JP2012086709A - Drive force control device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive force control device of a vehicle, which can suppress the vibration of a vehicle body accompanied by slips of drive wheels.SOLUTION: When left/right rear wheels 2c, 2d being the drive wheels are slipped, filter processing is performed which removes or reduces a component being an element of the vibration of the vehicle body resulting from the slips from target values (target engine torque tTe and target motor/generator torque tTm) of power sources (engine 1 and motor/generator 5) corresponding to target drive forces tFo0 of the vehicle.

Description

  The present invention relates to a driving force control apparatus for a vehicle.

  Patent Document 1 discloses that vehicle body vibration caused by torsion of a drive shaft caused by accelerator on / off is suppressed by performing phase compensation on the accelerator opening.

JP 2004-322947 A

However, in the above prior art, when a drive wheel slips on a low μ road such as a snowy road and vibration occurs in the drive system, the slip state of the tire is maintained when the traction control intervenes, so the vibration does not occur. There was a problem that the drivability continued to deteriorate.
An object of the present invention is to provide a driving force control device for a vehicle that can suppress vehicle body vibration caused by slipping of driving wheels.

  In order to achieve the above object, in the present invention, when a drive wheel slips, a component that causes vehicle body vibration caused by the slip is removed or reduced from a target value of a power source according to a target drive force of the vehicle.

  Therefore, in the present invention, the power source is driven by the target value from which the component that causes the vehicle body vibration due to the slip of the drive wheel is removed or reduced, so that the vehicle body vibration accompanying the slip of the drive wheel can be suppressed.

It is a top view which shows the powertrain of the hybrid vehicle of Example 1. FIG. FIG. 2 is a control block diagram of the vehicle driving force control apparatus according to the first embodiment. FIG. 6 is a characteristic diagram of target driving force. FIG. 2 is an area diagram showing an electric travel (EV) mode area and a hybrid travel (HEV) mode area of a hybrid vehicle. It is a characteristic diagram which shows the target charging / discharging amount characteristic with respect to the battery electrical storage state of a hybrid vehicle. It is an example of the shift map which determines a target gear stage. It is engine torque increase progress explanatory drawing which shows the increase progress of the engine torque to the best fuel consumption line according to a vehicle speed. 3 is a flowchart illustrating a flow of filter processing according to the first exemplary embodiment. FIG. 6 is a control block diagram of a vehicle control apparatus according to a second embodiment. FIG. 6 is a control block diagram of a vehicle control apparatus according to a third embodiment. FIG. 10 is a plan view showing a powertrain of a vehicle in Example 4; FIG. 10 is a control block diagram of a vehicle control apparatus according to a fourth embodiment.

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing the driving force control apparatus of the vehicle of this invention is demonstrated in detail based on the Example shown on drawing.
[Example 1]
FIG. 1 is a plan view showing a powertrain of the hybrid vehicle of the first embodiment.
The hybrid vehicle of the first embodiment is a hybrid vehicle based on a front engine / rear wheel drive vehicle (rear wheel drive vehicle). 1 is an engine, and 2c and 2d are left and right rear wheels as drive wheels. It is a ring.
In the power train of 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 engine 1 (crankshaft 1a) is rotated. A motor / generator 5 is provided in combination with the shaft 4 that transmits to the input shaft 3a of the automatic transmission 3, and this motor / generator 5 is provided as a second power source.

The motor / generator 5 acts as a drive motor and a generator, and is disposed between the engine 1 and the automatic transmission 3.
The first clutch 6 can be inserted between the motor / generator 5 and the engine 1, more specifically, between the shaft 4 and the engine crankshaft 1a, and the engine 1 and the motor / generator 5 can be disconnected by the first clutch 6. To join.
Here, the first clutch 6 is capable of changing the transmission torque capacity continuously or stepwise, for example, by controlling the clutch hydraulic oil flow rate and the clutch operation oil pressure continuously or stepwise with a proportional solenoid. It consists of a wet multi-plate clutch whose capacity can be changed.

A second clutch (clutch) 7 is inserted between the motor / generator 5 and the left and right rear wheels (drive wheels) 2c, 2d, and the motor / generator 5 and the left and right rear wheels 2c, 2d can be separated by the second clutch 7. Join.
Similarly to the first clutch 6, the second clutch 7 can change the transmission torque capacity continuously or stepwise. For example, the proportional hydraulic solenoid controls the clutch hydraulic fluid flow rate and the clutch hydraulic pressure continuously or stepwise. And a wet multi-plate clutch whose transmission torque capacity can be changed.

