JP3852250B2 - Control device for front and rear wheel drive vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention includes a first prime mover that drives a first drive wheel that is one of front wheels and rear wheels, and a second prime mover that drives a second drive wheel that is the other of front wheels and rear wheels. The present invention relates to a control device for a front and rear wheel drive vehicle.
[0002]
[Prior art]
A front and rear wheel drive vehicle of the type comprising a first prime mover that drives a first drive wheel that is one of front wheels and rear wheels, and a second prime mover that drives a second drive wheel that is the other of front wheels and rear wheels. That is, there are known front and rear wheel drive vehicles in which one of a front wheel drive system and a rear wheel drive system is driven by an engine (internal combustion engine) and the other is driven by an electric motor, a hydraulic motor, or the like. For example, this is the front and rear wheel drive vehicle described in Japanese Utility Model Laid-Open No. 55-110328.
[0003]
By the way, according to such a control device for a front and rear wheel drive vehicle, it is determined that the vehicle is in a slip state when a difference in rotational speed between the front wheels and the rear wheels occurs, and the electric motor is driven by electric power from a generator driven by the engine. The other drive system is driven auxiliary by the electric motor, and the driving force of the vehicle at the time of slip is compensated. For example, when a driver performs an acceleration operation on a road surface having a low road surface friction coefficient such as a frozen road or a snowy snow road, if a slip occurs on a wheel driven by the engine, for example, a front wheel, power generation driven by the engine is performed. When the electric motor is operated using the machine as a power source and the rear wheels are driven, a part of the output of the engine is consumed to drive the generator, thereby simultaneously reducing the driving force of the front wheels. Then, the driving force of the rear wheels by the electric motor is generated with a size corresponding to the decrease, and the four-wheel drive state is obtained.
[0004]
[Problems to be solved by the invention]
However, in the above conventional control device for front and rear wheel drive vehicles, even when the rear wheels are driven by the electric motor, it is not possible to cope with the case where the slip of the front wheels is not eliminated, and the driving force of the vehicle cannot be obtained sufficiently There was a problem that there was.
[0005]
The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide a control device for a front and rear wheel drive vehicle capable of reliably preventing vehicle slip and sufficiently obtaining the drive force of the vehicle. Is to provide.
[0006]
[Means for Solving the Problems]
  In order to achieve this object, the gist of the present invention is to drive a first prime mover that drives a first drive wheel that is one of the front wheels and the rear wheels, and a second drive wheel that is the other of the front wheels and the rear wheels. A front and rear wheel drive vehicle control device comprising: (a) slip detection means for detecting a slip of the first drive wheel driven by the first prime mover; and (b) the slip detection means. When a slip of the first driving wheel is detected, the energy obtained from the energy generating means driven by the first prime mover is supplied to the electric motor to drive the second driving wheel, whereby the front and rear wheel driving state is established. Second driving wheel drive control means, and (c) when the slippage of the first driving wheel is not resolved despite the fact that the second driving wheel drive control means is in the front-rear wheel driving state. The driving force of the drive wheelDecreaseIncluding first driving wheel driving force control means.Only d ) The first driving wheel driving force control means reduces the driving force of the first driving wheel based on a load state of the first prime mover by the energy generating means.There is.
[0007]
【The invention's effect】
  In this way, when the first drive wheel driven by the first prime mover slips, energy is generated by the energy generating means driven by the first prime mover, so that a part of the output of the first prime mover is generated. When the driving force of the first driving wheel is reduced and the energy generated by the energy generating means is supplied to the electric motor to drive the second driving wheel, the first driving wheel Even if it tries to slip, the driving force of the first driving wheel is further increased by the first driving wheel driving force control means.DecreaseTherefore, the slip of the first drive wheel is surely eliminated and the driving force of the vehicle can be sufficiently obtained.Further, the first driving wheel driving force control means reduces the driving force of the first driving wheel based on the load state of the first driving machine by the energy generating means, so that the energy generating means imposed on the first driving machine. Since the output of the first prime mover, that is, the driving force of the first driving wheel is reduced according to the driving load state, slip of the first driving wheel is more appropriately suppressed.
[0009]
Other aspects of the invention
  herePreferably, when the vehicle driving force decreases after the driving force of the first driving wheel is reduced by the first driving wheel driving force control means, the output of the second prime mover is increased. Further, 2 prime mover output increasing means is included. In this way, if the acceleration of the vehicle decreases after the driving force of the first driving wheel is reduced, the output of the second prime mover is increased and the vehicle is driven even if the accelerator pedal is not operated. Since the power is increased, the power performance of the vehicle is improved.
