DE102019217334A1 - Method and control system for operating a drive train - Google Patents

Abstract

Method for operating a drive train of a motor vehicle with an internal combustion engine (1), with an electric machine (2), with a transmission (3), and with an output (4), the electric machine (2) between the internal combustion engine (1) and the transmission (3) is coupled to a transmission input shaft (5), and a disconnect clutch (6) is connected between the internal combustion engine (1) and the electrical machine (2), via which the internal combustion engine (1) is decoupled from the drive train and connected the same can be coupled. To carry out a shift in the transmission (3), an actual gear is designed, a target gear is engaged and, after the target gear of the shift has been engaged with the separating clutch (6) at least partially closed, an engine torque provided by the internal combustion engine (1) is dependent on a Setpoint gradient of a setpoint engine torque of the internal combustion engine (1) is increased in the direction of a torque desired by the driver. The actual gradient of the engine torque of the internal combustion engine that develops when the engine torque is increased is monitored. Then, if the actual gradient that forms when the engine torque of the internal combustion engine (1) increases, an additional torque is provided via the electric machine (2) such that the increase in the engine torque of the reduced as a result of the reduced actual gradient Internal combustion engine (1) is compensated by the torque provided by the electrical machine (2).

Description

The invention relates to a method for operating a drive train. The invention also relates to a control system for operating a drive train.

A drive train of a motor vehicle has a drive unit and a transmission connected between the drive unit and an output. The gearbox converts speeds and torques and thus provides the tractive power of the drive unit at the output.

In hybrid vehicles, the drive unit includes an electric machine in addition to an internal combustion engine. The electric machine is typically coupled to a transmission input shaft of the transmission and connected between the transmission and the internal combustion engine. A separating clutch is connected between the electrical machine and the internal combustion engine. When the separating clutch is open, the internal combustion engine is decoupled from the electrical machine and thus from the drive train. When the separating clutch is closed, on the other hand, the internal combustion engine is coupled to the drive train.

Then, when a shift and thus a gear change is to be carried out in the transmission, an actual gear of the shift is disengaged in the transmission and a target gear of the shift is engaged. From the DE 10 2010 043 530 A1 it is known in connection with the execution of a shift or a gear change in the transmission that when a shift is executed, a synchronization of the target gear is supported by the electrical machine with the disengaging clutch partially closed.

Also from the DE 10 2005 007 966 A1 details for operating a drive train of a motor vehicle with an electric machine, an internal combustion engine, a transmission and a clutch are known, it being disclosed here to carry out a targeted torque overlap of the electric machine and internal combustion engine in order to improve the load reduction or load build-up in gearshifts.

So far, it has been difficult to increase the torque applied to the transmission input or to a transmission input shaft harmoniously, in particular with a constant gradient, towards a torque desired by the driver after a shift has been carried out, i.e. after the target gear has been engaged in the transmission. One of the reasons for this is that when the engine torque provided by the internal combustion engine is increased, the gradient of the engine torque of the internal combustion engine can change unexpectedly, for example in order to comply with emission limit values of the internal combustion engine.

Proceeding from this, the invention is based on the object of creating a novel method for operating a drive train and a control system for operating a drive train. This object is achieved by a method for operating a drive train according to patent claim 1. Advantageous configurations emerge from the dependent claims, the description and the figures.

According to the invention, the actual gradient of the engine torque of the internal combustion engine that develops when the engine torque of the internal combustion engine is increased is monitored. Then, when the actual gradient of the engine torque of the internal combustion engine, which develops when the engine torque is increased, is reduced, according to the invention, an additional torque is provided via the electrical machine such that the increase in the engine torque of the internal combustion engine is reduced as a result of the reduced actual gradient is compensated for by the torque provided by the electrical machine.

With the present invention, it is proposed to monitor the actual gradient of the engine torque of the internal combustion engine, which develops when the engine torque provided by the internal combustion engine is increased after the shift has been carried out, i.e. after the target gear has been engaged in the transmission. If the actual gradient of the engine torque of the internal combustion engine decreases, then an additional torque is provided at the transmission input via the electrical machine. The additional torque at the transmission input is provided via the electrical machine in such a way that the increase in the engine torque of the internal combustion engine, which is reduced as a result of the reduced actual gradient of the engine torque of the internal combustion engine, is compensated for by the torque provided by the electrical machine.

The invention makes it possible to provide a harmonious load build-up after the actual circuit implementation, even if, for example, the actual gradient of the engine torque of the internal combustion engine changes due to compliance with emission regulations.

