JP2012086810A - Vehicle controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle controller which restrains the occurrence of shock during regenerative braking.SOLUTION: The vehicle controller is configured to brake a vehicle by at least one of regenerative braking force to be generated by a motor generator and friction braking force to be generated by a wheel brake. An integrated controller calculates regenerative torque and friction braking torque during regenerative braking, calculates transmission output torque on the basis of the calculated regenerative torque when the speed is change by a transmission during regenerative braking, calculates a friction braking torque correction value which is balanced out with a fluctuation in the transmission output torque during a torque phase when the calculated friction braking torque is not zero, and causes the wheel brake to generate the friction braking force on the basis of the calculated friction braking torque correction value.

Description

  The present invention relates to a vehicle control device.

  Conventionally, in a hybrid vehicle equipped with a stepped automatic transmission, Patent Document 1 discloses a technique in which a regenerative torque of a motor generator is reduced simultaneously with the start of a shift when performing a shift during regenerative braking.

JP 2010-74886 A

  However, the above-described invention does not consider the cooperative regenerative control at the time of regenerative braking, and there is a problem that the regenerative torque decreases during the cooperative regenerative control and the charge amount of the battery in the motor generator decreases.

  The present invention has been invented to solve such problems. When shifting is performed during regenerative braking, the occurrence of shock at the time of shifting is suppressed, and the reduction of the regenerative torque in the motor generator is suppressed. The purpose is to increase the amount of charge of the battery.

  The vehicle control device according to an aspect of the present invention is configured to brake the vehicle with at least one of a regenerative braking force generated by a motor generator and a friction braking force generated by a wheel brake during braking, and generate electric power generated by the motor generator. Is a vehicle control device that charges the power storage device. The vehicle braking device calculates torque output means for calculating regenerative torque and friction braking torque during regenerative braking, and transmission output torque based on the regenerative torque when shifting is performed by the transmission during regenerative braking. Output torque calculating means, friction friction torque correcting means for calculating a friction braking torque correction value that cancels fluctuations in transmission output torque during the torque phase when the friction braking torque is not zero, and a friction braking torque correction value. And a friction braking force generating means for generating a friction braking force by the wheel brake.

  According to the present invention, when a shift is performed during regenerative braking, a friction braking torque correction value that cancels a change in transmission output torque during the torque phase is calculated, and the friction braking force is calculated based on the friction braking torque correction value. Therefore, it is possible to suppress a shock at the time of shifting, suppress a decrease in regenerative torque, and increase a charge amount of the battery.

It is the schematic which shows the power train of the hybrid vehicle of this embodiment. It is the schematic which shows the power train of the other hybrid vehicle which can apply this embodiment. It is the schematic which shows the power train of the further another hybrid vehicle which can apply this embodiment. It is a block diagram which shows the control system of this embodiment. It is a flowchart explaining the control at the time of regenerative braking of this embodiment. It is a time chart explaining the control at the time of regenerative braking of this embodiment. It is a time chart explaining the control at the time of regenerative braking of this embodiment.

  Hereinafter, embodiments of the present invention will be described in detail based on examples shown in the drawings.

  FIG. 1 shows a part of a front engine / rear wheel drive hybrid vehicle having a hybrid drive device to which the control device of this embodiment can be applied. The driving wheel 2 is provided with a wheel brake 25.

  In the hybrid vehicle shown in FIG. 1, the automatic transmission 3 is arranged in tandem at the rear of the engine 1 in the vehicle front-rear direction in the same manner as a normal rear wheel drive vehicle, and the automatic transmission is rotated from the engine 1 (crankshaft 1a). A motor generator 5 is provided in combination with the shaft 4 that transmits to the three input shafts 3a.

  The motor generator 5 acts as a motor or acts as a generator (generator), and is disposed between the engine 1 and the automatic transmission 3.

  More specifically, a first clutch 6 is inserted between the motor generator 5 and the engine 1, and more specifically, between the shaft 4 and the engine crankshaft 1 a, and the engine 1 and the motor generator 5 can be disconnected by the first clutch 6. Join.

