CN112606823A

CN112606823A - Control device for internal combustion engine in hybrid vehicle, power train, hybrid vehicle and method

Info

Publication number: CN112606823A
Application number: CN202010986250.2A
Authority: CN
Inventors: J·德吕克汉默
Original assignee: Volkswagen AG
Current assignee: Volkswagen AG
Priority date: 2019-09-18
Filing date: 2020-09-18
Publication date: 2021-04-06
Also published as: DE102019214208A1

Abstract

A control device for correcting a torque determination for an internal combustion engine in a hybrid vehicle is configured to determine a first approximate torque signal of an actual torque curve of the internal combustion engine adjusted on the basis of a setpoint torque signal and to correct the first approximate torque signal on the basis of an EM counter torque signal measured in/at the electric machine in order to determine a more accurate second approximate torque signal.

Description

Control device for internal combustion engine in hybrid vehicle, power train, hybrid vehicle and method

Technical Field

The invention relates to a control device for an internal combustion engine in a hybrid vehicle for correcting a torque determination, to a drive train for a hybrid vehicle, to a hybrid vehicle and to a method for correcting a torque determination in a control device for an internal combustion engine.

Background

It is known that the torque generated or emitted by an internal combustion engine in a motor vehicle depends on different factors. Here, the main influencing quantities are the fuel mass supplied to the combustion chamber, the air-fuel ratio and the friction torque of the engine. The torque delivered by the internal combustion engine is an important characteristic variable for a large number of functions in the drive train control.

The torque determined in a control device for an internal combustion engine can be based substantially on a relatively inaccurate calculation method based on an estimated value of the mass of fuel supplied and the friction torque per combustion. These are calculated from the signals of a plurality of sensors in the intake tract, exhaust tract and, if appropriate, in/at the internal combustion engine. Of the utmost importance is the intake pipe pressure sensor and/or the mass air flow sensor and, if present, the cylinder pressure sensor.

The torque determined in the control device for the internal combustion engine can furthermore be determined from a family of torque characteristics previously determined at the reference internal combustion engine by means of sensors. However, continuous fluctuations may occur, so that the torque varies from vehicle to vehicle.

Due to the relatively slow dynamics of the sensors, sensor tolerances, different components, temperature effects and friction tolerances, the average torque error is mostly in the range of approximately 10%. If the characteristics of the engine components change (ageing, deposits, defects), the errors rise significantly.

As a result, static and dynamic deviations between the requested setpoint torque of the internal combustion engine, which is determined by the driver or in the control unit, and the actual torque curve often occur. This can be particularly uncomfortable in the case of rapid torque changes, as occur, for example, when the engine is started, when the gearbox is shifted or when an internal shift in the internal combustion engine (for example, cylinder deactivation) is taking place.

Control methods for torque are known for hybrid or electric vehicles.

A torque control method for a hybrid vehicle is known from german publication DE 102015115714 a 1. The hybrid vehicle can be switched in a certain operating mode. In this operating mode, the torques of the internal combustion engine and of the two electric machines are determined. These torques are then modified according to the active anti-slip strategy and the operational stability strategy.

A drive arrangement for a motor vehicle having a first and a second electric machine is known from german publication DE 102014214514 a1, wherein the two electric machines are mechanically coupled. The second motor can compensate for the torque deviation if the torque produced by the first motor differs from the nominal value.

In principle, torque sensors and methods for torque determination in a drive train or a drive arrangement of a vehicle are known.

It is furthermore known from german patent document DE 102016212113B 3 that the torque transmitted by the first drive element to the second drive element is preferably determined in an electric or hybrid vehicle by means of a strain gauge element (dehnmessel). Here, the torque is transmitted through the shaft. The two drive elements are connected to one another via a connecting element or a fastening means and the strain measuring element is connected to the two drive elements here. As a result of this torque, a counter-torque is produced, which leads to a twisting of the two drive elements and thus to a deformation of the connecting element or of the fastening means. The evaluation device calculates the transmitted torque from the deformation.

Furthermore, a method for determining a force and/or a torque between two elements that can be moved relative to one another or between regions of an elastically deformable element is known from german patent document DE 102015111409B 3. The method may be used in a drive train or in a drive arrangement of a vehicle. In this case, sensors (transmitters) are respectively associated with the two displaceable elements, for example the engine output shaft and the elastic sideshaft to the drive wheel, which emit time-and/or value-discrete signals that are synchronized at a common time reference point. The force and/or torque is calculated from the time profile of the relative movement (relative Torsion angle) and/or Torsion (Torsion) of the elastic side shaft determined from the transmitter signal.

A disadvantage of the above method is the necessity of additional sensors. Direct measurement of the torque by means of torque sensors is currently not possible in mass production due to the lack of available installation space and sufficient, inexpensive and small sensors.

Disclosure of Invention

It is an object of the present invention to provide a correction for torque determination of an internal combustion engine in a hybrid vehicle, which at least partly overcomes the above-mentioned disadvantages.

This object is achieved by a control device, a drive train, a hybrid vehicle and a method according to the invention.

According to a first aspect, the invention provides a control device for correcting a torque determination for an internal combustion engine in a hybrid vehicle, which is set to determine a first approximation torque signal (naehernundrehmingsignal) of an actual torque curve of the internal combustion engine adjusted on the basis of a setpoint torque signal, and to correct the first approximation torque signal on the basis of an EM anti-torque signal measured in/at the electric machine in order to determine a more accurate second approximation torque signal.

According to a second aspect, the invention proposes a drive train for a hybrid vehicle having a control device for an internal combustion engine according to the first aspect.

According to a third aspect, the invention proposes a hybrid vehicle, wherein the hybrid vehicle has a drive train according to the second aspect.

