JP4910361B2 - Vehicle driving force control device - Google Patents

Description

  The present invention relates to a vehicle driving force control device, and more particularly, to a driving force control device that controls the driving force of a vehicle based on the driving operation status of a passenger and the traveling status of the vehicle.

As one of driving force control devices for vehicles such as automobiles, for example, as described in the following Patent Document 1 relating to the application of the present applicant, the target driving force of the vehicle is calculated in response to the driver's acceleration request. The engine target throttle opening and the transmission target gear are determined based on the target driving force, the engine output is controlled based on the target throttle opening, and the transmission gear is controlled based on the target gear. A driving force control device configured as described above is conventionally known.
JP 2003-191774 A

  In the conventional driving force control apparatus as described above, the target shift speed of the transmission is uniquely determined by the target driving force of the vehicle and a preset shift line. Immediately after passing a low friction coefficient road surface such as a frozen part, an excessive drive slip occurs momentarily, the traction control shifts up the transmission speed, and immediately after the vehicle passes the low friction coefficient road surface. Vehicle acceleration may be insufficient.

  The present invention provides a conventional driving force control apparatus configured such that a target driving force is calculated in response to a driver's acceleration request, and a target gear position of the transmission is determined by the target driving force and a preset shift line. The present invention has been made in view of the above-described problems, and a main object of the present invention is to suppress a decrease in target driving force used for determining a target gear position of the transmission, thereby temporarily Prevents transmission gears from being shifted up when passing through a low friction coefficient road surface and prevents the vehicle from becoming insufficiently accelerated immediately after passing through a low friction coefficient road surface. That is.

According to the present invention, the above-mentioned main problem is that the configuration of claim 1, that is, means for calculating the target driving force based on the driving operation status of the occupant and the driving status of the vehicle, and lower than the target driving force. Means for calculating a lower limit target driving force having a small change; means for controlling a driving force of a driving source based on the target driving force; and means for controlling a transmission gear ratio based on the lower limit target driving force. In the vehicle driving force control apparatus, the vehicle stabilizes the traveling motion of the vehicle by calculating the driving slip suppression target driving force for suppressing the driving slip of the driving wheel and the braking / driving force of each wheel. Means for calculating a travel motion control target driving force for reducing the reduction limiting target driving force, and the means for calculating the reduction limiting target driving force has a reduction change smaller than the driving slip suppression target driving force. And a means for calculating a lower limit travel motion control target drive force having a smaller decrease in comparison with the travel motion control target drive force, and the lower limit drive slip suppression target. The vehicle driving force control device is characterized in that the larger value of the driving force and the lower limit travel motion control target driving force is set as the lower limit target driving force .

According to the present invention, the means for calculating the lower limit slip suppression target driving force increases the responsiveness of the lower change in the configuration of claim 1 so as to effectively achieve the main problem described above. filtering lower than the response of the change calculating the reduction limiting drive slip suppression target driving force by performing relative to the drive slip suppression target driving force, means for calculating the reduction limited driving dynamics control target driving force is reduced The lower limit travel motion control target driving force is configured to be calculated by performing a filtering process on the travel motion control target driving force with a change responsiveness lower than the increase change responsiveness. ).

According to the present invention, in order to effectively achieve the above main problems, in the configuration of claim 1 or 2, the means for calculating the lower limit slip suppression target driving force and the lower limit travel motion lowering limit degree of the control target driving force means for computing each said reduced limit slip suppression target driving force than when the occupant of the acceleration demand is low when the occupant of the acceleration demand is high and the decrease limited driving dynamics control target driving force Is configured to be high (configuration of claim 3).

According to the invention, to the aspect of the effective, in the configuration of the claims 1 to 3, it means for calculating the pre-Symbol target driving force is the drive slip suppression target driving force and When the travel motion control target driving force is calculated, the target driving force is calculated based on the smaller one of them (configuration of claim 4).

According to the present invention, in order to effectively achieve the main problems described above, in the configuration of claim 1 , the means for calculating the lower limit target driving force includes the traveling motion control target driving force. or when the vehicle is computed has a means to calculating the decrease change is small turning control target driving force than the tire force of the driving wheels when in the high lateral force turning state, before Symbol drop-limiting drive A maximum value among the slip suppression target drive force, the lower limit travel motion control target drive force, and the turning control target drive force is set as the lower limit target drive force (configuration of claim 5).

According to the invention, to the aspect of the effective, in the configuration of the claims 1 to 5, decreased limited degree before Symbol drop limited driving dynamics control target driving force is the reduction limit It is comprised so that it may be lower than the fall restriction | limiting limit of a driving slip suppression target driving force (structure of Claim 6).

According to the configuration of the first aspect, the target driving force is calculated based on the driving operation state of the occupant and the traveling state of the vehicle, the driving slip suppression target driving force for suppressing the driving slip of the driving wheel is calculated, and each wheel is calculated. A travel motion control target drive force for stabilizing the travel motion of the vehicle is calculated by controlling the braking / driving force. In addition, a lower limit driving slip suppression target driving force having a smaller decrease compared to the driving slip suppression target driving force is calculated, and a lower limiting traveling motion control target driving force having a lower decrease compared to the traveling motion control target driving force is obtained. The larger one of the lower limit drive slip suppression target drive force and the lower limit travel motion control target drive force is calculated and set as the lower limit target drive force. Then, the driving force of the driving source is controlled based on the target driving force, and the transmission gear ratio is controlled based on the lower limit target driving force . Therefore , transmission shift-up can be suppressed as compared with the conventional driving force control device in which the transmission gear ratio is also controlled based on the target driving force, which makes the vehicle temporarily have a low friction coefficient. It is possible to prevent the shift stage of the transmission from being shifted up when passing through the road surface, and to prevent the vehicle from being insufficiently accelerated immediately after passing through the road surface having a low coefficient of friction.

