JP2005184998A - Motor output controller of motor four wheel drive vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor output controller of a motor four wheel drive vehicle capable of ensuring stability of the vehicle upon occurrence of driven wheel acceleration slip by suppressing the acceleration slip quickly. <P>SOLUTION: The motor four wheel drive vehicle where the main drive wheel is driven through an engine 2, and the driven wheel is driven through a motor 4 which is driven with electric energy generated from a generator 7 being driven through the engine 2 comprises a regulation relay having a semiconductor switch element provided in the way of a wire 9 coupling the generator 7 and the motor 4, a means for detecting acceleration slip of the driven wheel, and a motor output control means for controlling the regulation relay to suppress output from the motor 4 when acceleration slip of the driven wheel is detected. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention drives a main driving wheel by an engine, drives a driven wheel by an electric motor, and the electric motor is driven by electric energy generated by a generator driven by the engine. The present invention relates to a motor output control device.

In a conventional motor four-wheel drive vehicle, a generator driven by an engine and an electric motor that drives a rear wheel are connected by an electric wire through a junction box, and a solenoid-driven mechanical relay is provided in the junction box. The interruption and connection of electric power (current) supplied to the electric motor are controlled by a built-in command from the 4WD controller to the mechanical relay.
JP 2001-225144 A

  In a conventional motor four-wheel drive vehicle, the drive torque of the driven wheel can be cut off by a command to a mechanical relay having an on / off switch function. In order to suppress the acceleration slip by adjusting the driving torque, it is necessary to adjust the power generated by the generator.

  However, since the field current of the generator is not responsive due to the reactance of the field coil, the adjustment response of the generated power is also low. For this reason, in order to ensure the stability of the vehicle at the time of the acceleration slip of the driven wheel, even if the output of the electric motor is reduced quickly, the control response of the drive torque is reduced due to the low adjustment response of the generated power. There was a problem that the driven wheel acceleration slip was not converged immediately because it was not obtained sufficiently.

  Also, when controlling the motor field current and adjusting the driving torque of the driven wheel to suppress the acceleration slip, the response of the field current is not good. There was a problem of not converging.

  The present invention has been made paying attention to the above problems, and can quickly suppress the acceleration slip of the driven wheel and ensure the stability of the vehicle when the driven wheel acceleration slip occurs. An object is to provide a control device.

In order to achieve the above object, according to the present invention, main drive wheels are driven by an engine, slave drive wheels are driven by an electric motor, and the electric motor generates electric energy generated by a generator driven by the engine. In a motor four-wheel drive vehicle driven by
An adjustable relay having a semiconductor switch element provided at an intermediate position of an electric wire connecting the generator and the electric motor, slave drive wheel acceleration slip detection means for detecting acceleration slip of the slave drive wheel, and slave drive wheel Motor output control means for controlling the adjustable relay so as to suppress the output of the electric motor when acceleration slip is detected.

  Therefore, in the motor output control device for a motor four-wheel drive vehicle according to the present invention, the adjustable relay is controlled by the motor output control means so as to suppress the output of the electric motor when the slave drive wheel acceleration slip is detected. The Here, the response speed of the adjustable relay having the semiconductor switch element is much faster than the field response speed of the generator. Therefore, by controlling the adjustable relay having a high response, it is possible to quickly suppress the acceleration slip of the driven wheel and to ensure the stability of the vehicle when the driven wheel acceleration slip occurs.

  Hereinafter, the best mode for realizing a motor output control device for a motor four-wheel drive vehicle of the present invention will be described based on Examples 1 to 3 shown in the drawings.

First, the configuration will be described.
FIG. 1 is an overall system diagram showing a motor four-wheel drive vehicle to which the motor output control apparatus of the first embodiment is applied, and FIG. 2 is a block diagram showing a 4WD control system of the motor four-wheel drive vehicle of the first embodiment. In the first embodiment, as shown in FIG. 1, left and right front wheels 1L and 1R (main drive wheels) are driven by an engine 2 which is an internal combustion engine, and left and right rear wheels 3L and 3R (secondary drive wheels) are DC motors 4. It is an example in the case of the vehicle which can be driven by (electric motor).

  As shown in FIG. 1, the output torque Te of the engine 2 is transmitted to the left and right front wheels 1L and 1R via the transmission & differential gear 5. A part of the output torque Te of the engine 2 is transmitted to the generator 7 via the endless belt 6.