According to an advantageous development, torque is provided via the electrical machine in such a way that a gradient of the total torque from the engine torque of the internal combustion engine and the torque of the electrical machine corresponds to the target gradient of the target engine torque of the internal combustion engine, and a sum torque from the engine torque of the internal combustion engine and the torque of the electric machine corresponds at most to the torque requested by the driver. This is particularly preferred for a harmonious load build-up. During the load build-up, a constant torque gradient is made available on the transmission input shaft and thus at the transmission input. A reduction in the actual gradient of the engine torque of the internal combustion engine is compensated for by the electric machine. The total torque from the engine torque provided by the internal combustion engine and the torque provided by the electric machine corresponds at most to the torque requested by the driver.

Preferably, the torque provided by the electrical machine is first increased and then reduced again, preferably between a steady, in particular ramp-like or linear increase and a constant, in particular ramp-like or linear, reduction in the torque provided by the electrical machine that of the electrical machine provided moment is changed parabolically. This is particularly preferred for the desired harmonious load build-up. An abrupt change in the torque at the transmission input and thus in the gradient of the torque at the transmission input can be prevented via the parabolic change in the torque provided by the electrical machine between the preferably linear increase and preferably linear reduction in the torque provided by the electrical machine. This can reduce vibrations in the drive train and increase driving comfort.

According to an advantageous development, a dead time in the build-up of the engine torque of the internal combustion engine is also compensated for via the torque provided by the electrical machine. This allows the load to be built up even more harmoniously. A dead time on the internal combustion engine side in the engine torque build-up can be compensated for.

The control system according to the invention is defined in claim 9.

• 1 ein exemplarisches Antriebstrangschema eines Kraftfahrzeugs mit Baugruppen eines Steuerungssystems zum Betreiben eines Antriebsstrangs,
• 2 Details eines erfindungsgemäßen Verfahrens zum Betreiben eines Antriebsstrangs;
• 3 Details eines weiteren erfindungsgemäßen Verfahrens zum Betreiben eines Antriebsstrangs;
• 4 Details eines weiteren erfindungsgemäßen Verfahrens zum Betreiben eines Antriebsstrangs.

Preferred developments emerge from the subclaims and the following description. Exemplary embodiments of the invention are explained in more detail with reference to the drawing, without being restricted thereto. It shows:

• 1 an exemplary drive train diagram of a motor vehicle with assemblies of a control system for operating a drive train,
• 2 Details of a method according to the invention for operating a drive train;
• 3rd Details of a further method according to the invention for operating a drive train;
• 4th Details of a further method according to the invention for operating a drive train.

1 shows, in a highly schematic manner, a drive train of a motor vehicle with an internal combustion engine 1 , with an electric machine 2 , with a gear 3rd and with one output 4th . The electric machine 2 is between the internal combustion engine 1 and the transmission 3rd to a transmission input shaft 5 of the transmission 3rd switched. The gear 3rd is between the electric machine 2 and the downforce 4th switched. 1 also shows a disconnect clutch 6th that between the internal combustion engine 1 and the electric machine 2 is switched. With the separating clutch open 6th is the internal combustion engine 1 disconnected. With the separating clutch closed 6th is the internal combustion engine 1 coupled.

1 also shows assemblies of a control system of the drive train. So shows 1 an engine control unit 7th , which is the regulation and / or control of the operation of the internal combustion engine 1 serves. For regulating and / or controlling the operation of the transmission 3rd a transmission control unit is used 8th and for regulating and / or controlling the operation of the electrical machine 2 a hybrid control unit is used 9 , in the 1 are provided by a common assembly, in particular by a transmission control unit 8th into which the hybrid control unit 9 is integrated. Hybrid control unit 9 and gearbox control unit 8th can also be provided by separate control units. The dashed arrows of the 1 visualize a data exchange between the control units 7th , 8th and 9 and the assemblies operated by them 1 , 2 and 3rd of the drive train.

Then when in the transmission 3rd a shift or a gear change from an actual gear to a target gear is first carried out in the transmission 3rd the actual gear and then the target gear in the transmission 3rd inserted. The transmission is then located between disengaging the actual gear and engaging the target gear 3rd in neutral, with the disconnect clutch in neutral 6th is preferably at least partially closed to the internal combustion engine 1 through support from the electrical machine 2 to bring it up to a target speed quickly, either to accelerate or to decelerate.

The present invention now relates to details after the actual shift execution, namely after the target gear of the gear change to be carried out has been engaged, in order to harmoniously to accomplish a load build-up in the direction of a torque desired by the driver.