According to the second aspect of the present invention, the lower limit driving slip suppression target driving force is calculated by performing filtering processing on the driving slip suppression target driving force in which the responsiveness of the decrease change is lower than the responsiveness of the increase change. and the operation is lowered limited driving dynamics control target driving force by performing a filter processing lower than the response of the increase change in responsiveness of the reduced variation with respect to the driving dynamics control target driving force Runode, reduced to the target driving force There can be reliably calculated based on the limited reduction limiting drive slip suppression target driving force and lowering limited driving dynamics control target driving force of each driving slip suppression target driving force and vehicle dynamics control target driving force.

According to the third aspect of the present invention, when the occupant's acceleration request is high, the lower limit slip suppression target drive force and the lower limit travel motion control target drive force are less limited than when the occupant's acceleration request is low. Be raised . Therefore, when the occupant's acceleration request is high, it is possible to suppress a decrease in the lower limit target driving force compared to when the occupant's acceleration request is low. To reduce the driving force and to satisfy the occupant's acceleration request as much as possible, and when the occupant's acceleration request is low, the transmission is shifted up relatively easily and the driving force is quickly reduced. Can do.

According to the foregoing aspect 4, the means for calculating the goals driving force when the drive slip suppression target driving force and vehicle dynamics control target driving force is calculated, the basis of the value of the smaller of those among To calculate the target driving force . Therefore, even when the driving slip of the driving wheel is excessive and the driving force of the vehicle is excessive, the driving slip is reduced and the driving motion of the vehicle is stabilized even when the driving motion of the vehicle is unstable. The driving force of the vehicle can be reliably reduced to the driving force required for the vehicle.

In the above-described configuration according to claim 5, means for calculating a reduced limit target driving force, run line or when vehicle motion control target driving force is operation of the drive wheel when in the high lateral force turning state has a means to calculating the decrease change is small turning control target driving force than the tire force, low lower limiting drive slip suppression target driving force, reduction limited driving dynamics control target driving force, the turning control target driving force The maximum value is set as the reduction limit target driving force . Therefore, if the driving slip is excessive, the driving movement of the vehicle is unstable due to excessive driving force, or the transmission shifts in any case where the vehicle is in a high lateral force turning state. In particular, when the vehicle is in a high lateral force turning state, it is possible to effectively suppress a sudden change in vehicle driving force due to a shift-up of the transmission and a sudden change in lateral force of the driving wheel resulting from this. it can.

In the above-described configuration according to claim 6, lowering limit the degree of low lower limit vehicle dynamics control target driving force is less than the decrease limit the degree of reduction limiting drive slip suppression target driving force. Therefore, the decrease gradient of the lower limit travel motion control target drive force is made larger than the decrease gradient of the lower limit drive slip suppression target drive force with respect to the same target drive force, and thereby the drive force is excessive. When the running motion of the vehicle is unstable, the driving force of the vehicle can be quickly reduced to effectively stabilize the running motion.

[Preferred embodiment of problem solving means]
According to one preferred embodiment of the invention, the claims at the construction of claim 2, means for calculating the reduced limit slip suppression target driving force is the target driving force及beauty filtering process before the target driving after filter processing The larger value of the forces is set as the lower limit driving slip suppression target driving force, and the means for calculating the lower limit driving motion control target driving force is the target driving force after filtering and the target driving force before filtering. The larger value is configured to be the lower limit travel motion control target driving force (preferred aspect 1 ).

According to the aspect of the present invention, in the configuration of the second aspect, when high-ride membered acceleration demand high variation reduction degree of filtering than when the occupant of the acceleration request is lower (Preferred embodiment 2 ).

According to another preferred aspect of the present invention, in the configuration of claim 4, the means for calculating the target driving force calculates both the driving slip suppression target driving force and the travel motion control target driving force. If not, the target driving force is calculated based on the occupant's driving request, and when the driving slip suppression target driving force is calculated, the driving slip suppression target driving force is set as the target driving force, and the travel motion control target driving force is calculated. The driving motion control target driving force is used as the target driving force when the driving slip control target driving force is calculated. When the driving slip suppression target driving force and the driving motion control target driving force are calculated, the driving slip control target driving force and the driving motion control target driving force are small. One of the values is set as the target driving force (preferred aspect 3 ).

  The present invention will now be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic configuration diagram showing one embodiment of a vehicle driving force control apparatus according to the present invention applied to a rear wheel drive vehicle, and FIG. 2 is a block diagram showing a control system of the first embodiment.

  In FIG. 1, reference numeral 10 denotes an engine, and the driving force of the engine 10 is transmitted to a propeller shaft 18 via an automatic transmission 16 including a torque converter 12 and a transmission 14. The driving force of the propeller shaft 18 is transmitted to the left rear wheel axle 22L and the right rear wheel axle 22R by the differential 20, whereby the left and right rear wheels 24RL and 24RR which are driving wheels are rotationally driven.

  On the other hand, the left and right front wheels 24FL and 24FR are both driven wheels and steered wheels, which are not shown in FIG. 1, but are rack and pinion type driven in response to steering of the steering wheel by the driver. It is steered via a tie rod by a power steering device.

