JP2015089735A - Motor control device of hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a shock resulting from the backlash of a gear of a power transmission system, in a hybrid vehicle in which an MG (motor) is connected to the power transmission system of an engine.SOLUTION: When a vehicle drive requirement is generated during a fuel stop of an engine 11 at the deceleration of a vehicle, an MG 12 generates torque at a backlash torque command value after performing inverse filter processing for attenuating a resonant component of a drive shaft 15. The generation of the resonance of a drive shaft 15 generated by the backlash torque of the MG 12 is thereby suppressed while suppressing the generation of a shock caused by the gear tooth hammering of a power transmission system, and the generation of a shock caused by the resonance of the drive shaft 15 is suppressed. Furthermore, after changing the torque of the drive shaft 15 to a positive value from a negative value by the backlash torque of the MG 12, the combustion of the engine 11 is permitted. By this constitution, it is avoided that gears are strongly tooth-hammered by a synergy effect of the initial explosion torque of the engine 11 and the backlash of the gear, and the generation of the large shock is prevented.

Description

  The present invention relates to a motor control device for a hybrid vehicle equipped with an engine and a motor as a power source for the vehicle.

  In recent years, a hybrid vehicle equipped with an engine and a motor as a power source of the vehicle has attracted attention because of the social demand for low fuel consumption and low exhaust emissions. As this hybrid vehicle, for example, there is one in which a motor is connected to a power transmission system (for example, between an engine and a transmission) that transmits engine power to a drive shaft of a wheel.

  In such a hybrid vehicle, when the vehicle driving torque is switched from negative to positive based on the driver's accelerator operation while the vehicle is decelerating, a backlash (backlash) such as a differential gear or final gear of the power transmission system is generated. There is a possibility that a shock will occur due to the gear rattling caused by.

  Therefore, as described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2012-91618), when the driving torque of the vehicle is switched from negative to positive, a backlash torque (torque smaller than the target driving torque) is applied to the motor. There is a type in which play control is performed to generate gear play.

JP 2012-91618 A

  However, in the technique disclosed in Patent Document 1, if the resonance component of the drive shaft included in the backlash torque of the motor is large during backlash control, a shock due to resonance of the drive shaft may occur. In addition, if a vehicle drive request is generated while the vehicle is decelerating and the combustion of the engine is stopped (fuel cut), the combustion of the engine may be resumed during the backlash control. If the engine detonates for the first time, the gear may strike hard due to the synergistic effect of the steep initial detonation torque of the engine and the gear backlash.

  Accordingly, an object of the present invention is to provide a motor controller for a hybrid vehicle that can effectively suppress a shock caused by a backlash of a gear of a power transmission system.

  In order to solve the above-mentioned problem, the invention according to claim 1 is equipped with an engine (11) and a motor (12) as a power source of a vehicle, and the power of the engine (11) is transmitted to a drive shaft ( 15) In the hybrid vehicle motor control device in which the motor (12) is connected to the power transmission system for transmission to 15) so that the power can be transmitted, the resonance component of the drive shaft (15) is attenuated with respect to the torque command value of the motor (12). Motor control means (24) for performing a vibration damping feedback process for correcting the torque command value of the motor (12) so as to cancel the resonance of the drive shaft (15) based on the rotational speed of the motor (12) while performing the filter process The motor control means (24) reduces the torque of the drive shaft (15) from negative when a vehicle drive request is generated while the vehicle is decelerating and the combustion of the engine (11) is stopped. After generating torque in the motor (12) with the torque command value after the filter processing is performed on the backlash torque command value for changing the torque, the torque of the drive shaft (15) is changed from negative to positive, The combustion of the engine (11) is permitted.

  In this configuration, when a vehicle drive request is generated while the engine is stopped while the vehicle is decelerating, first, before starting combustion of the engine, a play for changing the torque of the drive shaft from negative to positive is started. Torque is generated in the motor with the backlash torque command value after the filter processing for attenuating the resonance component of the drive shaft with respect to the backfill torque command value. As a result, when changing the torque of the drive shaft from negative to positive due to the backlash torque of the motor, the drive shaft included in the backlash torque of the motor is suppressed while suppressing the occurrence of shock due to gear rattling of the power transmission system. Can be attenuated. As a result, the resonance of the drive shaft due to the backlash torque of the motor can be suppressed, and the occurrence of shock due to the resonance of the drive shaft can be effectively suppressed.

