Method and device for determining engine reference torque of motor vehicle
Through the mass and speed value of computer EMU, combined with the engine speed function, the engine reference torque is estimated, which solves the problem that traditional systems cannot obtain the engine reference torque, and realizes high-performance drag torque adjustment under special conditions.
Patent Information
- Application Number
- CN202380042894.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-06-20
- Filing Date
- 2023-05-17
- Publication Date
- 2024-12-31
AI Technical Summary
Under special types of motor vehicles or failure conditions, traditional CAN bus systems cannot effectively obtain information on the engine reference torque, resulting in limited engine drag torque regulation performance.
By estimating the engine reference torque, the engine power is calculated using the mass of the motor vehicle and the speed value of the acceleration period, and the power and torque curves stored in the engine speed function are estimated, taking into account correction factors and state models to improve accuracy.
Without relying on CAN bus information, the engine reference torque can be accurately determined, which is suitable for special motor vehicle types and fault conditions, improving the performance of engine towing torque adjustment.
Smart Images
Figure CN119233914A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a method and a device for determining an engine reference torque of an engine of a motor vehicle for use in a controller of the motor vehicle, as well as a controller of a braking system of a motor vehicle having such a device and / or having hardware and / or software modules for executing the steps of the method. Background Art
[0002] In conventional commercial vehicles, anti-lock braking systems (ABS) or electronic braking systems (EBS) are usually installed, which use the value of the engine reference torque (or the maximum engine torque) for internal calculations, such as for engine drag torque regulation (SMR). The value of the engine reference torque is usually sent by the engine control unit of the motor vehicle or its transmission control unit via the CAN bus of the motor vehicle.
[0003] However, in certain types of CAN buses or certain types of vehicles or in the event of a fault, the ABS system or EBS system cannot obtain information about the engine reference torque from the CAN bus of the vehicle. This may be due, for example, to a specification by the vehicle manufacturer.
[0004] Furthermore, in hybrid vehicles, ie vehicles with a hybrid drive which, in addition to the internal combustion engine, usually also contains an electric motor, information about the engine reference torque of the internal combustion engine is not sufficient as the relevant engine reference torque since the additional drive would be neglected. Summary of the invention
[0005] The object of the present invention is therefore to determine the engine reference torque independently of any information about the engine reference torque that is transmitted via a CAN bus.
[0006] The invention achieves this object with the features of the method according to claim 1 , with the device according to claim 14 and with a control unit for a brake system of a motor vehicle according to claim 15 .
[0007] The method according to the invention for determining an engine reference torque (maximum engine torque) of an engine of a motor vehicle for use in a control unit of a motor vehicle provides for determining the engine reference torque by estimation. For this purpose, the value of the mass of the motor vehicle is known. In addition, values of the motor vehicle speed are respectively known at two different points in time during the acceleration of the motor vehicle. In this sense, acceleration refers only to positive acceleration, i.e. not to deceleration, i.e. the vehicle will travel faster at a later point in time than at an earlier point in time.
[0008] For example, the motor vehicle speed value can be determined from the wheel speeds of the vehicle. This is advantageous because in modern brake systems (such as ABS brake systems and EBS brake systems) wheel speed sensors are installed on all or at least a plurality of wheels, which provide wheel speeds from which the vehicle speed can be determined with little effort and thus inexpensively.
[0009] The current engine power of the engine is calculated from the value of the mass of the motor vehicle and the two vehicle speed values. The calculation is preferably carried out based on the equation of motion for the moving motor vehicle.
[0010] Starting from the calculated engine power, the value of the engine reference torque is estimated based on a power and torque curve stored in the controller or other module of the vehicle as a function of the engine speed. However, the estimation of the engine reference torque can (but not necessarily) take into account the engine speed, because the engine torque can be directly inferred from the engine power.
[0011] If the current engine power cannot be clearly assigned to the current engine torque (for example, because there may be two different engine torques for the determined engine power), the previous or previous course of the engine power can be taken into account, which allows a clear assignment of engine power and engine torque.
[0012] The determination of the engine reference torque (maximum engine torque) according to the invention allows the value of the engine reference torque to be determined independently of the CAN bus, taking into account the actual performance characteristics of the drive of the motor vehicle.