  The generator 7 is rotated at a rotational speed Nh obtained by multiplying the engine rotational speed Ne by a pulley ratio, and becomes a load on the engine 2 in accordance with the field current Ifh adjusted by the 4WD controller 8. Power generated. The electric power generated by the generator 7 can be supplied to the DC motor 4 via the electric wire 9. A junction box 10 is provided in the middle of the electric wire 9.

  The driving torque of the DC motor 4 can be transmitted to the left and right rear wheels 3L and 3R via the gear reducer 11 and the 4WD clutch 12. Reference numeral 13 denotes a differential gear for the left and right rear wheels 3L, 3R.

  A throttle valve 15 is interposed in the intake pipe 14 (for example, intake manifold) of the engine 2. The throttle valve 15 is an accelerator-by-wire system in which the throttle opening is adjusted and controlled according to the depression amount of the accelerator pedal 17 and the like. That is, the throttle valve 15 uses the step motor 19 as an actuator, and the valve opening degree is adjusted and controlled by the rotation angle corresponding to the number of steps of the step motor 19. The rotation angle of the step motor 19 is adjusted and controlled by an opening signal from the engine controller 18.

  The throttle sensor 16 detects the valve opening of the throttle valve 15, and the throttle sensor 16 outputs a detection signal corresponding to the detected valve opening to the engine controller 18 and the 4WD controller 8.

  The accelerator sensor 20 detects the depression amount of the accelerator pedal 17, and the accelerator sensor 20 outputs a detection signal corresponding to the detected depression amount to the engine controller 18 and the 4WD controller 8.

  In addition, an engine speed detection sensor 21 that detects the speed of the engine 2 is provided. The engine speed sensor 21 outputs a detection signal corresponding to the detected engine speed to the engine controller 18 and the 4WD controller 8. Yes.

  In the engine controller 18, valve opening control processing is performed based on each input signal at every predetermined sampling time.

  As shown in FIG. 2, the generator 7 includes a voltage regulator 22 (regulator) for adjusting the output voltage V, and the field current Ifh is adjusted by the 4WD controller 8, thereby generating power for the engine 2. The load torque Th and the voltage V to be generated are controlled. The voltage regulator 22 receives a generator control command (field current value) from the 4WD controller 8 and adjusts the field current Ifh of the generator 7 to a value according to the generator control command. The output voltage V can be detected and output to the 4WD controller 8. The rotational speed Nh of the generator 7 can be calculated from the rotational speed Ne of the engine 2 based on the pulley ratio.

  The junction box 10 is provided with a current sensor 23, which detects the current value Ia of the electric power supplied from the generator 7 to the DC motor 4 and detects the detected armature current signal. Is output to the 4WD controller 8. Further, the voltage value of the electric wire 9 (the voltage of the DC motor 4) is detected by the 4WD controller 8.

  In this junction box 10, a semiconductor relay 24 (adjustable relay) using a semiconductor switch element is provided, and this semiconductor relay 24 is supplied with electric power (current) supplied to the DC motor 4 according to a command from the 4WD controller 8. ) Control and disconnection. Further, during acceleration slip of the left and right rear wheels 3L, 3R, PWM control (Pulse Width Modulation) is executed so as to suppress the output of the DC motor 4 according to the motor output control processing described later, The motor torque TM of the motor 4 is adjusted. Reference numeral 25 denotes a thermistor that measures the temperature of the DC motor 4.

  The motor rotation speed sensor 26 for detecting the rotation speed Nm of the drive shaft of the DC motor 4 is provided, and the motor rotation speed sensor 26 outputs the detected motor rotation speed signal to the 4WD controller 8.

  The 4WD clutch 12 is configured by a hydraulic clutch, an electromagnetic clutch, or the like, and transmits torque at a torque transmission rate according to a clutch control command from the 4WD controller 8.

  Each of the wheels 1L, 1R, 3L, 3R is provided with a wheel speed sensor 27FL, 27FR, 27RL, 27RR. Each wheel speed sensor 27FL, 27FR, 27RL, 27RR outputs a pulse signal corresponding to the rotation speed of the corresponding wheel 1L, 1R, 3L, 3R to the 4WD controller 8 as a wheel speed detection value.

  The 4WD controller 8 drives and controls the DC motor 4 so as to generate a driving force corresponding to the accelerator opening from the accelerator sensor 20. In the driving force control in this case, the field current Ifm of the generator 7 is controlled by a command from the 4WD controller 8, and the motor torque TM is adjusted by adjusting the field current Ifm.