  Then, after changing the torque of the drive shaft from negative to positive by the backlash torque of the motor (that is, after completion of backlash of the gear), combustion of the engine is permitted. As a result, it is possible to prevent the engine from undergoing the first explosion in the middle of the backlash control, so that a large shock is avoided by avoiding the gears striking hard due to the synergistic effect of the initial explosion torque and the gear backlash. Occurrence can be prevented.

FIG. 1 is a diagram showing a schematic configuration of a hybrid vehicle drive system in an embodiment of the present invention. FIG. 2 is a block diagram showing the vibration suppression control function of the MG-ECU. FIG. 3 is a time chart for explaining the control of the comparative example. FIG. 4 is a time chart for explaining the control of this embodiment. FIG. 5 is a flowchart showing the flow of processing of the shock suppression routine.

Hereinafter, an embodiment embodying a mode for carrying out the present invention will be described.
First, a schematic configuration of a hybrid vehicle drive system will be described with reference to FIG.
An engine 11 that is an internal combustion engine and a motor generator (hereinafter referred to as “MG”) 12 are mounted as power sources for the vehicle. The power of the output shaft (crankshaft) of the engine 11 is transmitted to the transmission 13 via the MG 12, and the power of the output shaft of the transmission 13 is transmitted through the gear mechanism 14 including a differential gear, a final gear, and the drive shaft 15. Via the wheel 16. The transmission 13 may be a stepped transmission that switches the shift speed step by step from a plurality of shift speeds, or may be a CVT (continuously variable transmission) that shifts continuously.

  A rotary shaft of the MG 12 is connected between the engine 11 and the transmission 13 in a power transmission system for transmitting the power of the engine 11 to the drive shaft 15 of the wheel 16 so that the power can be transmitted. A first clutch 17 for interrupting power transmission is provided between the engine 11 and the MG 12, and a second clutch for interrupting power transmission is provided between the MG 12 and the transmission 13. 18 is provided. These clutches 17 and 18 may be hydraulically driven hydraulic clutches or electromagnetically driven electromagnetic clutches.

  An inverter 19 that drives the MG 12 is connected to the battery 20, and the MG 12 exchanges power with the battery 20 via the inverter 19. The MG 12 is provided with a rotation speed sensor 21 that detects the rotation speed of the MG 12.

  The hybrid ECU 22 is a computer that comprehensively controls the entire vehicle, and reads output signals from various sensors and switches such as an accelerator sensor, a brake switch, and a vehicle speed sensor (all of which are not shown) to determine the driving state of the vehicle. To detect. The hybrid ECU 22 transmits and receives control signals and data signals to and from the engine ECU 23 that controls the operation of the engine 11 and the MG-ECU 24 (motor control means) that controls the MG 12 by controlling the inverter 19. To control the engine 11, the MG 12, and the like according to the driving state of the vehicle.

Hereinafter, the control when the first and second clutches 17 and 18 are both engaged (that is, the state where the engine 11, the MG 12, and the drive shaft 15 transmit power) will be described.
The MG-ECU 24 executes vibration suppression control for suppressing resonance of the drive shaft 15. In this vibration suppression control, as shown in FIG. 2, an inverse filter process for attenuating the resonance component of the drive shaft 15 with respect to the torque command value of the MG 12 is performed by the inverse filter 25. Further, the damping F / B (feedback) processing unit 26 performs a damping F / B process for correcting the torque command value of the MG 12 so as to cancel the resonance of the drive shaft 15 based on the rotational speed of the MG 12.

  Specifically, the MG-ECU 24 inputs the torque command value of the MG 12 output from the hybrid ECU 22 to the inverse filter 25, and among the torque command values of the MG 12, the resonance component of the drive shaft 15 (in the resonance frequency band). Inverse filter processing for attenuating the signal component) is performed. The transfer function of the inverse filter 25 is expressed by the following equation, for example.

Here, ξp is the attenuation rate, and fp is the resonance frequency of the drive shaft 15 in the torsional direction.
Further, the MG-ECU 24 inputs the rotational speed of the MG 12 detected by the rotational speed sensor 21 to the bandpass filter 27 of the vibration suppression F / B processing unit 26, and the resonance of the drive shaft 15 in the rotational speed of the MG 12 A band-pass filter process for extracting components is performed.

  Thereafter, the converter 28 converts the rotational speed (that is, the rotational speed resonance component) after the bandpass filter processing into a torque resonance component, and then the gain unit 29 multiplies the torque resonance component by the gain K. Then, a torque correction value for canceling the resonance of the drive shaft 15 is obtained.