  The braking forces of the left and right front wheels 24FL, 24FR and the left and right rear wheels 24RL, 24RR are controlled by controlling the braking pressures of the corresponding wheel cylinders 30FL, 30FR, 30RL, 30RR by the hydraulic circuit 28 of the braking device 26. Although not shown in FIG. 1, the hydraulic circuit 28 includes an oil reservoir, an oil pump, various valve devices, and the like.

  The braking / driving force of the vehicle is controlled by the integrated control electronic control unit 32. The integrated control electronic control unit 32 normally controls the output of the engine 10 and the gear position of the transmission 14 according to the operation of the accelerator pedal 34 by the driver, the engine load, etc., and allows the driver to depress the brake pedal 36. The hydraulic circuit 28 is controlled accordingly, and if necessary, the output of the engine 10 and the gear stage of the transmission 14 are controlled to control the running movement of the vehicle, and the hydraulic circuit 28 is controlled, thereby controlling the braking / driving of the vehicle. Control the power.

  As shown in FIG. 2, the integrated control electronic control device 32 includes a driving force control electronic control device 40 and a vehicle motion control electronic control device 42, and the driving force control electronic control device 40 and the vehicle motion control electronic control device 42. Exchanges necessary information with each other, and cooperates with each other to control the braking / driving force of the vehicle according to the driving request and braking request of the driver, and also to control the vehicle driving motion by controlling the braking / driving force of each wheel. To stabilize. Although not shown in detail in FIG. 2, each of the driving force control electronic control device 40 and the vehicle motion control electronic control device 42 has a CPU, a ROM, a RAM, and an input / output port device, which are bidirectional. The microcomputer and the drive circuit may be connected to each other by a common bus.

  As shown in FIG. 2, the driving force control electronic control unit 40 includes a driver request target driving force calculation unit 44, an arbitration unit 46, a distribution unit 48, and a generated driving force calculation unit 50. The apparatus 42 includes a motion state estimation unit 54, a braking / driving force distribution unit 56, and a decrease suppression target driving force calculation unit 58.

  A signal indicating the driving operation amount A of the driver is input to the driver request target driving force calculation unit 44 from the driving operation amount detection sensor 62 such as an accelerator opening sensor provided in the accelerator pedal 34. The driver required target driving force calculating unit 44 calculates the driver required target driving force Fp_dvm based on the driving operation amount A of the driver, and outputs a signal indicating the driver required target driving force Fp_dvm to the arbitrating unit 46. This is output to the motion state estimation unit 54 and the decrease suppression target driving force calculation unit 58 of the vehicle motion control electronic control unit 42.

  In addition to the signal indicating the driver required target driving force Fp_dvm, the arbitration unit 46 also includes a signal indicating the target driving force Fp_t_now after the braking / driving force distribution from the braking / driving force distributing unit 56 of the vehicle motion control electronic control device 42 and the control. A flag F_FP_NOW signal indicating whether or not the target driving force Fp_t_now after the driving force distribution is present (“Yes” when ON, “No” when OFF) is input, and the reduction suppression target driving force calculation unit 58 limits the reduction. A signal indicating the target driving force Fp_t_future and a flag F_FP_FUTURE signal indicating whether or not there is a lower limit target driving force Fp_t_future ("ON" when ON, "NO" when OFF) are input.

  When the flag F_FP_NOW signal is OFF, the arbitration unit 46 sets the target driving force Fp_now after the arbitration to the driver request target driving force Fp_dvm, and when the flag F_FP_FUTURE signal is OFF, the reduction limiting target driving force after arbitration is set. Fp_future is set to the driver request target driving force Fp_dvm. On the other hand, the arbitration unit 46 sets the target driving force Fp_now after the arbitration to the target driving force Fp_t_now after the braking / driving force distribution when the flag F_FP_NOW signal is ON, and after the arbitration when the flag F_FP_FUTURE signal is ON. The lower limit target driving force Fp_future is set to the lower limit target driving force Fp_t_future.

  A signal indicating the target driving force Fp_now after the arbitration and a signal indicating the lower limit target driving force Fp_future after the arbitration are input to the distributing unit 48 from the arbitrating unit 46, and the distributing unit 48 is based on the target driving force Fp_now after the arbitrating. The target engine output torque Tet is calculated, a signal indicating the target engine output torque Tet is output to the engine control device 64, and the transmission target shift stage St is calculated based on the reduction limited target driving force Fp_future after arbitration. A signal indicating the gear stage St is output to the automatic transmission control device 66, whereby the driving torque Fp of the vehicle, that is, the output torque of the driving source consisting of the engine 10 and the automatic transmission 16, becomes the target driving force Fp_now after the arbitration. Control as follows.

  A signal indicating the current engine output torque Tea is input from the engine control device 64 to the generated driving force calculation unit 50, and a signal indicating the current gear stage Sa is input from the automatic transmission control device 66 to generate the generated driving force. The unit 50 calculates the current driving torque Fp_current of the vehicle based on the current engine output torque Tea and the current shift speed Sa, and outputs a signal indicating the current driving torque Fp_current of the vehicle to the motion state of the vehicle motion control electronic control unit 42. It outputs to the estimation part 54.

  The motion state estimation unit 54 is based on the wheel speed Vwi (i = fl, fr, rl, rr) of each wheel detected by the wheel speed sensor 68i (i = fl, fr, rl, rr). The vehicle speed Vb is calculated in a known manner, and the acceleration slip amounts SArl and SArr of the left and right rear wheels are calculated. The acceleration slip amounts SArl and SArr become larger than the reference value for starting the traction control (TRC control), and the traction When the control start condition is satisfied, the traction control target driving force Fp_t_now_trc for keeping the acceleration slip amount of the wheel within a predetermined range is calculated until the traction control end condition is satisfied.

