DE102007050774A1 - Method for operating a drive train - Google Patents

Abstract

The invention relates to a method for operating a drive train of a motor vehicle, wherein the drive train comprises at least one hybrid drive with an internal combustion engine and an electric motor, a transmission arranged between the hybrid drive and an output drive and a clutch arranged between the internal combustion engine and the electric motor in an electric mode, only the electric motor is coupled to the output and the running internal combustion engine is decoupled from the output, this can be used to switch to hybrid operation, so that the clutch arranged between the internal combustion engine and the electric motor is closed. According to the invention, the procedure for changing from electric operation to hybrid operation is such that a speed of the internal combustion engine is regulated as a function of a rotational speed of the electric motor, wherein the clutch arranged between the internal combustion engine and the electric motor is closed in such a way that it is first closed up to an application point. that subsequently, when the rotational speed of the internal combustion engine follows the rotational speed of the electric motor, the clutch is closed to a point of adhesion, and that subsequently with a clutch adhering a torque guide from the electric motor to the internal combustion engine and at the same time the clutch is fully closed.

Description

The The invention relates to a method for operating at least one Transmission and a hybrid drive powertrain comprehensive Motor vehicle according to the preamble of claim 1.

The Main components of a drive train of a motor vehicle are a drive unit and a transmission. A gearbox converts torques and speeds and thus sets the traction power supply of the drive unit around. The present invention relates to a method of operation a drive train, the at least one gear and as a drive unit includes a hybrid drive.

One Powertrain with a hybrid drive is in an electric mode exclusively operated by the electric motor, wherein in electric mode, the internal combustion engine is decoupled from the output of the drive train. In electrical operation the combustion engine can either run or stand still. in the Hybrid operation are both the running internal combustion engine as well the electric motor coupled to the output of the drive train. Depending on Operation of the motor vehicle, it is necessary to the hybrid drive from electrical operation to hybrid operation, in such a way that the running internal combustion engine in addition to the electric motor the output is coupled. In known from practice drive trains with a hybrid drive is this one between the engine and the electric motor arranged clutch suddenly closed, where then the drive torque abruptly not only more exclusively from Electric motor but in combination of electric motor and combustion engine provided. When suddenly closing the between the engine and the electric motor arranged clutch results in a jerk in the powertrain, the for the driver noticeable is, and affects the ride comfort.

It There is therefore a need for a method for operating a a powertrain comprising a hybrid drive, with which without impairment the driving comfort of the electric operation in the hybrid mode changed can be, with which so the engine without jerk on the Drive train can be coupled to the output.

Of these, Based on the present invention, the problem underlying a novel method of operating a transmission and a Hybrid drive comprehensive powertrain to create.

This Problem is solved by a method of operating a transmission and a hybrid drive powertrain according to claim 1 solved.

According to the invention is for Switching from electrical operation to hybrid operation proceeded in such a way that a speed of the internal combustion engine depends on a speed of the Electric motor is controlled, taking the between the internal combustion engine and the electric motor arranged clutch is closed so that it is first closed to a point of application of the same will that subsequently, When the speed of the engine, the speed of the electric motor follows, the clutch closed to an adhesive point of the same will, and that afterwards with an adhesive coupling, a torque control from the electric motor transmit the internal combustion engine and at the same time the clutch is completely closed.

With Help of the method according to the invention can the internal combustion engine smoothly without torque shocks on the drive train the output of the drive train during the transition from electrical operation in be coupled to the hybrid operation. By coupling the internal combustion engine to the output of the drive train there is no loss of comfort for the driver.

To an advantageous development of the invention, the transfer takes place the torque control from the electric motor to the combustion engine and the simultaneous Shut down the clutch such that the clutch with a steeper gradient is closed as the delivery the torque control on the internal combustion engine, so that the clutch more and more Transmit moment can be provided as the internal combustion engine.

Preferably become a handover the torque control from the electric motor to the internal combustion engine of the internal combustion engine and the electric motor in the sense of a sliding transfer controlled, that provided by the internal combustion engine torque raised to a target torque of the internal combustion engine and that of the Electric motor provided torque to a target value of the electric motor is lowered from non-zero or zero, the same of the same in sum provided moment corresponds to the target moment.

preferred Further developments of the invention will become apparent from the dependent claims and the following description. Embodiments of the invention without being limited to this to be closer to the drawing explained. Showing:

1 a first drive train scheme of a motor vehicle, in which the erfindungsge appropriate method is used;

2 a second drive train scheme of a motor vehicle, in which the inventive method can be used; and

3 a diagram illustrating a preferred embodiment of the method according to the invention for operating a drive train of a motor vehicle.

The The present invention relates to a method of operation a comprehensive at least one transmission and a hybrid drive Powertrain of a motor vehicle.

One Hybrid drive includes an internal combustion engine and an electric motor.

1 and 2 show exemplary powertrain schemes of a motor vehicle, in which the inventive method is used.

