DE102011086729A1 - Method for monitoring motor drive system for e.g. diesel engine mounted in motor car, involves detecting error in overrun mode, if overrun maximum tolerable control variable is smaller than read-back control variable of power amplifier - Google Patents

Abstract

The method involves comparing overrun maximum tolerable control variable with read back control variable of a power amplifier (4). The read back control variable is set corresponding to predetermined total torque for operating the drive motor (2). An error is detected in the overrun mode, if the overrun maximum tolerable control variable is smaller than the read-back control variable of power amplifier. Independent claims are included for the following: (1) computing device for monitoring drive system; (2) drive system; (3) computer program for monitoring drive system; and (4) computer program product for monitoring drive system for drive motor.

Description

Technical area

The present invention relates to drive systems having drive motors, in particular to methods of monitoring an engine control device for a drive system having a drive motor.

State of the art

Engine control units for use in drive systems for motor vehicles usually have functions with which incorrect calculations of internal variables and control variables can be detected. For example, multi-level concepts can be provided, in a first level, the control level, system states are determined and a default size, for example, a driver's desired torque as an indication of a position of an accelerator pedal, evaluated and from a target torque is determined. The setpoint torque is converted into one or more corresponding control variables. In internal combustion engines, these control variables may include the amount of fuel to be injected, the injection angle, the air supply and / or the like. In electromotive drive systems, the drive quantity may for example correspond to a motor current.

In a second level, which is referred to as a monitoring level, the target torque is determined redundantly according to the functions of the control plane. For this purpose, a total torque corresponding to an allowable torque is calculated from all increasing torque requesters. However, instead of calculating the drive quantity directly from the total torque, the drive quantity provided by the control level of an output stage for driving corresponding actuators or the like in the drive motor is read back from the output stage into the engine control unit by a corresponding function in the monitoring level is determined by an inverse to the control plane calculation thereof provided by the drive motor actual torque.

The monitoring level now provides, on the one hand, to limit the setpoint torque determined in the control plane with the setpoint torque determined in the monitoring plane and, on the other hand, to check the conversion of the setpoint torque determined in the control plane into the corresponding control variable by reading back the control variable from the output stage and from this an actual torque is calculated. By comparing the recalculated actual torque with the determined in the control plane target torque then an error in the implementation of the setpoint torque in the control variable in the control plane can be determined.

In drive motors, the height of a given state variable can have a very large influence on the actual torque. For cost reasons, however, often only one sensor is provided for detecting this state variable, so that the value of the state variable can not be made plausible by a redundant sensor. If, therefore, the state variable is erroneously determined on the basis of a faulty sensor, this can lead to large deviations of the control variable from the correct control variable, in particular with small desired torques, which can occur during overrun operation. Therefore, the so-called thrust monitoring is provided in parallel with the continuous torque monitoring described above.

Disclosure of the invention

According to the invention a method for monitoring an engine control unit in overrun operation according to claim 1 and the device, the motor system and the computer program product according to the independent claims are provided.

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

• – Vergleichen einer im Schubbetrieb maximal tolerierbaren Ansteuergröße mit einer aus einer Endstufe rückgelesenen Ansteuergröße, wobei die rückgelesene Ansteuergröße einer Ansteuergröße entspricht, die dem Antriebsmotor entsprechend einem angeforderten vorgegebenen Gesamtmoment zum Betreiben des Antriebsmotors bereitgestellt wird;
• – Erkennen eines Fehlers im Schubbetrieb, wenn festgestellt wird, dass die im Schubbetrieb maximal tolerierbare Ansteuergröße kleiner ist als die aus der Endstufe rückgelesene Ansteuergröße.

According to a first aspect, a method for monitoring a drive system for a drive motor of a motor vehicle is provided. The method comprises the following steps:

• - Comparing a maximum controllable in overrun control variable with a read from an amplifier control variable, the feedback control variable corresponds to a drive, which is provided to the drive motor according to a requested predetermined total torque for operating the drive motor;
• - Detecting a fault in overrun mode, if it is determined that the maximum controllable control variable in overrun mode is smaller than the control variable read back from the final stage.

The above method makes it possible to dispense with the previously provided redundantly calculated thrust monitoring and instead only perform a threshold comparison of a feedback from a power amplifier control variable with a tolerated in overrun maximum control variable when the total torque, z. For example, the sum of torque requests is less than a given coasting threshold.

The previously used method for monitoring in overrun mode had to be deactivated up to the maximum threshold speed of the idle controller, even if it was not engaged was. With the above method, however, z. B. can be achieved that already below the maximum target speed of the idle controller monitoring can be performed.