  The motion state estimation unit 54 also includes a signal indicating the driver required target driving force Fp_dvm from the driver required target driving force calculation unit 44 of the driving force control electronic control unit 40 and the current vehicle state from the generated driving force calculation unit 50. In addition to the signal indicating the driving torque Fp_current, although not shown in FIG. 2, the wheel speed Vwi of each wheel is obtained from the wheel speed sensor 68i (i = fl, fr, rl, rr) as shown in FIG. (I = fl, fr, rl, rr) is input, and the steering angle θ and the vehicle longitudinal acceleration are detected by the vehicle state quantity detection sensor 70 such as a steering angle sensor, a longitudinal acceleration sensor, a lateral acceleration sensor, and a yaw rate sensor. A signal indicating Gx, a lateral acceleration Gy of the vehicle, a yaw rate γ of the vehicle, and the like are input.

  The motion state estimation unit 54 calculates the target yaw rate γt of the vehicle based on the vehicle speed V based on the wheel speed of each wheel and the steering angle θ in a manner known in the art, and calculates the actual yaw rate γ and the target of the vehicle. The vehicle behavior is determined based on the deviation Δγ from the yaw rate γt, and when the yaw rate deviation Δγ is large and the vehicle behavior needs to be controlled, the target driving force for reducing the yaw rate deviation Δγ A target driving force Fp_t_now_vsc is calculated.

  It should be noted that the motion state estimation unit 54 at the time of braking is based on the vehicle state quantity such as the longitudinal acceleration Gx of the vehicle and the spin state quantity SS indicating the degree of vehicle spin and the degree of vehicle drift-out in a manner known in the art. Is calculated, and the behavior of the vehicle is determined based on the spin state amount SS and the drift-out state amount DS. When the vehicle behavior is in the spin state or the drift-out state, a behavior for suppressing these is shown. The target braking force Fbvti (i = fl, fr, rl, rr) of each wheel for control is calculated.

  Note that the calculation of the target driving force Fp_t_now_vsc and the target braking force Fbvti for determining the vehicle behavior and for controlling the behavior for stabilizing the traveling motion of the vehicle itself does not form the gist of the present invention, and is well known in the art. It may be performed in any manner.

  The motion state estimation unit 54 estimates the road surface friction coefficient μ and the lateral force Fwyi (i = fl, fr, rl, rr) of each wheel in a manner known in the art, and the road surface friction coefficient μ. Is greater than the reference value μo (positive constant) and the lateral force Fwyi of any wheel is greater than the reference value Fwyo (positive constant), it is determined that the vehicle is in a high lateral force turning state.

  Further, when the behavior of the vehicle is stable, traction control and behavior control are unnecessary, and the vehicle is not in a high lateral force turning state, the motion state estimation unit 54 uses the target braking / driving force F_t of the vehicle as the driver requested target driving force. A signal indicating the target braking / driving force F_t of the vehicle set to Fp_dvm is output to the braking / driving force distribution unit 56. On the other hand, when it is determined that the traction control is necessary, the motion state estimation unit 54 sets the target braking / driving force F_t of the vehicle to the target driving force Fp_t_now_trc of the traction control, and the determination result of the traction control and the target of the vehicle. A signal indicating the braking / driving force F_t is output to the braking / driving force distribution unit 56. When the motion state estimation unit 54 determines that the behavior control is necessary, it sets the target braking / driving force F_t of the vehicle to the target driving force Fp_t_now_vsc of the behavior control, and also determines the vehicle behavior determination result and the target braking / driving of the vehicle. A signal indicating the force F_t is output to the braking / driving force distribution unit 56.

Further, when traction control and behavior control are required, the motion state estimation unit 54 uses the smaller value of the target drive force Fp_t_now_trc for traction control and the target drive force Fp_t_now_vsc for behavior control according to the following equation (1). The signal is calculated as the force F_t, and a signal indicating the determination result of the traction control and the vehicle behavior and the target braking / driving force F_t of the vehicle is output to the braking / driving force distribution unit 56.
F_t = MIN (Fp_t_now_trc, Fp_t_now_vsc) (1)

  The braking / driving force distribution unit 56 sets the target braking / driving force F_t as the target driving force Fp_t_now after distributing the braking / driving force when the target braking / driving force F_t of the vehicle is a positive value and is a driving force. A signal indicating the target driving force Fp_t_now is output to the arbitration unit 46 and the decrease suppression target driving force calculation unit 58 of the driving force control electronic control unit 40, and a flag indicating whether or not there is the target driving force Fp_t_now after the braking / driving force distribution The F_FP_NOW signal is output to the arbitration unit 46.

  Further, the braking / driving force distribution unit 56 calculates the vehicle body speed Vb based on the wheel speed Vwi of each wheel in a manner known in the art, and the braking slip amount SBi (i = fl, fr, rl) of each wheel. , Rr), and when the braking slip amount SBi becomes larger than the reference value for starting anti-skid control (ABS control) and the anti-skid control start condition is satisfied, the anti-skid control end condition is satisfied. A target braking force Fbvti (i = fl, fr, rl, rr) for anti-skid control for bringing the braking slip amount of the wheel into a predetermined range is calculated.

  When the traction control or the behavior control is necessary, the braking / driving force distribution unit 56 calculates the target braking force Fbvti of each wheel based on each determination result. The braking / driving force distribution unit 56 outputs a signal indicating the target braking force Fbvti to the braking force control device 72 when the target braking force Fbvti is present.