  Further, the 4WD controller 8 prevents the DC motor 4 from rotating by the left and right rear wheels 3L, 3R, and reduces the friction. Therefore, when the DC motor 4 is stopped by motor drive control, the 4WD clutch 12 is operated. Control to disconnect.

  Next, the operation will be described.

[Motor output control processing]
FIG. 3 is a flowchart showing the flow of the motor output control process executed by the 4WD controller 8 according to the first embodiment. Each step will be described below.

  In step S1, it is determined whether or not the motor torque TM is TM> 0 in order to determine whether or not the driven wheel is being driven. If yes, the process proceeds to step S2, and if no, a return ( Move to main routine.

In step S2, the driven wheel acceleration slip is detected based on the determination that the driven wheel is driven in step S1, and the process proceeds to step S3.
Here, “slave driven wheel acceleration slip” is, for example, subtracting the lower wheel speed of the left and right front wheels from the higher wheel speed of the left and right rear wheels, Detection is performed by obtaining the information (see JP 2002-347599 A).

In step S3, based on the detection of the driven wheel acceleration slip in step S2, it is determined whether or not the driven wheel acceleration slip is being performed. If yes, the process proceeds to step S4. If no, the process proceeds to step S8. Migrate to
Here, the “slave drive wheel acceleration slip determination” is, for example, a wheel speed difference obtained by subtracting the lower wheel speed of the left and right front wheels from the higher wheel speed of the left and right rear wheels. If it is equal to or greater than the set threshold value, it is determined that the driven wheel acceleration slip (see JP 2002-347599 A).

  In step S4, based on the determination of the driven wheel acceleration slip in step S3, the acceleration slip ratio S (an example of the driven wheel acceleration slip amount) of the driven wheel is obtained based on the angular wheel speeds of the four wheels. In order to know the change gradient of the rate S, a differential value dS (= dS / dt) of the acceleration slip rate S is calculated, and the process proceeds to step S5.

In step S5, using the differential value dS of the acceleration slip ratio S calculated in step S4, a reduced on-pulse width α for reducing the on-pulse width of the pulse wave output to the DC motor 4 is calculated, and the process proceeds to step S6.
Here, the reduced on-pulse width α is
α = k · dS (dS> 0)
α = 0 (dS ≦ 0) where k is a conversion constant and the unit of α is%.
It is calculated by the following formula. That is, as the acceleration slip change gradient is larger on the increase side, the differential value dS becomes a larger value, and thus the decreased on-pulse width α also becomes a larger value. On the decrease side of the acceleration slip change gradient, the on-pulse width (duty ratio) at the time of shifting to the decrease is maintained.

  In step S6, based on the calculation of the reduced on-pulse width α in step S5, it is determined whether or not the previous value of the on-pulse width (value before one control period) is α% or more. If yes, the process proceeds to step S7. If no, (if less than 0% due to subtraction), move to return.

  In step S7, based on the determination that the on-pulse width previous value ≧ α% in step S6, the on-pulse width current value is calculated by subtracting α% from the on-pulse width previous value, and the process proceeds to return (main routine). In the main routine, a command for obtaining the current value of the on-pulse width calculated in step S7 is output to the semiconductor relay 24.

  In step S8, it is determined whether or not the previous value of the on-pulse width is 99% or less based on the determination that the driven wheel acceleration slip is not in step S3. If yes, the process proceeds to step S9. (If it exceeds 100% due to addition), move to return.

  In step S9, based on the determination that the on-pulse width previous value ≦ 99% in step S8, the on-pulse width current value is calculated by adding 1% to the on-pulse width previous value, and the process proceeds to return (main routine). . In the main routine, a command for obtaining the current value of the on-pulse width calculated in step S9 is output to the semiconductor relay 24.

  In the flowchart of FIG. 3, step S2 corresponds to the driven wheel acceleration slip detection means, steps S3, S6, and S7 correspond to the motor output control means, and steps S4 and S5 correspond to the pulse width calculation means. .

[Motor output control operation]
For example, when starting on a slippery low μ road such as an icy road, when a driven wheel acceleration slip starts to occur, at the initial stage of generation of the driven wheel acceleration slip below the driven wheel acceleration slip judgment threshold In the flowchart of FIG. 3, the flow from step S1 → step S2 → step S3 → step S8 to return is repeated.
Therefore, in the PWM duty control for controlling the on-pulse time and the off-pulse time of the pulse wave having a constant amplitude and repetition period for the semiconductor relay 24, the control for setting the on-pulse time to 100% is repeated.