According to a fourth aspect, the present invention proposes a method for correcting torque determination in the control apparatus for an internal combustion engine according to the first aspect, wherein the method includes:

determining a first approximate torque signal of an actual torque curve of the internal combustion engine adjusted on the basis of the setpoint torque signal; and is

The first approximate torque signal is modified based on the EM anti-torque signal measured in/at the motor to facilitate determination of a more accurate second approximate torque signal.

Further advantageous embodiments of the invention result from the dependent claims and the following description of preferred embodiments of the invention.

A control device according to the invention for correcting a torque determination for an internal combustion engine in a hybrid vehicle is set up to determine a first approximation torque signal of an actual torque curve of the internal combustion engine adjusted on the basis of a setpoint torque signal and to correct the first approximation torque signal on the basis of an EM reaction torque signal measured in/at the electric machine in order to determine a more precise second approximation torque signal.

The control device for an internal combustion engine can in principle be an Engine Control Unit (ECU) for an internal combustion engine, which receives sensor signals from sensors installed in/at the internal combustion engine (e.g. crankshaft and camshaft sensors, mass air flow sensors, oxygen sensors, intake manifold pressure sensors, temperature sensors, etc.) on the one hand and signals generated by the driver (e.g. accelerator pedal angle, brake signals, driving speed regulation, etc.) via an interface to a bus system on the other hand. Furthermore, the control device can exchange data with a further controller installed in the vehicle, for example a controller for the electric Machine (MCU), a drive train controller (PCU) in a hybrid vehicle or a gearbox controller in a parallel drive train of a hybrid vehicle. The drive train controller may, for example, record and coordinate the determined operating conditions of the hybrid vehicle.

Usually, however, several of the above-mentioned control devices and controllers or further control devices and controllers installed in the hybrid vehicle may also be combined in one. For example, the control device for the internal combustion engine can also be integrated in the drive train controller or combined with the controller for the electric machine or the like. In such an embodiment, the correction of the torque determination can therefore also be carried out in a control device for the internal combustion engine, which control device can then be understood as a component or a functional unit in the superordinate controller, for example. Therefore, the embodiment as a separate control device for an internal combustion engine should not be construed as limiting.

Furthermore, the control device for an internal combustion engine can store operating-related programs and data, characteristic maps (torque characteristic maps or torque variation characteristic maps), and the like in the memory. Correction values for the different operating variables and regulating variables (which may change over time, since, for example, the control device has already carried out a correction method) may likewise be held in the memory.

From the stored data and the signals obtained (operating variables in this case), the control device for the internal combustion engine can determine further manipulated variables (for example, the fuel quality supplied, the required setpoint torque, etc.) which are important for setting the operating range of the internal combustion engine (for example, the rotational speed and the required setpoint torque signal) and it can thus determine the necessary manipulated variables for the actuators installed in the internal combustion engine and actuate them accordingly.

In order to perform the above functions, the control device has electronic components, a memory unit, a circuit, and the like. For example, the control device may include one or more processors (CPUs), one or more microcontrollers, FPGAs, and the like. The memory unit may be, for example, a magnetic memory or a semiconductor memory. The interface to the bus system may be, for example, a CAN interface to facilitate communication with the CAN bus system. The bus system may likewise be LIN or FlexRay or the like.

The internal combustion engine can in principle be any internal combustion engine, such as a gasoline engine, a diesel engine, etc.

The hybrid vehicle may be a vehicle with a parallel or series drive train, wherein the hybrid vehicle has an internal combustion engine and at least one electric machine. Furthermore, hybrid vehicles with a parallel drive train have a gearbox. The motor may be a synchronous or asynchronous motor.

The torque present at the gearbox in a hybrid vehicle with a parallel drive train (referred to below as the gearbox input torque) is statically the sum of the actual torque of the internal combustion engine and the (actual) EM torque of the electric machine.

As mentioned above, the determination of the actual torque curve of the internal combustion engine (which is unknown due to the absence of sensors) is often inaccurate. It is therefore desirable to perform a correction of the torque determination in order to obtain a more accurate value.

The control device determines a first approximation torque signal of the actual torque curve. This can be determined, as mentioned above, for example on the basis of the supplied fuel mass and the estimate of the friction torque or from a torque characteristic map for the respective operating range of the internal combustion engine (for example the rotational speed and the requested setpoint torque signal).

The first approximation torque signal may be an absolute torque or a torque variation. The first approximation torque signal may be, for example, a single value at a specific time and/or in a specific operating state (e.g., vehicle stopped, braking, etc.) and/or in a specific operating range of the actual torque curve. The first approximation torque signal may be a time sample of the actual torque curve composed of a plurality of values.

The actual torque curve is set on the basis of a setpoint torque signal, which, as mentioned above, is determined from the different operating variables in the control device for the internal combustion engine and which yields the requested setpoint torque signal. The required setpoint torque signal can also be applied independently of this to the test torque signal in order to generate the setpoint torque signal.

The accuracy of the first approximation torque signal can be improved in that the electric machine present in the drive train of the hybrid vehicle is taken into account for measuring an absolute torque or a torque change. The reason for this is, in particular, that the determination of the EM anti-torque signal can be achieved significantly more accurately on the basis of more accurate sensors installed in/at the electric machine. The controller of the electric machine, which is present in the drive train, determines an EM anti-torque signal from the sensor signal generated in the electric machine, which corresponds very precisely to the (actual) EM torque or the (actual) EM torque variation.

In order to determine the EM reaction torque signal, the actual torque curve generated by the internal combustion engine in suitable operating conditions is compensated for by a reaction torque of the same magnitude at the electric motor. The counter torque can be determined relatively accurately in the control of the electric machine as mentioned above.