For this purpose, the separating clutch is at least partially closed 6th one from the internal combustion engine 1 engine torque provided in the direction of the driver's desired torque as a function of a target engine torque requested or specified by the control for the internal combustion engine 1 increased, the course of the target engine torque for the internal combustion engine 1 is characterized by a target gradient.

Which increases when the engine torque of the internal combustion engine 1 actually developing actual gradient of the actual engine torque of the internal combustion engine 1 is monitored. Then, when the increase in engine torque of the internal combustion engine 1 The actual training gradient is reduced via the electrical machine 2 an additional torque is provided, namely in such a way that the result of the reduced actual gradient of the engine torque of the internal combustion engine 1 reduced increase in the actual engine torque of the internal combustion engine 1 about that of the electric machine 2 provided moment is compensated.

This is preferably done via the electrical machine 2 a torque provided, so that a sum torque from that of the internal combustion engine 1 provided engine torque and that of the electrical machine 2 The torque provided corresponds to a maximum of the torque requested by the driver, and that a gradient of the sum torque from the engine torque of the internal combustion engine 1 and the moment of the electric machine 2 corresponds to the target gradient of the target engine torque. This then enables a particularly harmonious load build-up according to the circuit design.

Further details of the invention are provided below with reference to the timing diagrams of FIG 2 , 3rd and 4th described. So are in the 2 to 4th Torque curves of torques M are shown over time t, namely, on the one hand, a torque desired by the driver to be built up at the transmission input after a gear change has been carried out 10 , a course of a target engine torque specified by the control 11 for the internal combustion engine 1 over which that from the internal combustion engine 1 engine torque provided via a defined target gradient to the torque desired by the driver 10 should be increased, a result of increasing the engine torque of the internal combustion engine 1 developing actual engine torque 12th of the internal combustion engine 1 , one of the electric machine 2 provided moment 13th as well as a sum moment 14th that is derived from the actual engine torque of the internal combustion engine 1 and the moment of the electric machine 2 assembled and on the transmission input shaft 5 of the transmission 3rd is applied.

In 2 the actual gear change is completed at time t ₀ , that is, at time t ₀ the target gear is that in the transmission 3rd circuit to be carried out is already inserted. The disconnect clutch is at time t ₀ 6th at least partially closed and can transmit torque, preferably without slipping on the same.

At time t ₀ , the setpoint engine torque is set on the control side for a load build-up 11 from the internal combustion engine 1 requested to do this from the internal combustion engine 1 provided engine torque in the direction of the driver's desired torque 10 to increase.

2 can be seen that the internal combustion engine 1 with a certain delay time only beginning at time t ₁ to the setpoint engine torque requested by the control 11 reacts and therefore delayed by the dead time of the internal combustion engine 1 , which corresponds to the difference between the times t ₁ and t ₀ , the actual engine torque 12th builds up.

The internal combustion engine builds between times t ₁ and t ₂ 1 the actual engine torque 12th with an actual gradient, which is the setpoint gradient of the setpoint engine torque 11 corresponds to.

At time t ₂ , the actual gradient of the actual engine torque decreases 12th of the internal combustion engine 1 by more than a limit value, this reduction being caused, for example, by the internal combustion engine 1 Must comply with emission limit values.

According to the invention, the actual gradient of the actual engine torque becomes 12th of the internal combustion engine 1 monitored and then, if it is determined that the actual gradient of the engine torque 12th of the internal combustion engine 1 is reduced by more than a limit value via the electrical machine 2 an extra moment 13th provided, then at the input of the transmission 3rd or on the transmission input shaft 5 the actual engine torque 12th of the internal combustion engine 1 and that extra moment 13th of the electric machine 2 to a sum moment 14th overlay.

Providing that extra moment 13th about the electric machine 2 takes place in such a way that the result of the reduced actual gradient of the engine torque 12th of the internal combustion engine 1 reduced increase in the actual engine torque of the internal combustion engine 1 about that of the electric machine 2 provided moment 13th is compensated, preferably in such a way that the gradient of the sum torque 14th from the actual Engine torque 12th of the internal combustion engine 1 and the extra moment 13th of the electric machine 2 the desired target gradient of the target engine torque 11 corresponds to. The sum moment 14th from the actual engine torque 12th of the internal combustion engine 1 and the extra moment 13th of the electric machine 2 corresponds at most to the torque requested by the driver 10 .

