Control Device and Method for Operating a Hybrid Drive

Abstract

A hybrid drive includes an internal combustion engine, an electrical machine, at least one torsional vibration damper, and an electronic control unit. The torsional vibration damper is designed for optimal vibration damping during operation of the internal combustion engine with the full number of cylinders of the internal combustion engine switched-on in internal-combustion-engine mode. The electronic control unit is further designed such that, in purely electric-motor mode where no cylinders are switched on, the electrical machine simulates the cylinder-ignition-dependent torque excitations of the switched-off internal combustion engine substantially identically until the internal combustion engine is switched back on.

Claims

1.-10. (canceled)

11. A control device for a hybrid drive comprising: a combustion engine comprising a plurality of cylinders; an electric machine; a torsional vibration stabilizer; and an electronic control unit, wherein the torsional vibration stabilizer is configured to achieve vibration damping in a combustion engine mode with all of the plurality of cylinders of the combustion engine operating; and the electronic control unit is configured such that, in a completely switched-off mode of the combustion engine where all of the plurality of cylinders are switched off, the electric machine substantially simulates the cylinder-ignition-dependent torque excitations of the combustion engine using electric motor generated torque excitations until re-activation of the combustion engine.

12. A control device for a hybrid drive comprising: a combustion engine comprising a plurality of cylinders; an electric machine; a torsional vibration stabilizer; and an electronic control unit, wherein the torsional vibration stabilizer is configured to achieve vibration damping in a combustion engine mode with all of the plurality of cylinders of the combustion engine operating; the combustion engine is configured to implement full and partial cylinder operation modes in which one or more cylinders are switched-off; and the control unit is configured such that, in the partial cylinder operation mode, the electric machine substantially replaces missing cylinder-ignition-dependent torque excitations of the switched off cylinders in the partial cylinder operation mode of the combustion engine using electric motor generated torque excitations until all cylinders of the combustion engine are reactivated.

13. The control device according to claim 11, wherein the combustion engine is configured to be dragged by the electric machine in the completely switched-off mode or a partially switched-off mode.

14. The control device according to claim 11, wherein the combustion engine comprises adjustment devices for deactivating the inlet and exhaust valve opening actuations; and the electronic control unit is configured to deactivate the inlet and exhaust valve opening actuations when the combustion engine is dragged by the electric machine when in the completely switched-off mode or a partially switched-off mode.

15. The control device according to claim 11, further comprising: an additional torsional vibration damper arranged between the combustion engine and the electric machine.

16. The control device according to claim 11, wherein the torsional vibration stabilizer is arranged downstream of the electric machine.

17. The control device according to claim 11, wherein the torsional vibration damper is configured as a spring stage for vibration damping in an entire revolution rate range.

18. The control device according to claim 11, wherein the torsional vibration stabilizer is configured as a revolution rate-dependent centrifugal pendulum for vibration damping in a relatively low revolution rate range.

19. A method for operating a hybrid drive by using of an electronic control unit according to claim 11, comprising: actuating the electric machine using the electronic control unit; in the completely switched off mode, substantially simulating the cylinder-ignition-dependent torque excitations using the electric motor until reactivation of the combustion engine; and/or in a partially switched-off mode where less than all of the plurality of cylinders are switched off, substantially simulating missing torque excitations of the switched-off cylinders of the combustion engine by using the electric motor to generate torque excitations the reactivation of all of the plurality of cylinders of the combustion engine.

20. A method of using the control device according to claim 11, wherein the hybrid drive is a P2 topology hybrid drive comprising a separating clutch that remains engaged between the combustion engine and the electric motor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] FIG. 1 shows schematically a vehicle with a hybrid drivetrain, which can be optionally configured as a P1 or P2 architecture, and with an electronic control unit for the activation according to the present subject matter of the electric machine as an electric drive motor,

[0031] FIG. 2 shows an example of the actuation according to the present subject matter of the electric machine and

[0032] FIG. 3 shows an example of the actuation according to the present subject matter of the electric machine.

DETAILED DESCRIPTION OF THE DRAWINGS

[0033] FIG. 1 includes a combustion engine 3 and an electric machine 5, such as an electric motor, which can be used individually or together to generate a drive torque for a vehicle 1. The combustion engine 3 and the electric motor 5 are arranged in such a way that the torques generated by the respective drive motors add to form a total drive torque, which for example is transmitted via a transmission 7 and an output shaft of the transmission 7, usually to at least two drive wheels of the vehicle 1. The electrical energy for the operation of the electric machine 5 is supplied in an electrical energy storage device (e.g., a 48V battery or a high-voltage battery, not illustrated in detail here).