Then, if the driven wheel acceleration slip increases and exceeds the acceleration slip determination threshold value, it is determined that the driven wheel acceleration slip has occurred. In the flowchart of FIG. 3, step S1 → step S2 → step S3 → The flow from step S4 → step S5 → step S6 → step S7 is repeated.
Accordingly, on the increase side of the driven wheel acceleration slip, the decrease on-pulse width α that is decreased for each control cycle increases as the acceleration slope ratio S increases, in other words, the off-pulse width decreases by the decrease on-pulse width α. Increased PWM duty control is performed on the semiconductor relay 24. It should be noted that the on-pulse width and the off-pulse width at the time of shifting to the decrease are maintained on the decrease side of the driven wheel acceleration slip.

When the driven wheel acceleration slip becomes equal to or less than the acceleration slip determination threshold due to the reduction of the motor torque TM by the PWM duty control for the semiconductor relay 24, step S1 → step S2 → step S3 → step in the flowchart of FIG. The flow from S8 to step S9 is repeated until the on-pulse time reaches 100%.
Therefore, when the driven wheel acceleration slip converges, PWM duty control is executed on the semiconductor relay 24 to increase the on-pulse width by 1% for each control period and to slowly increase the motor torque TM.

[Motor output control action]
The motor output control action when starting on a slippery icy and snowy road will be described with reference to a timing chart showing the driven wheel speed characteristics, acceleration slip detection characteristics, and on-pulse width characteristics shown in FIG.

  When the occurrence of the driven wheel acceleration slip is detected at time t0 in FIG. 5, the time between the time t0 and the time t1 when the driven wheel acceleration slip increases increases as the rising gradient of the driven wheel acceleration slip increases. PWM duty control is performed on the semiconductor relay 24 to increase the decreased on-pulse width α that is decreased every control cycle. For this reason, the motor torque TM is quickly reduced according to the rising gradient of the driven wheel acceleration slip, and the increase of the driven wheel acceleration slip is suppressed in a short time.

  And, from time t1 when the driven wheel acceleration slip reaches a peak until time t2 when the convergence of the driven wheel acceleration slip is detected, the on-pulse at time t1 regardless of the descending gradient of the driven wheel acceleration slip. PWM duty control for maintaining the width and off-pulse width as they are is executed for the semiconductor relay 24. For this reason, for example, the time required for convergence of the driven wheel acceleration slip can be shortened as compared with the case where the on-pulse width is increased while the driven wheel acceleration slip exhibits a downward gradient characteristic. In addition, for example, the motor torque TM after the driven wheel acceleration slip converges can be ensured higher than when the on-pulse width is decreased while the driven wheel acceleration slip exhibits a downward gradient characteristic.

  From the time t2 when the convergence of the driven wheel acceleration slip is detected to the time t3 when the occurrence of the next driven wheel acceleration slip is detected, the PWM duty control increases the on-pulse width by 1% every control cycle. Is executed for the semiconductor relay 24. Therefore, the motor torque TM does not return to the original motor torque TM immediately after the convergence of the driven wheel acceleration slip, and the driven wheel acceleration slip occurs again immediately after the convergence of the driven wheel acceleration slip. Is prevented.

  And since it is a start on a slippery icy and snowy road, from time t3 to time t4 at which the occurrence of the second driven wheel acceleration slip is detected by the accelerator depressing operation or the like, the driven wheel is similar to the above. PWM duty control is performed on the semiconductor relay 24 so that the decreasing on-pulse width α that is decreased for each control cycle is increased as the rising slope of the acceleration slip increases. From time t4 to time t5, the on-pulse width at time t4 is PWM duty control for maintaining the off-pulse width as it is is executed for the semiconductor relay 24, and after time t5, PWM duty control for increasing the on-pulse width by 1% every control cycle is executed for the semiconductor relay 24.

  For the second driven wheel acceleration slip, the on-pulse width for starting the motor output reduction control is 100% or less, so that at time t5, the low motor torque TM is maintained. As long as the operation amount is not increased or the road surface μ is not changed to the lower μ side, the generation of the driven wheel acceleration slip is suppressed for the time being.