The automatic transmission 3 may be any known one, and by selectively engaging and releasing a plurality of speed change friction elements (clutch, brake, etc.), a transmission system is obtained by combining these speed change friction elements. (Shift stage) shall be determined.
Accordingly, the automatic transmission 3 shifts the rotation from the input shaft 3a at a gear ratio corresponding to the selected shift speed and outputs the same to the output shaft 3b.
This output rotation is distributed and transmitted to the left and right rear wheels 2c, 2d by the differential gear device 8, and is used for traveling of the vehicle.

By the way, in FIG. 1, instead of newly providing a dedicated second clutch 7 for releasably coupling the motor / generator 5 and the drive wheel 2, an existing shift friction element is used in the automatic transmission 3. .
In this case, the second clutch 7 performs the above-described shift speed selection function (shift function) by engaging, and the automatic transmission 3 is brought into the power transmission state, and in addition, the first clutch 6 is released and engaged, A mode selection function to be described later can be achieved, and a dedicated second clutch is unnecessary, which is very advantageous in terms of cost.

In the hybrid vehicle powertrain shown in 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 first clutch 6 is released. When the second clutch 7 is engaged, the automatic transmission 3 is brought into a power transmission state.
The second clutch 7 is a shift friction element to be fastened at the current shift stage among the shift friction elements in the automatic transmission 3, and is different for each selected shift stage.
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 shift speed. The speed is changed according to the speed and output from the transmission output shaft 3b.
The rotation from the transmission output shaft 3b then reaches the left and right rear wheels 2c, 2d via the differential gear device 8, and the vehicle can be electrically driven (EV traveling) only by the motor / generator 5.

When the hybrid travel (HEV travel) mode used for high speed travel or heavy load travel is required, the automatic transmission 3 remains in the corresponding gear selection state (power transmission state) by engaging the second clutch 7 The first clutch 6 is also engaged.
In this state, 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 changes the rotation to the input shaft 3a to the selected shift speed. The speed is changed according to the speed and output from the transmission output shaft 3b.
The rotation from the transmission output shaft 3b then reaches the left and right rear wheels 2c, 2d via the differential gear device 8, and the vehicle can be hybrid-run (HEV-run) by both the engine 1 and the motor / generator 5.

  In such HEV traveling, when the engine 1 is operated with the optimal fuel efficiency, if the energy becomes surplus, the surplus energy is converted into electric power by operating the motor / generator 5 as a generator by this surplus energy, and this generated power is converted into electric power. By accumulating power to be used for driving the motor of the motor / generator 5, the fuel consumption of the engine 1 can be improved.

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 FIG. 1 are controlled by a system as shown in FIG.
The control system of FIG. 2 includes a hybrid controller (HCM) 9 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, the target motor / generator (MG) torque tTm, It is defined by the target first clutch torque tTc1 of the first clutch 6 and the target second clutch torque tTc2 of the second clutch 7.

  The HCM 9 includes a signal from the engine rotation sensor 10 that detects the engine rotation speed Ne, a signal from the MG rotation sensor 11 that detects the MG rotation speed NM, and a transmission to determine the operating point of the power train. A signal from the input rotation sensor 12 for detecting the input rotation speed Ni, a signal from the output rotation sensor 13 for detecting the transmission output rotation No, a signal from the accelerator opening sensor 14 for detecting the accelerator opening APO, A signal from a storage state sensor 15 that detects a storage state SOC (carryable power) of a battery (not shown) that stores power for the motor / generator 5 is input.

The HCM9 has an operation mode (EV mode, HEV mode) that 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). At the same time, the target engine torque tTe, the target MG torque tTm, the target first clutch torque tTc1, and the target second clutch torque tTc2 are calculated.
The target engine torque tTe is supplied to the engine controller 17, and the target MG torque tTm is supplied to the motor controller 18.

The engine controller 17 controls the engine 1 so that the engine torque Te becomes the target engine torque tTe, and the motor controller 18 controls the battery and inverter (not shown) so that the torque Tm of the motor / generator 5 becomes the target MG torque tTm. The motor / generator 5 is controlled via
The HCM 9 supplies a solenoid current corresponding to the target first clutch torque tTc1 and the target second clutch torque tTc2 to the engagement control solenoids (not shown) of the first clutch 6 and the second clutch 7, and the transmission torque of the first clutch 6 The first clutch so that the capacity matches the transmission torque capacity corresponding to the target first clutch torque tTc1, and the transmission torque capacity of the second clutch 7 matches the transmission torque capacity corresponding to the target second clutch torque tTc2. The fastening force of the 6 and the second clutch 7 is individually controlled.

