METHOD FOR CONTROLLING A HYBRID DRIVE TRAIN

Abstract

A method is provided for controlling a hybrid drive train comprising a first partial drive train including an internal combustion engine having a crankshaft and a second partial drive train, which is separated from the first partial drive train by a torsional elasticity having an electric machine with a rotor A rotational characteristic value of the first partial drive train is detected via a sensor arranged on the torsional elasticity A rotational characteristic value of the rotor is detected via a device engaged with the rotor. A quality index is determined based on the rotational characteristic value of the first partial drive train and the rotational characteristic value of the rotor. The electric machine is controller to optimize the quality index.

Claims

1. A method for controlling a hybrid drive train including a first partial drive train with an internal combustion engine having a crankshaft and a second partial drive train, which is separated from the first partial drive train by a torsional elasticity including an electric machine having a rotor, the method comprising: detecting a rotational characteristic value of the first partial drive train via a sensor arranged on the torsional elasticity; detecting a rotational characteristic value of the rotor via a device engaged with the rotor; determining a quality index based on the rotational characteristic value of the first partial drive train and the rotational characteristic value of the rotor; and controlling the electric machine to optimize the quality index.

2. The method according to claim 1, further comprising: determining a vibration amplitude at the torsional elasticity based on the rotational characteristic value of the first partial drive train and the rotationai characteristic value of the rotor; and optimizing the quality index by controlling the electric machine to reduce the vibration amplitude.

3. The method according to claim 1, further comprising: determining an existing resonance of the torsional elasticity based on the rotational characteristic value of the first partial drive train aid the rotational characteristic value of the rotor: and optimizing the quality index by controlling the electric machine to eliminate the existing renance.

4. The method according to claim 1, further comprising determining; the quality index as a function of a relative rotational characteristic value between the crankshaft and the rotor.

5. The method according to claim 1, further comprising, after determining the quality index, controlling the electric machine via a controller configured to control the internal combustion engine.

6. The method according to claim 1, further comprising controlling the electric machine as a function of the quality index.

7. The method according to claim 1, further comprising optimizing the quality index bv controlling the electric machine to minimize a difference between the rotational characteristic value of the first partial drive train and the rotational characteristic value of the rotor.

8. The method according to claim 1, further comprising extracting vibration energy from the torsional elasticity by imposing a predetermined rotational non-uniformity on the electric machine via a controller.

9. The method according to claim 1, further comprising controlling the electric machine such that the rotational characteristic value of the first partial drive train and the rotational characteristic value of the rotor do not exceed corresponding predetermined values within stops of the torsional elasticity.

10. The method according to claim 1, wherein the hybrid drive train includes a separating clutch downstream of the electric machine, the separating clutch at least partially open when the quality index exceeds a predetermined quality index.

11. A hybrid drive train, comprising: a first partial drive train including an internal combustion engine having a crankshaft a second partial drive train including an electric machine having a rotor; a torsional elasticity arranged between the first partial drive train and the second partial drive train, the torsional elasticity being connected to the crankshaft and the rotor; a sensor arranged on the torsional elasticity and configured to detect a rotational characteristic value of the crankshaft; a device engaged with the rotor and configured to detect a rotational characteristic value of the rotor; and a controller in communication with the sensor and the device, the controller being configured to: receive the rotational characteristic value of the first partial drive train from the sensor; receive the rotational characteristic value of the rotor from the device; determine a quality index based on the rotational characteristic value of the first partial drive train and the rotational characteristic value of the rotor; and control the electric machine to optimize the quality index.

12. The hybrid drive train according to claim 11, wherein the controller is further configured to: determine a vibration amplitude at the torsional elasticity based on the rotational characteristic value of the first partial drive train and the rotational characteristic value of the rotor; and optimize the quality index by controlling the electric machine to reduce the vibration amplitude.

13. The hybrid drive train according to claim 11, wherein the controller is further configured to: determine an existing resonance of the torsional elasticity based on the rotational characteristic value of the first partial drive train and the rotational characteristic value of the rotor; and optimize the quality index by controlling the electric machine to eliminate the existing resonance.

14. The hybrid drive train according to claim 11, wherein the controller is further configured to determine the quality index as a function of a relative rotational characteristic value between the crankshaft and the rotor.

15. The hybrid drive train according to claim 11, wherein the device is a sensor configured to control electronic communication of the electric machine.

16. The hybrid drive train according to claim 11, wherein the device is a state observer configured to control the electric machine based on evaluating electrical variables in a stator of the electric machine.