  Here, the first clutch 6 can change the transmission torque capacity continuously or stepwise. For example, the transmission torque capacity can be changed by continuously controlling the clutch hydraulic oil flow rate and the clutch hydraulic pressure with a proportional solenoid. It consists of a simple wet multi-plate clutch.

  More specifically, a second clutch 7 is inserted between the motor generator 5 and the automatic transmission 3, and more specifically between the shaft 4 and the transmission input shaft 3 a, and the second clutch 7 is used between the motor generator 5 and the automatic transmission 3. Are detachably coupled.

  Similarly to the first clutch 6, the second clutch 7 can change the transmission torque capacity continuously or stepwise, for example, by continuously controlling the clutch hydraulic fluid flow rate and the clutch hydraulic pressure with a proportional solenoid. It consists of a wet multi-plate clutch whose capacity can be changed.

  The automatic transmission 3 is the same as that described in the "Skyline New Car (CV35) Description Manual" pages C-9 to C-22 issued in January 2003 by Nissan Motor Co., Ltd. By selectively engaging and releasing friction elements (clutch, brake, etc.), the transmission system path (shift stage) is determined by the combination of engagement and release of these friction elements.

  Therefore, the automatic transmission 3 shifts the rotation from the input shaft 3a with a gear ratio corresponding to the selected shift speed, and outputs it to the output shaft 3b.

  This output rotation is distributed and transmitted to the left and right rear wheels 2 by the differential gear device 8 and is used for traveling of the vehicle.

  However, it goes without saying that the automatic transmission 3 is not limited to the stepped type as described above, and may be a continuously variable transmission.

  In the power train of FIG. 1 described above, when the electric travel (EV) mode used at the time of low load and low vehicle speed including when starting from a stopped state is required, the power from the engine 1 is unnecessary. Is stopped and the first clutch 6 is released, while the second clutch 7 is engaged and the automatic transmission 3 is in a power transmission state.

  When the motor generator 5 is driven in this state, only the output rotation from the motor generator 5 reaches the transmission input shaft 3a, and the automatic transmission 3 changes the rotation to the input shaft 3a to the selected gear stage. The speed is changed accordingly and output from the transmission output shaft 3b.

  Then, the rotation from the transmission output shaft 3b reaches the drive wheel 2 through the differential gear device 8, and the vehicle can be electrically driven (EV mode traveling) only by the motor generator 5.

  When a hybrid travel (HEV) mode used during high speed travel or heavy load travel is required, both the first clutch 6 and the second clutch 7 are engaged to place the automatic transmission 3 in a power transmission state.

  In this state, the output rotation from the engine 1 or both the output rotation from the engine 1 and the output rotation from the motor generator 5 reach the transmission input shaft 3a, and the automatic transmission 3 is directed to the input shaft 3a. Is rotated according to the selected gear position and output from the transmission output shaft 3b.

  Thereafter, the rotation from the transmission output shaft 3b reaches the drive wheel 2 through the differential gear device 8, and the vehicle can be hybrid-driven (HEV mode travel) by both the engine 1 and the motor generator 5.

  When the engine 1 is operated at the optimum fuel efficiency during the HEV traveling, when the energy becomes surplus, the surplus energy is converted into electric power by operating the motor generator 5 as a generator by the surplus energy, and this generated power is converted into the motor. By storing electricity so as to be used for driving the motor of the generator 5, the fuel consumption of the engine 1 can be improved.

  In FIG. 1, the second clutch 7 for releasably coupling the motor generator 5 and the drive wheel 2 is interposed between the motor generator 5 and the automatic transmission 3. However, as shown in FIG. Even if it is interposed between the automatic transmission 3 and the differential gear unit 8, the same function can be achieved.

  In FIGS. 1 and 2, a dedicated second clutch 7 is added before or after the automatic transmission 3, but instead, as the second clutch 7, as shown in FIG. The friction element for selecting the forward shift stage or the friction element for selecting the reverse shift stage existing in the machine 3 may be used.