In this context, in the exemplary embodiment 2 starting with time t ₂ up to time t ₃ that of the electrical machine 2 provided moment 13th initially increased and then subsequently reduced again _{between times t 3} and t _4. As already stated, the actual gradient of the actual engine torque _{changes at time t 2} 12th of the internal combustion engine 1 . At time t ₃ corresponds to the sum torque 14th the driver's request moment 10 so that then starting at time t ₃ as a result of the further increase in the actual engine torque 12th of the internal combustion engine 1 the moment 13th of the electric machine 2 until time t ₄ is reduced again, with the actual engine torque _{at time t 4} 12th of the internal combustion engine 1 the driver's request moment 10 has reached.

In 2 the torque is increased 13th of the electric machine 2 between times t ₂ and t _3, ramp-shaped or linear, also the reduction of the torque 13th of the electric machine 2 between times t ₃ and t ₄ takes place in a ramp-shaped or linear manner.

With the invention, during the load build-up after a shift has been carried out in the transmission 3rd ensure that the load build-up at the input of the gearbox 3rd harmoniously with a constant gradient in the direction of the driver's request torque 10 he follows. For example, a reduction in the actual gradient of the combustion engine due to emission limits 1 The actual engine torque provided can be via the electrical machine 2 be compensated.

3rd shows a further development of the 2 , in which additionally the dead time of the internal combustion engine 1 is compensated. About the dead time of the internal combustion engine 1 to compensate is provided by the electric machine 2 a moment already starting at time t ₀ 13th ready, which is increased between the times t ₀ and t ₁ with a gradient which corresponds to the setpoint gradient of the setpoint engine torque 11 of the internal combustion engine 1 corresponds to. The dead time in the build-up of the engine torque of the internal combustion engine 1 is either stored on the control side or is dependent on the developing actual gradient of the actual engine torque 12th determined. When the dead time has elapsed at time t ₁ , that remains from the electrical machine 2 provided moment 13th constant, up to time t ₂ , that is, until it is established that the actual gradient of the engine torque is 12th of the internal combustion engine 1 reduced. This reduced actual gradient of the internal combustion engine 1 provided actual engine torque 12th is in turn via the electrical machine 2 , namely via that of the electrical machine 2 provided moment 13th , in analogy to the embodiment of 2 compensated, namely between the times t ₂ and t ₃ by an increase of the electrical machine 2 provided moments 13th and between times t ₃ and t ₄ by reducing the output from the electrical machine 2 provided moments 13th . In 3rd reaches the sum moment 14th at the entrance of the gearbox 3rd faster the driver's request moment 10 than in 2 . The gradient of the sum moment 14th corresponds to the target gradient of the target engine torque 11 .

Another development of the invention shows 4th . In 4th takes place between the increase and the decrease of the from the electrical machine 2 provided moments 13th a parabolic change in that of the electrical machine 2 provided torque to a discontinuous change in torque at time t ₃ and thus a discontinuous change in the total torque 14th to be avoided at time t _3. As a result, a so-called rounding of the course of the sum torque can accordingly be achieved 14th be provided around the time t ₃ , whereby vibrations in the drive train can be avoided. Abrupt changes in vehicle acceleration are also avoided.

With the invention, a harmonious load build-up at the input of the transmission 3rd after executing a shift in the transmission 3rd respectively.

The invention further relates to a control system for carrying out the method according to the invention, the control system being the engine control unit 7th , the transmission control unit 8th and the hybrid control unit 9 includes.

To carry out a shift in the transmission 3rd controls the control unit 8th The gear 3rd on the one hand for interpreting the actual gear and on the other hand for engaging the target gear of the shift to be carried out. After engaging the target gear of the shift to be carried out, the gearbox control unit gives 8th to the engine control unit 7th the target engine torque 11 for the internal combustion engine 1 before to about the internal combustion engine 1 at the entrance of the gearbox 3rd the driver's request moment 10 provide. The engine control unit 7th controls the combustion engine 1 depending on this target engine torque 11 at.

The increase in the internal combustion engine engine torque 11 actual training gradient of the actual engine torque 12th of the internal combustion engine 1 can be monitored by the gearbox control unit 8th , which has corresponding data from the engine control unit 7th receives. Then when the gearbox control unit 8th determines that the internal combustion engine increases when the engine torque is increased 1 developing actual gradient of the engine torque 12th is reduced, controls the hybrid control unit 9 the electric machine 3rd to provide the additional moment 13th on, in particular triggered by the transmission control unit 8th .

The hybrid control unit 9 then controls the electric machine 3rd in such a way that the result of the reduced actual gradient of the engine torque 12th of the internal combustion engine 1 reduced increase in engine torque 12th of the internal combustion engine 1 about that of the electric machine 3rd provided moment 13th is compensated in the manner described above.