[0010]
Preferably, the turning determination unit for determining turning of the vehicle, and when the turning determination of the vehicle is determined by the turning determination unit, the output of the first prime mover is reduced or slipping is performed. The vehicle further includes turning traveling stabilization means for preferentially performing braking of the wheel. In this way, since the output of the first prime mover or the braking of the slipping wheel is preferentially performed during turning of the vehicle, the slipping of the wheel during turning is suppressed. The running stability of the vehicle is improved.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
[0012]
FIG. 1 shows a power transmission device for a vehicle having a control device according to an embodiment of the present invention, and shows a front and rear wheel drive vehicle based on a front engine front wheel drive (FF), that is, a four wheel drive vehicle. In the figure, an engine 10 functioning as a first prime mover or a main prime mover is an internal combustion engine such as a gasoline engine or a diesel engine, and its output torque includes a torque converter 12, a transmission 14, a differential gear device 16 for front wheels, It is transmitted to the pair of front wheels 20 via the axle 18. A generator 24 exclusively for power generation is provided in the engine 10. The engine 10 to the front wheel 20 correspond to the front wheel drive system, and the front wheel 20 corresponds to the first drive wheel or the main drive wheel. This type of vehicle is a four-wheel drive vehicle that does not use a propeller shaft.
[0013]
The output torque of an electric motor / generator (hereinafter referred to as MG) 28 functioning as a second prime mover or sub prime mover is transmitted to a pair of rear wheels 34 via a rear wheel differential gear device 30 and an axle 32. It is to be transmitted. The MG 28 to the rear wheel 34 correspond to the rear wheel drive system, and the rear wheel 34 corresponds to the second drive wheel or the auxiliary drive wheel. When the rear wheel 34 is driven by the MG 28, the four-wheel drive state is set. The MG 28 also has a function as a generator (generator) that generates electric power by being rotationally driven by the braking energy of the vehicle and outputs generated electric power (regenerative energy). Preferably, the generator 24, which may supply power directly to the MG 28 during four-wheel drive, has a power generation capacity with a capacity slightly larger than the capacity of the MG 28.
[0014]
The transmission 14 includes, for example, a constant-mesh type parallel two-shaft manual transmission, and a plurality of gears when elements of a plurality of planetary gear units are selectively connected or stopped by a hydraulic friction engagement device. An automatic transmission that achieves a stage, a belt-type continuously variable transmission in which a transmission belt is wound around a pair of pulleys having a variable effective diameter, and the like.
[0015]
The engine and shift electronic control unit 38 determines the actual engine speed N from the relationship stored in advance._E, Fuel injection control for controlling the fuel injection time based on the intake air amount Q / N or the intake pipe pressure, and the actual engine speed N from the previously stored relationship_EThe ignition timing control for controlling the basic ignition timing based on the intake air amount Q / N, the target idle rotation speed when the engine 10 is idle is determined, and the idle control is performed so that the actual idle rotation becomes the target idle rotation speed. When the transmission 14 is an automatic transmission, for example, when the transmission 14 is an automatic transmission, the actual vehicle speed V and the accelerator opening θ (the depression amount A of the accelerator pedal 36) are determined from a previously stored shift diagram._CCOr throttle valve opening θ_TH) To determine the transmission gear stage and execute automatic transmission control for switching to the transmission gear stage. Normally, the opening θ of the throttle valve 41_THIs the depression amount A of the accelerator pedal 36_CCThe throttle actuator 43 is controlled so as to have a size corresponding to.
[0016]
The electronic controller 40 for traction control includes a wheel speed sensor 42 provided on each of the pair of front wheels 20 and the pair of rear wheels 34._FR, 42_FL, 42_RR, 42_RLVehicle speed (vehicle speed converted based on wheel rotation speed) V_FR, V_FL, V_RR, V_RL, Front wheel speed V_F[= (V_FR+ V_FL) / 2], rear wheel speed V_R[= (V_RR+ V_RL) / 2], and vehicle body speed V (for example, wheel speed V_FR, V_FL, V_RR, V_RLIs calculated as the vehicle speed V, that is, the vehicle speed V), while the rear wheel vehicle speed V obtained from the rear wheel 34 not driven by the engine 10, for example, is calculated._RAnd front wheel speed V obtained from the front wheel 20 which is the main drive wheel_FIs a preset control start slip speed ΔV₂If the slip determination of the main drive wheel (front wheel 20) is made by exceeding the traction control, the traction control for increasing the traction force of the vehicle at the start is executed, and the slip speed ΔV and the front wheel vehicle speed V are executed._FThe slip ratio R_S[= (ΔV / V_F) × 100%] is a preset target slip ratio range R_S ^*The output of the engine 10 is suppressed using a throttle actuator 43 that drives the throttle valve 41 or a fuel injection valve (not shown) so that the rotation of the front wheel 20 is controlled using the front wheel brake 44 so that the front wheel 20 Suppresses driving force. Since the friction coefficient μ of the wheel with respect to the road surface has a property of changing as shown in FIG. 2, for example, the target slip ratio range R_S ^*Is set in a region where the friction coefficient μ of the wheel is maximum.