  In this case, in addition to the second clutch 7 fulfilling the above-described mode selection function, the automatic transmission is brought into a power transmission state when engaged so as to fulfill this function. The top is very advantageous.

  The engine 1, the motor generator 5, the first clutch 6, and the second clutch 7 that constitute the power train of the hybrid vehicle shown in FIGS. 1 to 3 are controlled by a system as shown in FIG.

  The control system of FIG. 4 includes an integrated controller 20 that integrally controls the operating point of the power train. The operating point of the power train is set to the target engine torque tTe and the target motor generator torque tTm (may be the target motor generator rotational speed tNm). And the target transmission torque capacity tTc1 of the first clutch 6 and the target transmission torque capacity tTc2 of the second clutch 7.

  The integrated controller 20 includes a signal from the engine rotation sensor 11 that detects the engine speed Ne and a signal from the motor generator rotation sensor 12 that detects the motor generator speed Nm in order to determine the operating point of the power train. A signal from the input rotation sensor 13 for detecting the transmission input rotation speed Ni, a signal from the output rotation sensor 14 for detecting the transmission output rotation speed No, and an accelerator pedal depression amount representing the required load state of the engine 1 A signal from the accelerator opening sensor 15 for detecting (accelerator opening APO) and a storage state sensor 16 for detecting the storage state SOC (carryable power) of the battery 9 that stores the electric power for the motor generator 5. Signal and a signal from the brake switch 17 that is turned on when the brake pedal is depressed. Forces.

  Of the sensors described above, the engine rotation sensor 11, the motor generator rotation sensor 12, the input rotation sensor 13, and the output rotation sensor 14 can be arranged as shown in FIGS.

  The integrated controller 20 can realize the driving force of the vehicle desired by the driver from the accelerator opening APO, the battery storage state SOC, and the transmission output speed No (vehicle speed VSP) among the input information. (EV mode, HEV mode), target engine torque tTe, target motor generator torque tTm (may be target motor generator rotation speed tNm), target first clutch transmission torque capacity tTc1, and target second clutch transmission torque capacity Each of tTc2 is calculated.

  The target engine torque tTe is supplied to the engine controller 21, and the target motor generator torque tTm (which may be the target motor generator rotational speed tNm) is supplied to the motor generator controller 22.

  The engine controller 21 controls the engine 1 so that the engine torque Te becomes the target engine torque tTe, and the motor generator controller 22 determines that the torque Tm (or the rotational speed Nm) of the motor generator 5 is the target motor generator torque tTm (or the target motor generator). The motor generator 5 is controlled via the battery 9 and the inverter 10 so that the rotation speed becomes tNm).

  The integrated controller 20 supplies a solenoid current corresponding to the target first clutch transmission torque capacity tTc1 and the target second clutch transmission torque capacity tTc2 to an engagement control solenoid (not shown) of the first clutch 6 and the second clutch 7, The first clutch 6 and the first clutch 6 so that the transmission torque capacity Tc1 of the first clutch 6 matches the target transmission torque capacity tTc1, and the transmission torque capacity Tc2 of the second clutch 7 matches the target second clutch transmission torque capacity tTc2. The second clutch 7 is individually controlled for fastening force.

  The integrated controller 20 sets the gear position of the automatic transmission 3 based on the accelerator opening APO, the transmission output rotational speed No, and the like, and outputs the information to the AT controller.

  The AT controller controls the hydraulic pressure of the frictional engagement element of the automatic transmission 3 based on the information from the integrated controller 20 and executes the shift control by the automatic transmission 3.

  Next, control during regenerative braking according to the present embodiment will be described with reference to the flowchart of FIG. Here, it is assumed that the driver depresses the brake pedal and determines that the automatic transmission 3 performs a downshift while regenerative braking is being performed. The control described below is performed by the integrated controller 20, but is not limited thereto. Further, all or part of the control described below may be performed by the AT controller 23.

  In step S100, a deceleration to be achieved by the vehicle is calculated based on the driver's brake pedal operation (depression amount, intention to decelerate), and a braking force for achieving the calculated deceleration is calculated.