So shows 1 a schematic of a powertrain 1 of a motor vehicle, wherein the drive train 1 according to 1 a hybrid drive that comes from an internal combustion engine 2 and an electric motor 3 is formed. Between the internal combustion engine 2 and the electric motor 3 is a clutch 4 switched, which is when the powertrain 1 exclusively from the electric motor 3 is operated, is open. In addition to the hybrid drive includes the powertrain 1 according to 1 continue a gear 5 , which provides the traction offered by the hybrid drive on an output 6 , To be driven wheels, the drive train converts. Another scheme of a powertrain 7 of a motor vehicle 2 , wherein the drive train of the 2 from the powertrain of 1 this distinguishes that between the electric motor 3 the hybrid drive and the transmission 5 a clutch 8th is switched.

In the electrical operation of such a drive train according to 1 and 2 is exclusively the electric motor 3 to the output 6 coupled the respective drive train, the internal combustion engine 2 is on the other hand with the clutch open 4 decoupled from the drive train, in which case the electric motor of the internal combustion engine 2 either walk or stand still. In hybrid mode, both the electric motor 3 as well as the running internal combustion engine 2 to the output 6 coupled to the respective drive train, for which purpose the clutch 4 closed is.

Will a powertrain according to 1 or 2 operated in electric mode, in which only the electric motor 3 with the downforce 6 is coupled and in which the internal combustion engine 2 with the clutch open 4 running, it may be necessary under certain operating conditions, the current and still from the output 6 decoupled internal combustion engine 2 to the output 6 to pair. The present invention now relates to such details, with which at a transition from electrical operation to the hybrid operation of the running internal combustion engine 2 jerk-free without torque surges on the drive train to the output 6 the same can be coupled. The method according to the invention will be described below with reference to FIG 3 described.

So contains 3 altogether three diagrams with temporal signal curves, namely in the upper diagram of the 3 temporal profiles of rotational speeds, in the middle diagram temporal signal curves of moments and in the lower diagram a temporal signal curve of a coupling position. So in the upper diagram of the 2 time profiles of the speed n _{EM of} the electric motor 3 and the speed n _{VM of} the internal combustion engine 2 shown. In the middle diagram of the 3 are a time course of the electric motor 3 provided Moments M _EM , a time course of the internal combustion engine 2 provided moments M _VM and a time course of a target torque M _SOLL presented. In the lower diagram of the 3 is the time course X of the clutch position between the engine 2 and the electric motor 3 switched clutch 4 shown. In the 3 Signal curves shown result in execution of the method according to the invention.

Until time t ₁ , the hybrid drive of the drive train is operated in electric mode, in which case only the electric motor 3 to the output 6 is coupled to the drive train and the running internal combustion engine via the open clutch 4 from the downforce 6 disconnected.

Until time t ₁ , the internal combustion engine 2 thus operated with a so-called idle speed. In addition, until the time t _1, the internal combustion engine 2 at the output 6 no moment ready. Rather, until the time t _1, a target torque M _SOLL , which preferably corresponds to a driver's _desired torque, exclusively from the electric motor 3 provided. Until time t ₁ is between the engine 2 and the electric motor 3 positioned coupling 4 fully open.

If a transition from electrical operation to hybrid operation is now to take place, then according to 3 starting at time t _1, the rotational speed of the internal combustion engine n _VM depends on the rotational speed n _{EM of} the electric motor 3 regulated, so that therefore between the times t ₁ and t _2, the speed n _{VM of} the engine 2 the speed n _{EM of} the electric motors 3 approaches. It should be assumed that a target value for controlling the rotational speed n _{VM of} the internal combustion engine 2 that is the speed n _{EM of} the electric motor 3 equivalent. The internal combustion engine 2 is thus controlled so speed controlled that the speed of the engine 2 the speed of the electric motor 3 follows.

Furthermore, like the lower diagram of the 3 can be taken, starting with the time t ₁ between the internal combustion engine 2 and the electric motor 3 arranged clutch 4 closed to a position X _A , the point of application of the clutch 4 equivalent. The coupling 4 is held so long in the Anlegepunkt until the time t _2, the speed n _{VM of} the engine 2 the speed n _{EM of} the electric motor 3 follows, until so combustion engine 2 and electric motor 3 run synchronously. At time t ₂ , therefore, the synchronization point is between the rotational speed of the internal combustion engine 2 and the speed of the electric motor 3 in front.

Subsequent to reaching the synchronization point at time t ₂ , the clutch 4 between the internal combustion engine 2 and the electric motor 3 is positioned, starting from the engagement point corresponding to the closed position X _A in the direction of a closed position X _H further closed, wherein the closed position X _H the adhesion point of the clutch 4 equivalent. At time t ₃ , the clutch has 4 reached the adhesion point corresponding closed position.

After reaching the adhesion point of the coupling 4 At time t ₃ , on the one hand between the times t ₃ and t _{4 is} a transmission of a torque control from the electric motor 3 on the internal combustion engine 2 , continues to be the clutch simultaneously 4 between the internal combustion engine 2 and the electric motor 3 is switched on, completely closed.