For example, for the execution of the correction, the drive train control can determine, for example, from various sensor signals (for example, the speed of the vehicle, the pedal angle, the rotational speed, the brake signal, the disengaged clutch, etc.), whether the transmission input torque is zero or remains statically constant. The opening of the clutch is for example performed by the gearbox controller and can be accurately detected.

If, for example, the transmission input torque is zero (idle, coasting with disengaged clutch, vehicle stop), since the clutch is disengaged, it can be unambiguously detected and the EM torque can then be adjusted such that it exactly compensates the actual torque curve. The EM anti-torque signal thus obtained may be used to determine a correction to the first approximation torque signal in order to determine a more accurate second approximation torque signal.

In general, the requirements for performing the correction can however be limited by different sensor signals.

In the case of an offset (test torque signal) applied to the internal combustion engine, the electric machine can be adjusted such that it produces exactly the offset counter torque in order to keep the transmission input torque constant. The counter-torque of the motor can be measured very accurately, so that an EM counter-torque signal for correction is obtained.

The controller of the electric machine can transmit the EM anti-torque signal to a control device of the internal combustion engine. Thus, the first approximate torque signal is modified based on the EM anti-torque signal measured in/at the motor in order to determine a more accurate second approximate torque signal.

The second, more accurate approximation torque signal can then be used to determine a manipulated variable of the internal combustion engine. Furthermore, a more precise second approximation torque signal for each operating range of the internal combustion engine can be stored in the control device and thus a corrected, more precise torque characteristic map and/or torque characteristic map can be obtained. Furthermore, the deviation between the first approximation torque signal and the EM torque signal can also be recorded (eigenragen) in the torque correction characteristic map, so that a more precise second approximation torque signal is then determined during driving operation as the sum of the first approximation torque signal and the correction value from the torque correction characteristic map. This can be done for absolute torques (torque correction characteristic map) and for torque changes (torque change correction characteristic map).

In this case, the characteristic diagram is a tabular, simple and less computationally demanding type of model which reflects the relationship between the input variables and the output variables of the system. It is therefore used in controllers, in particular also for adapting characteristic maps. In the case of fitting a family of characteristic curves, the value (content) during operation can be changed depending on the measurement result or calculation result (fitting result).

Almost any mathematical relationship or any formula can be described using characteristic maps, wherein the number of input variables is limited. At present, characteristic maps with up to four input variables are known in the control unit.

Further methods for storing the adaptation results in the control device and the controller may be, for example, physical models, polynomial models, neural networks or Local Linear Model Trees, which are suitable as alternatives to the use of characteristic curve families. These methods require less memory and can handle a higher number of input variables, however they require more computational effort. These methods are currently used less frequently, since parameterization (e.g. training of neural networks) requires a lot of time and computational effort.

In methods with artificial intelligence, neural networks are currently emerging and are incorporated into vehicle controllers, for example, in controllers for automatic driving or voice input.

In principle, these methods are also suitable as alternatives for the torque characteristic map or the heating value characteristic map or their correction characteristic maps and can be used in vehicles as the calculated power increases.

Likewise, the adaptation result (correction value) can also be transmitted to the cloud and stored there (for example in a memory on a server), for example via a network connection (for example a wireless network connection). The correction value for the determined operating range can be requested in such an embodiment via the network connection, so that the more precise second approximation torque signal is then determined during driving operation as the sum of the first approximation torque signal and the correction value from the cloud.

Furthermore, the above method can also be extended to the cloud and no longer be computed in the controller but in the cloud. This is also conceivable in a control device for an internal combustion engine for the torque determination described herein, which is then implemented wholly or partially in the cloud.

A more precise determination of the actual torque curve of the internal combustion engine by means of the electric machine present in the hybrid vehicle is advantageous, since no additional sensors or components have to be installed in the internal combustion engine and are therefore cost-effective. Furthermore, the fuel mass and/or the air-fuel ratio can thereby be adjusted more precisely in a certain operating range. This is therefore also important, for example, for exhaust gas aftertreatment.

Furthermore, the accuracy of the interaction between the internal combustion engine, the electric machine and the gearbox can be improved in hybrid vehicles with a parallel drive train having a gearbox. This can have a clearly positive effect, for example, when starting the internal combustion engine, when shifting the transmission or changing the load, or in general in dynamic operating situations.

In some embodiments, the control means is arranged to apply the test torque signal to a required rated torque signal in order to generate the rated torque signal.

The test torque signal may be, for example, an additional torque (increase or decrease) for a shorter period of time, which may cause a smaller change in the actual torque curve. However, it can also consist of a plurality of additional torques applied one after the other.

The manipulated variable of the internal combustion engine is adjusted as a function of the setpoint torque signal and therefore deviates from the requested setpoint torque signal when the test torque signal is applied. Accordingly, the internal combustion engine is responsive to the test torque signal. The magnitude of the test torque signal is small compared to the required nominal torque signal.

If the test torque signal is an additional torque (increase or decrease) for a shorter period of time, in such an embodiment the first approximation of the actual torque curve is an estimate of the variation of the actual torque curve in the operating range of the internal combustion engine. This variation is compensated by the motor as described above and is measured relatively accurately so that the EM anti-torque signal can be used to correct the first approximate torque signal. Thus, torque variations in such embodiments may be more accurately determined over a certain operating range.

The deviation between the first approximate torque signal and the EM anti-torque signal indicates an increased tolerance, aging or an error or defect in the internal combustion engine, such as a faulty fuel metering (e.g. of an injector or the like) or a faulty air mass flow (e.g. due to a faulty sensor, a non-sealed intake pipe, a damaged turbocharger or the like).

In some embodiments, the test torque signal is comprised of a plurality of test torque pulses.