Furthermore, in the presence of an anti-bounce damper with a fixed maximum runtime in the previous push monitoring, an error reaction can only be triggered after a debounce time. This leads to a delayed error reaction. This delayed error reaction also takes place when the error case is generated by an actual error source. This debounce time need not be provided in the above method because at the time the above threshold comparison is made, the total torque is less than the predetermined coasting threshold.

Furthermore, the comparison of the maximum controllable in overrun control variable with the feedback from a power amplifier control variable can only be performed when the total torque falls below a predetermined overrun threshold.

In particular, the comparison of the maximum controllable in overrun control variable with the feedback from an amplifier control variable can only be performed when the total torque is zero.

According to one embodiment, the drive quantity of the output stage can be provided in order to drive a controller of the drive motor.

The predetermined total torque can be compared with an actual torque to detect a fault in a deviation between the total torque and the actual torque, in particular exceeding the total torque by the actual torque, the actual torque is determined by a retroactive calculation of the provided to the output stage control variable.

• – eine im Schubbetrieb maximal tolerierbare Ansteuergröße mit einer aus einer Endstufe rückgelesenen Ansteuergröße zu vergleichen, wobei die rückgelesene Ansteuergröße einer Ansteuergröße entspricht, die dem Antriebsmotor entsprechend einem angeforderten vorgegebenen Gesamtmoment zum Betreiben des Antriebsmotors bereitgestellt wird; und
• – einen Fehler im Schubbetrieb zu erkennen, wenn festgestellt wird, dass die im Schubbetrieb maximal tolerierbare Ansteuergröße kleiner ist als die aus der Endstufe rückgelesene Ansteuergröße.

According to a further aspect, an apparatus for monitoring a drive system for a drive motor of a motor vehicle is provided, wherein the device is designed to:

• - To compare a maximum tolerable in overrun control variable with a read from an amplifier control variable, the feedback control variable corresponds to a control variable, which is provided to the drive motor according to a requested predetermined total torque for operating the drive motor; and
• - Recognize a fault in overrun mode, if it is determined that the maximum tolerable in overrun control variable is smaller than the read from the power amplifier control variable.

• – einen Antriebsmotor;
• – eine Endstufe zum Betrieben des Antriebsmotors gemäß einer oder mehrerer Ansteuergrößen;
• – die obige Vorrichtung.

In another aspect, a drive system is provided. The drive system includes:

• A drive motor;
• - An output stage for operating the drive motor according to one or more control variables;
• - The above device.

According to another aspect, there is provided a computer program product including program code which, when executed on a data processing device, performs the above method.

Brief description of the drawings

Preferred embodiments of the present invention will be explained in more detail with reference to the accompanying drawings. Show it:

1 a schematic representation of a drive system with a control unit and a drive motor for a motor vehicle; and

2 a block diagram illustrating the monitoring of functions implemented in the controller.

Description of embodiments

1 schematically shows a drive system 1 For example, for use in a motor vehicle. The drive system 1 includes a drive motor 2 in accordance with one of an engine control unit 3 provided control variable A is operated. The drive quantity A becomes an output stage 4 supplied, which converts them into corresponding manipulated variables S for setting of actuators or the like.

The drive motor 2 may be an internal combustion engine, such as a diesel engine or gasoline engine. The drive motor 2 however, it may also include an electric motor.

In the case of a diesel engine, which is fuel-driven, the control variable A may correspond to an indication of an injection quantity, that of the final stage 4 in corresponding opening times for a fuel injection valve (not shown) is implemented. That is, the output stage electrically controls the injectors according to an opening and closing time to inject a predetermined amount of fuel into combustion chambers of the cylinders through the opening periods of the injectors.

In the case of a gasoline engine, the control variables generally relate to a throttle position and ignition times of an ignition device, whose activation likewise takes place with the aid of a suitable output stage 4 is made. The fuel injection follows the amount of air admitted into the combustion chambers of the cylinders. The control variable for the throttle position corresponds to an indication of the position of the throttle valve in the form of an electrical variable and the control variable for the ignition timing corresponds to trigger pulses to trigger the ignition.

In the case of an electric motor as a drive motor 2 The drive quantity A corresponds to an indication of a motor current that is generated by the output stage 4 is set. The final stage 4 then continues to take the appropriate control of the electric motor, for example, in the case of a synchronous motor, the electronic commutation of the phases of the electric motor in known manner from the prior art.