Next, the effect will be described.
In the motor output control device of the motor four-wheel drive vehicle of the first embodiment, the effects listed below can be obtained.

  (1) The main drive wheel is driven by the engine 2 and the slave drive wheel is driven by the electric motor 4, and the electric motor 4 is driven by electric energy generated by the generator 7 driven by the engine 2. In the motor four-wheel drive vehicle, an adjustable relay having a semiconductor switch element provided at an intermediate position of the electric wire 9 connecting the generator 7 and the electric motor 4, and a slave detecting an acceleration slip of the slave drive wheel. Drive wheel acceleration slip detection means and motor output control means for controlling the adjustable relay so as to suppress the output of the electric motor 4 at the time of detection of slave drive wheel acceleration slip. Slip can be quickly suppressed and the stability of the vehicle can be ensured when the driven wheel acceleration slip occurs.

  (2) In accordance with the change gradient of the driven drive wheel acceleration slip amount, pulse width calculation steps S4 and S5 are provided for narrowing the on-pulse width and increasing the off-pulse width as the acceleration slip change gradient increases on the increasing side, and the motor output control means Outputs a command to obtain a pulse wave based on the on / off ratio calculated in the pulse width calculation steps S4 and S5 when the driven wheel acceleration slip is detected, so that the driven wheel acceleration slip is detected. Compared with the case where the on-pulse width is narrowed at a constant ratio, the acceleration slip of the driven wheel can be suppressed with better response.

  (3) Since the adjustable relay is a semiconductor relay 24 using a semiconductor switch element, and the electric motor is a DC motor 4 driven by a DC current from the semiconductor relay 24, the driven wheel is connected to a DC. In the motor four-wheel drive vehicle driven by the motor 4, by adopting the semiconductor relay 24 which is advantageous in response instead of the mechanical relay, it is possible to more quickly suppress the driven wheel acceleration slip. Furthermore, no welding failure occurs unlike a mechanical relay.

  The second embodiment is an example in which the adjustable relay is an inverter 30 using a semiconductor switch element, and the electric motor is an AC motor 4 ′ driven by an AC current from the inverter 30.

  First, the configuration will be described. As shown in FIG. 5, an inverter 30 using a semiconductor switch element is interposed between the electric wire 9 connecting the generator 7 and the three-phase AC motor 4 ′ and the three-phase electric wire 9 ′. Provided. Since other configurations are the same as those of the first embodiment shown in FIGS. 1 and 2, the corresponding components are denoted by the same reference numerals and description thereof is omitted.

  Next, the operation will be described.

[Motor output control processing]
FIG. 6 is a flowchart showing the flow of the motor output control process executed by the 4WD controller 8 according to the second embodiment. Each step will be described below. Note that steps S21 to S23 in FIG. 6 correspond to steps S1 to S3 in FIG.

  In step S26, it is determined whether or not the previous value of the inverter pulse width (on-pulse width) is 5% or more based on the determination of the driven wheel acceleration slip in step S23. If yes, the process proceeds to step S27. If no (if less than 0% due to subtraction), move to return. Here, 5%, which is the inverter pulse width that is reduced in one control cycle, is a value that is set in advance as an appropriate value that suppresses acceleration slip early when the driven wheel acceleration slip occurs (pulse width setting). means).

  In step S27, based on the determination that the inverter pulse width previous value ≧ 5% in step S26, the inverter pulse width current value is calculated by subtracting 5% from the inverter pulse width previous value, and the process returns to the main routine. Transition. In the main routine, a command for obtaining the current value of the inverter pulse width calculated in step S27 is output to the inverter 30.

  In step S28, it is determined whether or not the previous value of the inverter pulse width is 99% or less based on the determination that it is not the driven wheel acceleration slip in step S23. If yes, the process proceeds to step S29, and no In the case (when it exceeds 100% by addition), it shifts to return.

  In step S29, based on the determination that the inverter pulse width previous value ≦ 99% in step S28, the inverter pulse width current value is calculated by adding 1% to the inverter pulse width previous value, and the return (main routine) Migrate to In the main routine, a command for obtaining the current value of the inverter pulse width calculated in step S29 is output to the inverter 30.

  In the flowchart of FIG. 6, step S22 corresponds to the driven wheel acceleration slip detection means, and steps S23, S26, and S27 correspond to the motor output control means.