The test torque signal may, for example, represent a binary pseudo-random signal (PRBS) with a predetermined number of test torque pulses, and thus a predetermined duration, in time, wherein the test torque pulses have a smaller amplitude. The control device for an internal combustion engine can have a test sample generator for this purpose.

In such embodiments, the value of the first approximation torque signal and the value of the EM anti-torque signal (the torque change in the actual torque curve) may be determined at each new test torque pulse, with the EM anti-torque signal compensating the test torque pulse as good as possible. In the case where the correlation (korrilation) of all values at the end of the torque signal is tested, each value of the first approximation torque signal may be corrected based on the EM anti-torque signal.

Correlation (e.g., cross-correlation) is a statistical method for determining a statistical relationship between two signals. One advantage of correlation is that the correlation is very sensitive and at the same time not prone to interference. In this way, even small torque changes in the actual torque curve can be detected in the normal driving mode or in the dynamic operating mode.

In some embodiments, the control means is arranged to modify the EM anti-torque signal based on the required nominal torque signal so as to obtain a modified EM anti-torque signal.

In normal driving operation of the hybrid vehicle, the requested setpoint torque signal varies over time. In order to keep the influence of this change on the correlation determination, for example, low, the required setpoint torque can be taken into account for correcting the EM anti-torque signal. For example, the rise in the required setpoint torque in the case of acceleration of the hybrid vehicle can be calculated from the EM anti-torque signal accordingly, in order to obtain a corrected EM anti-torque signal.

In some embodiments, the control means additionally has at least one shift register (schiebergister) and is configured to store in the shift register a plurality of values of the summed input signal consisting of the demanded nominal torque signal and the first approximated torque signal and the output signal corresponding to the modified EM anti-torque signal at times within the duration of the test torque signal.

The shift register or registers are, for example, logic switching mechanisms which can be formed by a series connection of memory cells which can preferably store integer values and which can operate according to the FIFO principle (first-in first-out).

The control variable for controlling the internal combustion engine is set as a function of the setpoint torque signal. If for example a test torque signal consisting of a plurality of test torque pulses is applied for the required setpoint torque, the change in the actual torque curve caused by the test torque pulses can be estimated as a first approximation torque signal. Thus, the value determined for each test torque pulse of the sum of the first approximation torque signal and the demanded rated torque forms an input signal for determining a correlation with the output signal, which in such embodiments is a modified EM anti-torque signal.

The shift register is preferably designed such that all values can be stored until the test torque signal ends.

In some embodiments, the instants of time at which the values of the input signal and the output signal differ by a predetermined time delay.

In general, it is conceivable for the internal combustion engine to carry out the applied test torque pulses with a time delay. In such cases, it is therefore expedient to determine the value of the output signal (corrected EM anti-torque signal) with the same time delay in order to achieve the greatest possible correlation of the input signal and the output signal.

In some embodiments, the control means is arranged to determine the correlation coefficient from stored values of the input signal and the output signal.

The correlation coefficient (CCC) is a statistical variable and is a measure for the similarity between two signals or for the statistical relationship between two signals. For example, a correlation coefficient of 1 is obtained for the same signal curve and for a direct relationship between the two signals. Conversely, a value of 0 means that there is no similarity between the signals.

In some embodiments, the time delay is selected according to the maximum value of the correlation coefficient.

Thereby, the relation between the two signals is maximal and the correction of the first approximation torque signal becomes feasible and more accurate. The time delay may be determined experimentally for each operating range.

In some embodiments, the controller is configured to determine a weighting factor (gewichtungfaktor) from the stored values of the input signal and the output signal.

In some embodiments, the control means is arranged to determine a more accurate second approximation torque signal based on the stored value of the output signal and the weighting factor.

In some embodiments, the control means is arranged to determine the more accurate second approximation torque signal only when the correlation coefficient exceeds a predetermined threshold.

The modification of the first approximation torque signal based on the stored value of the output signal and the weighting factor is only meaningful if the input signal and the output signal have a certain degree of similarity.

In some embodiments, the control device is set to determine the more accurate second approximation torque signal only when one or more release conditions (freebiabeddingung) are met.

The release conditions may be: the maximum torque of the electric machine is greater than or equal to the maximum torque of the internal combustion engine, the rotational speed is in the permitted range, the load is in the permitted range, the rotational speed and the load dynamics, the ambient pressure is below a limit value, the ambient temperature is above a limit value, the cooling water temperature is above a limit value, the on-board system voltage is in the permitted range, the diagnosis of all the involved sensors and actuators is carried out completely and no error is recognized, the waiting time for repeated correction expires at the current operating point and the transmission input torque is constant or variable. As an alternative to time, for example, a selectable number of starts of the internal combustion engine or a distance traveled may also be used.

In the case of a correction of the absolute torque, the transmission input torque must furthermore be zero or known.

Furthermore, the execution of the correction torque determination may be interrupted when the release condition is no longer fulfilled, because a very high inaccuracy of the result may be expected. The above conditions therefore also have to be continuously checked during the defined activation of the correction torque.

Some embodiments relate to a drive train for a hybrid vehicle having a control arrangement for an internal combustion engine as described herein.

Some embodiments relate to a hybrid vehicle, wherein the hybrid vehicle has a driveline as described herein.

Some embodiments relate to a method for correcting torque determination in a control apparatus for an internal combustion engine, wherein the method includes:

Drawings

Embodiments of the invention are now described, by way of example and with reference to the accompanying drawings, in which:

fig. 1 schematically shows the structure of a parallel drive train in the form of a P1 arrangement in a hybrid vehicle.