[0017]
The motor control electronic control unit 46, for example, as shown in the double line section of FIG. 3, regenerative control for storing the regenerative power output from the MG 28 in the capacitor 48 during vehicle braking, and for example, the thick line of FIG. As shown in the section, for example, the actual accelerator opening θ and the accelerator opening are determined from the relationship stored in advance when starting or accelerating on a high friction coefficient road surface (high μ road) such as a normal road surface or a dry road. Based on the rate of change dθ / dt, a basic assist torque of a predetermined ratio of, for example, about 20 to 30% of the total driving torque of the vehicle is determined, and stored in the capacitor 48 in advance so as to obtain the basic assist torque. By supplying electric power to the MG 28 through the inverter 50, the driving force of the MG 28 is added to the driving force of the engine 10 to assist the acceleration of the vehicle (assist). In order to increase the vehicle starting ability, the transmission 14 is simultaneously operated to drive the MG 28 at the time of start on a high μ road assist control for improving fuel efficiency and on a low friction coefficient road surface (low μ road) such as a frozen road or a snowy road. Execute low-μ road assist control to shift down. The output current and drive current of the MG 28, the output current of the generator 24, the storage current and output current of the capacitor 48 are controlled by an inverter 50 controlled by the motor control electronic control unit 46.
[0018]
The road surface gradient sensor 52 is composed of a G sensor or an inclinometer used at a vehicle speed of approximately zero, and the road surface inclination angle θ_ROADOr gradient (tilt) α (= tan θ_ROAD) Is supplied to the motor control electronic control unit 46. The accelerator opening sensor 54 detects the accelerator opening θ from the operation amount of the accelerator pedal 36 and supplies a signal representing the accelerator opening θ to the engine and the shift electronic control device 38. The power mode selection switch 56 is operated to select a mode in which travel is emphasized by accelerating by changing the shift line so that the transmission gear ratio of the transmission 14 becomes low. Is supplied to the motor control electronic control unit 46. The engine and shift electronic control device 38, the traction control electronic control device 40, and the motor control electronic control device 46 are so-called microcomputers including a CPU, a ROM, a RAM, an input / output interface, and the like. The input signal is processed in accordance with a program stored in advance in the ROM while using the storage function, and the control signal is output. These input signal, storage signal, and operation value are exchanged via a communication line as necessary. Is to be given and received.
[0019]
FIG. 4 is a functional block diagram mainly illustrating the main part of the control function of the motor control electronic control unit 46. In FIG. 4, the acceleration operation determining means 58 determines whether or not an acceleration operation has been performed by the driver when the vehicle is stopped or traveling at a low speed based on, for example, a change in the throttle opening θ. The first slip determination means 60 determines whether or not a slip has occurred in the front wheels 20 driven by the engine 10 with the assist torque generated in the MG 28 in advance using the electrical energy stored in the capacitor 48, for example, the front wheels. Based on the fact that the rotational speed of 20 exceeds the rotational speed of the rear wheel 34, or the slip speed ΔV is set to a predetermined value such as a control start slip speed ΔV.₂The determination is based on the above. The vehicle speed increase determination means 62 determines whether or not the vehicle speed V is increasing in a state where the assist torque is generated in advance in the MG 28 based on the change in the vehicle speed V, for example.
[0020]
The low μ road assist control end determination means 64 determines that the throttle opening θ is at the fully closed value (0%), and the slip speed ΔV is a predetermined value ΔV.₁Low μ road assist control means based on the fact that the slippage of the front wheel 20 has been eliminated, or that the elapsed time from the acceleration operation has reached a predetermined value, for example, 5 seconds or more. 66, the end of the low μ road assist control is determined.
