WO2007025844A1

WO2007025844A1 - Method for increasing the availability of motor vehicles engines

Info

Publication number: WO2007025844A1
Application number: PCT/EP2006/065091
Authority: WO
Inventors: Oliver Kaefer; Holger Niemann; Per Hagman; Andreas Seel
Original assignee: Robert Bosch Gmbh
Priority date: 2005-08-29
Filing date: 2006-08-04
Publication date: 2007-03-08
Also published as: DE102005040780B4; DE102005040780A1

Abstract

The invention relates to a method for operating a motor vehicle drive, in particular a hybrid drive, wherein at least one desired torque (120, 140, 142) is calculated in a first step. The at least one desire torque (120, 140, 142) is converted into at least one control variable (130, 158, 162) for the motor vehicle drive in a second step. Also, at least one actual torque (132, 168, 170) of the motor vehicle (actual torque) is determined, and a comparison is carried out between the at least one actual torque (132; 168, 170) and the at least one desired torque (120; 140, 142). A difference between the at least one actual torque (132, 168, 170) and the at least one desired torque (120, 140, 142), which exceeds a predetermined threshold value, is determined, the error control drive (138) is switched on. The at least one control variable (130; 158, 162) is replaced by at least one replacement control variable.

Description

Method for increasing the availability of motor vehicle engines

The invention relates to a method for controlling a motor vehicle drive, in particular a hybrid drive. Furthermore, the invention relates to a motor control device for implementing the method according to the invention in one of its embodiments.

State of the art

In the prior art (eg from DE 103 20 017 A1), control devices for a drive unit are known, which control or regulate the drive unit, in particular with regard to an output drive torque, the drive unit being an internal combustion engine of a motor vehicle. In this case, the motor vehicle usually comprises a driver request recording device which can be actuated by the driver of the motor vehicle, in particular a foot-operated accelerator pedal which is provided to emit an output signal representing a current actuation state of the driver request recording device. A control unit receives the output signal from the driver request recording device and assigns to the received output signal at least one desired output variable, in particular a desired drive torque of the drive unit. The drive unit is controlled by the control unit in such a way that an actual output quantity output by the drive unit approaches the desired output variable. Such control devices are known in various interpretations for conventional motor vehicle engines, in particular gasoline engines and diesel engines, such. For example, the Bosch Engine Control System with Electronic Accelerator (EGAS).

Furthermore, it is known in the prior art to perform a continuous torque monitoring to detect malfunctions in the control unit. This serves in particular for the protection of passengers in the motor vehicle and external road users. It is to prevent unwanted acceleration of the vehicle. The core of the continuous torque monitoring is the comparison of an actual torque provided by the motor with a permissible torque. Normally, the actual torque is smaller than the permissible torque. If the actual torque exceeds the allowable torque, there is a fault in the engine control unit and an error response leading to a safe vehicle condition is initiated. The monitoring of the engine control units usually takes place after a 3-level monitoring concept. The engine control itself, in particular the specification of the desired torque, takes place in the first plane designated as the functional plane. The second level (monitoring level) is executed as the continuous torque monitoring. In this level, among other things, a permissible torque is determined as a function of vehicle and engine functions and compared with an actual engine torque. Level 2 is extensively secured (double storage of all variables, cyclic RAM and ROM check, program sequence check, command test). Level 3 is used for computer backup.

DE 102 10 684 A1 relates to a method for monitoring a moment of a drive unit of a vehicle. The torque to be monitored is compared with a permissible torque, the permissible torque is readjusted to the torque to be monitored and an error is detected if the torque to be monitored deviates more than a first predetermined value from the permissible torque, the error only in that case is detected, in which a position of a control element, in particular an accelerator pedal position, at least for a first predetermined time is within a predetermined tolerance range.

DE 197 39 565 A1 relates to a method for controlling the torque of a drive unit of a motor vehicle, in which the torque of the drive unit is set at least in accordance with the driver's request, wherein the actual torque of the drive unit is determined and at least on the basis of the driver's request maximum permissible torque is determined. There is a torque reduction and / or limitation when the maximum permissible torque is exceeded by the actual torque. In this case, at least one operating state is determined, in which the torque of the drive unit is increased by additional load. During this at least one operating state, the maximum permissible torque is increased. In particular, the permissible torque is thereby increased during operation with a cold drive unit and / or load-consuming consumers during operation.

