JP2005035475A - Controller of hybrid four-wheel driving vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller of a hybrid four-wheel driving vehicle which extends cruising distance as long as possible when the vehicle is moved back by four-wheel driving. <P>SOLUTION: The controller of the hybrid four-wheel driving vehicle includes a second motor operation control means 160 (S6 and S7) for restricting the output torque T<SB>RMG</SB>of an RMG 18 when the vehicle is moved back by four-wheel driving. Thus, power consumption by the RMG 18 is reduced, the cruising distance when the vehicle is moved back by four-wheel driving is extended as long as possible. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a control device for a hybrid four-wheel drive vehicle in which one of a front wheel and a rear wheel can be driven by an internal combustion engine and a first electric motor, and the other can be driven by a second electric motor. The present invention relates to a technique for extending the cruising distance during reverse travel.

  2. Description of the Related Art A control device for a hybrid four-wheel drive vehicle in which one of a front wheel and a rear wheel can be driven by an internal combustion engine and a first electric motor and the other can be driven by a second electric motor is known. For example, this is the control device for a four-wheel drive vehicle described in Patent Document 1. According to this control device for a four-wheel drive vehicle, the operation of the second electric motor is controlled based on the output torque region selected according to the traveling state of the vehicle, so that the traveling performance of the vehicle is improved as much as possible. Be made.

JP 2001-186603 A

  However, in the conventional technique, when the vehicle is reverse driven by four-wheel drive, the battery charge SOC is reduced by repeating the reverse drive for a relatively long time or when the vehicle is going uphill, so that the battery charge SOC is reduced. There was a possibility that performance could not be obtained. That is, there is a limit to the cruising distance when the vehicle is driven backward by four-wheel drive, and a technique for extending the cruising distance has been demanded.

  The present invention has been made in the background of the above circumstances, and the object of the present invention is to control a hybrid four-wheel drive vehicle capable of extending the cruising distance when the vehicle reverses by four-wheel drive as much as possible. Is to provide.

  In order to achieve such an object, the gist of the present invention is that the hybrid four-wheels in which one of the front wheels and the rear wheels can be driven by the internal combustion engine and the first motor and the other can be driven by the second motor. A drive vehicle control device includes a second motor operation control means for limiting the output torque of the second motor when the vehicle is moving backward.

  In this case, since the second motor operation control means for limiting the output torque of the second motor is included when the vehicle reverses, the power consumption by the second motor is reduced, and the cruising in the vehicle reverse by four-wheel drive is achieved. It is possible to provide a control device for a hybrid four-wheel drive vehicle capable of extending the distance as much as possible.

  Here, preferably, the second electric motor operation control means reduces the output torque of the second prime mover when the vehicle moves backward than when the vehicle moves forward. In this way, there is an advantage that the cruising distance can be extended as much as possible when the vehicle reverses by four-wheel drive in a practical manner.

  Preferably, the first electric motor cannot generate power when the vehicle is moving backward. In this manner, there is an advantage that the cruising distance can be extended as much as possible even when electric power is taken out from the battery by the first electric motor when the vehicle reverses by four-wheel drive.

  Preferably, the apparatus further includes slip determination means for determining whether or not the wheel slips between the traveling path of the vehicle, and the second motor operation control means has a positive determination of the slip determination means. Does not limit the output torque of the second electric motor. In this way, there is an advantage that sufficient four-wheel drive performance can be secured on a low μ road.

  Preferably, the second motor operation control means does not limit the output torque of the second motor when the outside air temperature is lower than a predetermined temperature. In this way, there is an advantage that sufficient four-wheel drive performance can be ensured when the outside air temperature is relatively low and the road surface is expected to freeze.

  Preferably, the second motor operation control means does not limit the output torque of the second motor when the accelerator opening is equal to or greater than a predetermined value. In this way, there is an advantage that sufficient four-wheel drive performance can be ensured when the driver intends to start the vehicle.