[0021]
The low μ road assist control means 66 slips on the front wheels 20 driven by the engine 10 in a state where the acceleration operation is determined by the acceleration operation determination means 58 and the first slip determination means 60 has generated the assist torque in the MG 28 in advance. If the vehicle speed V is determined not to increase by the vehicle speed increase determination means 62, the inverter 50 is controlled to start acceleration driving on a low μ road. Perform appropriate assist control. The low μ road assist control means 66 functions as second drive wheel drive control means. For example, electric energy is supplied from the generator 24 driven by the engine 10 to the MG 28 so that the MG 28 is powered to the maximum. By executing the direct assist and driving the rear wheel 34 with the assist torque generated in the MG 28, the four-wheel drive state is set together with the front wheel 20 driven by the engine 10. Then, the low μ road assist control by the low μ road assist control means 66 is terminated when the low μ road assist control end determination means 64 determines the end of the low μ road assist control.
[0022]
Here, in the direct assist in which the MG 28 is driven by the electric energy from the generator 24 as described above, a part of the output of the engine 10 is consumed by the generator 24, and at the same time, the driving force of the front wheels 20 is reduced. The rear wheel 34 is driven based on the output of the assist torque from the MG 28. When the vehicle starts, the initial torque of the MG 28 is larger than the amount of decrease in the driving torque of the front wheels 20, so that the capacitor is used when the vehicle starts. The assist effect is the same as the assist from 48 alone. FIG. 5 shows the output torque T of the engine 10_EThe broken line indicates the characteristic before the direct assist is started, the solid line indicates a case where the direct assist is lowered, and the difference between the broken line and the solid line is the amount of decrease in the driving torque of the front wheel 20. It corresponds to. FIG. 6 shows the output torque (rotational torque) T of the generator 24._GThe characteristics are shown.
[0023]
The second slip determination means 68 determines whether or not a slip of the vehicle, that is, a slip of the front wheel 20 has occurred under the assist driving of the rear wheel 34 by the low μ road assist control means 66, for example, the slip speed ΔV is a predetermined value ΔV.₁Judgment is made on the basis of having fallen below. This predetermined value ΔV₁Is usually a predetermined value ΔV used for slip determination in the first slip determination means 60.₂Is set to a smaller value, and a hysteresis is provided in the slip determination reference value.
[0024]
The first drive wheel drive control means, that is, the first drive wheel drive force reduction means 70, still causes the front wheel 20 to slip even under the assist drive of the rear wheel 34 by the low μ road assist control means 66 by the second slip determination means 68. If it is determined that the vehicle has been generated, the throttle pedal 36 is used to generate the grip of the front wheel 20 by reducing the driving force of the front wheel 20 further than the previous value while maintaining the operation state of the accelerator pedal 36. Throttle valve opening θ using actuator 43_THAnd reducing the fuel injection amount using a fuel injection valve (not shown) or braking the front wheel 20 that is slipping using the front wheel brake 44 to reduce the output of the engine 10 or the driving force of the front wheel 20. Thus, the driving force of the front wheel 20 is controlled. Further, the first driving wheel driving force reducing means 70 is connected to the engine speed N in relation to overtaking traveling and downshifting of the transmission 14._EWhen the engine speed increases, the engine speed N_EDepending on the amount of increase in the throttle valve opening θ_THAlternatively, the reduction amount of the fuel injection amount is increased. The electric load generated by driving the generator 24 for the direct assist, that is, the load torque of the engine 10 is the engine rotational speed N as shown in FIG._EThis is to cope with the fact that the slippage of the front wheel 20 is more easily generated. The reduction amount of the output of the engine 10 is, for example, an amount corresponding to the shaded area in FIG._EIt is increased according to the amount of increase. Further, the first driving wheel driving force reducing means 70 is configured so that the throttle valve opening degree θ corresponds to the decrease in the electrical load of the generator 24 even when the electrical load becomes insufficient due to the thermal restriction of the generator 24._THAlternatively, the reduction amount of the fuel injection amount is increased. For example, when the generator 24 generates heat as it is used, it may be detected by a thermal sensor or a thermal switch, and the output of the generated power of the generator 24 may be automatically limited. Therefore, the output of the engine 10 is suppressed in order to cope with the fact that the load on the engine 10 is reduced and slipping of the front wheels 20 is more likely to occur.