To transfer the torque control from the electric motor 3 on the internal combustion engine 2 become the internal combustion engine 2 and electric motor 3 controlled such that the combustion engine 2 provided moment M _{VM is raised} to the target torque M _SOLL , which preferably corresponds to the driver's _desired torque, whereas that of the electric motor 3 provided moment M _EM is lowered to zero. The transfer of the torque control is preferably carried out in a sliding manner, in such a way that the torque provided by the same in total corresponds to the target torque M _SOLL . The enlargement of the internal combustion engine 2 provided moments as well as reducing the electric motor 3 provided moments is preferably linear along ramps.

Likewise, the complete closing takes place between the engine 2 and the electric motor 3 positioned coupling 4 starting from the adhesion point in the direction of the full closed position, preferably linearly along a ramp.

As 3 can be removed, the clutch is 4 closed with a steeper gradient than the transfer of torque control from the electric motor to the engine, so that the clutch 4 can transmit more and more momentum than the internal combustion engine 2 provides.

The inventive method is at time t ₄ , to which the coupling 4 is completely closed and the target torque M _SOLL exclusively from the internal combustion engine 2 is finished. Beginning with the time t ₄ is a hybrid operation of the drive train before.

With reference to 3 It was assumed that, during the method according to the invention, the rotational speed of the internal combustion engine is regulated in such a way that a desired value for controlling the rotational speed n _{VM of} the internal combustion engine corresponds to the actual rotational speed of the electric motor. In contrast, it is also possible that a target value for controlling the rotational speed n _{VM of} the internal combustion engine corresponds to the actual rotational speed of the electric motor plus a derivative component.

About such a Vorhalteanteil can offset between the speed n _{VM of} the engine 2 and the speed n _{EM of} the electric motor 3 be realized, with the advantage of such Vorhalteanteils is that with increasing and decreasing speed of the electric motor 3 the internal combustion engine 2 the synchronous speed can reach faster. Since, at the beginning of the method according to the invention, the internal combustion engine rotates at an idling speed, the initial rotational speed of the internal combustion engine is 2 smaller than the target speed of the same, so that a positive-gradient lead part is needed.

Of the Derivative share can be dependent calculated from the gradient of the rotational speed of the electric motor via a characteristic curve become.

Furthermore, with reference to 3 assumed that the target torque M _SOLL corresponds to a driver's _desired torque. In contrast to this, it is likewise possible for the target torque M _SOLL to be predetermined by a motor vehicle control system.

1

powertrain

2

internal combustion engine

3

electric motor

4

clutch

5

transmission

6

output

7

powertrain

8th

clutch

Claims (7)

Method for operating a drive train of a motor vehicle, wherein the drive train comprises at least one hybrid drive with an internal combustion engine and an electric motor, a transmission arranged between the hybrid drive and an output drive and a clutch arranged between the internal combustion engine and the electric motor, wherein when in an electric mode exclusively coupled the electric motor to the output and the current engine is decoupled from the output, it can be changed to a hybrid operation that the arranged between the engine and the electric motor clutch is closed, characterized in that to proceed from the electrical operation in the hybrid mode in that a rotational speed of the internal combustion engine is regulated as a function of a rotational speed of the electric motor, wherein the clutch arranged between the internal combustion engine and the electric motor is closed in such a way that it first opens bi S is concluded to a Anlegepunkt that subsequently, when the speed of the engine, the speed of the electric motor follows, the clutch is closed to a point of adhesion, and that then with adhesive clutch torque transfer from the electric motor to the engine and at the same time fully closed the clutch becomes. Method according to claim 1, characterized in that that a setpoint for controlling the speed of the internal combustion engine the actual speed of the electric motor corresponds. Method according to claim 1, characterized in that that a setpoint for controlling the speed of the internal combustion engine the actual speed the electric motor plus corresponds to a percentage of ownership. Method according to claim 2 or 3, characterized that if the actual speed of the internal combustion engine, the target value has reached the same, the clutch starting from the application point of the same closed to the point of detention. Method according to one of claims 1 to 4, characterized that to the transfer the torque control from the electric motor to the internal combustion engine of the internal combustion engine and the electric motor are driven in such a way that that of the internal combustion engine provided moment to a target torque of the internal combustion engine lifted and the moment provided by the electric motor to a Target value of the electric motor is lowered. Method according to claim 5, characterized in that that to the transfer the torque control from the electric motor to the internal combustion engine of the internal combustion engine and the electric motor are driven in the sense of a sliding transfer in such a way that the moment provided by them in total is the target moment equivalent. Method according to one of claims 1 to 6, characterized that the surrender the torque control from the electric motor to the combustion engine and the simultaneous Shut down the clutch is made such that the clutch with a steeper Gradient is closed as the transfer of torque control on the internal combustion engine takes place so that the clutch transmit more and more torque can be provided as the internal combustion engine.