  Preferably, the second motor operation control means does not limit the output torque of the second motor when the rotational speed of the second motor is less than a predetermined value. In this way, there is an advantage that sufficient four-wheel drive performance can be ensured when the vehicle starts.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a skeleton diagram illustrating a configuration of a power transmission device 10 to which a control device for a hybrid four-wheel drive vehicle according to an embodiment of the present invention is applied. In this hybrid four-wheel drive vehicle, a front wheel system is driven by a main drive device 16 using an engine 12 and a motor generator (hereinafter referred to as MG) 14 as a driving force source, and a rear motor generator (hereinafter referred to as RMG) 18. This is a front and rear wheel drive vehicle of the type in which the rear wheel system is driven by the auxiliary drive device 20 using as a driving force source.

The main drive device 16 generates electric energy by receiving an engine 12 that is an internal combustion engine that generates driving force by combustion of a mixture of air and fuel, an electric motor that generates driving force by electric energy, and mechanical power. MG14 which is the 1st electric motor which functions selectively as a generator, double pinion type planetary gear unit 22, and continuously variable transmission 24 in which a gear ratio is changed continuously are provided. The engine 12 includes a throttle actuator 26 that drives the throttle valve in order to change the opening degree θ _TH of the throttle valve that controls the intake air amount of the intake pipe.

  The planetary gear device 22 is a combining / distributing mechanism that mechanically combines or distributes force, and is a three-rotating element that is independently rotatable about a common axis, that is, a damper device for the engine 12. 28, a sun gear 30 connected through the first clutch C1, a carrier 34 connected through the first clutch C1 to the input shaft 32 of the continuously variable transmission 24 and the output shaft of the MG 14, and a second clutch C2. And a ring gear 38 which is connected to the input shaft 32 of the continuously variable transmission 24 and to the housing 36 which is a non-rotating member via the brake B1. The carrier 34 supports a pair of pinions (planetary gears) 40 and 42 that mesh with the sun gear 30 and the ring gear 38 and mesh with each other so that the pinions 40 and 42 can rotate. The first clutch C1, the second clutch C2, and the brake B1 are all engaged when a plurality of friction plates stacked on each other are pressed by a hydraulic actuator, or released by releasing the press. It is a hydraulic friction engagement device.

  The MG 14 connected to the planetary gear unit 22 and the carrier 34 is driven so that the reaction force, which is the rotational driving torque of the MG 14, increases sequentially in the operating state of the engine 12, that is, the rotating state of the sun gear 30. Thus, an electric torque converter (ETC) device that smoothly increases the number of rotations of the ring gear 38 to enable smooth start acceleration of the vehicle is configured. At this time, assuming that the gear ratio ρ (the number of teeth of the sun gear 30 / the number of teeth of the ring gear 38) of the planetary gear unit 22 is 0.5, which is a general value, for example, the torque of the ring gear 38: the torque of the carrier 34 : The torque of the sun gear 30 = 1 / ρ: (1-ρ) / ρ: From the relationship, the torque of the engine 12 is amplified 1 / ρ times, for example, 2 times, and transmitted to the continuously variable transmission 24. Therefore, it is called a torque amplification mode.

  The continuously variable transmission 24 is wound around a pair of variable pulleys 46 and 48 having variable effective diameters provided on the input shaft 32 and the output shaft 44, respectively, and the pair of variable pulleys 46 and 48. An endless annular transmission belt 50 is provided. The pair of variable pulleys 46 and 48 form a V-groove between the fixed rotating bodies 52 and 54 fixed to the input shaft 32 and the output shaft 44, respectively, and the fixed rotating bodies 52 and 54. Movable rotating bodies 56 and 58 that are movable in the axial direction with respect to the input shaft 32 and the output shaft 44 and that are not relatively rotatable around the axial center, and thrust is applied to the movable rotating bodies 56 and 58. A pair of hydraulic cylinders 60 and 62 that change the transmission gear ratio γ (= input shaft rotational speed / output shaft rotational speed) by changing the engagement diameter, that is, the effective diameter of the variable pulleys 46 and 48 are provided.