[0025]
The first driving wheel driving force reduction ending means 72 indicates that no slip of the vehicle, that is, no slip of the front wheel 20 occurs under the assist driving of the rear wheel 34 by the low μ road assist control means 66 by the second slip determination means 68. If it is determined, the reduction of the driving force of the front wheels 20 by the first driving wheel driving force reducing means 70 is terminated or prohibited. In other words, the first driving wheel driving force reducing means 70 suppresses the driving force of the front wheels 20 while the second slip determining means 68 determines that the front wheels 20 are slipping.
[0026]
FIG. 7 is a flowchart for mainly explaining the main part of the control operation of the motor control electronic control unit 46. The low μ road slip assist control routine in FIG. 7 is normally executed when it is determined that the road surface is a low μ road with a low coefficient of friction, such as a frozen road or a snowy road. First, in SA1, a determination reference value V set to, for example, about several km / h in order to determine that the vehicle speed V is traveling._x1It is determined whether or not: If the determination at SA1 is negative, it is determined based on, for example, a change in the throttle opening θ whether or not an acceleration operation has been performed at SA2 corresponding to the acceleration operation determination means 58. If the determination of SA1 is affirmed or the determination of SA2 is negative, the routine is terminated. If the determination of SA1 is negative and the determination of SA2 is affirmative, the routine is terminated. In the corresponding SA3, the accumulated energy, that is, the remaining charge SOC for generating the assist torque in the capacitor 48 corresponding to the energy storage means, is set in advance to determine the amount necessary for executing the assist operation by the MG 28. Judgment value SOC_OIt is determined whether or not the value exceeds.
[0027]
When the determination at SA3 is affirmed, assist control at an assist ratio suitable for the low μ road is executed for a short time based on the electrical energy stored in the capacitor 48 at SA4, and when the determination at SA3 is negative In SA5, the direct assist control with the assist ratio suitable for the low μ road is executed for a short time based on the electric energy supplied from the generator 24 driven by the engine 10.
[0028]
Next, in SA6 corresponding to the first slip determination means 60, has the wheel slip occurred in the state where the assist control based on the electric energy stored in the capacitor 48 or the electric energy generated by the generator 24 is executed? Whether or not the slip speed ΔV is a preset reference value ΔV₂It is determined based on the fact that it has become larger. If the determination at SA6 is affirmative, it is determined at SA7 corresponding to the vehicle speed increase determination means 62 whether the effect by the assist has occurred, that is, whether the vehicle speed V has increased._{t + 1}Is the previous vehicle speed V_tDetermined based on greater.
[0029]
If the determination at SA6 is negative or the determination at SA7 is affirmative, that is, if the slip does not occur or the vehicle speed V increases even if slip occurs, this routine is terminated. Is affirmative and the determination of SA7 is negative, that is, when slip occurs and the vehicle speed does not increase, the engine 10 is controlled by controlling the inverter 50 in SA8 corresponding to the low μ road assist control means 66. The low μ road direct assist control suitable for the low μ road is executed based on the supply of the electric energy supplied from the generator 24 driven by the MG 28 to the MG 28.
[0030]
Subsequently, in SA9 corresponding to the second slip determination means 68, whether or not the front wheel 20 is still slipping regardless of the execution of the low μ road direct assist control is determined by the slip speed ΔV based on the determination criterion. Value ΔV₂Criterion value ΔV preset to a value smaller than₁It is determined based on the fact that it has become larger. If the determination at SA9 is affirmative, since the slip is still occurring even when the electric load of the generator 24 is applied to the engine 10 by the direct assist, the first driving wheel driving force reducing means 70 is in the state. In the corresponding SA10, the throttle valve opening θ using the throttle actuator 43 while the operation position of the accelerator pedal 36 remains unchanged._THIs made smaller than the previous value or the fuel injection amount is made smaller than the previous value by using the fuel injection valve, whereby the output of the engine 10 is made smaller than before, and the driving force of the front wheels 20 is reduced. Further reduced.
[0031]
Next, in SA12, SA13, and SA14, it is determined whether or not an assist end condition is satisfied. That is, in SA12, it is determined whether or not the throttle opening θ is fully closed (0%), and in SA13, the slip speed ΔV is determined as the determination reference value ΔV.₁In SA14, it is determined whether the elapsed time after the acceleration operation by the driver has reached a predetermined value, for example, 5 seconds. Initially, the determinations of SA12, SA13, and SA14 are all denied, so that SA8 and subsequent steps are repeatedly executed.