  Thereafter, upper / lower limit guard processing unit 30 performs upper / lower limit guard processing for guarding the torque correction value with a predetermined upper limit guard value and lower limit guard value, and then torque corrected unit 31 performs torque after upper / lower limit guard processing. The final torque command value of the MG 12 is obtained by correcting the torque command value after the inverse filter processing using the correction value.

  The MG-ECU 24 controls the inverter 19 so as to realize the final torque command value of the MG 12 to control the voltage applied to the MG 12. The attenuation rate ξp of the inverse filter 25 and the gain K of the damping F / B processing are switched according to the driving state of the vehicle. The driving state of the vehicle includes, for example, a driving method of the wheels 16 (two-wheel drive, four-wheel drive), a travel mode (HV mode that travels with both the power of the engine 11 and the power of the MG 12, and EV that travels only with the power of the MG 12) Mode), traveling direction (forward, reverse), transmission gear ratio of the transmission 13, and the like.

  Incidentally, as in the comparative example shown in FIG. 3, when a vehicle drive request is generated based on the driver's accelerator operation while the vehicle is decelerating and the combustion of the engine is stopped (fuel cut), at that time, The system that starts engine combustion has the following problems. When the drive shaft torque is switched from negative to positive by the engine torque, there is a possibility that a shock may occur due to gear rattling caused by backlash (backlash) such as a differential gear or final gear of the power transmission system. At this time, there is a possibility that a large shock may occur due to the gears striking vigorously due to the synergistic effect of the steep initial explosion torque of the engine and the backlash of the gear. Furthermore, there is a possibility that resonance of the drive shaft occurs due to gear rattling and a shock due to resonance of the drive shaft occurs.

  Therefore, in this embodiment, the MG-ECU 24 executes a shock suppression routine shown in FIG. 5 described later, so that when the vehicle drive request is generated while the combustion of the engine 11 is stopped while the vehicle is decelerating, the drive shaft 15 After generating torque in the MG 12 with the torque command value after performing the inverse filter processing on the backlash torque command value for changing the torque from negative to positive, and changing the torque of the drive shaft 15 from negative to positive The combustion of the engine 11 is permitted.

  Specifically, as shown in FIG. 4, when a vehicle drive request is generated based on the driver's accelerator operation while the vehicle is decelerating and the combustion of the engine 11 is stopped (fuel cut), first, Before starting combustion of the engine 11, an inverse filter process for attenuating the resonance component of the drive shaft 15 with respect to the backlash torque command value for changing the torque of the drive shaft 15 from negative to positive is performed. Torque is generated in the MG 12 with the backlash torque command value after performing the inverse filter processing. As a result, when the torque of the drive shaft 15 is changed from negative to positive by the backlash torque of the MG 12, the drive included in the backlash torque of the MG 12 is suppressed while suppressing the occurrence of shock due to gear rattling of the power transmission system. The resonance component of the shaft 15 can be attenuated. As a result, the resonance of the drive shaft 15 due to the backlash torque of the MG 12 can be suppressed, and the occurrence of shock due to the resonance of the drive shaft 15 can be effectively suppressed.

  Then, after changing the torque of the drive shaft 15 from negative to positive by the backlash torque of the MG 12 (that is, after completion of backlash of the gear), the combustion of the engine 11 is permitted. As a result, it is possible to prevent the first explosion of the engine 11 in the middle of the backlash control. Therefore, it is possible to prevent the gear from striking hard due to the synergistic effect of the initial explosion torque and the gear backlash, and thus a large shock. Can be prevented.

Hereinafter, the processing content of the shock suppression routine of FIG. 5 executed by the MG-ECU 24 in the present embodiment will be described.
The shock suppression routine shown in FIG. 5 is repeatedly executed at a predetermined cycle. When this routine is started, first, at step 101, it is determined whether or not the vehicle is decelerating (for example, the accelerator is off) and the combustion of the engine 11 is being stopped (for example, the fuel is being cut). If it is determined in step 101 that the vehicle is not decelerating and the combustion of the engine 11 is not stopped, this routine is terminated without executing the processing from step 102 onward.

  On the other hand, if it is determined in step 101 that the vehicle is decelerating and the combustion of the engine 11 is stopped, the process proceeds to step 102 to determine whether or not a vehicle drive request has occurred, for example, from accelerator off. Judgment is made based on whether or not the accelerator is on. If it is determined in step 102 that a vehicle drive request has not occurred, this routine is terminated without executing the processing from step 103 onward.