The HCM 9 executes selection of the above-described operation mode (EV mode, HEV mode) and calculation of the target engine torque tTe, the target MG torque tTm, the target first clutch torque tTc1, and the target second clutch torque tTc2 by each control block. .
The target driving force calculation / operation mode selection unit 19 calculates the target driving force tFo0 of the vehicle from the accelerator opening APO and the vehicle speed VSP using the target driving force map shown in FIG. Further, using the EV-HEV region map shown in FIG. 4, a target operation mode is determined from the accelerator opening APO and the vehicle speed VSP.
As is clear from the EV-HEV region map shown in FIG. 4, the HEV mode is selected at high load / high vehicle speed, the EV mode is selected at low load / low vehicle speed, and the accelerator opening APO and EV When the driving point determined by the combination of the vehicle speed VSP exceeds the EV → HEV switching line and enters the HEV region, the mode switching from EV mode to HEV mode with engine start is performed, and the driving point is changed to HEV during HEV driving → When the vehicle enters the EV region beyond the EV switching line, the mode is switched from the HEV mode to the EV mode with engine stop and engine disconnection. Here, it is assumed that the EV → HEV switching line and the HEV → EV switching line move in a direction in which the accelerator opening APO decreases as the battery storage state decreases.

The target charge / discharge calculation unit 20 calculates a target charge / discharge amount (power) tP from the battery storage state SOC using the charge / discharge amount map shown in FIG.
The target input torque calculation unit 21 uses the accelerator opening APO, the target driving force tFo0, the target operation mode, the vehicle speed VSP, and the target charge / discharge amount tP as the operating point arrival target, and changes from moment to moment. Target engine torque tTe, target transmission input torque (target input torque) tTi, and target transmission output torque (target drive torque) tTd are calculated.
Further, the output required to increase the engine torque from the current operating point to the best fuel consumption line shown in FIG. 6 is calculated, and this is compared with the target charge / discharge amount tP, and the smaller output is set as the required output. Add to the target engine torque tTe.
In the drive torque distribution calculation unit 22, the target engine torque tTe, the target input torque tTi, and the target drive torque tTd, the target MG torque tTm, the target first clutch torque tTc1, the target second clutch torque tTc2, and the automatic The target shift stage SHIFT of the transmission 3 is calculated. FIG. 7 is an example of a shift map for determining the target shift stage SHIFT, and the target shift stage SHIFT is set according to the vehicle speed VSP and the accelerator opening APO.
The automatic transmission 3 enters the power transmission state in which the target shift stage SHIFT is selected while the second clutch 7 is engaged and controlled to achieve a transmission torque capacity corresponding to the target second clutch torque tTc2.

The TCS controller 16 detects the front left wheel speed signal V _FL , the right front wheel speed signal V _FR , and the left rear wheel from each wheel speed sensor 23a, 23b, 23c, 23d that detects the rotational speed of each wheel 2a, 2b, 2c, 2d. Input speed signal V _RL and right rear wheel speed signal V _RR . The TCS control operation determination unit 24 of the TCS controller 16 determines the average value of the left front wheel speed V _FL and the right front wheel speed V _FR as the driven wheel speed V _F , and the average value of the left rear wheel speed V _RL and the right rear wheel speed V _{RR as} the average value. a drive wheel speed V _R, when the drive slip value S obtained by subtracting the driven wheel speed V _F from the driving wheel speed V _R is equal to or larger than the predetermined value Sth, with sets TCS control request flag FTCS, drive slip A TCS control required torque (required driving force reduction amount) Ttcs for reducing the target input torque tTi according to the amount S is determined. The TCS control request torque Ttcs increases as the drive slip amount S increases, and the target input torque tTi is further decreased. The TCS request control flag and the TCS control request torque Ttcs are input to the filter processing unit (vibration suppression unit) 25 of the target input torque calculation unit 21.

ここで、sはラプラス演算子、ω_pは自車両の固有振動数、ζ_pは自車両の減衰率であり、
ζ_p<1.0の場合は減衰振動、
ζ_p=1.0の場合は臨界減衰、
ζ_p>1.0の場合は過減衰、
となる。 When the TCS request control flag is set, the filter processing unit 25 is a filter for reducing the component (frequency component) that causes the vehicle body vibration caused by the slip of the left and right rear wheels 2c and 2d from the TCS control request torque Ttcs. Process. The calculation logic of the filter transfer function C (s) used for the filter processing is shown below.
Transfer function G (s) with transmission input torque u (s) as input and drive wheel speed y (s) as output must be expressed as a second-order lag transfer function as shown in equation (1) below. Can do.