[0032]
While the above SA8 and subsequent steps are repeatedly executed, if the slip of the front wheel 20 of the vehicle is eliminated due to the reduction of the output of the engine 10, that is, the driving force of the front wheel 20, the determination of SA9 becomes negative. Although the output restriction is terminated, the direct assist is continued. Next, the throttle opening degree θ indicating the driver's intention to finish acceleration is fully closed, or the slip of the vehicle is canceled and the slip speed ΔV is set to the determination reference value ΔV.₁If any one of SA12, SA13, and SA14 is affirmed and the assist control is performed in SA15 Is terminated. These SA12, SA13, SA14, and SA15 correspond to the first driving wheel driving force reduction ending means 72.
[0033]
In SA16, the remaining charge SOC of the capacitor 48 is determined as the determination reference value SOC._OIf the determination of SA16 is negative, the capacitor 48 is charged by the generator 24 in SA17. When the determination at SA16 becomes affirmative, charging of the capacitor 48 by the generator 24 is terminated at SA18, and the routine is terminated by clearing the flag at SA19.
[0034]
As described above, according to the present embodiment, when the front wheel 20 driven by the engine 10 slips, energy is generated by the generator (energy generating means) 24 driven by the engine 10, thereby causing the engine 10. When the rear wheel 34 is driven when the energy generated by the generator 24 is supplied to the MG 28 and the rear wheel 34 is driven, the front wheel 20 is still slipped. Even if it is going to do, since the driving force of the front wheel 20 is further reduced by the first driving wheel driving force reducing means 70, the slip of the front wheel 20 is eliminated, the front wheel 20 is securely gripped on the road surface, and the driving force of the vehicle is sufficient Will be obtained.
[0035]
Further, according to this embodiment, the first driving wheel driving force reducing means 70 is imposed on the engine 10 because it reduces the driving force of the front wheels 20 based on the load state of the engine 10 with respect to the generator 24. Since the output of the engine 10, that is, the driving force of the front wheels 20 is reduced according to the driving load state of the generator 24, the slip of the front wheels 20 is more appropriately suppressed.
[0036]
Next, another embodiment of the present invention will be described. In the following description, parts common to those in the above-described embodiment are denoted by the same reference numerals and description thereof is omitted.
[0037]
FIG. 8 is a functional block diagram illustrating a main part of the control function of the motor control electronic control unit 46 according to another embodiment of the present invention. In the function block diagram of FIG. 8, the function block diagram of FIG. 4 is added in that an acceleration decrease judging means 76, a second motor output increasing means 78, a turning travel judging means 80, and a turning travel stabilizing means 82 are added. Is different. Hereinafter, the difference will be mainly described.
[0038]
The acceleration decrease determination means 76, that is, the deceleration behavior determination means is used to determine the actual acceleration G of the vehicle._{t + 1}Is calculated from the amount of change in the vehicle speed, for example, and the acceleration G_{t + 1}And acceleration G calculated in the previous control cycle_tAnd difference (| G_{t + 1}-G_tBased on || exceeding a predetermined value, it is determined whether or not the acceleration of the vehicle has decreased, that is, whether or not the vehicle has decelerated. The second prime mover output increasing means 78 performs the acceleration after the direct assist by the low μ road assist control means 66 is executed and the driving force of the front wheels 20 is reduced by the first driving wheel driving force reducing means 70. When it is determined by the decrease determining means 76 that the acceleration of the vehicle has decreased, the output of the MG 28 is increased so as not to cause a sense of incongruity due to a change in acceleration and to prevent the slip of the rear wheel 34 from increasing extremely. . That is, the second prime mover output increasing means 78 is, for example, the throttle valve opening θ by the first driving wheel driving force reducing means 70._THThe assist torque of the MG 28 is corrected to increase in accordance with the decrease amount. Since the grip of the rear wheel 34 still exists, increasing the driving force of the rear wheel 34 eliminates the uncomfortable feeling of reduced acceleration due to the deceleration behavior.
[0039]
The turning traveling determination means 80 determines the turning traveling of the vehicle based on, for example, that the operation angle of the steering wheel, that is, the steering angle exceeds a predetermined criterion value. When the turning determination unit 80 determines that the vehicle is turning, the turning stabilization means 82 uses, for example, the throttle valve opening θ using the throttle actuator 43._THThe output of the engine 10 is suppressed by decreasing the fuel injection amount by a predetermined amount, or the front wheel 20 that is slipping is braked using the front wheel brake 44, and priority is given to suppression of the driving force of the front wheel 20 Run it. This is to suppress understeer so that the slip rate is within the turning range.