  On the other hand, if it is determined in step 102 that a vehicle drive request has occurred, the process proceeds to step 103, where the attenuation rate ξp of the inverse filter 25 is switched to a predetermined value smaller than that. As a result, the degree of attenuation of the resonance component of the drive shaft 15 by the inverse filter processing is increased.

  Thereafter, the process proceeds to step 104, and the backlash torque command value output from the hybrid ECU 22 is read. The backlash torque command value is a torque command value for changing the torque of the drive shaft 15 from negative to positive, and is a torque value smaller than the required torque corresponding to the accelerator opening.

  Thereafter, the process proceeds to step 105, where an inverse filter process for attenuating the resonance component of the drive shaft 15 with respect to the backlash torque command value is performed. Then, the process proceeds to step 106, where the backlash torque command after the inverse filter process is performed. Torque is generated in MG12 by the value. More specifically, the backlash torque command value after the inverse filter processing is corrected using the torque correction value calculated by the vibration suppression F / B processing unit 26 to obtain the final backlash torque command value of the MG 12. The inverter 19 is controlled so as to realize the final backlash torque command value of the MG 12 to control the voltage applied to the MG 12.

  Thereafter, the routine proceeds to step 107, where it is determined whether or not the torque of the drive shaft 15 has changed from negative to positive. In this case, for example, the friction torque of the engine 11 is estimated based on the rotational speed of the MG 12, the torque of the drive shaft 12 is estimated based on the friction torque of the engine 11 and the torque of the MG 12, and the torque of the drive shaft 15 It is determined whether or not has changed from negative to positive.

  Before the combustion of the engine 11 starts, the rotation speed of the engine 11 changes according to the rotation speed of the MG 12 and the friction torque of the engine 11 changes. Therefore, the friction torque of the engine 11 is accurately estimated based on the rotation speed of the MG 12. can do. Furthermore, since the torque of the drive shaft 15 varies depending on the friction torque of the engine 11 and the torque of the MG 12, the torque of the drive shaft 15 can be accurately estimated based on the friction torque of the engine 11 and the torque of the MG 12. By using the torque of the drive shaft 15 estimated in this way, it can be accurately determined whether or not the torque of the drive shaft 15 has changed from negative to positive.

  Alternatively, the torque of the drive shaft 12 is based on one or more of the change rate of the vehicle speed (vehicle speed), the change rate of the rotation speed of the MG 12, and the change rate of the rotation speed of the engine 11 in a predetermined period. You may make it determine whether it changed from negative to positive.

When the torque of the drive shaft 12 changes from negative to positive, the behavior of the vehicle speed, the rotational speed of the MG 12 and the rotational speed of the engine 11 changes. Therefore, if at least one of the change rate of the vehicle speed, the change rate of the rotation speed of the MG 12 and the change rate of the rotation speed of the engine 11 is monitored, it is determined whether or not the torque of the drive shaft 15 has changed from negative to positive. It can be determined with high accuracy.
If it is determined in step 107 that the torque of the drive shaft 15 has not yet changed from negative to positive, the process returns to step 104 described above.

  Thereafter, if it is determined in step 107 that the torque of the drive shaft 15 has changed from negative to positive, the process proceeds to step 108, after allowing the engine 11 to combust, the process proceeds to step 109, where the vibration suppression F / The gain K of the B process is switched to a predetermined value larger than before. After the combustion of the engine 11 is permitted (that is, after the torque of the drive shaft 15 changes from negative to positive), the engine ECU 23 restarts the combustion of the engine 11.

  In the present embodiment described above, the backlash torque command after performing the inverse filter processing for attenuating the resonance component of the drive shaft 15 when the vehicle drive request is generated while the combustion of the engine 11 is stopped while the vehicle is decelerating. The torque is generated in the MG 12 by the value. Accordingly, when the torque of the drive shaft 15 is changed from negative to positive by the backlash torque of the MG 12, the drive shaft 15 due to the backlash torque of the MG 12 is suppressed while suppressing the occurrence of a shock due to the gear rattling of the power transmission system. The occurrence of shock due to the resonance of the drive shaft 15 can be effectively suppressed. Further, after the torque of the drive shaft 15 is changed from negative to positive by the backlash torque of the MG 12 (that is, after completion of backlash of the gear), the combustion of the engine 11 is permitted. Thereby, it is possible to prevent the gear from striking vigorously by the synergistic effect of the initial explosion torque of the engine 11 and the backlash of the gear, thereby preventing a large shock from occurring.