  In step S101, a regenerative torque by the motor generator 5 and a mechanical brake torque (friction braking torque) by the wheel brake 25 are calculated from the calculated braking force. In this step, cooperative control is performed so that the ratio between the regenerative torque and the mechanical brake torque is optimized. This regenerative torque is calculated according to the gear position (speed ratio) of the automatic transmission 3. That is, the sum of the braking force (regenerative braking force) achieved by the torque obtained by multiplying the regenerative torque by the gear ratio and the braking force (friction braking force) achieved by the mechanical brake torque by the wheel brake 25, The regenerative torque and the mechanical brake torque are calculated so as to be the braking force in step S100.

  In step S102, when the regenerative torque calculated in step S101 is generated by the motor generator 5, the output torque (transmission output torque) that is actually output to the transmission output shaft 3b of the automatic transmission 3 is calculated. The output torque is calculated by equation (1).

  Output torque = regenerative torque × (CURGR + (SFTGR−CURGR) × engagement clutch advancement degree) (1)

  CURGR is a gear ratio before shifting, and SFTGR is a gear ratio after shifting. Further, the degree of progress of the engagement clutch indicates a torque transmission characteristic during the torque phase, and is calculated by Expression (2).

  Engagement clutch progression time = time T1 / predetermined time T2 + offset value (2)

  The time T1 is the time from the start of the torque phase, and the predetermined time T2 is the time until the engagement-side clutch torque capacity actually reaches the target engagement-side clutch torque capacity, and is set in advance by experiments or the like. The offset value is a value that takes into account the hydraulic response delay in the engagement-side friction element, and is set by a table based on the ATF oil temperature for each gear position.

  In step S103, it is determined whether there is a braking force assigned by the wheel brake 25 or not. That is, it is determined whether or not the mechanical brake torque calculated in step S101 is zero. If the mechanical brake torque is not zero, the process proceeds to step S104. If the mechanical brake torque is zero, the process proceeds to step S106.

  In step S104, a mechanical brake torque correction value (friction braking torque correction value) that achieves the braking force calculated in step S100 is calculated with respect to the braking force based on the output torque calculated in step S102. That is, a mechanical brake torque correction value that cancels the output torque that varies with the progress of the shift in the automatic transmission 3 is calculated. Specifically, the deviation between the braking force based on the output torque calculated in step S102 and the braking force corresponding to the regenerative torque by the motor generator 5 calculated in step S101 is calculated. This deviation becomes the mechanical brake torque correction value.

  In step S105, the wheel brake 25 generates a torque obtained by adding the mechanical brake torque correction value and the mechanical brake torque calculated in step S101. Further, the motor generator 5 generates the regenerative torque calculated in step S101. As a result, a braking force corresponding to the driver's operation of the brake pedal is generated.

  In step S106, the corrected regenerative torque is calculated so that the output torque of the transmission output shaft 3b of the automatic transmission 3 becomes a torque corresponding to the regenerative torque calculated in step S101, that is, a torque that takes into account the output torque variation due to the torque phase. To do. The corrected regenerative torque is calculated by equation (3).

  Correction regenerative torque = regenerative torque / ((CURGR + (SFTGR−CURGR) × engagement clutch progress)) (3)

  The regenerative torque in equation (3) is the regenerative torque calculated in step S101. The corrected regenerative torque is calculated based on the torque transmission characteristic during the torque phase.

  In step S107, the torque of the motor generator 5 is set as the corrected regenerative torque calculated in step S106. By setting the torque of the motor generator 5 as the corrected regenerative torque, the output torque of the transmission output shaft 3b of the automatic transmission 3 is constant regardless of the shift state of the automatic transmission 3, and according to the driver's brake pedal operation. Braking force is generated.

  In step S108, it is determined whether or not the shift of the automatic transmission 3 has been completed. When the ratio between the transmission input rotational speed Ni and the transmission output rotational speed No reaches a set value, it is determined that the shift of the self-propelled transmission 3 has been completed. Then, when the shift of the automatic transmission 3 is finished, this control is finished. If the shift of the automatic transmission 3 has not been completed, the process returns to step S102 and the above control is repeated.