The engine control unit 3 generates the drive quantity A based on an external default quantity V, which can correspond to a driver's desired torque, and dependent on state variables Z, which are generated by means of sensors in the drive motor 2 be calculated or calculated from them according to a suitable model.

• – einen Geschwindigkeitsregler 22, beispielsweise in Form einer Cruise-Control-Funktion, die ein mit dem Antriebsmotor betriebenes Fahrzeug ohne Fahrpedalbetätigung mit konstanter Geschwindigkeit fährt, wobei der Geschwindigkeitsregler 22 als Stellgröße der Regelung ein angefordertes Moment an den Gesamtmoment-Berechnungsblock 21 bereitstellt;
• – ein Fahrpedal 23, das entsprechend einer Betätigung eine Angabe über ein Fahrerwunschmoment als angefordertes Moment an den Gesamtmoment-Berechnungsblock 21 bereitstellt,
• – einen Leerlaufregler 24, der in einem bestimmten Drehzahlbereich und bei nicht betätigtem Fahrpedal 23 eine Drehzahlregelung aktiviert und als Stellgröße der Regelung ein angefordertes Moment an den Gesamtmoment-Berechnungsblock 21 bereitstellt; sowie
• – einen Antiruckeldämpfer 25, der zum Erhöhen des Fahrkomforts als Stellgröße einer entsprechenden Antiruckeldämpferregelung ein angefordertes Moment an den Gesamtmoment-Berechnungsblock 21 bereitstellt, um Schwingungen in der Längsrichtung des Fahrzeugs zu reduzieren.

In 2 is a block diagram in the engine control unit 3 realized function to monitor the engine system 1 shown. The function includes a total torque calculation block 21 , that of several moment requesters 22 to 25 the respective torque requests are provided. For example, the torque requesters 22 to 25 one or more of the following facilities include:

• - a speed controller 22 in the form of a cruise control function, for example, which drives a vehicle operated by the drive engine without accelerator operation at a constant speed, the speed controller 22 as control value of the control a requested torque to the total torque calculation block 21 providing;
• - an accelerator pedal 23 that according to an operation, an indication of a driver request torque as requested torque to the total torque calculation block 21 provides,
• - an idle controller 24 in a certain speed range and when the accelerator pedal is not actuated 23 a speed control activated and as a control variable of a requested torque to the total torque calculation block 21 providing; such as
• - an anti-bouncer 25 to increase the ride comfort as a control variable of a corresponding anti-bucking control a requested torque to the total torque calculation block 21 provides to reduce vibrations in the longitudinal direction of the vehicle.

There may be more torque requesters 26 be provided, which is a requested moment to the total torque calculation block 21 provide.

In the total moment calculation block 21 the requested moments are added to a total moment M _G.

That in the total moment calculation block 21 calculated total moment M _G becomes a control block 33 fed, in which the total moment M _G as A drive amount of the final stage 4 supplied and converted there into one or more corresponding manipulated variables S. The final stage 4 is with a recalculation block 30 connected to that of the power amplifier 4 provided control variable A or the provided to the drive motor manipulated variable S and therefrom one of the drive motor 2 provided actual moment M _is calculated.

In a comparison block 27 a threshold comparison is made. That of the total moment calculation block 21 provided total torque is compared with a predetermined thrust torque threshold SMS and it is detected a coasting operation when the calculated total torque is smaller than the thrust torque threshold SMS. Depending on the result of the comparison in the comparison block 27 becomes a maximum drive amount A _max in a maximum drive amount block 28 provided.

For detecting the overrun operation can in the comparison block 27 also be determined if that in the total momentum calculation block 21 calculated total torque corresponds to a moment of zero to reliably detect a coasting operation.

Is through the comparison block 27 If it is detected that overrun is present (total torque has fallen below the torque threshold value SMS), then a drive _variable A _{max_Schub} , which is the maximum tolerated in overrun mode, becomes the maximum drive _block 28

If there is no overrun, then the maximum control block is used 28 as the maximum control variable A _max, a maximum control variable A _{Ansteuer_max} provided which essentially corresponds to a maximum possible control variable.

In another comparison block 29 becomes that of the maximum drive size block 28 provided maximum control variable A _max, namely the maximum possible control variable A _{Ansteuer_max} or the maximum tolerated during coasting control variable A _{max_Schub} with from the final stage 4 feedback control _variable A _back compared. The power amp 4 from the drive size block 33 supplied control variable A is in the final stage 4 cached and can accordingly in the engine control unit 3 be read back.