DE 197 48 355 A1 has a method for controlling the drive unit of a vehicle to the object, wherein the torque of the drive unit depends on a derived from the position of a driver operable control element driver input torque and depending on at least one target torque, which is predetermined by at least one external function that influences the torque instead of or in addition to the driver's specification. A maximum permissible torque is specified and when this maximum permissible value is exceeded, a reduction of the torque is made by the corresponding actual value. The maximum permissible torque is at least formed depending on the position of the operating element and the maximum permissible torque is formed depending on the target torque of the at least one external function, if this target torque is greater than the permissible torque dependent on the control element position. The external function can, for. B. increase the torque over the driver's request, such as a motor drag torque control or a vehicle speed control.

The described, from the prior art known methods of torque monitoring are not readily transferable to hybrid vehicles. In hybrid vehicles, at least one additional torque source (motor) is used in addition to an internal combustion engine. In most cases this is an electric drive.

In the prior art, there is only one engine in a vehicle that includes an engine controller that receives a variety of torque request information from an external source (eg, by a brake controller or an ACC) over a signal bus. The engine control unit checks the integrity of the received external component request signals and plausibility of the torque request information based on available vehicle status signals. The engine control unit then uses the external information and other signals (including the driver's request, which is set, for example, via the accelerator pedal) to determine the torque (target torque) to be requested by the engine and directly controls the engine without having to use another control unit to communicate.

In the engine control, the torque required by the driver, which is set, for example, by operating an accelerator pedal, must be divided among the existing torque source (at least two motors) for several existing engines. This happens in dependence of numerous environment variables, u. a. with the aim of setting the most fuel-efficient operating point for all torque sources. Such a method is described for example in DE 102 02 531 Al. The divided moments must then be transmitted from the engine control unit, where appropriate, to further, the individual motors associated with control units.

In order to increase the availability of an engine, in the prior art, in addition to the continuous torque monitoring in level 2, the requested torque is checked for plausibility prior to driving the engine in level 1. If the calculated desired torque to be requested is marked too high, the torque is limited to a plausible torque. By means of this torque limitation, the above-described error reaction triggered in level 2 of the monitoring concept can be avoided, even if the torque to be requested is too high. Such an error reaction should be avoided as far as possible, since it can be very uncomfortable for an occupant of the vehicle. Such a torque limit is barely noticeable to the driver of the vehicle, so that the loss of comfort is minimal. A shortcoming of this method from the prior art, however, is that although errors in the calculation of the setpoint torque are intercepted, but that errors in the implementation of the limited setpoint torques in corresponding actual moments are no longer detected and prevented. Such a faulty conversion of the setpoint torque into an actual moment again leads to an uncomfortable error reaction that should be avoided.

Advantages of the invention

Therefore, a method for controlling a motor vehicle drive is proposed which avoids the disadvantages of the methods known from the prior art. The method is particularly suitable for reliably intercepting errors in the implementation of a desired torque in control variables, whereby the availability of the motor vehicle is increased. The method according to the invention is also suitable for the operation of a hybrid vehicle, it being possible to determine the defective modifier already in level 1 and to appropriately choose an operating strategy before the level 2 error reaction mode is triggered.

A basic idea of the invention is the testing of the conversion of a setpoint torque into control variables and an actual moment in the first level designated as the function level. Thus, errors in the calculation of the control variables can be intercepted.

As with methods known from the prior art, in the method according to the invention for operating a motor vehicle drive in a first step, at least one desired torque is calculated. In a second step, the at least one desired torque is converted into at least one drive variable for the motor vehicle drive.

A core element of the present invention is to determine at least one actual torque, ie an actual moment of the motor vehicle drive in the first, the functional level and then to perform a comparison between the at least one actual torque torque and the at least one desired torque. Exceeds the deviation between the at least one actual torque and the at least one desired torque a predetermined threshold, it is switched to a fault drive operation, in which the at least one control variable is replaced by at least one Ersatzansteuergröße. The predetermined threshold can be chosen arbitrarily and also assume the value zero. Thus, even with very small deviations, the at least one control variable can be replaced by the at least one substitute control variable. A replacement Control can z. B. consist in that changes the operating strategy of the hybrid vehicle from hybrid to pure combustion engine drive.