  When the corrected regenerative torque is calculated in step S106 of the control, a corrected engagement side clutch torque capacity corresponding to the corrected regenerative torque is calculated. When the regenerative torque of the motor generator 5 is reduced, the engagement-side clutch torque capacity necessary for shifting is also reduced. The corrected engagement side clutch torque capacity is calculated by equation (4).

  Correction engagement side clutch torque capacity = engagement side clutch torque capacity / ((CURGR + (SFTGR−CURGR) × engagement clutch progress)) (4)

  The engagement-side clutch torque capacity of equation (4) corresponds to the regenerative torque calculated in step S101 and is set in advance.

  The hydraulic pressure supplied to the engagement-side friction element is controlled based on the calculated corrected engagement-side clutch torque capacity.

  This control may be executed by a control different from the control described above, or may be executed by the control described above.

  Next, control during regenerative braking according to the present embodiment will be described with reference to time charts of FIGS. FIG. 6 is a time chart when the mechanical brake torque is not zero, and FIG. 7 is a time chart when the mechanical brake torque is zero. In FIGS. 6 and 7, the instruction value for the gear position is shown. First, the case where the mechanical brake torque is not zero will be described with reference to FIG.

  At time t0, the automatic transmission 3 starts shifting. When the shift is started, the hydraulic pressure of the engagement-side friction element is temporarily increased to start a precharge phase in which the piston stroke of the engagement-side friction element is advanced. Thereafter, the hydraulic pressure of the friction element on the engagement side is maintained at a predetermined hydraulic pressure that is smaller than the hydraulic pressure that is temporarily increased. The hydraulic pressure of the disengagement friction element decreases after the start of shifting and is maintained at a predetermined hydraulic pressure.

  At time t1, the hydraulic pressure of the engagement-side friction element is increased, the engagement-side clutch torque capacity is increased, and the torque phase is started. Even if the regenerative torque of the motor generator 5 is constant, when the engagement-side clutch torque capacity increases, the torque transmitted from the motor generator 5 to the transmission output shaft 3b of the transmission 3 increases, and the braking force by the motor generator 5 increases. growing. Here, the increasing torque is calculated, and the braking force of the wheel brake 25 is decreased so as to cancel the braking force corresponding to this torque. Thereby, the fluctuation | variation of the braking force during a torque phase can be suppressed.

  When the change of the gear ratio in the automatic transmission 3 actually starts at time t2, the torque phase is ended and the inertia phase is started.

  Next, the case where the mechanical brake torque is zero will be described with reference to FIG. Here, since the mechanical brake torque is zero, the braking force of the wheel brake 25 is zero.

  At time t0, the automatic transmission 3 starts shifting. When the shift is started, the hydraulic pressure of the engagement-side friction element is temporarily increased to start a precharge phase in which the piston stroke of the engagement-side friction element is advanced. Thereafter, the hydraulic pressure of the friction element on the engagement side is maintained at a predetermined hydraulic pressure that is smaller than the hydraulic pressure that is temporarily increased. The hydraulic pressure of the disengagement friction element decreases after the start of shifting and is maintained at a predetermined hydraulic pressure.

  At time t1, the hydraulic pressure of the engagement-side friction element is increased, the engagement-side clutch torque capacity is increased, and the torque phase is started. Here, by setting the torque of the motor generator 5 as the corrected regenerative torque, the torque of the motor generator 5 is reduced, the fluctuation of the output torque of the transmission output shaft 3b during the torque phase is suppressed, and the control during the torque phase is suppressed. Power fluctuation can be suppressed.

  When the change of the gear ratio in the automatic transmission 3 actually starts at time t2, the torque phase is ended and the inertia phase is started.

  The effect of the embodiment of the present invention will be described.