[0013] The determination of the engine reference torque according to the invention is therefore also applicable to special motor vehicle CAN types or under fault conditions in which conventionally no information or no correct information about the engine reference torque is available via the CAN bus of the motor vehicle.
[0014] A particular advantage of the invention is that the engine reference torque can be inferred using only a small number of input variables. No further information about the engine or the transmission is required.
[0015] In summary, the present invention advantageously enables providing engine drag torque regulation with higher performance without having to send a signal regarding engine reference torque information via a CAN bus.
[0016] The device according to the invention for determining an engine reference torque for use in a controller of a motor vehicle comprises a calculator which calculates the engine power of the engine of the motor vehicle based on a value of the mass of the motor vehicle and values of the motor vehicle speed obtained at two different time points during acceleration of the motor vehicle.
[0017] The device also includes an estimator that estimates a value of the engine reference torque based on a power and torque curve stored as a function of the engine speed in the controller or other module in combination with the calculated engine power.
[0018] Preferably, the device comprises (further) hardware and / or software modules for carrying out the steps of the method according to the invention and the further developments of the method explained below.
[0019] The control unit of the braking system of the motor vehicle according to the invention comprises a device of the type described above for determining an engine reference torque and / or hardware and / or software modules for carrying out the steps of the method according to the invention and the further developments of the method explained below.
[0020] According to an improved solution of the present invention, two time points close to each other are selected so that the acceleration values of the motor vehicle at these time points do not differ significantly from each other. This makes it possible to base the model on uniformly accelerated motion. In addition, the influence of other driving resistances can be kept to a minimum in this way.
[0021] One development of the invention provides that the mass of the motor vehicle is determined from the air suspension pressure measured on the motor vehicle. The air suspension pressure depends on the load of the motor vehicle and thus on the mass of the motor vehicle overall. The air suspension pressure can thus provide information about the mass of the motor vehicle. Using the air suspension pressure to determine the mass of the motor vehicle is advantageous because it thus avoids having to weigh the motor vehicle and the load on a weighing table. Weighing on a weighing table is disadvantageous because it is associated with considerable effort, in particular because the mass determined by weighing must also be communicated to the motor vehicle and its control unit. This effort can be avoided thanks to this development of the invention.
[0022] According to an improved solution of the present invention, the engine power is calculated as follows:
[0023]
[0024] Where P is the engine power, m is the value of the mass of the vehicle, v(t1) is the value of the vehicle speed at time t1, and v(t2) is the value of the vehicle speed at time t2. A simplified basic energy equation is used for the calculation of the engine power:
[0025]
[0026] and
[0027]
[0028] Here, E is the kinetic energy of the motor vehicle, and ΔE / Δt represents the change in the kinetic energy of the motor vehicle over time. The motor vehicle is traveling faster at time t2 than at time t1, because these times are within the acceleration phase of the motor vehicle.
[0029] One development of the invention provides that one or more of the following correction factors are taken into account when calculating the engine power:
[0030] - Correction factor corr a,rot , which represents the acceleration of the rotating masses of the motor vehicle, for example the wheels, and / or the acceleration of the rotating masses in the engine and drive train,
[0031] - Correction factor corr R , which represents the rolling resistance of the wheels of a motor vehicle,
[0032] - Correction factor corr L , which represents the air resistance of the motor vehicle,
[0033] - Correction factor corr St , which represents the slope resistance of the slope of the lane used by the motor vehicle,
[0034] - Correction factor corr div , which represents other frictional resistance.
[0035] Taking these correction factors into account means that the calculated engine power only takes into account the energy for the translational acceleration in the plane, thereby eliminating other driving resistances that could lead to an incorrect determination of the engine reference torque.
[0036] Depending on the type of motor vehicle and thus its use and / or on the driving situation, either no correction factors, only one of the correction factors, only selected correction factors or all correction factors are taken into account. When selecting the correction factors, all possible combinations are taken into account, i.e., of the five correction factors mentioned above, in particular the first and second, the first and third, the first and fourth, the first and fifth, the second and third, the second and fourth, the second and fifth, the third and fourth, the third and fifth, the fourth and fifth, the first and second and third, the first and second and fourth, the first and second and fifth, the first and third and fourth. 4th, 1st and 3rd and 5th, 1st and 4th and 5th, 2nd and 3rd and 4th, 2nd and 3rd and 5th, 2nd and 4th and 5th, 3rd and 4th and 5th, 1st and 2nd and 3rd and 4th, 1st and 2nd and 3rd and 5th, 1st and 2nd and 4th and 5th, 1st and 3rd and 4th and 5th, 2nd and 3rd and 4th and 5th correction factors, etc.