[Motor output control operation]
For example, when starting on a slippery low μ road such as an icy road, when a driven wheel acceleration slip starts to occur, at the initial stage of generation of the driven wheel acceleration slip below the driven wheel acceleration slip judgment threshold In the flowchart of FIG. 6, the flow from step S21 to step S22 to step S23 to step S28 is repeated.
Therefore, PWM duty control is executed for the inverter 30 so that the inverter pulse time in each phase is 100%.

Then, when the driven wheel acceleration slip increases and exceeds the acceleration slip determination threshold value, it is determined that the driven wheel acceleration slip occurs, step S21 → step S22 → step S23 → in the flowchart of FIG. The flow from step S26 to step S27 is repeated.
Therefore, on the increase side of the driven wheel acceleration slip, PWM duty control is performed on the inverter 30 so that the inverter pulse width at each phase is 5%, which is a reduced inverter pulse width that is decreased every control cycle.

When the driven wheel acceleration slip becomes equal to or less than the acceleration slip determination threshold due to the reduction of the motor torque TM by the PWM duty control for the inverter 30, step S21 → step S22 → step S23 → step S28 in the flowchart of FIG. → The process of proceeding to step S29 is repeated until the inverter pulse time reaches 100%.
Therefore, when the driven wheel acceleration slip converges, PWM duty control is executed on the inverter 30 to increase the inverter pulse width by 1% every control cycle and to slowly increase the motor torque TM.

[Motor output control action]
The motor output control action when starting on a slippery icy and snowy road will be described with reference to a timing chart showing the driven wheel speed characteristics, acceleration slip detection characteristics, and inverter pulse width characteristics shown in FIG.

  When occurrence of the driven wheel acceleration slip is detected at time t0 in FIG. 7, the reduced inverter pulse width reduced by one control cycle is set to 5 from time t0 to time t1 when the driven wheel acceleration slip converges. % PWM duty control is executed for the inverter 30. Therefore, the motor torque TM is quickly reduced, and the driven wheel acceleration slip is suppressed in a short time.

  From time t1 when the convergence of the driven wheel acceleration slip is detected to time t2 when the occurrence of the next driven wheel acceleration slip is detected, the PWM duty increases the inverter pulse width by 1% for each control period. Control is performed on the inverter 30. For this reason, the motor torque TM does not return to the original motor torque TM immediately after the convergence of the driven wheel acceleration slip, and the driven wheel acceleration slip occurs again immediately after the convergence of the driven wheel acceleration slip. Is prevented.

  Since it is at the time of starting on a slippery icy and snowy road, from time t2 to time t3 at which occurrence of the second driven wheel acceleration slip is detected by the accelerator depressing operation, etc., one control cycle PWM duty control is performed on the inverter 30 so that the inverter pulse width reduced every time is 5%. After the time t3, the PWM duty control that increases the inverter pulse width by 1% every control cycle is performed on the inverter 30. Executed.

  In addition, with respect to the occurrence of the second driven wheel acceleration slip, the inverter pulse width for starting the motor output reduction control is 100% or less, so that at the time t3, the low motor torque TM is maintained. As long as the accelerator operation amount is not increased or the road surface μ is not changed to the lower μ side, the generation of the driven wheel acceleration slip is suppressed for the time being.

Next, the effect will be described.
In the motor output control device for the motor four-wheel drive vehicle of the second embodiment, in addition to the effect of (1) of the first embodiment, the following effects can be obtained.

  (4) The on-pulse width that is reduced in one control cycle when detecting the acceleration slip of the driven wheel is set to a larger value than the on-pulse width that is increased in one control cycle after the acceleration slip of the driven wheel is converged. Pulse width setting means is provided, and the motor output control means outputs a command to obtain a pulse wave with an on / off ratio set by the pulse width setting means to the adjustable relay upon detection of driven wheel acceleration slip. Therefore, when the driven wheel acceleration slip is detected, the driven wheel acceleration slip can be quickly suppressed by a simple control that gives a reduced on-pulse width per control cycle as a fixed value.

  (5) Since the adjustable relay is an inverter 30 using a semiconductor switch element, and the electric motor is an AC motor 4 ′ driven by an AC current from the inverter 30, the driven wheel is replaced with an AC motor. In a motor four-wheel drive vehicle driven by 4 ′, a semiconductor switch element is used as a constituent element, and an existing inverter 30 that converts a direct current from the generator 7 into an alternating current at a desired frequency is used, so that the driven wheel is more driven. Accelerated slip can be quickly suppressed.