Where s is the Laplace operator, ω _p is the natural frequency of the host vehicle, ζ _p is the damping factor of the host vehicle,
If ζ _p <1.0, damped vibration,
critical damping for ζ _p = 1.0,
If ζ _p > 1.0, overdamping,
It becomes.

ここで、ω_mは目標伝達特性の固有振動数、ζ_mは目標伝達特性の減衰率であり、これらを適宜の値に設定することで、トラクション(TCS)制御介入時の車体振動（8Hz近傍）の振動レベルを抑制できる。なお、車体振動の周波数は自動変速機3の変速段毎に変化するため、フィルタに幅を持たせる。
目標入力トルク演算部21は、算出した目標入力トルクtTiからフィルタ処理後のTCS制御要求トルクTtcsを減算して目標入力トルクtTiを減少補正する。 Based on the equation (1), the transfer function C (s) of the filter inserted before the transfer function G (s) is set as the following equation (2).

Here, ω _m is the natural frequency of the target transfer characteristic, and ζ _m is the damping factor of the target transfer characteristic. By setting these to appropriate values, the vehicle vibration (near 8 Hz) during traction (TCS) control intervention ) Vibration level can be suppressed. Since the frequency of the vehicle body vibration changes for each gear position of the automatic transmission 3, the filter has a width.
The target input torque calculator 21 subtracts the filtered TCS control request torque Ttcs from the calculated target input torque tTi and corrects the target input torque tTi by decreasing it.

[Filter processing]
FIG. 8 is a flowchart illustrating the flow of the filtering process according to the first embodiment.
In step S1, it is determined whether or not the TCS control operation is being performed. If YES, the process proceeds to step S2, and if NO, the control is terminated.
In step S2, the TCS control request torque Ttcs is filtered.
Therefore, the filter processing by the filter processing unit 25 is performed only at the time of TCS control intervention.

Next, the operation of the first embodiment will be described.
In a vehicle that does not have a torque converter in the drive system, vehicle body vibration (around 8 Hz) may occur during tire slip on a low μ road. This is a phenomenon that occurs when torque fluctuations due to μ-S characteristics between the tire and road surface are input to the vibration system with the tire as the mass and the drive shaft as the spring. Become prominent. And in vehicles that perform TCS control that suppresses drive wheel slip, the slip state of the drive wheel is maintained by TCS control intervention, so this phenomenon tends to continue, resulting in deterioration of drivability and abnormal vibration to the driver Give a sense of incongruity.

  Here, Japanese Patent Application Laid-Open No. 2004-322947 discloses a technique for suppressing vehicle body vibration (so-called rattling vibration) caused by drive shaft torsion caused by accelerator on / off. However, this prior art is intended to suppress vibrations when the tire is not slipping, and the frequency differs from the vibration at the time of tire slip. Therefore, the driving wheel slips on a low μ road such as a snowy road. When vibration occurs in the drive system, if the TCS control intervenes, the tire slip state is maintained, so the vibration continues. In addition, since conventional vibration suppression always operates with respect to input torque, it is not possible to suppress vibration that occurs only under certain conditions (when the tire slips). In the case of the state, the vibration suppression control works and the drivability is deteriorated.

In contrast, the filter processing unit 25 according to the first embodiment reduces the component that causes the vehicle body vibration caused by the slip of the left and right rear wheels 2c and 2d with respect to the TCS control request torque Ttcs during the TCS control intervention. Perform the process. As a result, the engine 1 and the motor / generator 5 are driven by the target engine torque tTe and the target MG torque tTm that reduce the components that cause the vehicle body vibration accompanying the slip of the left and right rear wheels 2c, 2d. Vehicle vibration can be suppressed.
Here, for example, when a filter process is performed on the target engine torque tTe and the target MG torque tTm in a travel scene other than during the TCS control intervention, the vehicle drive force varies due to the filter process. This may affect the driving of the driver and the driver and may lead to deterioration of driving performance.
Therefore, in the first embodiment, the filter process is performed only at the time of the TCS control intervention in which the vehicle body vibration accompanying the slip of the left and right rear wheels 2c and 2d is likely to continue, and the filter process is not performed in other driving scenes. It is possible to prevent deterioration in drivability of the vehicle due to the filter processing.

Next, the effect will be described.
The vehicle driving force control apparatus according to the first embodiment has the following effects.
(1) When the left and right rear wheels 2c, 2d, which are driving wheels, slip, the target values (target engine torque tTe, target MG torque) of the power source (engine 1, motor / generator 5) corresponding to the target driving force tFo0 of the vehicle From tTm), a filter processing unit 25 that performs a filter process for reducing a component that causes a vehicle body vibration caused by the slip is provided.
As a result, the power source (engine 1, motor / generator 5) is driven by the target value in which the component that causes the vehicle body vibration is reduced, so that the vehicle body vibration accompanying the slip of the left and right rear wheels 2c, 2d can be suppressed.