The at least one actual moment can be obtained from different sources. Thus, in internal combustion engines (eg in diesel engines with diesel injection systems) a measurement of internal cylinder pressures is recommended. These internal cylinder pressures can in turn be converted into torques. Alternatively or additionally, in internal combustion engines from the oscillation of a rotational speed signal of a crankshaft and / or camshaft to a torque can be deduced. Furthermore, in the case of combustion and / or electric motors, it is possible to calculate back to the torques from the control variables (in level 1 and / or in level 2). Alternatively or additionally, in the case of electric motors, it is possible to calculate the torque back from the motor current, motor voltage and speed. If external torque actuators are used to set a torque, feedback to the engine control unit, for example via a bus system, can be provided, which contains information about the torque. Finally, alternatively or additionally, torque sensors can be applied to the crankshaft in most types of engines, which sensors detect the torques directly and report them back to the engine control unit as an actual torque.

The method described for operating a motor vehicle drive can be advantageously developed in various ways. Thus, in addition to the already described comparison of the actual torque with a desired torque, an additional, preceding comparison step can also be carried out in which the calculated target torque is checked by comparing this with at least one permissible torque. When the permitted torque is exceeded by the calculated setpoint torque, the calculated setpoint torque is replaced by a fault setpoint torque. For example, in this comparison step, the calculated target torque can be replaced in each case by the smaller of the two values, namely the calculated target torque and the permissible torque.

This development of the method according to the invention combines the control method known from the prior art for checking the calculated moments with the method according to the invention, in which the actual moments are checked and monitored. Thus, this method provides protection against errors occurring, since now errors in the functional level (first level) can be detected and compensated, without necessarily switching immediately to the level 2 uncomfortable fault reaction mode.

In a further embodiment of the method, the comparison of the at least one actual torque and the at least one desired torque with the aid of filters and / or deadtime members performed. In this way, for example, runtime differences can be compensated for as well as time differences which are due to a time-delayed conversion of the drive signals into corresponding motor torques.

The method according to the invention can be used particularly advantageously for hybrid drives. In this case, the motor vehicle drive has at least one internal combustion engine and at least one further motor, preferably an electric motor. In the following, the at least one further motor will be referred to as an electric motor, whereby analogously hybrid drives with other types of motors should also be covered by the invention as a further motor.

Instead of at least one calculated desired torque, at least two desired torques are now calculated in the first method step: at least one engine nominal torque and at least one electric motor nominal torque. These are converted in the second method step into corresponding control variables, namely at least one internal combustion engine control variable and at least one electric motor control variable.

In hybrid drives, the actual torque (actual torque) is composed of individual torques of the motors, ie of the at least one internal combustion engine and of the at least one electric motor. The inventive method generates separate control variables for these individual torque controllers, which may have separate engine control units.

For fault diagnosis, a comparison can now be made between the setpoint torques of the individual motors and the actual moments of these motors. Thus, a comparison is made between the at least one actual torque of the at least one internal combustion engine and the at least one engine nominal torque and, analogously, a comparison between at least one actual torque of the at least one electric motor and the at least one electric motor nominal torque. By means of this method, it is possible in particular to diagnose in which torque controller a possible error has occurred.

Depending on which torque controller an error has been detected, an operating mode can be selected which responds to this error and is adapted. Thus, for example, in the case of a deviation of the at least one actual torque of the at least one internal combustion engine that exceeds a predetermined engine threshold, it is possible to switch over from the at least one desired engine torque to an internal combustion engine fault control operation. In this engine failure driving operation, the at least one engine control amount is replaced with at least one engine replacement drive amount. In addition, other control large be replaced by Ersatzansteuergrößen. Analogously, when a deviation of the at least one actual torque of the at least one electric motor exceeding a predetermined electric motor threshold is detected by the at least one electric motor nominal torque, an electric motor fault driving operation is switched over. In this electric motor fault driving operation, the at least one electric motor drive amount is replaced by at least one electric motor drive drive amount. Again, additional control variables can be replaced by Ersatzansteuergrößen.

These Ersatzansteuergrößen can be configured in various ways. Thus, these Ersatzansteuergrößen example cause a particularly low moment of the respective affected by the error engines. In particular, these can also trigger a complete shutdown of each affected by the fault motors, so that, for example, in the engine fault drive operation, the at least one internal combustion engine is completely switched off and the electric motor fault driving operation of the at least one electric motor is completely switched off. In this way, for example, in the engine fault control operation can be switched to a purely electric driving, so that the at least one torque controller of the at least one electric motor now takes over the tasks of at least one torque controller of the internal combustion engine. In this way, errors can be compensated complementarily. The case perceived by the driver of the motor vehicle comfort loss is extremely low. In this way, errors in the torque conversion of hybrid drives can be detected and compensated particularly effectively and efficiently, without having to switch to a fault reaction mode of level 2. In addition, however, the driver can also be informed of the occurring error, for example by means of a corresponding cockpit display, which indicates to the driver that a visit to a workshop is required in the near future.

drawing

Reference to the drawings, the invention will be explained in more detail below.