17. The hybrid drive train according to claim 11, wherein the controller is further configured to optimize the quality index by controlling the electric machine to minimize a difference between the rotational characteristic value of the first partial drive train and the rotational characteristic value of the rotor.

18. The hybrid drive train according to claim 11, wherein the controller is further configured to extract vibration energy from the torsional elasticity by imposing a predetermined rotational non-uniformity on the electric machine.

19. The hybrid drive train according to claim 11, wherein the controller is further configured to control the electric machine such that the rotational characteristic value of the first partial drive train and the rotational characteristic value of the rotor do not exceed corresponding predetermined values within stops of the torsional elasticity.

20. The hybrid drive train according to claim 11, further comprising a separating clutch downstream of the electric machine, the separating clutch being at least partially opened when the quality index exceeds a predetermined quality index.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The invention is explained in more detail with reference to the exemplary embodiment in the single figure. FIG. 1 shows a schematic representation of a hybrid drive train.

DETAILED DESCRIPTION

[0030] A hybrid drive train 1 shown schematically contains partial drive trains 2, 3. The partial drive train 2 contains an internal combustion engine 4, here with four cylinders 5, and a crankshaft 6 driven in rotation thereby. A torsional elasticity 7, here a torsional vibration damper such as a dual-mass flywheel, is accommodated on the crankshaft 6, which separates the partial drive train 2 from the partial drive train 3. A device 8 for detecting rotational characteristic values of the crankshaft 6 and thus the control of the internal combustion engine 4 is assigned to the first partial drive train 2. For this purpose, a sensor ring is arranged on an input part of the torsional elasticity 7, from the increments of which a measurement signal is detected by a sensor and corresponding rotational characteristic values, for example the speed, the rotational angle, the rotational acceleration, and/or the like, are determined from this.

[0031] An output part of the torsional elasticity 7 is connected to a rotor 10 of an electric machine 9 in a rotationally locked manner. The electric machine 9 is assigned to the second partial drive train 3. The electric machine 9 is controlled by means of a device 11 for determining rotational characteristic values. For example, the device 11 can be formed from one or more Hall sensors, which are arranged on the rotor 10 or on a component connected thereto in a rotationally locked manner, to detect increments distributed around the circumference of the rotor 10 and to use these to determine the rotational characteristic values of the rotor 10, and to control the commutation of the electric machine 9 and to determine the position of the rotor 10 as a function of time. Alternatively, the electric machine 9 can be controlled without sensors by means of the device 11 in that the electrical variables of a stator 12 are detected and evaluated by means of a state observer.

[0032] To quickly and reliably determine misfiring of the internal combustion engine 4 in the proposed method, and to control the electric machine 9 in such a way that if a quality index determined as a function of the detected measured values of the device 8, 11 is exceeded, vibration energy is withdrawn from the torsional elasticity 7, or this is brought outside of a resonance range, and the signals of the devices 8, 11 are evaluated together by a controller 13. As a result, the rotational characteristic values of the partial drive trains 2, 3 and thus, with knowledge or modeling of the system properties of the hybrid drive train 1, influencing variables on the partial drive trains 2, 3 and the torsional elasticity 7, such as applied torques, rotational acceleration, mass moment of inertia, and the like, can be determined or at least estimated and the quality index determined therefrom.

[0033] For example, by comparing the rotational characteristic values of the devices 8, 11, the effect of ignition curves before and after the torsional elasticity 7 can be detected and the influence of misfiring on the two partial drive trains 2, 3 can be recognized, and the quality index can be determined, which, for example, is a measure of the efficiency of the hybrid drive train 1, the comfort acting on the vehicle and/or the damage to the hybrid drive train 1, in particular the torsional elasticity 7. For example, the shapes of successive ignition curves of the cylinders 5 can be compared with one another and dropouts can be recognized in real time from a change in the shapes. Alternatively or additionally, by observing the rotational angle between the crankshaft 6 and the rotor 10 under otherwise constant conditions, such as without engine intervention in the internal combustion engine 4 and without changing the control of the electric machine 9, misfires due to changes in the rotational angle can be recognized.

LIST OF REFERENCE SYMBOLS

[0034] 1 Hybrid drive train [0035] 2 Partial drive train [0036] 3 Partial drive train [0037] 4 Internal combustion engine [0038] 5 Cylinder [0039] 6 Crankshaft [0040] 7 Torsional elasticity [0041] 8 Device [0042] 9 Electric machine [0043] 10 Rotor [0044] 11 Device [0045] 12 Stator [0046] 13 Controller