  During the regenerative braking, the regenerative torque and the mechanical brake torque are calculated, and the output torque of the transmission output shaft 3b of the automatic transmission 3 with respect to the regenerative torque is calculated. If the mechanical brake torque is not zero, a mechanical brake torque correction value that cancels the fluctuation of the output torque due to the torque phase is calculated, and a braking force is generated by the wheel brake based on the calculated mechanical brake torque correction value. Thus, it is possible to generate a braking force based on the driver's operation of the brake pedal without reducing the regenerative torque in the motor generator 5, and it is possible to reduce the shock generated during the shift. Therefore, the regeneration amount of the battery 9 in the regeneration control, that is, the charge amount can be increased, and the fuel efficiency can be improved.

  When the mechanical brake torque is zero, the motor generator 5 is configured such that the output torque of the transmission output shaft 3b of the automatic transmission 3 is equal to the regenerative torque calculated based on the driver's brake pedal operation. The corrected regenerative torque for correcting the regenerative torque is calculated, and the torque of the motor generator 5 is set as the corrected regenerative torque. As a result, it is possible to generate a braking force based on the driver's operation of the brake pedal, and to reduce a shock that occurs during a shift.

  During the shift, the braking force based on the driver's brake pedal operation, the output torque of the transmission output shaft 3b of the automatic transmission 3, etc. are repeatedly calculated, and the mechanical brake correction value or the corrected regenerative torque is calculated based on the calculated result. Calculate repeatedly and execute control during regenerative braking. Thus, depending on the driver's operation of the brake pedal and the shift state of the automatic transmission 3, the control during regenerative braking is executed separately when the mechanical brake torque is zero or when the mechanical brake torque is not zero. be able to. Therefore, even if the mechanical brake torque is changed from zero to zero when shifting, for example, the occurrence of shock due to this can be suppressed.

  When the mechanical brake torque is zero, by correcting the engagement-side clutch torque capacity according to the correction regenerative torque, it is possible to further reduce the shock during the shift. In addition, the hydraulic pressure required for shifting can be reduced.

  It goes without saying that the present invention is not limited to the above-described embodiments, and includes various modifications and improvements that can be made within the scope of the technical idea.

3 Automatic transmission (transmission)
5 Motor generator 9 Battery (power storage device)
20 integrated controller (torque calculation means, output torque calculation means, friction braking torque correction means, friction braking force generation means, corrected regenerative torque calculation means, regenerative braking force generation means, shift end determination means, clutch torque capacity correction means)
25 Wheel brake

Claims (4)

A vehicle control device that brakes a vehicle with at least one of a regenerative braking force generated by a motor generator and a friction braking force generated by a wheel brake during braking, and charges a power storage device with electric power generated by the motor generator. And
Torque calculating means for calculating regenerative torque and friction braking torque during regenerative braking;
An output torque calculating means for calculating a transmission output torque based on the regenerative torque when shifting is being performed by the transmission during the regenerative braking;
Friction braking torque correction means for calculating a friction braking torque correction value that offsets fluctuations in the transmission output torque during the torque phase when the friction braking torque is not zero;
A vehicle control apparatus comprising: friction braking force generating means for generating the friction braking force by the wheel brake based on the friction braking torque correction value. Corrected regenerative torque calculating means for calculating a corrected regenerative torque based on torque transmission characteristics during the torque phase when the friction braking torque is zero;
The vehicle control device according to claim 1, further comprising: a regenerative braking force generation unit configured to generate the regenerative braking force by the motor generator based on the corrected regenerative torque. Shift end determining means for determining whether the shift has ended,
When the shift is not completed, the torque calculation means calculates the regenerative torque and the friction braking torque again,
When the shift is not completed, the output torque calculating means calculates the transmission output torque again,
The friction braking torque correction means or the corrected regenerative torque calculation means is configured to recalculate the friction braking torque correction value or the corrected regenerative torque based on the recalculated regenerative torque, the friction braking torque, and the transmission output torque. The vehicle control device according to claim 2, wherein the calculation is performed again.   The clutch torque capacity correcting means for correcting the engagement side clutch torque capacity of the transmission corresponding to the correction regenerative torque when the friction braking torque is zero. Vehicle control device.

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