  Torque output from the output shaft 44 of the continuously variable transmission 24 is transmitted to a pair of front wheels 70 via a speed reducer 64, a differential gear device 66, and a pair of axles 68. . The sub-drive device 20 includes an RMG 18 that is an electric motor that generates a driving force by electric energy and a second electric motor that selectively functions as a generator that receives electric power and generates electric energy. The output torque is transmitted to a pair of rear wheels 78 via a speed reducer 72, a differential gear device 74, and a pair of axles 76. In this embodiment, a steering device that changes the rudder angle of the pair of front wheels 70 is omitted.

  FIG. 2 is a diagram illustrating the configuration of a control device provided in the power transmission device 10. Each of the engine control device 100, the shift control device 102, the hybrid control device 104, the power storage control device 106, and the brake control device 108 shown in FIG. 2 is a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface, and the like. The CPU performs various controls by processing the input signal according to a program stored in the ROM in advance while utilizing the temporary storage function of the RAM. In addition, these control devices are connected so as to be able to communicate with each other, and when a necessary signal is requested from a predetermined control device, the control device is appropriately transmitted from the other control device to the predetermined control device. ing.

  The engine control device 100 performs drive control of the engine 12. For example, a fuel injection valve (not shown) is controlled for fuel injection amount control, an igniter (not shown) is controlled for ignition timing control, and the traction control is performed so that the pair of front wheels 70 that are slipping grip the road surface. In order to temporarily reduce the output of the engine 12, the throttle actuator 26 is controlled.

For example, the transmission control device 102 determines the actual transmission ratio γ and the transmission torque, that is, the engine 12 based on a relationship set in advance so that the tension of the transmission belt 50 of the continuously variable transmission 24 becomes a necessary and sufficient value. And a pressure regulating valve for regulating the belt tension pressure based on the output torques T _E and T _MG of the _MG 14 to control the tension of the transmission belt 50 to an optimum value, and the engine 12 has a minimum fuel consumption rate curve or an optimum curve. From the relationship stored in advance so that the target speed ratio γ is based on the actual vehicle speed V and the engine load, for example, the throttle valve opening θ _TH expressed as the accelerator opening θ or the accelerator pedal operation amount A _CC. determining the _m, actual gear ratio gamma controls the speed ratio gamma of the continuously variable transmission 24 so as to match the target speed ratio gamma _m.

Further, the engine control device 100 and the speed change control device 102 are arranged so that the operating point of the engine 12, that is, the operating point moves along the best fuel consumption operating line shown in FIG. And the gear ratio γ of the continuously variable transmission 24 is changed. Further, in response to a command from the hybrid control unit 104, the change of the throttle actuator 26 and the speed ratio γ in order to change the output torque T _E or the rotational speed N _E of the engine 12, the operating point of the engine 12 Move.

The hybrid control device 104 controls an inverter 112 that controls a drive current supplied to the MG 14 from a power storage device (battery) 110 including a battery or a capacitor, or a power generation current output from the MG 14 to the power storage device 110. An MG control device 114 and an RMG control device 118 for controlling an inverter 116 for controlling a drive current supplied from the power storage device 110 to the RMG 18 or a generated current output from the RMG 18 to the power storage device 110. A signal representing an operation position P _SH of a shift lever (not shown) supplied from the shift position sensor 120, a signal representing an accelerator opening θ (an operation amount A _CC of the accelerator pedal 122), a vehicle speed V, and the power storage device 110 Based on the storage amount SOC, for example, as shown in FIG. Performs any one selected from among several operation modes, the accelerator opening theta, based on the operation amount B _F of the brake pedal 124, to generate a regenerative braking force by the torque required for power generation of the MG14 or RMG18 A torque regenerative braking mode or an engine braking mode for generating a braking force by the rotational resistance torque of the engine 12 is selected. The signal representing the accelerator opening theta, a signal representative of the outside air temperature _{T OA} supplied from outside air temperature sensor 126, and based on the rotational speed _{N RMG} like the RMG18, RMG18 of the vehicle during backward by 4-wheel drive Output torque control is executed.