  The third embodiment is an example in which the PWM duty command to be output to the semiconductor relay 24 and the inverter 30 is set by the acceleration slip amount differential value in the system using the first and second embodiments.

  Since the configuration is the same as in the first and second embodiments, illustration and description thereof are omitted.

The operation will be described. FIG. 8 is a timing chart showing slave drive wheel speed characteristics, acceleration slip amount characteristics, acceleration slip differential value characteristics, and PWM duty ratio characteristics when slave drive wheel acceleration slip occurs.
When a driven wheel acceleration slip as shown in the driven wheel speed characteristic of FIG. 8 occurs at the time of starting or the like, the acceleration slip amount ΔV increases from the slip start time t0 to the time t1, and accompanying this, Thus, the acceleration slip differential value β has a mountain-like characteristic that rapidly increases from 0 and returns to 0 from time t0 to time t1. Therefore, based on the acceleration slip amount differential value β, the PWM duty ratio obtained by the formula used in the following PID control decreases due to a steep slope in the slip start region from time t0 to time t ′, and time t ′. The lowest value.
PWM DUTY = KP ・ △ V + KD ・ β + KI ・ ∫ △ V
However, KP: proportional gain, KD: differential gain, KI: integral gain

  In the slip convergence range from time t ′ to time t2, the acceleration slip amount ΔV decreases, and the acceleration slip differential value β becomes a negative value, thereby showing a dotted line characteristic that gradually returns to 100%. . Here, the PID control is applied over the entire region from the start region to the convergence region of the acceleration slip, but the PID control is applied only in the slip start region from the time t0 to the time t ′. As shown by the solid line characteristic of FIG. 8, the PWM duty ratio may be returned to 100% at time t1 when the acceleration slip differential value β switches from positive to negative.

Next, the effect will be described.
In the motor output control device of the motor four-wheel drive vehicle of the third embodiment, in addition to the effects (1), (3) of the first embodiment and (5) of the second embodiment, the following effects can be obtained. it can.

  (6) An acceleration slip amount differential value calculating means for calculating a differential value of the driven wheel acceleration slip amount is provided, and the motor output control means is calculated by the acceleration slip amount differential value calculating means when the driven wheel acceleration slip is detected. In order to control the semiconductor relay 24 or the inverter 30 so as to suppress the output of the DC motor 4 or the AC motor 4 ′ based on the acceleration slip amount differential value β, the acceleration is caused when the acceleration slip of the driven wheel occurs. The acceleration slip amount of the driven wheel can be quickly suppressed by suppressing the motor output with high response according to the changing speed of the slip amount ΔV. In particular, by suppressing the acceleration slip with a good response at the initial stage of the acceleration slip, it is possible to prevent the development of an excessive acceleration slip.

  As mentioned above, although the motor output control apparatus of the motor four-wheel drive vehicle of this invention has been demonstrated based on Example 1 thru | or Example 3, about a concrete structure, it is not restricted to these Examples, Claim Changes and additions in the design are permitted without departing from the spirit of the invention according to each claim in the scope of the above.

  In Examples 1 and 2, as the driven wheel acceleration slip detection means, the wheel speed difference obtained by subtracting the lower wheel speed of the left and right front wheels from the higher wheel speed of the left and right rear wheel speeds. In this example, it is determined that the driven wheel acceleration slip is greater than or equal to the set threshold value. For example, the vehicle speed is estimated and the driven wheel acceleration slip is estimated based on the estimated vehicle speed and the left and right rear wheel speeds. For example, other detection means may be used.

  In the first embodiment, the reduced on-pulse width is given as a variable value by the differential value (acceleration slip change gradient) of the acceleration slip ratio, and in the third embodiment, the PWM duty ratio is given by the acceleration slip amount differential value. The reduced on-pulse width may be given as a variable value depending on other factors such as the amount, the accelerator operation amount, and the accelerator operation speed.

  In the second embodiment, an example in which the reduced inverter pulse width is set to 5% per control cycle is shown. However, when the reduced inverter pulse width is given as a fixed value, the value is not limited to 5%, and can be obtained by experiments or the like. Alternatively, a setting value other than 5% may be used.

  Although the motor output control device of the present invention has been shown to be applied to a front-wheel drive base motor four-wheel drive vehicle in which left and right front wheels are driven by an engine, a rear-wheel drive base motor four-wheel drive in which left and right rear wheels are driven by an engine It can also be applied to driving vehicles.