  A signal indicating the driver's braking operation amount Fb detected by a braking operation amount detection sensor 74 provided on the brake pedal 36 is input to the braking force control device 72, and the pressure sensor 76i (i = fl, fr, rl). , Rr), a signal indicating the braking pressure Pbi (i = fl, fr, rl, rr) of the wheel cylinders 30FL to 30RR detected is input. The braking force control device 72 calculates the target braking force Fbti (i = fl, fr, rl, rr) of each wheel based on the driver's braking operation amount Fbi, and the target control for traction control, behavior control or anti-skid control. When there is power Fbvti, the target braking force Fbti of the wheel is replaced with the target braking force Fbvti.

  Then, the braking force control device 72 calculates the target braking pressure Pbti (i = fl, fr, rl, rr) of each wheel based on the target braking force Fbti, and the target braking pressure Pbti corresponding to the braking pressure Pbi of each wheel respectively. The hydraulic circuit 28 is controlled so that the braking force Fbi (i = fl, fr, rl, rr) of each wheel becomes the corresponding target braking force Fbti.

  A signal indicating the driver required target driving force Fp_dvm is input from the driver required target driving force calculating unit 44 to the decrease suppression target driving force calculating unit 58, and the target driving after the braking / driving force distribution by the braking / driving force distributing unit 56 is performed. A signal indicating the force Fp_t_now is input.

When the target driving force Fp_t_now after distributing the braking / driving force is the target driving force Fp_t_now_trc after the distribution of the braking / driving force, the decrease suppressing target driving force calculating unit 58 calculates the target driving force Fp_t_now_trcf of the traction control after the filter processing according to the following equation 2. At the same time, the larger one of the target driving force Fp_t_now_trcf for traction control after the first-order lag filtering and the target driving force Fp_t_now_trc for traction control according to the following equation 3 is set as the target driving force Fp_t_future_trc for reducing the traction control.
Fp_t_now_trcf = (1-K1) / (1-K1Z- ¹ ) Fp_t_now_trc (2)
Fp_t_future_trc = MAX (Fp_t_now_trcf, Fp_t_now_trc) (3)

  For example, FIG. 3 shows that when the traction control is executed in the process in which the driver's acceleration request increases and the driver's required target driving force Fp_dvm increases, the driver's required target driving force Fp_dvm, the target drive of the traction control An example of changes in the force Fp_t_now_trc and the traction control decrease suppression target driving force Fp_t_future_trc is shown. As shown in FIG. 3, the traction control target driving force Fp_t_now_trc is calculated to be smaller than the driver required target driving force Fp_dvm by traction control, but the traction control decrease suppression target driving force Fp_t_future_trc It does not decrease, but gradually decreases after the start of traction control.

Further, when the target driving force Fp_t_now after distribution of the braking / driving force is the target driving force Fp_t_now_vsc for behavior control, the lowering suppression target driving force calculation unit 58 performs the target driving force for behavior control after first-order lag filtering according to the following equation 4. Fp_t_now_vscf is calculated, and the larger one of the behavior control target driving force Fp_t_now_vscf and the behavior control target driving force Fp_t_now_vsc according to the following equation 5 is set as the behavior control decrease suppression target driving force Fp_t_future_vsc. Fp_t_now_vscf = (1-K2) / (1-K2Z- ¹ ) Fp_t_now_vsc (4)
Fp_t_future_vsc = MAX (Fp_t_now_vscf, Fp_t_now_vsc) (5)

  For example, FIG. 4 shows that the driver required target driving force Fp_dvm and the behavior control target drive when behavior control is executed in the process where the driver's acceleration demand increases and the driver required target driving force Fp_dvm increases. An example of changes in the force Fp_t_now_vsc and the behavior control decrease suppression target driving force Fp_t_future_vsc is shown. As shown in FIG. 4, the behavior control target driving force Fp_t_now_vsc is calculated to be smaller than the driver required target driving force Fp_dvm by behavior control, but the behavior control decrease suppression target driving force Fp_t_future_vsc is abruptly increased. It does not decrease, but gradually decreases after the start of behavior control.

  Further, when the behavior control target driving force Fp_t_now_vsc is calculated and the behavior control is required or when it is determined that the vehicle is in a high lateral force turning state, the decrease suppression target driving force calculation unit 58 Then, the generated longitudinal force Fwxi and the generated lateral force Fwyi (i = fl, fr, rl, rr) of each wheel are calculated in a known manner. The reduction suppression target driving force calculation unit 58 calculates the left and right rear wheel tire generating forces F_current_tire_rl and F_current_tire_rr as the square sum of squares of the generated front / rear force Fwxi and the generated lateral force Fwyi for the left and right rear wheels, and calculates the sum of them as driving wheels. Tire generating force Fp_current_tire.

  When the vehicle is a front-wheel drive vehicle, the tire generation force Fp_current_tire of the drive wheel is set to the sum of the tire generation forces of the left and right front wheels. When the vehicle is a four-wheel drive vehicle, the tire generation force of the drive wheel is set. Fp_current_tire is set to the sum of the tire generating forces of the left and right front wheels and the left and right rear wheels.