  (2) Since the filter processing unit 25 performs the filter process only during the TCS control intervention that suppresses the idling of the left and right rear wheels 2c, 2d, the drivability of the vehicle deteriorates due to the filter process in the driving scene other than during the TCS control intervention. Can be prevented.

  (3) Since the filter processing unit 25 performs the filter processing on the TCS control request torque Ttcs, while suppressing the vehicle body vibration at the time of joining the TCS control due to the slip of the left and right rear wheels 2c, 2d, other traveling scenes It is possible to prevent the deterioration of the drivability of the vehicle due to the filtering process.

[Example 2]
FIG. 9 is a control block diagram of the vehicle control apparatus according to the second embodiment. The second embodiment is different from the first embodiment in that the filter processing unit 25 is provided on the TCS controller 16 side. 1 is the same.
Therefore, in Example 2, there exists an effect similar to Example 1.

Example 3
FIG. 10 is a control block diagram of the vehicle control apparatus according to the third embodiment, which is different from the first embodiment in that the filter processing unit 26 is provided on the motor controller 18 side.
When the TCS request control flag is set, the filter processing unit 26 performs a filter process for reducing a component that causes a vehicle body vibration caused by the slip of the left and right rear wheels 2c and 2d from the target MG torque tTm. The transfer function of the filter is the same as that of the filter of the first embodiment.
The motor controller 18 subtracts the filtered TCS control request torque Ttcs from the target MG torque tTm to correct the target MG torque tTm.
Other configurations are the same as those of the first embodiment.
Therefore, in Example 3, there exists an effect similar to Example 1.

Example 4
FIG. 11 is a plan view showing a powertrain of the vehicle in the fourth embodiment.
The vehicle of the fourth embodiment is an example in which the motor / generator 5 is omitted from the configuration of the first embodiment shown in FIG.
FIG. 12 is a control block diagram of the vehicle control apparatus according to the fourth embodiment.
The engine controller 27 includes a target driving force calculation unit 28 and a target engine torque calculation unit 29.
The target driving force calculation unit 28 calculates the target driving force tFo0 of the vehicle from the accelerator opening APO and the vehicle speed VSP.
The target engine torque calculation unit 29 calculates the target engine torque tTe from the target driving force tFo0, and controls the engine 1 so that the engine torque Te becomes the target engine torque tTe.
The target engine torque calculation unit 29 includes a filter processing unit 30.
When the TCS control request flag Ftcs is set, the filter processing unit 30 performs a filter process for reducing components that cause vehicle body vibration caused by slip of the left and right rear wheels 2c and 2d from the TCS control request torque Ttcs. .
The target engine torque calculation unit 29 corrects the target engine torque tTe by subtracting the TCS control request torque Ttcs after filtering from the calculated target engine torque tTe.
Therefore, the vehicle driving force control apparatus according to the fourth embodiment has the same effects as the first embodiment.

(Other examples)
As mentioned above, although the form for implementing the driving force control apparatus of the vehicle of this invention was demonstrated based on the Example, the specific structure of this invention is not limited to the structure as described in an Example. Design changes and the like within the scope not departing from the gist of the invention are included in the scope of the present invention.
The automatic transmission 3 is not limited to a stepped type, and may be a continuously variable transmission.
The second clutch 7 may not be a speed change friction element existing in the automatic transmission 3 but may be a dedicated one. In this case, the second clutch 7 is provided between the input shaft 3a of the automatic transmission 3 and the motor / generator shaft 4, or between the output shaft 3b of the automatic transmission 3 and the rear wheel drive system. Can do.

1 Engine (power source)
2c, 2d Left and right rear wheels (drive wheels)
5 Motor / generator (power source)
25,26,29 Filter processing unit (vibration suppression means)

Claims (3)

  A vehicle comprising vibration suppression means for removing or reducing a component that causes a vehicle body vibration caused by the slip from a target value of a power source corresponding to the target driving force of the vehicle when the driving wheel slips Driving force control device. The vehicle driving force control apparatus according to claim 1,
The vehicle driving force control apparatus according to claim 1, wherein the vibration suppressing means removes or reduces a component that causes the vehicle body vibration only at the time of traction control intervention for suppressing idling of the driving wheel. In the vehicle driving force control device according to claim 2,
The vehicle driving force control apparatus according to claim 1, wherein the vibration suppressing means removes or reduces a component that causes the vehicle body vibration with respect to a required driving force reduction amount of the traction control.

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