[0040]
FIG. 9 is a flow chart for explaining the operation corresponding to the control function shown in FIG. 8, which is a main part of the control operation of the motor control electronic control unit 46 in another embodiment of the present invention. In the low μ road slip traveling assist control routine shown in FIG. 9, compared with that shown in FIG. 7, SA20 and SA21 are provided between SA7 and SA8, and SA22 and SA23 are provided between SA10 and SA12. Is different in that it is provided. Hereinafter, the differences will be mainly described.
[0041]
Subsequent to SA7, at SA20 corresponding to the turning traveling determination means 80, the turning traveling of the vehicle is determined based on the steering angle of the steering wheel. If the determination at SA20 is negative, the electrical energy supplied from the generator 24 driven by the engine 10 to the MG 28 is controlled by the inverter 50 at SA8 corresponding to the low μ road assist control means 66. Based on the supply, low μ road direct assist control suitable for the low μ road is executed. However, if the determination at SA20 is affirmative, at the SA21 corresponding to the turning travel stabilization means 82, for example, the throttle valve opening θ using the throttle actuator 43 is used._THIs reduced by a predetermined amount, the output of the engine 10 is suppressed, that is, the driving force of the front wheels 20 is preferentially executed, and this routine is terminated. As a result, understeer that is likely to occur when the vehicle is turning on a low μ road is suitably suppressed.
[0042]
Further, after SA10, at SA22 corresponding to the acceleration reduction determination means 76, whether the acceleration of the vehicle has decreased based on the change in the actual acceleration G of the vehicle, that is, whether the deceleration behavior of the vehicle has occurred. Is determined. If the determination at SA22 is negative, it is determined at SA12 and thereafter whether or not the assist control end condition is satisfied as described above. However, if the determination at SA22 is affirmative, at SA23 corresponding to the second prime mover output increasing means 78, the throttle valve opening θ by the first drive wheel driving force reducing means 70 is obtained._THThe assist torque of the MG 28 is corrected to increase according to the decrease amount. For example, throttle valve opening θ_THThe greater the amount of decrease in is, the larger the correction is made and the driving force of the rear wheel 34 is increased, so that the uncomfortable feeling of acceleration reduction due to deceleration behavior is eliminated.
[0043]
As described above, according to this embodiment, in addition to the effects of the above-described embodiment, the acceleration of the vehicle after the driving force of the front wheels 20 is reduced by the first driving wheel driving force reducing means 70. If there is a decrease, the output of the MG 28 is corrected to be increased by the second prime mover output increasing means 78. Therefore, if there is a decrease in the acceleration of the vehicle after the driving force of the front wheels 20 is reduced, the accelerator pedal Even if is not operated, the output of the MG 28 is increased and the driving force of the vehicle is increased, so that the power performance of the vehicle is improved.
[0044]
Further, according to the present embodiment, the turning travel determination means 80 for determining the turning travel of the vehicle, and when the turning travel determination means 80 determines the turning travel of the vehicle, the driving force of the front wheels 20 is given priority. A turning traveling stabilization means 82 is provided for reducing the turning speed. For this reason, since the reduction of the output of the engine 10 or the reduction of the driving force of the front wheels 20 or the braking is preferentially performed during the turning of the vehicle, the slip of the wheels 20 during the turning of the vehicle is suppressed. Driving stability is improved.
[0045]
As mentioned above, although one Example of this invention was described based on drawing, this invention can be applied also in another aspect.
[0046]
For example, in the above-described embodiment, there is a so-called electric four-wheel drive vehicle based on the front wheel drive (FF) in which the front wheel 20 is driven by the engine 10 provided at the front portion of the vehicle and the rear wheel 34 is driven by the MG 28. Although it was used, an electric four-wheel drive vehicle that drives the front wheels 20 with the MG 28 based on the front engine rear wheel drive (FR), and the front wheels 20 to the MG 28 based on the rear engine rear wheel drive (RR). Alternatively, an electric four-wheel drive vehicle may be used.
[0047]
Further, in the vehicle of the above-described embodiment, the engine 10 and the MG 28 are provided as a plurality of prime movers. However, a prime mover provided with two motor generators, or a prime mover constituted by a combination of an engine and a motor, etc. There may be a thing provided in place of the engine 10 or the MG 28 with other types of prime movers having different operating principles such as those provided at a plurality of places, such as hydraulic motors. In addition, a power transmission device different from the above-described embodiment may be provided between the prime mover and the wheels as necessary.