It shows:

FIG. 1 shows a flowchart of a method according to the prior art for torque monitoring with a torque limitation in level 1;

Figure 2 shows an embodiment of a method according to the invention with a test of the implementation of the desired moments; and FIG. 3 shows a method analogous to FIG. 2 in a hybrid drive.

Exemplary embodiments

FIG. 1 shows a method corresponding to the prior art in which erroneously too high torques are detected by means of a so-called torque limitation in plane 1 (reference numeral 110 in FIG. 1).

The method is divided into two consecutive method steps, which are here symbolically separated by the dividing line 112. The dividing line 112 separates the torque calculation (reference numeral 110) from the torque conversion (reference numeral 114). In the moment calculation 110, target moments 120 are first of all calculated from various input variables 116 in a calculation step 118. For example, the inputs 116 may include electronic information of an accelerator pedal through which a driver's request for a particular torque is communicated to an engine control device. In the calculation step 118, these input quantities 116 are converted into corresponding setpoint moments 120. For example, this conversion may be performed continuously or at predetermined time intervals in step 118. The conversion in step 118 can take place, for example, with the aid of characteristic fields, functions, or electronic tables.

The desired torques 120 generated in this way in step 118 are compared in a torque limitation 122 with permissible moments 124. If it is ascertained that the calculated desired torques 120 exceed these permissible torques 124, then the desired torques 120 are replaced by fault set torques. For example, these fault set torques may be permissible moments 124. The limited setpoint moments 126 generated in this manner in the torque limitation 122 thus do not exceed the permissible moments 124.

By means of these limited target moments 126, a conversion step 128 is then carried out for the torque conversion (reference numeral 114). In this conversion step 128, the limited target torques 126 are converted into drive variables 130. These on-control variables 130 may be, for example, electronic signals which are transmitted to torque controllers of a motor vehicle drive (not shown in FIG. 1). The control variables 130 thus represent the "hardware analog" to the limited setpoint torques 126 in the case of an error-free operation of the conversion step 128. The illustrated in Figure 1, the prior art corresponding method can be accommodated for example in a conventional engine control unit. For example, this engine control device may include a microcomputer and other electronic components. The engine control unit does not necessarily have to be integrated in an electronic unit, but can also be housed decentrally in the motor vehicle, for example. Advantageously, the method steps executed in the moment calculation (reference numeral 110) are wholly or partially designed as a computer program, the computer program, for example, converting the input variables 116 into the setpoint moments 120 in the calculation step 118. The torque limitation 122 can also be realized by a computer program. Alternatively or additionally, however, this torque limitation 122 can also be realized by a corresponding electronic circuit, for example an electronic comparison circuit, by means of which the setpoint moments 120 are compared with the permissible moments 124 and in each case limit the minimum of these two values 120, 124 as limited setpoint moment 126. is passed.

Analogously, the conversion step 128 shown in the torque conversion (reference numeral 114) can also be implemented completely or partially in an engine control device. In particular, this method step 128 can in turn be implemented in whole or in part in a microcomputer of the engine control unit. This microcomputer can be the same microcomputer as used for torque calculation (reference numeral 110), or it can be a separate microcomputer. Furthermore, alternatively or additionally, electronic components can be used. For example, corresponding electronic converters, filters, output stages or the like can be used to generate the control variables 130, so that suitable control variables 130 for torque controllers of the motor vehicle drive are generated. These control variables 130 can be transmitted via a corresponding line system, for example suitable interface cables (BUS system), to the moment controller (s) of the motor vehicle.

As described above, the prior art method illustrated in FIG. 1 suffers from the defect that, although errors in the torque calculation 110, that is, errors occurring in the calculation step 118 in the calculation of the target torque 120, are detected and compensated. However, control of the implementation of these torque moments 120 or of the limited setpoint moments 126 in the conversion step 128 of the torque conversion 114 into corresponding control variables 130 does not take place.