  In the operation mode selection control by the hybrid control device 104, when the shift position is in the B range or the D range, for example, in a relatively low load start or constant speed travel, the motor travel mode is selected and the first clutch C1 is engaged. When the second clutch C2 and the brake B1 are released together, the vehicle is driven exclusively by the MG 14. In this motor travel mode, when the storage amount SOC of the power storage device 110 falls below a preset lower limit value, or when the engine 12 is started to require more driving force. Is switched to an ETC mode or a direct connection mode, which will be described later, and the MG 14 or RMG 18 is driven while maintaining the traveling so far, and the power storage device 110 is charged by the MG 14 or RMG 18.

Further, in the comparatively medium load traveling or the high load traveling, the direct connection mode is selected, the first clutch C1 and the second clutch C2 are both engaged, and the brake B1 is released, so that the planetary gear device 22 is integrated. And the vehicle is driven exclusively by the engine 12 or by the engine 12 and the MG 14, or the vehicle is exclusively driven by the engine 12, and at the same time, the MG 14 charges the power storage device 110. In this direct mode, the rotation speed that is, the engine rotational speed N _E of the sun gear 30, the rotational speed N _MG rotational speed i.e. the MG14 carrier 34, the ring gear 38 rpm i.e. the input shaft 32 of the continuously variable transmission 24 Since the rotational speed N _IN is the same value, three rotational speed axes (vertical axes), that is, a sun gear rotational speed axis S, a ring gear rotational speed axis R, a carrier rotational speed axis C, and a gear ratio axis in a two-dimensional plane. In the collinear diagram of FIG. 5 drawn from (horizontal axis), for example, it is shown by a one-dot chain line. In FIG. 5, the distance between the sun gear rotational speed axis S and the carrier rotational speed axis C is 1, and the distance between the ring gear rotational speed R and the carrier rotational speed axis C is the gear ratio ρ of the planetary gear unit 22. It corresponds to.

Further, for example, in start acceleration running, the ETC mode, that is, the torque amplification mode is selected, the second clutch C2 is engaged, and both the first clutch C1 and the brake B1 are released, and the power generation amount (regeneration amount) of the MG 14 ) that is, by the reaction force of the MG 14 (the drive torque for rotating the MG 14) is gradually increased, the vehicle is allowed to smoothly started in a state where the engine 12 is maintained at a predetermined rotational speed N _E. In this way, when the vehicle and the MG 14 are driven by the engine 12, if the torque of the engine 12 is 1 / ρ times, for example, ρ = 0.5, the torque is amplified twice and the steplessly It is transmitted to the transmission 24. That is, when the rotation speed N _MG of the MG14 is a point A in FIG. 5 (a negative rotational speed, that the power generating state), the vehicle since the input shaft speed N _IN is zero of the continuously variable transmission 24 Although it is stopped, as shown by the broken line in FIG. 5, the continuously variable transmission is generated as the amount of power generated by the MG 14 is increased and the rotational speed N _MG is changed to the B point on the positive side. 24 input shaft speed N _iN is being increased, and it is the vehicle is allowed to start.

  When the shift position is the N range or the P range, the neutral mode 1 or 2 is basically selected, the first clutch C1, the second clutch C2, and the brake B1 are all released, and the planetary gear unit 22 The transmission path is released. In this state, when the charged amount SOC of the power storage device 110 falls below a preset lower limit value and becomes insufficient, the charging / engine start mode is set and the brake B1 is engaged. The engine 12 is started by the MG 14.

  When the shift position is in the R range, for example, in the light load reverse travel, the motor travel mode is selected, and the first clutch C1 is engaged and the second clutch C2 and the brake B1 are both disengaged. This causes the vehicle to travel backward. However, for example, in medium load or high load reverse travel, the friction travel mode is selected, the first clutch C1 is engaged, the second clutch C2 is released, and the brake B1 is slip-engaged. Thereby, the output torque of the engine 12 is added to the output torque of the MG 14 as a driving force for moving the vehicle backward. When the vehicle is moving backward, charging of the power storage device 110, that is, power generation by the MG 14 or RMG 18 is not executed.