1 is an overall system diagram showing a motor four-wheel drive vehicle to which a motor output control device of Embodiment 1 is applied. It is a block diagram which shows the control system of the motor four-wheel drive vehicle of Example 1. FIG. 3 is a flowchart illustrating a flow of a motor output control process executed by the 4WD controller according to the first embodiment. 3 is a timing chart showing a driven wheel speed characteristic, an acceleration slip detection characteristic, and an inverter pulse width characteristic when a driven wheel acceleration slip occurs in the first embodiment. It is a whole system figure which shows the motor four-wheel drive vehicle to which the motor output control apparatus of Example 2 was applied. 6 is a flowchart illustrating a flow of a motor output control process executed by the 4WD controller according to the second embodiment. 10 is a timing chart showing slave drive wheel speed characteristics, acceleration slip detection characteristics, and inverter pulse width characteristics when slave drive wheel acceleration slip occurs in the second embodiment. 12 is a timing chart showing slave drive wheel speed characteristics, acceleration slip amount characteristics, acceleration slip differential value characteristics, and PWM duty ratio characteristics when slave drive wheel acceleration slip occurs in the third embodiment.

Explanation of symbols

1L, 1R left and right front wheels (main drive wheels)
2 Engine
3L, 3R Left and right rear wheels (sub driven wheels)
4 DC motor (electric motor)
4 'AC motor (electric motor)
5 Transmission & differential gear 6 Endless belt 7 Generator 8 4WD controller (Motor output control means)
9 Electric wire 9 'Three-phase electric wire 10 Junction box 24 Semiconductor relay (adjustable relay)
30 Inverter (adjustable relay)

Claims (6)

In the motor four-wheel drive vehicle driven by the electric energy generated by the generator driven by the engine, the driven wheel driven by the engine, the driven wheel driven by the electric motor, and the electric motor generated by the generator driven by the engine,
An adjustable relay having a semiconductor switch element provided at an intermediate position of an electric wire connecting the generator and the electric motor;
Slave drive wheel acceleration slip detection means for detecting acceleration slip of the slave drive wheel;
Motor output control means for controlling the adjustable relay so as to suppress the output of the electric motor at the time of detecting a driven wheel acceleration slip;
A motor output control device for a motor four-wheel drive vehicle. In the motor output control device of the motor four-wheel drive vehicle according to claim 1,
According to the change gradient of the driven wheel acceleration slip amount, a pulse width calculation means is provided to narrow the on-pulse width and increase the off-pulse width as the acceleration slip change gradient increases on the increase side,
The motor output control means outputs a command to obtain a pulse wave based on the on / off ratio calculated by the pulse width calculation means to the adjustable relay upon detection of the driven wheel acceleration slip. Motor output control device for wheel drive vehicles. In the motor output control device for a motor four-wheel drive vehicle according to claim 1 or 2,
The adjustable relay is a semiconductor relay using a semiconductor switch element,
The motor output control device for a motor four-wheel drive vehicle, wherein the electric motor is a DC motor driven by a DC current from the semiconductor relay. In the motor output control device of the motor four-wheel drive vehicle according to claim 1,
Pulse width setting for setting the on-pulse width to be reduced in one control cycle when detecting the acceleration slip of the driven wheel to a value larger than the on-pulse width to be increased in one control cycle after the acceleration slip of the driven wheel is converged Providing means,
The motor output control means outputs a command to obtain a pulse wave with an on / off ratio set by the pulse width setting means to the adjustable relay when a driven wheel acceleration slip is detected. Motor output control device for wheel drive vehicles. In the motor output control device for a motor four-wheel drive vehicle according to claim 1 or 4,
The adjustable relay is an inverter using a semiconductor switch element,
The motor output control device for a motor four-wheel drive vehicle, wherein the electric motor is an AC motor driven by an AC current from the inverter. In the motor output control device of the motor four-wheel drive vehicle according to claim 1,
Acceleration slip amount differential value calculating means for calculating the differential value of the driven wheel acceleration slip amount is provided,
The motor output control means is configured to control the output of the electric motor so as to suppress the output of the electric motor based on the acceleration slip amount differential value calculated by the acceleration slip amount differential value calculation means when detecting the driven wheel acceleration slip. A motor output control device for a motor four-wheel drive vehicle.

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