Further, the reduction suppression target driving force calculating unit 58 calculates the tire generating force Fp_current_tiref of the drive wheel after the filtering process according to the following formula 6 with respect to the tire generating force Fp_current_tire of the driving wheel, and after the filtering process according to the following formula 7. The larger value of the tire generating force Fp_current_tiref of the driving wheel and the tire generating force Fp_current_tire of the driving wheel is set as the target driving force Fp_t_future_tire of the high lateral force turning control.
Fp_current_tiref = (1-K3) / (1-K3Z- ¹ ) Fp_current_tire (6)
Fp_current_tire = MAX (Fp_current_tiref, Fp_current_tire) (7)

  The filter time constants K1, K2, and K3 in the above formulas 2, 4, and 6 are different from each other, and sometimes K2 is set to a value that is larger than K1 and K3. The filter time constants K1, K2, and K3 may be constants. However, in the illustrated embodiment, the higher the driver's driving operation amount A detected by the driving operation amount detection sensor 62, the larger the time constants. It is variably set according to the driving operation amount A of the driver.

Further, the reduction suppression target driving force calculation unit 58 includes a reduction suppression target driving force Fp_t_future_trc for traction control, a reduction suppression target driving force Fp_t_future_vsc for behavior control, and a reduction suppression target driving force Fp_t_future_tire for high lateral force turning control according to Equation 8 below. Is set as a decrease suppression target driving force Fp_t_future for determining the gear position of the transmission 14 in preparation for the subsequent change in the motion state of the wheels and the vehicle.
Fp_t_future = MAX (Fp_t_future_trc, Fp_t_future_vsc, Fp_t_future_tire)
...... (8)

  Further, the reduction suppression target driving force calculation unit 58 turns on the flag F_FP_FUTURE indicating whether or not there is a reduction suppression target driving force Fp_t_future when it is determined that the traction control or the behavior control is in progress or the high lateral force turning state. In addition, a signal indicating the reduction suppression target driving force Fp_t_future and a flag F_FP_FUTURE signal are output to the arbitration unit 46 of the driving force control electronic control unit 40, and neither traction control nor behavior control is executed. When it is not determined that the vehicle is in the turning state, the flag F_FP_FUTURE indicating whether or not there is a decrease suppression target drive force Fp_t_future is set to OFF, the decrease suppression target drive force Fp_t_future is set to 0, and the decrease suppression target drive force A signal indicating Fp_t_future and a flag F_FP_FUTURE signal are output to the arbitration unit 46 of the driving force control electronic control unit 40.

  When neither the traction control nor the behavior control is executed and it is determined that the vehicle is in the high lateral force turning state, the decrease suppression target driving force Fp_t_future may be set to the driver required target driving force Fp_dvm.

  Next, the operation of the illustrated embodiment configured as described above will be described in various traveling situations of the vehicle.

(1) When neither traction control nor behavior control is required When the vehicle's behavior is stable and neither traction control nor behavior control is required and the vehicle is not in a high lateral force turning state, the flags F_FP_NOW and F_FP_FUTURE are OFF. Since the target driving force Fp_now after the arbitration and the lower limit target driving force Fp_future after the arbitration are set to the driver required target driving force Fp_dvm, the target engine output torque Tet and the target shift stage St of the transmission 14 are the driver required target. Calculation is performed based on the driving force Fp_dvm, and as in the case of the conventional driving force control device, the output of the engine 10 and the gear ratio of the transmission 14 are controlled in accordance with the driving request of the driver.

(2) When traction control is required but behavior control is not required When drive slip of the drive wheels is excessive and traction control is required, but the vehicle's running motion is stable and behavior control is not required Is set based on the target driving force Fp_t_now_trc of the traction control after the braking / driving force distribution, and the reduction driving target driving force Fp_t_future_trc of the traction control is calculated based on the target driving force Fp_t_now_trc of the traction control. The flags F_FP_NOW and F_FP_FUTURE are set to ON, and the target driving force Fp_now after arbitration and the reduction limited target driving force Fp_future after arbitration are set to the target driving force Fp_t_now_trc for traction control and the reduction suppression target driving force Fp_t_future_trc for traction control, respectively. .

  Therefore, in this case, the target engine output torque Tet is calculated based on the target drive force Fp_t_now_trc of traction control, and the output slip of the engine 10 can be reliably reduced to effectively reduce the drive slip of the drive wheels. The target shift stage St of the transmission 14 can be calculated based on the traction control decrease suppression target drive force Fp_t_future_trc in which the decrease change is smaller than the target drive force Fp_t_now_trc, so that the vehicle temporarily has a low friction coefficient such as a manhole. Even when passing on the road surface, the gear stage of the transmission 14 is shifted up by traction control, and due to this, insufficient acceleration immediately after the vehicle passes the road surface with a low friction coefficient is effectively prevented. Can do.

  When the vehicle travels on a long road surface with a low coefficient of friction, such as an icy and snowy road, the gear stage of the transmission 14 is shifted up when the traction control lowering suppression target driving force Fp_t_future_trc decreases to the shift line. The situation in which the drive slip of the drive wheels is excessive does not continue for a long time.

(3) When traction control is not necessary but behavior control is necessary The driving force of the drive wheels is not excessive and traction control is not necessary, but the vehicle's running motion is unstable and the vehicle driving force is reduced. When the behavior control by is required, the target driving force Fp_t_now after the distribution of the braking / driving force is set based on the target driving force Fp_t_now_vsc of the behavior control, and the decrease in the behavior control is suppressed based on the target driving force Fp_t_now_vsc of the behavior control The target driving force Fp_t_future_vsc is calculated, the flags F_FP_NOW and F_FP_FUTURE are set to ON, and the target driving force Fp_now after arbitration and the reduction limited target driving force Fp_future after arbitration are the target driving force Fp_t_now_vsc for behavior control, and the suppression suppression of the behavior control, respectively. The target driving force Fp_t_future_vsc is set.