In contrast, an embodiment of a method according to the invention for motor control is shown in Figure 2, which the described disadvantages of the method according to Figure 1 avoids. In the method according to the invention, first analogous method steps are carried out in the moment calculation 110 as in the method according to FIG. Accordingly, in a calculation step 118, target values 120 are first calculated from input variables 116. These setpoint moments are compared with permissible moments 124 in a torque limit 122. Accordingly, in accordance with the method described above, limited setpoint moments 126 are generated in which it is ensured that they do not exceed the permissible moments 124. These limited setpoint moments 126 are transferred to the torque conversion 114 in order to be converted there into a control step 130 analogous to FIG. 1 into control variables 130 for at least one momentum generator.

In the method according to the invention according to FIG. 2, however, a feedback of actual moments 132 from the torque actuators to the engine control unit additionally takes place. These actual moments 132 are detected in the form of signals for determining the actual moments 134, which, as described above, for example, surround the signals of corresponding torque sensors on a crankshaft. These signals 134 can be converted accordingly, in order then to be compared as actual moments 132 with the corresponding limited desired torques 126. If necessary, runtime differences, which are caused, for example, by a time-delayed conversion of the limited setpoint moment 126 into corresponding actual moments 132, can be compensated by filters and deadtime elements (not shown) before the comparison with the limited setpoint moments 126 is carried out.

This comparison between the actual moments 132 and the limited setpoint moments 126 is performed in a test for implementing the setpoint moments 136 in the torque conversion 114. If implausible actual moments 132 are detected, it is possible to switch over to a comfortable substitute operating mode instead of switching over to the abovementioned EMF operation. By "implausible moments" it can be understood, for example, that when the actual moments 132 deviate from the limited setpoint torques 126 by more than a predefined tolerance threshold, the system switches to an error drive mode 138. In this fault drive mode, the drive variables 130 can be used in particular corresponding Ersatzansteuergrößen be replaced.

FIG. 3 shows a preferred embodiment of a method according to the invention, in which the method illustrated in FIG. 2 has been modified for the operation of a hybrid drive. Analogously to FIG. 2, input variables, for example signals of an accelerator pedal and / or other signals, are first converted into setpoint moments in a calculation step. It is assumed that the hybrid drive in this embodiment has an internal combustion engine and an electric motor. DEM Accordingly, in the calculation step, a target engine torque and an engine target torque are generated. The distribution of the moments to these individual moments can be optimally adapted to the operating state, so that in particular an energy-saving operation is possible.

According to FIG. 2, these individual setpoint moments can be compared with permissible moments in a torque limitation. In this way, a limited engine target torque 152 and a limited motor motor torque 154 may be generated. The limited set torques 152, 154 are then transferred to the momentum number 114.

Analogous to FIG. 2, in the torque conversion 114, a conversion of the limited setpoint torques 152, 154 into control variables takes place. This implementation is divided into two to meet the requirements of the hybrid drive. Thus, in a torque conversion of the engine 156, the limited engine target torque 152 is converted to an engine control variable 158. These engine control variables 158 may then be forwarded to one or more internal combustion engines. Similarly, in a torque reduction of the electric motor 160, the limited electric motor desired torque 154 is converted into corresponding electric motor drive variables 162, which in turn are forwarded to one or more electric motors.

Analogously to FIG. 2, in the embodiment according to FIG. 3 there is once again a feedback of actual moments for error compensation. This feedback takes place, according to the nature of the hybrid drive, via signals for determining the actual moments of the internal combustion engine or electric motor 164, 166 .. Analogous to step 132 in Figure 2, the signals 164, 166 in an actual torque 168 of the engine and an actual torque 170 of the electric motor converted. Again, a delay and filtering of the signals can take place.

Subsequently, the actual moments 168, 170 are compared in a test of the implementation of the setpoint torque 136 with the limited setpoint torques 152, 154. Due to the doubling of the number of signals, this test 136 in the embodiment according to FIG. 3 is made more complex than the test 136 in FIG. 2. For example, the actual torque 168 of the internal combustion engine can be compared with the limited internal combustion engine torque 152 and, in parallel, the actual torque. Moment 170 of the electric motor with the limited Elektromotorsollmoment 154. If in one or both cases deviations are detected, which each exceed predetermined tolerance thresholds (which in turn may be configured arbitrarily and in particular can be zero), it is switched to a Fehleransteuerbetrieb 138. In this error drive operation 138, the drive quantities 158, 162 can each be replaced by corresponding substitute drive quantities. For example, as described above, upon detection of a fault in the internal combustion engine, the engine may be completely turned off by the engine control variables 158, whereas the electric motor drive variables 162 may be modified accordingly for the electric motor to take over the engine failure. Thus, the total torque of the motor vehicle drive, for example, be kept constant despite failure of one of the two motors, so that a driver of the motor vehicle perceives no change. Again, the Fehleransteuerbetrieb 138 but also an error message z. B. on a display or acoustic type to stop a driver to visit a workshop.