[0037] According to a further development of the invention, one or more of the correction factors are determined in dependence on the speed or their determination is speed-dependent. Typically, the air resistance of a motor vehicle is speed-dependent; it can be assumed that the air resistance increases with the square of the speed.
[0038] Furthermore, the acceleration of rotating masses of the motor vehicle (eg wheels) and / or the acceleration of rotating masses in the engine and drive train is speed-dependent; it can be assumed that the kinetic energy stored in the rotating masses increases with their rotational speed or rotational velocity.
[0039] Other phenomena may affect additional correction factors.
[0040] When the correction factor is taken into account, the preliminary engine power is first calculated without taking the correction factor into account; then the value of the preliminary engine power is multiplied by one or more correction factors to be taken into account, thereby obtaining the calculated engine power.
[0041] Thanks to the consideration of these correction factors, a higher accuracy is achieved when estimating the engine reference torque.
[0042] One development of the invention provides for the engine reference torque to be estimated repeatedly, wherein a state model of the motor vehicle is taken into account and / or a recursive or iterative estimation algorithm is applied, for example using a Kalman filter, thereby also achieving a higher accuracy in the estimation of the engine reference torque.
[0043] According to a further development of the invention, the suitability of the time point when the vehicle speed value is obtained is checked, and if the time point is found to be unsuitable, the associated vehicle speed value is discarded or filtered out. This method of operation is advantageous because unsuitable speed values thus do not distort the estimation of the engine reference torque.
[0044] One development of the invention provides that when checking the suitability of the time point, a signal from a braking system of the motor vehicle, for example from a control unit of an anti-lock braking system or an electronic braking system, which may indicate that the motor vehicle behavior is unsuitable, is taken into account. In this way, driving conditions that are unfavorable for estimating the engine reference torque can be excluded.
[0045] According to a further development of the invention, the signals include a brake actuation signal for signaling a brake actuation and / or an ABS activation signal for signaling activation of an anti-lock braking system. Thus, information available in the brake system can be used to improve the estimation of the engine reference torque.
[0046] In one embodiment of the present invention, the slope resistance is calculated by means of an inclination sensor and a correction factor corr representing the slope resistance of the lane used by the motor vehicle is calculated as a function of the calculated slope resistance. St , and / or if the inclination angle is detected outside a predetermined range in conjunction with the slope angle generated by the inclination sensor, the vehicle speed value acquired at this time is excluded or interpreted as unsuitable. In this way, measurements on uneven sections of road can be discarded without distorting the estimation of the engine reference torque.
[0047] According to a further development of the invention, the engine power is calculated repeatedly and the maximum value Pmax of the engine power is determined by replacing the existing value Pmax with a calculated higher value of the engine power, provided that the calculated higher value has been evaluated as reliable in advance. In this way, the motor vehicle or its control unit will obtain the maximum engine power after a certain observation period only based on the measurements and calculations performed during driving operation. Thus, it is not necessary to program the maximum engine power into the corresponding control unit. This is particularly advantageous if the engine power is unknown when producing such a control unit, because it is not yet clear in which vehicle such a control unit will be installed.
[0048] A further development of the invention provides that measured engine speed information or engine speed information derived from information about the engaged gear and the wheel speed is taken into account and the engine reference torque is determined as a function of the engine speed information and the engine power.
[0049] According to one refinement, the engine reference torque is estimated repeatedly and its maximum value is determined by replacing an existing maximum value with a greater estimated value of the engine reference torque if the greater estimated value has been evaluated as reliable.
[0050] A particular advantage of the invention is that no information about the clutch state of the vehicle has to be provided, since the maximum acceleration is in principle only achieved when the clutch is engaged.
