiting torque M _Limit , due to the reset integrator component IA in the integration block 22 ,

It is now provided, the upper limit value of the first limiting block 24 to set the filtered driver request torque FWMF, if this is greater than a provided Integratorgrenzmoment IGM and to adjust the Integratorgrenzmoment IGM, when the filtered driver desired torque FWMF is smaller than the Integratorgrenzmoment IGM. The Integratorgrenzmoment IGM may be fixed or a current load torque M _{load of} the engine 2 correspond to the current operating state or be dependent on this. There are different methods to determine the load moment M _load . A common method is to determine an acceleration of the vehicle via a change in speed and to determine the loss moments, which substantially correspond to the load torque M _load, via the difference to the drive torque provided by the motor. The Integratorgrenzmoment IGM may generally be a fixed or variable adjustment limit, which must not be greater than the filtered driver's desired torque FWMF with active final speed control.

The upper limit of the second bounding block 27 , which limits the control manipulated variable RSG, corresponds in the illustrated Enddrehzahlregelgung the 2 the filtered driver request torque FWMF. In an alternative embodiment, the upper bounding value of the second bounding block 27 also be limited to the Integratorgrenzmoment IGM. A limit value that is different from the integrator limit torque IGM is also possible as long as it is not greater than the filtered driver request torque FWMF.

In 3b the timing diagram is shown, which represents the course of the engine speed n near the maximum speed n _max in the event of a brief drop in the specification of the driver command torque FWM. It can be seen that, after the reappearance of the predetermined driver desired torque FWM, the limiting torque M _{Limit increases} rapidly again, since the integrator component IA was not completely reset to 0 when the driver request torque FWM was withdrawn. The integrator component IA was reset only to the Integratorgrenzmoment IGM, so that the limiting torque M _limit the filtered driver desired torque FWMF to higher values than in the comparative example of 3a limited and thus the maximum speed n _max according to the final speed control can be achieved faster again. In the course of the engine speed n, it can be seen that immediately after the driver's desired torque FWM has risen again, the engine speed n increases, whereas in the example of a final speed control according to the prior art (see FIG 3a ) only with a time delay is the case.

The Limitation of the integrator component IA to the integrator limit torque IGM can be expanded accordingly when integrator portions IA of higher order are implemented become. Also, a differential component in a PID controller as End speed controller are provided accordingly. The differential share can optionally be an equivalent Get limit, either a limiting value of the Integratorgrenzmomentes IGM is or depends on this.

In contrast to the above-mentioned engine system 1 it is also possible, the final speed controller 5 in the engine control unit 3 to integrate.

Claims (7)

Method for operating a drive motor ( 2 ) of an engine system ( 1 ) with a speed limitation, wherein the drive motor ( 2 ) is operated with a manipulated variable (M _stell ), wherein the manipulated variable (M _stell ) is limited to one of an integrator value (IA) dependent limiting variable (M _Limit ), if a variable, in particular filtered default variable (FWM) for driving the drive motor ( 2 ) exceeds the limiting quantity (M _Limit ), comprising the following steps: - performing an integration function for integrating a speed deviation (Δn) between a predetermined maximum rotational speed (n _max ) of the drive motor ( 2 ) and a current speed of the drive motor ( 2 ) over time to provide the integrator value (IA); Limiting the integrator value (IA) of the integration function to a limiting value if the magnitude of the integrator value (IA) exceeds the magnitude of the limiting value, wherein the limiting value depends on the variable bias variable (FWM) and on an integrator limit variable (IGM), such that the limiting value is set below the Integrator Limit Size (IGM) by the magnitude of the Integrator Limit Size (IGM) by the amount of the default size (FWM) and is otherwise set to the default size. The method of claim 1, wherein a proportional function is performed to provide a proportional value depending on the speed deviation (Δn), the limiting quantity (M _Limit ) depending on the integrator value (IA) and depending on the proportional value (PA), in particular depending on their sum. A method according to claim 2, wherein the provided limit quantity (M _Limit ) is limited to one of the following quantities: the particular filtered default quantity; and - the limit value. Method according to one of claims 1 to 3, wherein the Integratorgrenzgröße (IGM) an instantaneous load torque of the drive motor ( 2 ) or depends on it. Method according to one of claims 1 to 4, wherein the manipulated variable for driving the drive motor ( 2 ) is determined by a minimum selection of the limit size (M _limit ) and the default size (FWM). Device for operating a drive motor ( 2 ) of an engine system ( 1 ) with a speed limitation, comprising: - an integrator block ( 22 ) for performing an integration function for integrating a rotational speed deviation (Δn) between a predetermined maximum rotational speed (n _max ) of the drive motor ( 2 ) and a current speed of the drive motor ( 2 ) over time to provide an integrator value (IA), the integrator block ( 22 ) is configured to limit the integrator value (IA) of the integration function to a limiting value when the magnitude of the integrator value (IA) exceeds the magnitude of the limiting value; - means for providing a limiting amount (M _limit ) depending on the integrator value (IA); A device for providing a variable, in particular filtered, default variable (FWM) for operating the drive motor ( 2 ); - a device for driving the drive motor ( 2 ) (With a manipulated variable M _alternate) which corresponds to (the limiting size M _Limit) limited predefined value (FWM), exceeds when the variable input quantity (FWM), the limiting size (M _Limit), - means for setting the limiting value depends on the variable default size (FWM) and Integrator Limit Size (IGM), such that when the Integrator Limit Size (IGM) is undershot, the Limit Value is set to Integrator Limit Size (IGM) by the amount of Default Size (FWM) and is otherwise set to the default size , Computer program containing a program code which, when running on a computing device, a method according to a the claims 1 to 5 executes.