  Further, in this embodiment, when a vehicle drive request is generated while the vehicle 11 is decelerating while the vehicle is decelerating, the attenuation rate ξp of the inverse filter 25 is reduced, and the resonance of the drive shaft 15 by the inverse filter filter processing is performed. The attenuation of the component is increased. Accordingly, when the torque of the drive shaft 15 is changed from negative to positive by the backlash torque of the MG 12, the resonance component of the drive shaft 15 included in the backlash torque of the MG 12 can be effectively attenuated. The effect of suppressing the resonance of the shaft 15 can be enhanced, and the effect of suppressing the shock due to the resonance of the drive shaft 15 can be enhanced.

  Further, in this embodiment, when the combustion of the engine 11 is permitted, the gain K of the damping F / B process is increased. Thereby, the shock by the initial explosion torque of the engine 11 can be effectively suppressed by the damping F / B process.

  In the above-described embodiment, the resonance component of the drive shaft 15 is attenuated by the inverse filter processing. However, the present invention is not limited to this. For example, the drive shaft is obtained by low-pass filter processing (smoothing processing), band-pass filter processing, or the like. Fifteen resonance components may be attenuated.

  Further, in the above embodiment, when a vehicle drive request is generated, the attenuation degree of the resonance component of the drive shaft 15 by the filter process is increased, but this process (the attenuation degree of the resonance component of the drive shaft 15 is increased). Processing) may be omitted.

  In the above embodiment, when the combustion of the engine 11 is permitted, the gain K of the damping F / B process is increased, but this process (a process of increasing the gain K) is omitted. Also good.

  Further, the present invention is not limited to the hybrid vehicle having the configuration shown in FIG. 1. For example, the first clutch 17 (a clutch between the engine 11 and the MG 12) and the second clutch 18 (the MG 12 and the transmission 13). The motor is connected to a power transmission system that transmits engine power to the drive shaft of the wheel so that the power can be transmitted, such as may be applied to a hybrid vehicle in which one or both of the two clutches are omitted. It can be widely applied to hybrid vehicles.

  DESCRIPTION OF SYMBOLS 11 ... Engine (internal combustion engine), 12 ... MG (motor generator), 15 ... Drive shaft, 16 ... Wheel, 24 ... MG-ECU (motor control means)

Claims (5)

An engine (11) and a motor (12) are mounted as power sources for the vehicle, and the motor (12) is connected to a power transmission system that transmits the power of the engine (11) to the drive shaft (15) of the wheels (16). In the motor control device of a hybrid vehicle connected so that power can be transmitted,
A filter process for attenuating the resonance component of the drive shaft (15) is performed on the torque command value of the motor (12), and the resonance of the drive shaft (15) is performed based on the rotational speed of the motor (12). Motor control means (24) for performing vibration damping feedback processing for correcting the torque command value of the motor (12) so as to cancel,
The motor control means (24) changes the torque of the drive shaft (15) from negative to positive when a vehicle drive request is generated while the combustion of the engine (11) is stopped during deceleration of the vehicle. After generating the torque (12) in the motor (12) with the torque command value after the filter processing is performed on the backlash torque command value, the torque of the drive shaft (15) is changed from negative to positive, A motor control device for a hybrid vehicle, characterized by permitting combustion of the engine (11).   The motor control device for a hybrid vehicle according to claim 1, wherein the motor control means (24) increases the attenuation degree of the resonance component by the filter processing when the vehicle drive request is generated.   The motor control of the hybrid vehicle according to claim 1 or 2, wherein the motor control means (24) increases the gain of the vibration damping feedback process when combustion of the engine (11) is permitted. apparatus.   The motor control means (24) estimates the friction torque of the engine (11) based on the rotational speed of the motor (12), and based on the friction torque of the engine (11) and the torque of the motor (12). The torque of the drive shaft (15) is estimated, and it is determined whether or not the torque of the drive shaft (15) has changed from negative to positive. Motor controller for hybrid vehicles.   The motor control means (24) sets at least one of a change rate of the vehicle speed, a change rate of the rotation speed of the motor (12), and a change rate of the rotation speed of the engine (11) in a predetermined period. 4. The motor control device for a hybrid vehicle according to claim 1, wherein it is determined whether or not the torque of the drive shaft (15) has changed from negative to positive.

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