  Further, the hybrid control device 104 operates the RMG 18 according to a predetermined driving force distribution ratio in order to temporarily increase the driving force of the vehicle when the vehicle starts or suddenly accelerates due to the driving force of the pair of front wheels 70. In addition, the vehicle start capability is improved during high μ road assist control for generating driving force from the pair of rear wheels 78 and when starting on low friction coefficient roads (low μ roads) such as frozen roads and snow-capped roads. In order to increase the driving force, the RMG 18 drives the pair of rear wheels 78, and at the same time, for example, low μ road assist control that reduces the gear ratio γ of the continuously variable transmission 24 to reduce the driving force of the pair of front wheels 70. Four-wheel drive control is executed.

The accumulator controller 106, when the electricity storage amount SOC of the electric storage device 110 falls below the lower limit SOC _D that is set in advance, charge or energy storage of the electric storage device 110 by the electric energy generated by the MG14 or RMG18 while, when the electricity storage amount SOC is exceeded the preset upper limit SOC _U prohibits be charged by electrical energy from the MG14 or RMG18. Also, in this power storage, the range between the temperature T function is a power or acceptance limit value of the electric energy W _IN and the draw limit value W _OUT of _B of the electric storage device 110, the actual power estimated value P _b ( = Generated power P _MG + Power consumption P _RMG ), the acceptance or take-out is prohibited.

The brake control device 108 executes, for example, TRC control, ABS control, VSC control, etc., in order to increase the stability of the vehicle during start running, braking, and turning on a low μ road or the like, or increase traction force. A wheel brake 130 provided on each wheel, that is, the pair of front wheels 70 and rear wheels 78 is controlled via a hydraulic brake control circuit 128. For example, in TRC control, based on a signal from a wheel rotational speed sensor (not shown) provided on each wheel, the wheel vehicle speed (the vehicle speed converted based on the wheel rotational speed), for example, the right front wheel vehicle speed V _FR , the left front wheel wheel Vehicle speed V _FL , right rear wheel speed V _RR , left rear wheel speed V _RL , front wheel speed V _F (= {V _FR + V _RL } / 2), rear wheel speed V _R (= {V _RR + V _RL } / 2), and the vehicle body speed _{V (V FR, V FL,} V RR, while calculating the slowest speed) of the _{V RL,} slip speed ΔV is the difference between the front wheel vehicle speed _{V F} and the rear wheel speed _{V R} Exceeds the preset control start judgment reference value ΔV ₁ , the pair of front wheels 70 are judged to slip, and the slip ratio R _S (= {ΔV / V _F } × 100%) is set in advance. To be within the rate R _S1 The driving force of the pair of front wheels 70 is reduced using the throttle actuator 26, the wheel brake 130, and the like. In the ABS control, the braking force of each wheel is maintained using the wheel brake 130 so that the slip rate of each wheel is within a predetermined target slip range during braking operation, thereby improving the directional stability of the vehicle. Increase. Further, in the VSC control, when the vehicle is turning, the vehicle oversteer is based on a steering angle from a steering angle sensor (not shown), a yaw rate from a yaw rate sensor, longitudinal acceleration and lateral (lateral) acceleration from a biaxial G sensor, and the like. The throttle actuator 26 and the wheel brake 130 are controlled so as to determine a tendency or an understeer tendency and suppress the oversteer or understeer.