Detailed Description

Parallel drivetrain 1 in the form of a P1 arrangement has an internal combustion engine 2, which produces an actual torque curve M at a crankshaft 3_V. The electric machine 4 is present in parallel thereto and generates an EM torque M_EMWhich is additional to the actual torque curve M_VAnd (4) acting. The clutch 5 is located between the electric machine 4 and the gearbox 6. The gearbox input shaft 7 will be driven by the actual torque curve M of the internal combustion engine 2_VAnd EM torque M_EMThe sum of the components is transmitted to the gearbox, so that the gearbox input torque M is transmitted_TMinStatically is given by:

(1)

.

torque is transmitted to one or more wheels 8. The drive train controller 9 is connected via a bus system (CAN bus system here) to a control device for the internal combustion engine 10 and to a controller for the electric machine 11. The controller for the electric motor 11 controls the electric motor 4 via the power electronics 12.

In this embodiment, the drive train controller 9, the control device for the internal combustion engine 10 and the controller for the electric machine 11 are each implemented as a separate control device and controller. However, this is by no means to be construed as limiting, as mentioned above.

Due to the EM torque M induced by the controller of the motor 11_EMThe detection of the current, voltage and operating frequency (caused by the power electronics 12) can be achieved significantly more precisely by means of relatively precise current sensors which can be provided inexpensively, the actual torque curve M_VCan be easily determined from the above equation if the transmission input torque M_TMinAre known.

However, for cost reasons and installation space reasons, no parallel drive train 1 in the form of a P1 arrangement is installed for M_TMinThe sensor of (1). The absolute torque in the operating range of internal combustion engine 2 is then determined in suitable operating situations in which the wheel torque requested by the driver is equal to zero (pushing, braking, coasting with a disengaged clutch, vehicle stopping, slight downhill slope, etc.), since then in the static state the transmission input torque M is_TMinAlso equal to zero. The operating conditions are identified and controlled by the drive train controller 9, that is to say the determination is interrupted as soon as the operating conditions no longer exist (release condition). For this purpose, the drive train controller 9 sends a release signal to the control device for the internal combustion engine 10.

The release conditions in this example are: the maximum torque of the electric machine 4 is greater than or equal to the maximum torque of the internal combustion engine 2, the rotational speed is in the permitted range, the load is in the permitted range, the ambient pressure is below a limit value, the ambient temperature is above a limit value, the cooling water temperature is above a limit value, the on-board system voltage is in the permitted range, all diagnostics relating to sensors and actuators are carried out completely and no error is recognized, the waiting time for repeated correction expires in the current operating range and the transmission input torque is zero or known.

The control device for the internal combustion engine 10 then determines the actual torque curve M_VFirst approximation torque signal M_VEi。

EM torque M_EMIs adjusted so that the counter torque with respect to the internal combustion engine is electrically accurately generated. The EM anti-torque signal M measured in/at the electric machine 4_EMi(calculated in the control unit of the electric machine 12) is then taken into account for correcting the torque determination in the control unit for the internal combustion engine 10. At a first approximate torque signal M_VEiWith EM counter-torque signal M_EMiAbsolute torque deviation Δ M therebetween_VEidIs given by (only the absolute values of the variables are considered below):

(2)

.

here, the index k indicates that the deviation is specific to the operating range of the internal combustion engine.

For the first approximate torque signal M_VEiThen a more accurate second approximation torque signal M is obtained_VEikIt is calculated as follows:

(3)

.

in this embodiment, the detected deviation Δ M_VEid(k) In turn, measured in different operating ranges with the index k and entered into the torque correction characteristic map. The correction values for the different operating ranges with index k must be determined in succession. If necessary, it is also necessary to carry out a plurality of measurements in succession for the operating point k, depending on the accuracy requirements, and to average these results.

Fig. 2 schematically shows the structure of a parallel drivetrain 20 in the form of a P2 arrangement in a hybrid vehicle.

In a parallel drive train in the P2 arrangement, only the order of the clutch 5 and the electric machine 4 is swapped. The above is therefore also valid in this embodiment.

In this embodiment, the drive train controller 9, the control device for the internal combustion engine 10 and the controller for the electric machine 11 are implemented as separate control devices and controllers, respectively. This should however not be construed as limiting in any way as mentioned above.

Fig. 3 schematically shows the structure of a series drive train 30 in a hybrid vehicle.

The series drive train 30 does not have a gearbox 6. The internal combustion engine 2 is used in this arrangement to charge the traction battery 13 via the electric machine 4 in the generating mode. The hybrid vehicle is driven via a second electric machine 14, which is supplied with energy via a traction battery 13.

In the series drive train 30, the transmission input torque M_TMinIs always equal to zero in the static state, since there is no gearbox 6. Thus, the second approximation torque signal can always be determined as an absolute torque in the series drive train 30 in accordance with the above considerations. The drive train controller 9 therefore always sends a release signal to the control device for the internal combustion engine 10, as long as the following release conditions are fulfilled: the maximum torque of the electric machine 4 is greater than or equal to the maximum torque of the internal combustion engine 2, the rotational speed is in the permitted range, the load is in the permitted range, the ambient pressure is below the limit value, the ambient temperature is above the limit value, the cooling water temperature is above the limit value, the on-board system voltage is in the permitted range, the diagnosis of all the sensors and actuators involved is carried out completely and no error is recognized, and the waiting time for repeated correction expires in the current operating range.

In this embodiment, the drive train controller 9, the control device for the internal combustion engine 10 and the controller for the electric machine 11 are each implemented as a separate control device and controller. However, as mentioned above, this should in no way be understood as limiting.

Fig. 4 shows an embodiment of a correction for determining a torque variation of the internal combustion engine 2.