The feedback control _variable A _back should, in the error-free case, be _equal to or smaller than the maximum control variable A _max . Will in the further comparison block 29 determined that the rückzurchnete control value A _{back is} greater than the maximum control amount A _max , so an error is detected. Was in the comparison block 27 However, a coasting operation detected and is characterized as the maximum control _variable A _max in the overrun maximum control _variable A _{max_Schub} to the other comparison _block 29 provided an error in overrun is detected. Depending on the amount of the predetermined maximum possible control variable A _{Ansteuer_max} for the non-coasting operation can in the further comparison block 29 no error can be detected, since the recalculated control value A _back can not exceed the maximum control value A _max .

Will in the further comparison block 29 an error is detected in the overrun mode, then an error reaction in an error reaction block 32 called the emergency operation or a complete shutdown of the internal combustion engine 2 may include.

Another monitoring function is the torque comparison block 31 realized that from the total moment calculation block 21 Calculated total torque with that from the retroactive accounting block 30 recalculated actual torque M _is compared and in exceeding the in the total torque calculation block 21 calculated total torque M _G by the _back- calculated actual torque M _{Ist_rück} an error _reaction in the error _{reaction block} 32 triggers.

The above monitoring method has the advantage that it can also be activated when the rotational speed of the drive motor compared to previously used thrust monitoring 2 still within a range up to the maximum setpoint speed of the idle controller 24 located. With the above monitoring procedure can be ensured that, once the idle controller 24 is no longer engaged, can already be tested under the maximum target speed on the presence of a pushing operation.

By combining the continuous torque monitoring in the torque comparison block 31 and the thrust monitoring by the further comparison block 29 the robustness of the monitoring is increased. Different calculation rasters between continuous monitoring, thrust monitoring and torque calculation are reduced to a minimum.

Claims (9)

Method for monitoring a drive system ( 1 ) for a drive motor ( 2 ) of a motor vehicle with the following steps: - comparison of a maximum controllable drive _variable (A _{max_Schub} ) in overrun mode with one of an output stage ( 4 ) Read back control variable (A _reset), the read-back control variable (A _re) corresponding to a control variable, which (the drive motor 2 ) corresponding to a requested predetermined total moment (M _G ) for operating the drive motor ( 2 ) provided; - Detecting a fault in overrun mode, if it is determined that the maximum controllable control _variable (A _{max_Schub} ) in overrun mode is less than that from the output stage ( 4 ) (A _return ). Method according to Claim 1, wherein the comparison of the maximum controllable drive _variable (A _{max_shift} ) in overrun mode with that of an output stage ( 4 ) Read back control variable (A _reset) is performed only if the total moment (M _G) falls below a predetermined threshold thrust operation. Method according to Claim 2, wherein the comparison of the maximum controllable drive _variable (A _{max_shift} ) in overrun mode with that of an output stage ( 4 ) Read back control variable (A _reset) is performed only if the total moment is zero. Method according to one of claims 1 to 3, wherein the drive quantity of the output stage ( 4 ) is provided to an actuator of the drive motor ( 2 ) head for. Method according to one of claims 1 to 4, wherein the predetermined total torque is compared with an actual torque to a deviation between the total torque (M _G ) and the actual torque (M _{ist_rück} ), in particular an exceeding of the total torque (M _G ) by the actual torque (M _{ist_rück} ), to detect an error, wherein the actual torque (M _{ist_rück} ) by a recalculation of the power amplifier ( 4 ) provided driving quantity (A) is determined. Device, in particular a computing unit, for monitoring a drive system ( 1 ) for a drive motor ( 2 ) of a motor vehicle, the device being designed to: A maximum controllable drive _variable (A _{max_Schub} ) in overrun mode with one of a final stage ( 4 ), wherein the read-back control variable (A _back ) corresponds to a drive _variable which is connected to the drive motor ( 2 ) corresponding to a requested predetermined total moment (M _G ) for operating the drive motor ( 2 ) provided; and - to detect an error in overrun mode when it is determined that the maximum controllable control _variable (A _{max_Schub} ) in overrun mode is less than that from the output stage ( 4 ) recaptured tax. Drive system ( 1 ), comprising: - a drive motor ( 2 ); - an amplifier ( 4 ) for operating the drive motor ( 2 ) according to one or more control variables; - The device according to claim 6. Computer program with program code means for performing all the steps of the method according to one of claims 1 to 5, when the computer program is executed on a computer or a corresponding computing unit, in particular in a device according to claim 6. A computer program product containing program code stored on a computer-readable medium and which, when executed on a data processing device, performs the method of any one of claims 1 to 5.

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