[0051] The invention can be used not only in conventional vehicles, but in particular in vehicles with an internal combustion engine and also in parallel hybrid vehicles, in which the input speed of the transmission is typically in the operating range of the diesel engine. BRIEF DESCRIPTION OF THE DRAWINGS
[0052] The improved scheme of the present invention is derived from the claims, the description and the drawings. The aforementioned advantages of the features and the combination of multiple features are exemplary and can be effective alternatively or cumulatively, and these advantages do not have to be obtained from the embodiments of the present invention. Other features are known from the drawings. The features of different embodiments of the present invention or the combination of features of different claims can also deviate from the reference relationship selected by the claims and are proposed here. This also relates to such features shown in a separate figure or described in its description. These features can also be combined with features of different claims. The features listed in the claims for other embodiments of the present invention can also be omitted.
[0053] In the figure:
[0054] Figure 1 An exemplary embodiment of a method for determining an engine reference torque of an engine of a motor vehicle according to the present invention is shown.
[0055] Figure 2 The method for utilizing the Figure 1 An embodiment of a method for determining an engine reference torque by a device,
[0056] Figure 3 Show Figure 1 The device shown in the embodiment is arranged outside the controller using the engine reference torque, and
[0057] Figure 4 Show Figure 1 The device shown in is alternatively arranged in an embodiment within a controller using an engine reference torque. DETAILED DESCRIPTION
[0058] Figure 1 An exemplary embodiment of a device 10 according to the invention for determining an engine reference torque of an engine of a motor vehicle is shown.
[0059] The engine of a motor vehicle is understood to be an engine system which in the simple case comprises only the internal combustion engine, but in more advanced engine systems (e.g. hybrid vehicles) comprises the sum of the drive units for driving the vehicle, e.g. the internal combustion engine and one or more electric motors. Depending on the operating mode, a hybrid vehicle is either driven only by one or more electric motors, only by the internal combustion engine, or simultaneously by the internal combustion engine and one or more electric motors. The engine reference torque represents the maximum torque of all drive units combined.
[0060] The device 10 is part of a motor vehicle, in particular part of a system component thereof.
[0061] The device 10 comprises a calculator 12 and an estimator 14 .
[0062] The computer 12 obtains variables and parameters, in particular the value of the mass m of the vehicle and two vehicle speed values v(t1), v(t2) obtained at different time points t1 and t2. The vehicle speed values v(t1), v(t2) can be obtained, for example, based on the wheel speed, which is obtained by a wheel speed sensor. Such a wheel speed sensor is usually installed on a vehicle with an anti-lock braking system or an electronic braking system. The vehicle speed values v(t1), v(t2) can also be transmitted directly to the device 10 from a controller of the anti-lock braking system or the electronic braking system, for example.
[0063] The mass m of the motor vehicle can be known, for example, from the air suspension pressure measured on the motor vehicle. To achieve this, the pressure in the air suspension system is measured and the mass m of the motor vehicle is calculated from the measured pressure.
[0064] The knowledge of the mass m of the motor vehicle is particularly useful in the case of commercial vehicles, since the load of commercial vehicles can vary significantly, and thus the mass of a fully loaded commercial vehicle can be several times the mass of the same commercial vehicle when unloaded.
[0065] The calculator 12 first calculates the engine power P based on the value of mass m and the vehicle speed values v(t1), v(t2) in combination with the equation:
[0066] .
[0067] Preferably, the engine power calculated in this way is regarded only as a preliminary value P', which is corrected by one or more of the correction factors by multiplying the preliminary value P' by one or more of the correction factors.
[0068] The correction factor includes the following parameters:
[0069] - Correction factor corr a,rot , which represents the acceleration of the rotating mass of the vehicle,
[0070] - Correction factor corr R , which represents the rolling resistance of the wheels of a motor vehicle,
[0071] - Correction factor corr L , which represents the air resistance of the motor vehicle,
[0072] - Correction factor corr St , which represents the slope resistance of the slope of the lane used by the motor vehicle,
[0073] - Correction factor corr div , which represents other frictional resistance.
[0074] Thus, the value of the engine power P output by the calculator 12 is obtained by multiplying the preliminary value P' by the correction factor corr a,rot , correction factor corr R , correction factor corr L , correction factor corr St and / or correction factor corr div get.
[0075] The computer 12 can obtain other variables and parameters, for example, the inclination or slope α of the vehicle which can be measured by means of an inclination sensor.
[0076] In addition, the calculator 12 can also obtain the engine speed n obtained by measurement. M , or (if available) other engine speeds, especially in hybrid vehicles.