In the following, the method illustrated in fig. 4 is premised on the

parallel drive trains

1 and 20 of the exemplary embodiments of fig. 1 and 2. The precondition for the method described in relation to fig. 1 and 2 for determining the correction of the absolute torque of the internal combustion engine 2 by means of the electric machine 4 installed in a hybrid vehicle with

parallel drives

1 and 20 is the known transmission input torque M_TMin. Therefore, this method is mostly not available during driving, because M_TMinNot measurable during driving.

However, the method shown in fig. 4 enables a corrected determination of the torque variation for the internal combustion engine 2. The operating conditions shown in fig. 4 correspond to a speed-regulated drive on a level road, so that the transmission input torque is to be constant over the period of the correction method.

In 41, a test torque signal is applied to the requested setpoint torque, which corresponds to a short-term increase in the setpoint torque signal. This causes a change Δ M in the actual torque curve (which would otherwise not have occurred due to the operating conditions assumed here) set at 42_V。

At 42, the change Δ M of the regulated actual torque curve is thus detected by the drive train controller 9_VAnd will generate an EM torque variation Δ M in the electrical machine 4_EMIs given to the controller of the electric machine 11, said EM torque variation exactly compensating the actual torque curve Δ M_VSo as to input the gearbox with a torque M_TMinAnd remain constant. It is adjusted at 43 so that the transmission input torque M_TMinAn initial value is assumed or an initial operating condition is established. Since statically should apply as follows:

(4)

a first approximation torque signal Δ M is then determined in the control device for the internal combustion engine 10 between 43 and 44_VEi(which in this embodiment is a torque variation) and determining the EM anti-torque signal Δ M in the controller of the electric machine 11_EMi. Then determined to be in the firstApproximate torque signal Δ M_VEiAnd EM counter torque signal Δ M_EMiTorque change Δ Δ M of_VEidDeviation therebetween:

(5)

.

For the first approximate torque signal Delta M_VEiThen a more accurate second approximation torque signal deltam is obtained_VEikIt is calculated as follows:

(6)

.

in this embodiment, the detected deviation Δ Δ M_VEid(k) In turn, measured in different operating ranges with the index k and entered into the torque curve correction characteristic map. The correction values for the different operating ranges with index k must be determined in succession. If necessary, it is also necessary to carry out a plurality of measurements in turn for each operating point k, depending on the accuracy requirements, and to average the results.

Determination of the first approximation torque signal Δ M by the control device for the internal combustion engine 10 at the operating point with index k_VEi(k) = 5 Nm. However, the actual torque curve of the internal combustion engine 2 changes only by Δ M_V= 4 Nm (because too little additional fuel is injected). EM counter-torque signal is also Δ M_EMi(k) = 4 Nm. Therefore, the correction value becomes Δ Δ M_VEid(k) A second approximation torque signal that is more accurate than 1 Nm is Δ M_VEik(k) = 4 Nm。

The release conditions in this example are: the maximum torque of the electric machine 4 is greater than or equal to the maximum torque of the internal combustion engine 2, the rotational speed is in the permitted range, the load is in the permitted range, the rotational speed and load dynamics are in the permitted range, the ambient pressure is below a limit value, the ambient temperature is above a limit value, the cooling water temperature is above a limit value, the vehicle electrical system voltage is in the permitted range, the diagnosis of all the sensors and actuators involved is carried out completely and no error is recognized, the waiting time for repeated correction is full in the current operating range and the transmission input torque is constant.

This method is advantageous because it can be carried out during driving (in the case of constant operating conditions) and is not expected to influence the driving behavior, the operating smoothness of the internal combustion engine or emissions, because of the change Δ M of the actual torque curve_VThe required amplitude of (c) is so small that it is not perceptible.

Fig. 5 shows an exemplary embodiment of a control device for an internal combustion engine 10 in a hybrid vehicle with

parallel drive trains

1 and 20.

The precondition for the method described with respect to fig. 4 for determining a correction of the torque change of the internal combustion engine 2 by means of the electric machine 4 installed in a hybrid vehicle with

parallel drives

1 and 20 is a constant transmission input torque M_TMin. This is very rare or often not long enough in real operating conditions. However, it is possible to determine the change in the actual torque curve more precisely in the case of a variable actual torque curve or a variable setpoint torque signal during driving, by means of a method referred to below as a correlation method.

In this embodiment, the control device for the internal combustion engine 10 and the controller for the electric motor 11 are implemented as separate control devices and controllers, respectively. This should however not be construed as limiting in any way as mentioned above.

The release conditions for the correlation method are: the maximum torque of the electric machine 4 is greater than or equal to the maximum torque of the internal combustion engine 2, the rotational speed is in the permitted range, the load is in the permitted range, the rotational speed and load dynamics are in the permitted range, the ambient pressure is below a limit value, the ambient temperature is above a limit value, the cooling water temperature is above a limit value, the vehicle electrical system voltage is in the permitted range, the diagnosis of all the sensors and actuators involved is carried out completely, no error is detected, and the waiting time for repeated correction expires in the current operating range.

The control device for the internal combustion engine 10 has a processor 50 with an integrated memory, which coordinates and partially assumes the basic control tasks described above. The processor 50 with integrated memory can in principle access all other components described below and exchange data and signals. The processor 50 with integrated memory unlocks the dependency method in case the release condition is met.

The division of the control device for an internal combustion engine into components is merely intended to illustrate and describe the operating principle and should not be understood as limiting in any way.