[0034] Vehicle 1 also includes an electronic control unit 10, such as engine control unit, which is set up to determine a requested total drive torque. The requested total drive torque can be specified by the driver of vehicle 1, for example by means of an accelerator pedal. For example, a driver can operate the accelerator pedal to request an increased total drive torque. The electronic control unit 10 can be set up to divide the requested total drive torque into a first torque for the combustion engine 3 and a second torque for the electric machine 5. In other words, the electronic control unit 10 may be set up to operate the combustion engine 3 and the electric machine 5 depending on a requested total drive torque.

[0035] Furthermore, FIG. 1 shows an optional separating clutch 8, by means of which the combustion engine 3 and the electric motor 5 can be decoupled. With this separating clutch 8, there is a so-called P2 hybrid topology. Without the separating clutch 8, there is a so-called P1 hybrid topology.

[0036] A torsional vibration damper 4 in the form of a spring stabilizer is preferably arranged between the combustion engine 3 and the electric motor 5. A torsional vibration stabilizer 9, for example in the form of a centrifugal pendulum, is arranged downstream of the electric motor 5.

[0037] The combustion engine 3 preferably has a first valve control device for closing the inlet valves and a second valve control device for closing the exhaust valves, which, in combination with a function module for reducing drag torque in the electronic control unit 10, allows effective drag reduction by closing the inlet and exhaust valves. Finally, a starting element 6 in the form of a clutch or torque converter with a lock-up clutch is provided, preferably before or in the transmission 7. The devices for reducing drag torque are indicated in FIG. 1 by the reference character 2.

[0038] The combustion engine 3 of a hybrid drive can be at least temporarily deactivated partly or completely, for example, in the case of purely electric operation of the hybrid drive, and/or in the case of recuperation in so-called thrust mode when the wheels of the vehicle drive the output shaft. The drive shaft of the deactivated combustion engine 3 can thus be operated in a non-running dragged mode by the electric machine 5 with the separating clutch 8 engaged and/or driven and/or rotated by the wheels of the vehicle 1. A non-running dragged mode of the combustion engine 3 has the advantage that the combustion engine 3 can be fired again rapidly and efficiently to contribute drive torque to the overall drive of the vehicle 1.

[0039] The torsional vibration stabilizer 9 is designed according to the present subject matter for optimal vibration damping with the full number of cylinders (e.g., four) of the combustion engine 3 in combustion engine mode.

[0040] The effect of the method according to the present subject matter according to an example is represented schematically or qualitatively by means of FIG. 2:

[0041] The electronic control unit 10 is designed in such a way that in purely electric motor mode the electric machine 5 at least almost identically, and/or to a large extent, substantially simulates the cylinder-ignition-dependent torque excitations Z1 to Z4 of the switched off combustion engine 3 as the electromotive torque excitation ME (Z1′ to Z4′) until the re-activation of the combustion engine 3. MS represents the summation signal of the two torque excitations MV and ME.

[0042] The effect of the method according to the present subject matter according to an example is represented by means of FIG. 3:

[0043] The electronic control unit 10 is designed in such a way that, with only some cylinders of the combustion engine 3 switched off (e.g., Z2 and Z4), the electric machine 5 at least almost identically simulates the missing cylinder-ignition-dependent torque excitations MV of the switched-off cylinders as electromotive torque excitations ME (e.g., Z2′ and Z4′) until all cylinders of the combustion engine 3 are reactivated.

[0044] Preferably, the combustion engine 3 is dragged by the electric machine 5 or remains coupled in partially or completely switched-off mode without combustion, wherein in particular the clutch 8 remains engaged in a P2 topology.

[0045] The torsional vibration damper 4, which is arranged between the combustion engine 3 and the electric machine 5, is preferably designed as a spring stage for vibration damping in the entire revolution rate range.

[0046] The torsional vibration stabilizer 9, which is arranged downstream of the electric machine 5, is preferably designed as a revolution rate-dependent centrifugal pendulum for vibration damping in the relatively low revolution rate range.

[0047] The present subject matter is not restricted to the example embodiments shown. It should be noted that the description and the figures are intended only to illustrate the principle of the proposed methods, devices and systems.