[0077] In addition, the calculator 12 can also obtain the rotation speed n of a wheel obtained by measurement. M Or the rotation speed of multiple wheels. In addition, the calculator 12 can also obtain information about the engaged gear G. The calculator 12 can calculate the rotation speed n of the wheels according to the information about the engaged gear G and the acquired wheel speed n. M Derive the engine speed.
[0078] The calculator 12 also receives information about the possible intervention of the anti-lock braking system ABS, the electronic braking system EBS, the driving dynamics control system ESP, the drive slip control system ASR and / or the engine drag torque control system MSR to operate the wheel brakes or the engine speed. Based on this information, it is deduced whether the vehicle speed values v(t1), v(t2) considered to be used within the scope of the estimation of the engine reference torque are suitable or unsuitable. Generally, if these vehicle speed values v(t1), v(t2) are known during the intervention of the system, they are unsuitable. If it is determined that the vehicle speed values v(t1), v(t2) considered to be used are unsuitable, then either the power calculation is not performed at all or the obtained power value P is discarded.
[0079] The calculator 12 transmits the appropriate power value P to the estimator 14. The estimator 14 combines the calculated engine power P with the power and torque curve 16 (which is expressed in terms of engine speed n M The value of the engine reference torque MRM is estimated by the device 10, if necessary, taking into account the state model of the vehicle and / or recursive and iterative estimation algorithms, such as the application of a Kalman filter, for further processing.
[0080] Finally, the device 10 supplies the value of the engine reference torque MRM to one or more controllers of the motor vehicle, for example to an engine drag torque regulation MSR controller, an ABS controller or an EBS controller.
[0081] Figure 2 An exemplary method sequence 20 for determining an engine reference torque MRM is shown.
[0082] After the start 22 of the method 20 , method parameters are first initialized in an initialization step 24 .
[0083] In a determination step 26 , the value m of the mass of the motor vehicle is determined, as described above, for example in conjunction with the pressure in the air suspension system.
[0084] In a further determination step 28 , vehicle speed values v( t1 ), v( t2 ) are determined at two different times t1 and t2 during acceleration of the vehicle.
[0085] In a checking step 30 , it is checked whether the acceleration of the motor vehicle is approximately the same at these two points in time, in order to ensure that the motor vehicle is moving in a nearly uniformly accelerated manner. If this is not the case, the method flow returns to the learning step 28 via a branch 32 .
[0086] If the motor vehicle is in a nearly uniformly accelerated motion, a further check step 34 is performed to check whether the times t1 and t2 and the motor vehicle speed values v(t1), v(t2) are suitable. To this end, it is checked whether these times are close enough to be able to take a uniformly accelerated motion as a starting point with sufficiently high accuracy. In addition, as described above, it is checked whether there is a possible intervention of a driver assistance system (e.g., an anti-lock braking system ABS, an electronic braking system EBS, an ESP driving dynamics control system, an ASR drive slip control system, and / or an engine drag torque control system MSR) at the times t1 and t2, which could interpret the motor vehicle speed values v(t1), v(t2) as being unsuitable.
[0087] Furthermore, if an inclination angle outside a predetermined range is detected in conjunction with the slope angle generated by the inclination sensor, the motor vehicle speed value determined in this case is excluded or interpreted as unsuitable.
[0088] If it is determined that the value taken into account, in particular the vehicle speed value, is unsuitable, the method flow returns via branch 36 to the determination step 28 .
[0089] In calculation step 38 , a preliminary value P′ of the engine power is calculated as a function of the mass m of the vehicle and the vehicle speed values v( t1 ), v( t2 ) and the time difference t2 − t1 between the two times t1 and t2 .
[0090] In a subsequent correction step 40 , this preliminary value P′ of the engine power is corrected by multiplication by one or more of the correction factors mentioned above.
[0091] In a check step 42, it is checked whether the calculated and possibly corrected current engine power Pneu is greater than the previously calculated and possibly corrected engine power Palt. If this is the case, a branch is made to a replacement step 44, in which the previously stored maximum value Pmax is replaced by the current value of the engine power Pneu, and an estimation step 46 is continued.
[0092] However, if it is determined in the checking step 42 that the calculated and possibly corrected current engine power Pneu is not greater than the previously calculated and possibly corrected engine power Palt, the replacement step 44 is skipped and the estimation step 46 is continued.