  Therefore, in this case, the target engine output torque Tet can be calculated based on the behavior control target driving force Fp_t_now_vsc, and the output of the engine 10 can be reliably reduced to effectively stabilize the running motion of the vehicle. The target shift stage St of the transmission 14 can be calculated on the basis of the decrease suppression target drive force Fp_t_future_vsc of the behavior control whose change in decrease is smaller than the target drive force Fp_t_now_vsc of the behavior control, thereby destabilizing the running motion of the vehicle. Effectively preventing the speed change of the transmission 14 from being unnecessarily shifted up by the behavior control when it is temporary and insufficient acceleration immediately after the temporary behavior control is completed due to this. Can do.

  If the unstable state of the running motion of the vehicle continues for a long time, the shift stage of the transmission 14 is shifted up when the target drive force Fp_t_future_vsc for suppressing the decrease in behavior control is lowered to the shift line. Even when a stable running state continues for a long time, a situation in which the driving force is excessive does not continue for a long time.

(4) When traction control and behavior control are necessary When both the traction control and behavior control are necessary because the driving force of the driving wheels is excessive and the running motion of the vehicle is unstable, braking / driving is required. The target driving force Fp_t_now after force distribution is set to the smaller value of the target driving force Fp_t_now_trc for traction control and the target driving force Fp_t_now_vsc for behavior control, and the target driving force Fp_t_now_trc for reducing traction control is set as the target driving force Fp_t_now_trc for traction control. Decrease suppression target drive force Fp_t_future_vsc for behavior control and decrease suppression target drive force Fp_t_future_tire for high lateral force turning control are set to the largest value, flags F_FP_NOW and F_FP_FUTURE are set to ON, and target drive force Fp_now after arbitration is set The reduction limited target driving force Fp_future after the arbitration is set to the target driving force Fp_t_now and the reduction suppressing target driving force Fp_t_future, respectively.

  Therefore, in this case, the target engine output torque Tet is calculated based on the target driving force Fp_t_now, and the output of the engine 10 is surely reduced to effectively reduce the driving slip of the driving wheels, and the vehicle traveling motion is effectively reduced. The target shift stage St of the transmission 14 can be calculated based on the decrease suppression target drive force Fp_t_future whose decrease change is smaller than the target drive force Fp_t_now. If slip or instability of the running motion of the vehicle is temporary, the gear stage of the transmission 14 is unnecessarily shifted up by traction control or behavior control, and temporary traction control or behavior due to this. It is possible to effectively prevent insufficient acceleration immediately after the control is completed.

  Particularly, according to the illustrated embodiment, the filter time constants K1, K2, and K3 are set to the driver's driving operation amount A so that the higher the driver's driving operation amount A detected by the driving operation amount detection sensor 62 is, the higher the driver time operation amount A is. Accordingly, the higher the driver's drive request is, the smaller the decrease gradient of the decrease suppression target drive force Fp_t_future is made, making it difficult for the transmission 14 to shift up, thereby reducing the vehicle friction coefficient. It is possible to effectively prevent shortage of acceleration immediately after passing the road surface to satisfy the driver's drive request, and to reduce the reduction target drive force Fp_t_future when the driver's drive request is not high. The reduction gradient of the transmission 14 is increased so that the shift stage of the transmission 14 can be easily shifted up, whereby the driving force of the vehicle can be quickly reduced.

  Further, according to the illustrated embodiment, it is determined whether or not the vehicle is in a high lateral force turning state by the motion state estimation unit 54, and the tire generation force Fp_current_tire of the drive wheel is calculated by the decrease suppression target drive force calculation unit 58. In addition, the target driving force Fp_t_future_tire of the high lateral force turning control having a lower gradient than the tire generating force Fp_current_tire is calculated, and the reduction suppressing target driving force Fp_t_future for determining the gear position of the transmission 14 is traction controlled according to the above equation 8. Is set to the largest value among the lower suppression target driving force Fp_t_future_trc, the lower suppression target driving force Fp_t_future_vsc of the behavior control, and the lower suppression target driving force Fp_t_future_tire of the high lateral force turning control. The transmission 14 is upshifted in situations where the vehicle is in a high lateral force turning state, compared to when not considered. Therefore, when the vehicle is in a high lateral force turning state, the transmission 14 is upshifted, so that the driving force of the driving wheel is abruptly reduced. It is possible to reliably reduce the possibility that the force changes suddenly and the behavior of the vehicle suddenly changes.

  Further, according to the illustrated embodiment, the filter time constant K2 is set to a value larger than the filter time constants K1 and K3, and the behavior control lowering suppression target driving force Fp_t_future_vsc of the same target driving force is seen. Since the decrease gradient is larger than the decrease gradient of the traction control decrease suppression target drive force Fp_t_future_trc and the high lateral force turning control decrease suppression target drive force Fp_t_future_tire, the drive force of the drive wheel is generated when the vehicle traveling motion is unstable. As a result, the transmission 14 can be upshifted early compared to when the vehicle is excessive, thereby effectively stabilizing the unstable running state of the vehicle due to the excessive driving force of the drive wheels. It can be made.

  Although the present invention has been described in detail with reference to specific embodiments, the present invention is not limited to the above-described embodiments, and various other embodiments are possible within the scope of the present invention. It will be apparent to those skilled in the art.