Bezueszeichenliste

110 moment calculation

112 dividing line

114 torque conversion

116 input variables

118 calculation step

120 set torques

122 torque limit

124 permissible moments

126 limited target moments

128 implementation step

130 control variables

132 actual moments

134 signals for determining the actual

Moments

136 Checking the implementation of the setpoint torques

138 Fault drive operation

152 limited internal combustion engine target torque

154 limited electric motor target torque

156 Torque conversion internal combustion engine

158 combustion engine control variables

160 torque conversion electric motor

162 electric motor control variables

164 signals for determining the actual

Moment of the internal combustion engine

166 signals for determining the actual

Moment of the electric motor

168 Actual moment internal combustion engine

170 Actual moment electric motor

Claims

claims

1. A method for controlling a motor vehicle drive, wherein in a first step at least one desired torque (120; 140, 142) is calculated and in a second step the at least one desired torque (120; 140, 142) is converted into at least one drive variable (130; 162) for the motor vehicle drive, characterized in that at least one actual torque (132; 168, 170) of the motor vehicle drive is determined, wherein a comparison between the at least one actual torque (132; 168, 170) and the at least one Target torque (120; 140, 142) is performed, wherein at a predetermined threshold exceeding deviation of the at least one actual torque (132; 168, 170) of the at least one target torque (120; 140, 142) switched to a Fehleransteuerbetrieb (138) is replaced, wherein the at least one control variable (130, 158, 162) is replaced by at least one Ersatzansteuergröße.

2. Method according to the preceding claim, characterized in that in addition the at least one calculated setpoint torque (120; 140, 142) is compared with at least one permissible moment (124; 148, 150) and that when the permissible torque (124; 148 , 150) the calculated target torque (120; 140, 142) is replaced by a fault set torque (124; 148, 150).

3. Method according to one of the two preceding claims, characterized in that the at least one actual torque (132; 168, 170) is determined by at least one of the following methods: a measurement of a cylinder internal pressure; an oscillation of a speed signal of a crankshaft; a conversion of the at least one control variable; a conversion of current, voltage and speed of an electric motor; by feedback via a BUS system; by at least one instantaneous sensor on a crankshaft or camshaft.

4. Method according to one of the preceding claims, characterized in that the at least one actual torque (132; 168, 170) and / or the at least one desired torque (120; 140, 142) are filtered before carrying out the comparison and / or by means of a Deadtime element are delayed.

5. The method according to any one of the preceding claims, wherein the motor vehicle drive comprises at least one internal combustion engine and at least one electric motor, characterized in that in the first step at least one engine nominal torque (140) is calculated, which is converted in the second step in at least one Verbrennungsmotoransteuergröße (158) and that in the first at least one electric motor target torque (142) is calculated, which is converted into at least one electric motor drive variable (162) in the second step.

6. The method according to the preceding claim, characterized in that a comparison between at least one actual torque (168) of the at least one internal combustion engine and the at least one engine nominal torque (140) and a comparison between at least one actual torque (170) of the at least one Electric motor and the at least one electric motor Sollmoment (142) is performed.

7. Method according to the preceding claim, characterized in that when the deviation of the at least one actual torque (168) of the at least one internal combustion engine exceeds at least one internal combustion engine setpoint torque (140) to a combustion engine fault control operation (138), wherein the at least one Verbrennungsmotoransteuergröße (158) is replaced by at least one Verbrennungsmotorersatzan- control variable and that at a predetermined electric motor threshold exceeding the at least one actual torque (170) of the at least one electric motor from at least one electric motor Sollmoment (142) to a

Electric motor fault drive operation (138), wherein the at least one electric motor drive quantity (162) is replaced by at least one electric motor drive drive amount.

A method according to the preceding claim, characterized in that in the engine fault drive operation (138) the at least one engine is completely shut down and in the electric motor fault drive operation (138) the at least one electric motor is completely shut down.

9. Engine control device with means for carrying out a method according to one of the preceding method claims.