[0093] In the estimation step 46, the engine reference torque MRM is estimated. Since the above steps 28, 30, 34, 38, 40, 42 and 44 are continuously and repeatedly executed, the engine reference torque is also estimated repeatedly. Here, a state model of the vehicle and / or a recursive or iterative estimation algorithm, for example, by a Kalman filter, can be used. Inappropriate values can be identified and filtered out.
[0094] In the checking step 48, it is checked whether the currently estimated engine reference torque MRMneu is greater than the previously estimated engine reference torque MRMalt. If this is the case, a branch is made to the replacement step 50, in which the previously stored engine reference torque MRMalt is replaced by the currently estimated engine reference torque MRMneu, and the learning step 28 is continued.
[0095] However, if it is confirmed in the checking step 48 that the currently estimated engine reference torque MRMneu is not greater than the previously estimated engine reference torque MRMalt, the replacing step 50 is skipped and the learning step 28 is continued.
[0096] Figure 3 Show Figure 1 In the case where the device 10 shown in FIG. 1 is arranged outside the controller 60, the controller obtains and uses the engine reference torque MRM from the device 10. Data can be exchanged between the controller 60 and the device 10 via the data connection 61 (in particular in conjunction with Figure 1 parameters described).
[0097] Figure 4 Show Figure 1 The device 10 shown is an alternative arrangement within such a control unit 62 which uses the engine reference torque MRM.
[0098] List of reference numerals (part of the description)
[0099] 10 Installation
[0100] 12Calculator
[0101] 14 Estimator
[0102] 16 Power and torque curves
[0103] 20 Method Flow
[0104] 22 Start
[0105] 24 Initialization steps
[0106] 26 Steps to learn
[0107] 28 Inspection steps
[0108] 30 Inspection steps
[0109] 32 branches
[0110] 34 Inspection steps
[0111] 36 branches
[0112] 38 Steps to learn
[0113] 40 Calibration steps
[0114] 42 Inspection steps
[0115] 44 Replacement Steps
[0116] 46 Estimation Steps
[0117] 48 Inspection steps
[0118] 50 Replacement Steps
[0119] 60 Controller
[0120] 61 Data connection unit
[0121] 62 Controller
[0122] mThe mass of the motor vehicle
[0123] t1 time point
[0124] t2 time point
[0125] v(t1) is the speed of the vehicle at time t1
[0126] v(t2) is the speed of the vehicle at time t2
[0127] a(t1) is the acceleration value of the vehicle at time t1
[0128] a(t2) is the acceleration value of the vehicle at time t2
[0129] corr a,rot Correction factor representing the acceleration of the rotating mass of the vehicle
[0130] corr R Correction factor representing the rolling resistance of the wheels of a motor vehicle
[0131] corr L Correction factor representing the air resistance of the vehicle
[0132] corr St Correction factor representing slope resistance
[0133] corr div Correction factor for other frictional resistance
[0134] α Tilt / slope
[0135] n M Engine speed
[0136] n R Wheel speed
[0137] G-speed
[0138] MRM engine reference torque
[0139] MRMneu current engine reference torque
[0140] MRMalt Previous engine reference torque
[0141] Engine power
[0142] P'Preliminary engine power
[0143] PneuCurrent engine power
[0144] Palt's previous engine power
[0145] Pmax maximum engine power
[0146] ABS Anti-lock Braking System
[0147] EBS Electronic Braking System
[0148] ESP driving dynamics control system
[0149] ASR drive anti-skid control system
[0150] MSR engine drag torque regulation system
Claims
1. A method for determining an engine reference torque (MRM) of an engine of a motor vehicle for use in a control unit (60, 62) of the motor vehicle, It is characterized in that The engine reference torque (MRM) is determined by estimating (46), The value of the mass (m) of the motor vehicle is known, and the values of the speed of the motor vehicle (v(t1), v(t2)) are respectively known at two different time points (t1, t2) during the acceleration of the motor vehicle. From these values (m, v(t1), v(t2)) the engine power (P'; P) of the engine is calculated, and Combined with the calculated engine power (P'; P), based on the engine speed (n M ) is used as a function of the stored power and torque curve (16) to estimate the value of the engine reference torque (MRM).