[0048]
In addition, the generator 24 of the above-described embodiment is exclusively used as a generator, but may be operated as a motor that starts the engine 10 or a motor that outputs driving torque when the vehicle starts, An auxiliary machine such as an air conditioner compressor or a power steering oil pump may be connected to rotate while the engine 10 is stopped when the vehicle is stopped.
[0049]
Further, in the control routines of FIGS. 7 and 9 described above, a part of steps may be deleted, added, or modified within a range in which the above functions can be obtained.
[0050]
The above description is only an example of the present invention, and the present invention can be variously modified without departing from the gist of the present invention.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of a control device according to an embodiment of the present invention and a power transmission device of a vehicle to which the control device is applied.
2 is a diagram for explaining the operation of the electronic controller for traction control in FIG. 1. FIG.
3 is a diagram showing the operation of the electric motor controlled by the motor control electronic control device of FIG. 1, wherein a thick line indicates an assist torque generation period of the motor generator, and a double line indicates a regeneration period of the motor generator. Yes.
4 is a functional block diagram illustrating a main part of a control function of the motor control electronic control device of FIG. 1; FIG.
5 shows engine output torque T decreased due to generator driving in the direct assist by the direct charge assist control means at the time of storage shortage in FIG. 4;_EFIG.
FIG. 6 is a diagram for explaining a large initial torque, which is a torque characteristic of MG used in the power storage shortage direct assist control means of FIG. 4;
FIG. 7 is a flowchart for explaining a main part of the control operation of the electronic control device for motor control, and is a diagram for explaining an assist control routine at the time of low μ road slip running.
FIG. 8 is a functional block diagram for explaining a main part of a control function of a motor control electronic control device according to another embodiment of the present invention, corresponding to FIG.
9 is a flowchart for explaining a main part of the control operation for realizing the function of the embodiment of FIG. 8, and corresponds to FIG.
[Explanation of symbols]
10: Engine (first prime mover)
20: Front wheel (first drive wheel)
24: Generator (energy generating means)
28: MG (second prime mover)
34: Rear wheel (second drive wheel)
48: Capacitor (energy storage means)
60: First slip determination means
66: Low μ road assist control means (second drive wheel drive control means)
70: First driving wheel driving force reducing means (first driving force reducing means)

Claims (4)

A control device for a front and rear wheel drive vehicle, comprising: a first prime mover that drives a first drive wheel that is one of a front wheel and a rear wheel; and an electric motor that drives a second drive wheel that is the other of the front wheel and the rear wheel. ,
Slip detecting means for detecting slip of the first drive wheel driven by the first prime mover;
When slip of the first drive wheel is detected by the slip detection means, the energy obtained from the energy generation means driven by the first prime mover is supplied to the electric motor to drive the second drive wheel. Second drive wheel drive control means for making the front and rear wheel drive state;
If the slip of the first drive wheel is not resolved despite being in the front and rear wheel drive state by the second drive wheel drive control means, the first drive wheel drive that reduces the drive force of the first drive wheel Force control means and
And the first driving wheel driving force control means reduces the driving force of the first driving wheel based on a load state of the first prime mover by the energy generating means. Vehicle control device. A second prime mover output increasing means for increasing the output of the electric motor when there is a decrease in acceleration of the vehicle after the driving force of the first driving wheel is reduced by the first driving wheel driving force control means; The front and rear wheel drive vehicle control device according to claim 1 . A front and rear wheel drive vehicle control device comprising a first prime mover for driving a first drive wheel that is one of a front wheel and a rear wheel, and a second prime mover for driving a second drive wheel that is the other of the front wheel and the rear wheel. There,
Slip detecting means for detecting slip of the first drive wheel driven by the first prime mover;
When the slip detection means detects the slip of the first drive wheel, the energy obtained from the energy generation means driven by the first prime mover is supplied to the second prime mover to drive the second drive wheel. Second drive wheel drive control means for making the front and rear wheel drive state by
If the slip of the first driving wheel despite being the front-rear wheel driving state by the second drive wheel drive control means persists, first drive wheel Ru reduce the driving force of the first drive wheel When the driving force control means and the first driving wheel driving force control means reduce the driving force of the first driving wheel and then the acceleration of the vehicle decreases , the second driving motor increases the output of the second prime mover. A control apparatus for a front and rear wheel drive vehicle, comprising: a motor output increasing means. Turning determination means for determining turning of the vehicle;
A turning stabilization means for reducing the output of the first prime mover or braking a slipping wheel when the turning determination means determines that the vehicle is turning. The control device for a front and rear wheel drive vehicle according to claim 1 or 3 .

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