The control device for an internal combustion engine 10 has a setpoint calculation means 51 which determines a requested setpoint torque signal M_VEs. The test sample generator 52 generates a test torque signal, in this embodiment by a test torque pulse Δ M_VEsi(i = 1, …, N) to a desired nominal torque signal M, a test torque pulse being applied to the desired nominal torque signal M_VEsIn order to generate a nominal torque signal. From the setpoint torque signal, the manipulated variable part 53 determines a manipulated variable for actuating the actuator in order to correspondingly adjust the internal combustion engine 2. The manipulated variable is transmitted via CAN interface 54 to CAN bus system 55 to internal combustion engine 2.

The actual torque curve M is then set_V. By testing the torque pulse Δ M_VEsiInfluencing the actual torque curve M_VAnd determining a first approximation torque signal Δ M_VEi. Required rated torque signal M_VEsAnd a first approximation torque signal Δ M_VEiThe sum of the components forms the input signal x_i(i = 1,…,N)：

(7)

.

Input signal xi for each test torque pulse Δ M_VEsiAnd is stored in the shift register 56.

The electric machine 4 is now adjusted such that the torque pulse Δ M is detected_VEsiThe resulting change in the actual torque curve M_VIs compensated as good as possible. Because of the variable desired rated torque signal M_VEs(dynamic operating conditions) act like disturbancesActing so that the actual torque curve M_VBy a test torque pulse Δ M_VEsiThe induced variations may not be exactly compensated as in the above described embodiments. Thus, the regulation is relative to the test torque pulse Δ M_VEsiThe time delay (time delay τ) is performed. The time delay tau is determined experimentally in order to achieve the desired effect on the input signal x_iA higher statistical relationship with the compensation by the motor 4, as described below.

EM counter torque signal Δ M_EMiMeasured in/at the motor and transmitted to the dynamic correction component 57 via the CAN bus system. The dynamic correction means 57 is based on the required nominal torque signal M_VEsThe EM counter-torque signal Δ M is modified as follows_EMiI.e. from the EM counter-torque signal DeltaM_EMiSubtracting the dynamic correction value a_dki. Thereby, the system impact can be reduced. This results in a corrected EM anti-torque signal and forms the output signal y_j(j=1,…N)：

(8)

.

Output signal y_jFor each test torque pulse Δ M_VEsiAnd is stored in the shift register 58.

Correlator 59 accesses input signal x in

shift registers

56 and 58_iAnd an output signal y_jIn order to calculate the correlation coefficient CCC and the weighting factor b_yx. The correlation coefficient CCC is between 0 and 1 and is for the input signal x_iAnd an output signal y_jA measure of similarity or consistency. A correlation coefficient of 1 is obtained for the same signal curve and means a direct relationship between the two signals. Conversely, a value of 0 means that there is no similarity between the signals.

Correlation coefficient CCC and weighting factor b_yxThe following calculations are made:

(9)

,

(10)

,

(11)

,

(12)

,

(13)

.

here, AM (x)_i) And AM (y)_j) Is the arithmetic mean of the input signal xi and the output signal yj. If the correlation coefficient CCC exceeds a certain threshold value CCCs, the two signals have such a high degree of agreement that a more accurate second approximation torque signal Δ M_VEikThe determination of (2) is feasible. The time delay τ is set according to the largest correlation coefficient. More accurate second approximation torque signal Δ M_VEikThen it is calculated as follows:

(14)

.

here, factor f_mk(k) Is a correction factor characteristic curve family, by means of which the second approximation torque signal Δ M is compensated for more precisely on the basis of the system influence_VEikAnd EM counter torque signal Δ M_EMiThe amplitude deviation therebetween. In the best case, f_mk(k) Are both 1.

In this embodiment, the more accurate second approximation torque signal Δ M_VEik(k) In turn, measured in different operating ranges with the index k and entered into the torque curve map 60. The correction values for the different operating ranges with index k must be determined in succession. If necessary, it is also necessary to carry out a plurality of measurements for each operating point k in turn, depending on the accuracy requirementsAmount and average the results.

The correlation method is advantageous in that it can be performed during driving and is not expected to affect driving characteristics, smoothness of the internal combustion engine, or emissions. In the described correlation method, the torque pulses Δ M are tested_VEsiThe required amplitude of (i = 1, …, N) is so small that it is not perceptible. By means of the correlation method, the actual torque curve M can also be checked in normal driving operation or dynamic operating conditions_VEven a small torque variation.

FIG. 6 shows a dynamic correction value a for the correlation method_dkiModifying EM counter-torque signal Δ M_EMiThe principle of (1).

The operating condition in fig. 6 is a hybrid vehicle being accelerated in which the correlation method is applied. The requested setpoint torque signal rises accordingly as a result of the acceleration. Because of the variable desired rated torque signal M_VEs(dynamic operating conditions) act as disturbances, the actual torque curve MV being determined by the test torque pulses Δ M_VEsiThe induced variations may not be exactly compensated as in the above described embodiments. Thus, the EM counter-torque signal Δ M_EMiAnd ascends systematically.

In order to reduce the systematic influence on the correlation determination and thus to increase the accuracy of the method, the EM anti-torque signal Δ M_EMiBy dynamic correction of value a_dkiIs modified so as to obtain a modified EM counter-torque signal, which forms the output signal y_j. Thus, at the output signal y_jAlso included in the EM counter-torque signal Δ M_EMiActual torque curve M in_VBy a test torque pulse Δ M_VEsiThe portion of the change caused. Thereby, the correlation coefficient CCC becomes larger.

Fig. 7 shows a flowchart for correcting the torque determination in the control apparatus for an internal combustion engine.

The embodiments according to fig. 1 and 2 are involved in the method. This should in no way be construed as limiting.

At 65, an actual torque curve of the internal combustion engine 2 adjusted on the basis of the setpoint torque signal is determinedLine M_VFirst approximation torque signal M_VEiAs described above.