2. The method according to claim 1, characterized in that Two temporally close points in time ( t1 , t2 ) are selected such that the acceleration values (a( t1 ), a( t2 )) of the motor vehicle at these points in time ( t1 , t2 ) do not differ significantly from one another.
3. The method according to claim 1 or 2, characterized in that: A value for the mass (m) of the motor vehicle is determined from the air suspension pressure measured on the motor vehicle.
4. The method according to any one of the preceding claims, characterized in that The engine power (P) is calculated as follows: Among them, P is the engine power, m is the value of the mass of the motor vehicle, v(t1) is the value of the motor vehicle speed obtained at time point t1, and v(t2) is the value of the motor vehicle speed obtained at time point t2.
5. The method according to any one of the preceding claims, characterized in that One or more of the following correction factors are taken into account when calculating the engine power (P): - Correction factor corr a,rot , which represents the acceleration of the rotating mass of the motor vehicle, - Correction factor corr R , which represents the rolling resistance of the wheels of the motor vehicle, - Correction factor corr L , which represents the air resistance of the motor vehicle, - Correction factor corr St , which represents the slope resistance of the slope of the lane used by the motor vehicle, - Correction factor corr div , which represents other frictional resistance.
6. The method according to any one of the preceding claims, characterized in that The engine reference torque (MRM) is estimated (46) repeatedly, wherein a state model of the motor vehicle is taken into account and / or a recursive or iterative estimation algorithm is applied, for example using a Kalman filter.
7. The method according to any one of the preceding claims, characterized in that The suitability of the time point (t1, t2) is reviewed (34), and when it is determined that the time point (t1, t2) is not suitable, the associated vehicle speed value (v(t1), v(t2)) is discarded or filtered out.
8. The method according to claim 7, characterized in that When checking ( 34 ) the suitability of the points in time ( t1 , t2 ), a signal from a brake system of the motor vehicle, for example from a control unit of an anti-lock braking system (ABS) or an electronic brake system (EBS), is taken into account, indicating that the motor vehicle behavior is unsuitable.
9. The method according to claim 8, characterized in that The signals include a brake actuation signal for signaling a brake actuation and / or an activation signal for signaling an activation of an anti-lock braking system (ABS).
10. The method according to any one of the preceding claims, characterized in that The slope resistance is calculated with the aid of the inclination sensor and a correction factor corr representing the slope resistance is calculated depending on the slope resistance. St , and / or when, in conjunction with the slope angle generated by the inclination sensor, an inclination angle is detected to be outside a predetermined range, the vehicle speed value determined at this time is excluded or interpreted as being unsuitable (34).
11. The method according to any one of the preceding claims, characterized in that The engine power (P) is calculated repeatedly and continuously, and a maximum value (Pmax) of the engine power is determined by replacing an existing maximum value (Pmax) of the engine power with a calculated greater value (Pneu) of the engine power, provided that the calculated greater value (Pneu) has been evaluated in advance as being reliable.
12. The method according to any one of the preceding claims, characterized in that Considering the measured engine speed information (n M ) or from the information on the engaged gear (G) and wheel speed (n R ) derived engine speed information (n M ), and according to the engine speed information (n M ) and the engine power (P) determine the engine reference torque.
13. The method according to any one of the preceding claims, characterized in that The engine reference torque (MRM) is estimated repeatedly and its maximum value (MRM) is determined by replacing an existing maximum value (MRMalt) with a larger estimated value (MRMneu) of the engine reference torque, provided that the larger estimated value (MRMneu) has been assessed to be reliable.
14. A device for determining an engine reference torque (MRM) of an engine of a motor vehicle for use in a control unit (60; 62) of the motor vehicle, Features have a calculator (12) for calculating the engine power (P', P) of the engine based on the value of the mass (m) of the motor vehicle and the values of the speed of the motor vehicle (a(t1), a(t2)) obtained at two different time points (t1, t2) during the acceleration of the motor vehicle, and An estimator (14) combines the calculated engine power (P', P) with the engine speed (n M ) to store the power and torque curve (16) and estimate the value of the engine reference torque (MRM).
15. Controllers for the braking systems of motor vehicles, Features have Device (10) for determining an engine reference torque (MRM) of an engine of a motor vehicle according to claim 14 and / or hardware and / or software modules for executing the method steps according to any one of claims 1 to 13.