List of reference symbols

1

Internal combustion engine

2

electric machine

3

transmission

4th

Downforce

5

Transmission input shaft

6th

Disconnect clutch

7th

Engine control unit

8th

Transmission control unit

9

Hybrid control unit

10

Driver request moment

11

Target engine torque internal combustion engine

12th

Actual engine torque of the internal combustion engine

13th

Moment electric machine

14th

Sum moment

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102010043530 A1 [0004]
• DE 102005007966 A1 [0005]

Claims (10)

Method for operating a drive train of a motor vehicle with an internal combustion engine (1), with an electric machine (2), with a transmission (3), and with an output (4), the electric machine (2) between the internal combustion engine (1) and the transmission (3) is coupled to a transmission input shaft (5), and a disconnect clutch (6) is connected between the internal combustion engine (1) and the electrical machine (2), via which the internal combustion engine (1) is decoupled from the drive train and connected the same can be coupled, whereby an actual gear is designed to perform a shift in the transmission (3), a target gear is engaged and, after the target gear of the shift to be performed is engaged, with the separating clutch (6) being at least partially closed, the internal combustion engine (1) engine torque provided is increased depending on a target gradient of a target engine torque of the internal combustion engine (1) in the direction of a torque desired by the driver, characterized in that d the actual gradient of the engine torque of the internal combustion engine (1) that develops when the engine torque is increased is monitored via the electric machine (2) when the actual gradient that forms when the engine torque of the internal combustion engine (1) decreases Additional torque is provided in such a way that the increase in the engine torque of the internal combustion engine (1), which is reduced as a result of the reduced actual gradient, is compensated for via the torque provided by the electrical machine (2). Procedure according to Claim 1 , characterized in that torque is provided via the electrical machine (2) in such a way that a gradient of the sum torque from the engine torque of the internal combustion engine (1) and the torque of the electrical machine (2) corresponds to the target gradient. Procedure according to Claim 1 or 2 , characterized in that torque is provided via the electric machine (2) in such a way that a sum of the engine torque of the internal combustion engine (1) and the torque of the electric machine (2) corresponds at most to the torque requested by the driver. Procedure according to Claim 2 or 3rd , characterized in that for this purpose the torque provided by the electrical machine (2) is first continuously increased and then continuously reduced again. Procedure according to Claim 4 , characterized in that the torque provided by the electrical machine (2) is initially increased in a ramp-shaped or linear manner and then reduced again in a ramp-shaped or linear manner. Procedure according to Claim 4 or 5 , characterized in that the torque provided by the electrical machine (2) is changed parabolically between the increase in the torque provided by the electrical machine (2) and the reduction in the torque provided by the electrical machine (2). Method according to one of the Claims 1 to 6th , characterized in that a dead time in the build-up of the engine torque of the internal combustion engine (1) is also compensated for by the torque provided by the electrical machine (2). Procedure according to Claim 7 , characterized in that the dead time in the build-up of the engine torque of the internal combustion engine (1) is either stored on the control side or is determined as a function of the actual gradient that develops. Control system of a drive train of a motor vehicle, the motor vehicle having an internal combustion engine (1), an electrical machine (2), a transmission (3) and an output (4), the electrical machine (2) between the internal combustion engine (1) and the transmission (3) is coupled to a transmission input shaft (5), and wherein between the internal combustion engine (1) and the electrical machine (2) a disconnect clutch (6) is connected, via which the internal combustion engine (1) can be decoupled, with a Motor control device (7) for controlling and / or regulating the operation of the internal combustion engine (1), with a transmission control device (8) for controlling and / or regulating the operation of the transmission (3), and with a hybrid control device (9) for controlling and / or Regulation of the operation of the electrical machine (2), the transmission control unit (8) controlling the transmission (3) to disengage an actual gear and to engage a target gear in order to execute a shift in the transmission (3) and after engaging the target gear of the shift to be executed with at least partially closed clutch (6) to the engine control unit (7) a target engine torque with a target gradient to increase the torque provided by the internal combustion engine (1) in the direction of a driver's desired torque, thereby characterized in that the transmission control unit (8) monitors an actual gradient of the engine torque of the internal combustion engine (1) that develops when the engine torque is increased, and the transmission control unit (8) monitors the actual gradient that develops when the engine torque of the internal combustion engine (1) increases -Gradient is reduced via the hybrid control unit (9) the electrical Controls the machine (2) to provide an additional torque in such a way that the increase in the engine torque of the internal combustion engine (1), which is reduced as a result of the reduced actual gradient, is compensated for by the torque provided by the electrical machine (2). Control system according to Claim 9 , characterized in that the same is set up the method according to one of the Claims 1 to 8th to be carried out on the control side.

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