  For example, in the above-described embodiment, the reduction suppression target driving forces Fp_t_future_trc, Fp_t_future_vsc, and Fp_t_future_tire are calculated by filtering the target driving forces Fp_t_future_trc, Fp_t_future_vsc, and Fp_current_tire, respectively. The target driving forces Fp_t_future_trc, Fp_t_future_vsc, and Fp_t_future_tire are calculated based on the target driving forces Fp_t_future_trc and Fp_t_future, respectively, as long as the decrease gradient is smaller than the target driving forces Fp_t_future_trc, Fp_t_future_vsc, and Fp_current_tire.

  Further, in the above-described embodiment, the target driving force Fp_t_future_tire for the high lateral force turning control is calculated by the reduction suppressing target driving force calculating unit 58, the traction control decreasing suppressing target driving force Fp_t_future_trc, the behavior control decreasing suppressing target drive. The maximum value of the force Fp_t_future_vsc and the reduction suppression target driving force Fp_t_future_tire of the high lateral force turning control is set as the reduction suppression target driving force Fp_t_future for determining the transmission gear stage. The target drive force Fp_t_future_tire for turning control is omitted, and the decrease suppression target drive force Fp_t_future is set to the larger value of the decrease suppression target drive force Fp_t_future_trc for traction control and the decrease suppression target drive force Fp_t_future_vsc for behavior control May be.

  In the above embodiment, the vehicle is a rear wheel drive vehicle, but the drive force control device of the present invention may be applied to a front wheel drive vehicle or a four wheel drive vehicle, and the drive force generation source is an engine. However, the driving force control apparatus of the present invention may be applied to a vehicle whose driving force generation source is a hybrid system.

  In the above-described embodiment, the transmission transmission is an automatic transmission. However, the transmission may be a continuously variable transmission, and in that case, the transmission is continuously variable based on the reduction suppression target driving force Fp_t_future. A target gear ratio of the transmission is calculated.

It is a schematic block diagram which shows one Example of the driving force control apparatus of the vehicle by this invention applied to the rear-wheel drive vehicle. It is a block diagram which shows the control system of an Example. The driver requested target driving force Fp_dvm, the traction control target driving force Fp_t_now_trc, the traction control when the traction control is executed in the process where the driver's acceleration request increases and the driver requested target driving force Fp_dvm increases. It is a graph which shows an example of change of control fall control target drive force Fp_t_future_trc. The driver required target driving force Fp_dvm, the behavior control target driving force Fp_t_now_vsc, the behavior when the behavior control is executed in the process where the driver's acceleration demand increases and the driver required target driving force Fp_dvm increases. It is a graph which shows an example of change of control fall suppression target drive force Fp_t_future_vsc.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Engine 16 Automatic transmission 26 Braking device 32 Integrated control electronic control device 34 Accelerator pedal 36 Brake pedal 40 Driving force control electronic control device 42 Braking force control electronic control device 64 Engine control device 66 Automatic transmission control device 68i Wheel speed Sensor 70 Vehicle state quantity detection sensor 72 Braking force control device

Claims (6)

Based on the target driving force, means for calculating a target driving force based on the driving operation status of the occupant and the traveling state of the vehicle, a means for calculating a lower limit target driving force with a lower change compared to the target driving force, and In a vehicle driving force control device, comprising: means for controlling the driving force of the driving source; and means for controlling the transmission gear ratio based on the lower limit target driving force.
The vehicle calculates the driving slip suppression target driving force for suppressing the driving slip of the driving wheel, and the driving motion control target driving force for stabilizing the traveling motion of the vehicle by controlling the braking / driving force of each wheel. Means,
The means for calculating the lower limit target driving force is a means for calculating a lower limit driving slip suppression target driving force whose change in reduction is smaller than that of the driving slip suppression target driving force. Means for calculating a lower limit travel motion control target driving force with a smaller lower change, and lowering the larger value of the lower limit driving slip suppression target driving force and the lower limit travel motion control target driving force. A driving force control apparatus for a vehicle, wherein the driving force control device is set to a target driving force . The means for calculating the lower limit slip suppression target drive force performs the lower limit response slip suppression target drive by performing a filtering process on the drive slip suppression target drive force in which the response of the lower change is lower than the response of the increase change. The means for calculating force and calculating the lower limit travel motion control target drive force is obtained by performing a filtering process on the travel motion control target drive force, wherein the response of the lower change is lower than the response of the increase change. The vehicle driving force control device according to claim 1, wherein a limited driving motion control target driving force is calculated. The means for calculating the lower limit slip suppression target driving force and the means for calculating the lower limit travel motion control target driving force are respectively the lower limit slip when the occupant acceleration request is high compared to when the occupant acceleration request is low. suppression target driving force and the vehicle driving force control apparatus according to claim 1 or 2, characterized in that to increase the reduction limit degree of the lowering limit driving dynamics control target driving force. When prior Symbol target driving force means for computing the said drive slip suppression target driving force and the vehicle dynamics control target driving force is computed, the computing the target driving force based on the value of the smaller of those among The vehicle driving force control device according to any one of claims 1 to 3. Means for calculating the reduction limit target driving force is lowered changes compared to tire force of the driving wheels when or the vehicle when the vehicle dynamics control target driving force is calculated is in the high lateral force turning state It has a means to calculating the small turning control target driving force, before Symbol drop-limiting drive slip suppression target driving force, the lowering limit driving dynamics control target driving force, the lower the maximum value of the turning control target driving force 2. The vehicle driving force control device according to claim 1 , wherein the driving force control device is set to a limited target driving force. Vehicle driving force control apparatus according lowering limit the degree of pre-Symbol drop limited driving dynamics control target driving force to claim 1, wherein the lower than the decrease limit the degree of the reduction limiting drive slip suppression target driving force .

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