At 66, based on the measured EM anti-torque signal M in/at the motor_VEiModifying the first approximation torque signal M_EMiIn order to determine a more accurate second approximation torque signal M_VEikAs described above.

FIG. 8 illustrates a flow chart for performing a correlation method.

The embodiment according to fig. 5 is involved in the method.

At 70, the internal combustion engine is started and initialized.

At 71, if a release condition is satisfied (as described above), a correlation method is initiated.

At 72, the torque pulse Δ M will be tested_VEsiApplied to the desired rated torque signal M_VEsAs described above.

At 73, a first approximation torque signal Δ M is determined_VEiAnd will input signal x_iStored in shift register 56 as described above.

At 74, in the actual torque curve M_VIn order to compensate for the test torque pulses Δ M by the electric machine 4 as well as possible_VEsiInduced changes and determining the EM counter-torque signal Δ M_EMi. Then, the dynamic correction value a is subtracted_dkiAnd forms an output signal y_jAnd the output signal is held in the shift register 58 as described above.

It is checked in 75 whether the release condition is still fulfilled. If not, step 71 is repeated.

If 75 is true, it is checked 76 whether the test torque signal is over. If not, step 72 is repeated.

If 76 is true, the correlation coefficient CCC is calculated at 77, as described above.

It is checked at 78 whether CCC exceeds a threshold CCCs. If not, step 71 is repeated.

If 78 yes, a weighting factor b is determined 79_yxAnd a more accurate second approximation torque signal Δ M_VEikAs described above.

At 80, a second more accurate approximation torque signal Δ M is determined in turn in different operating ranges with an index k_VEik(k) And is entered into the torque variation correction characteristic map 60. Immediately thereafter, step 71 is repeated. List of reference numerals:

1 parallel drive train in P1 arrangement

2 internal combustion engine

3 crankshaft

4 electric machine

5 Clutch

6 speed changing box

7 gearbox input shaft

8 wheel

9 drive train controller

10 control device for internal combustion engine

11 controller for an electric machine

12 power electronic device

13 traction battery

14 second electric machine

20 parallel drive train in P2 arrangement

30 series type transmission system

50 processor with integrated memory

51 rating calculating component

52 test sample generator

53 regulating variable part

54 CAN interface

55 CAN bus system

56 Shift register

57 dynamic correction component

58 shift register

59 correlator

60 family of torque variation correction characteristics

M_VActual torque curve

ΔM_VActual rotating deviceVariation of the moment curve

M_EMEM torque

ΔM_EMEM torque variation

M_TMinInput torque of gearbox

M_VEsRequired rated torque signal

ΔM_VEsiTesting torque pulses

M_VEi,ΔM_VEiFirst approximate torque signal

M_EMi,ΔM_EMiEM counter torque signal

ΔM_VEidDeviation of absolute torque

ΔΔM_VEidDeviation between torque changes

M_VEik,ΔM_VEikMore accurate second approximation torque signal

x_iInput signal

y_jOutput signal

a_dkiDynamic correction value

Tau time delay

Coefficient of CCC correlation

CCCs threshold

b_yxWeighting factor

f_mkFamily of correction factor characteristic curves

k is indexed.

Claims

1. A control device for correcting a torque determination for an internal combustion engine in a hybrid vehicle is configured to determine a first approximation torque signal of an actual torque curve of the internal combustion engine adjusted on the basis of a setpoint torque signal and to correct the first approximation torque signal on the basis of an EM counter-torque signal measured in/at an electric machine in order to determine a more accurate second approximation torque signal.

2. A control device according to claim 1, wherein the control device is arranged to apply a test torque signal to a demanded nominal torque signal in order to generate the nominal torque signal.

3. The control device of claim 2, wherein the test torque signal is comprised of a plurality of test torque pulses.

4. A control apparatus according to claim 2 or claim 3, wherein the control apparatus is arranged to modify the EM anti-torque signal based on a required nominal torque signal so as to obtain a modified EM anti-torque signal.

5. A control apparatus according to claim 4, wherein the control apparatus additionally has at least one shift register and the control apparatus is arranged to store in the shift register a plurality of values of the input signal which is a sum of the demanded nominal torque signal and the first approximated torque signal and a plurality of values of the output signal corresponding to the modified EM reaction torque signal at times within the duration of the test torque signal.

6. A control apparatus according to claim 5, wherein the values of the input and output signals differ in time by a predetermined time delay.

7. A control device according to claim 6, wherein the control device is arranged to determine a correlation coefficient from the stored values of the input and output signals.

8. The control device of claim 7, wherein the time delay is selected according to a maximum value of the correlation coefficient.

9. A control device according to any one of claims 6 to 8, wherein the control device is arranged to determine weighting factors from the stored values of the input and output signals.

10. A control arrangement according to claim 9, wherein the control arrangement is arranged to determine the second approximation torque signal on the basis of the stored value of the output signal and the weighting factor.

11. A control arrangement according to claim 10, wherein the control arrangement is configured to determine the second approximation torque signal only if the correlation coefficient exceeds a predetermined threshold.

12. A control arrangement according to any one of the preceding claims, wherein the control arrangement is arranged to determine the second approximation torque signal only when one or more release conditions are met.

13. Drive train for a hybrid vehicle having a control device for an internal combustion engine according to any one of the preceding claims.

14. Hybrid vehicle, wherein the hybrid vehicle has a drive train according to claim 14.

15. Method for correcting torque determination in the control apparatus for an internal combustion engine according to any one of claims 1 to 12, wherein the method includes:

determining a first approximate torque signal of an actual torque curve of the internal combustion engine adjusted on the basis of a setpoint torque signal; and is

The first approximation torque signal is modified based on the measured EM anti-torque signal in/at the motor in order to determine a more accurate second approximation torque signal.