FIG. 6 is a functional block diagram illustrating a main part of control functions of the hybrid control device 104 and the like during four-wheel drive. The shift position determination means 150 shown in FIG. 6 determines whether or not the shift position is in the R range from a signal representing the operation position P _SH of a shift lever (not shown) supplied from the shift position sensor 120. That is, it is determined whether or not the vehicle is moving backward. The slip determination unit 152 determines whether or not the wheel slips between the traveling path of the vehicle. For example, as in the above-described TRC control, it is determined whether or not the pair of front wheels 70 slips between the traveling path of the vehicle. That is, it is determined whether or not the vehicle traveling path is a low friction coefficient road surface, that is, a low μ road, on which slip is likely to occur between wheels. The outside air temperature determining means 154 determines whether or not the outside air temperature _TOA is _lower than a predetermined temperature T ₁ (for example, 5 ° C.) from the signal representing the outside air temperature _TOA supplied from the outside air temperature sensor 126. The accelerator opening determination means 156 determines whether or not the accelerator opening θ corresponding to the accelerator pedal operation amount _ACC or the throttle valve opening θ _TH is equal to or greater than a predetermined value θ ₁ (for example, 75%). The second motor rotation speed determination means 158 determines whether or not the absolute value of the rotation speed N _RMG of the _RMG 18 is less than a predetermined value N ₁ (for example, −200 rpm).

The second motor operation control means 160 limits the output torque TRMG of the _RMG 18 when the determination of the shift position sensor 120 is affirmed during four-wheel drive, that is, when the vehicle is moving backward. Preferably, when the vehicle travels forward the output torque _{T RMG} of the RMG18 when the vehicle backward is reduced by a predetermined value _{T CU} than (normal), for example, it is limited to be about -50 nm. Preferably, when a relatively large driving force is required for the pair of rear wheels 78, that is, the slip determination means 152, the outside air temperature determination means 154, the accelerator opening determination means 156, and the second motor rotation speed determination. When at least one determination of the means 158 is affirmed, the output torque TRMG of the _RMG 18 is not particularly limited, and normal torque control is executed.

  FIG. 7 is a flowchart for explaining a main part of the output torque control operation of the RMG 18 by the hybrid control device 104 or the like during four-wheel drive, and is repeatedly executed with a very short cycle time of about several milliseconds to several tens of milliseconds. Is.

First, in step (hereinafter, step is omitted) S1 corresponding to the shift position determination means 150, it is determined whether or not the shift position is in the R range. If the determination in S1 is negative, in S7, the routine is terminated after normal torque control in which the output torque TRMG of the _RMG 18 is not particularly limited is executed, but the determination in S1 is affirmed. In S2 corresponding to the slip determination means 152, it is determined whether or not the wheel slips between the traveling path of the vehicle (there is a slip history within a predetermined time). If the determination in S2 is affirmative, the routine is terminated after the normal torque control described above is executed in S7, but if the determination in S2 is negative, the outside air temperature determination in S3 corresponding to the means 154, the outside air temperature _{T OA} is equal to or lower than the predetermined temperature _{T 1} is is determined. If the determination in S3 is affirmative, the routine is terminated after the normal torque control described above is executed in S7, but if the determination in S3 is negative, the accelerator opening degree is determined. in S4 corresponding to the determining means 156, accelerator opening theta whether a predetermined value theta ₁ or more is determined. If the determination in S4 is affirmative, the routine is terminated after the normal torque control described above is executed in S7. If the determination in S4 is negative, the second motor in S5 corresponding to the rotational speed determining means 158, the rotational speed _{N RMG} of the RMG18 whether is less than the predetermined value _{N 1} is determined. If the determination in S5 is affirmative, the routine is terminated after the normal torque control described above is executed in S7. If the determination in S5 is negative, the routine proceeds to S6. After the output torque T _{RMG of the RMG} 18 is reduced by a predetermined value T _CU than when the vehicle is moving forward (normal time), this routine is terminated. In the above control, S6 and S7 correspond to the second motor operation control means 160.

As described above, according to the present embodiment, since the second motor operation control means 160 (S6 and S7) for limiting the output torque TRMG of the _RMG 18, which is the second motor, is included when the vehicle moves backward, the consumption by the RMG 18 It is possible to provide a control device for a hybrid four-wheel drive vehicle in which electric power is reduced and the cruising distance can be extended as much as possible when the vehicle reverses by four-wheel drive.

Further, the second electric motor operation control means 160, for the output torque T _RMG of the RMG18 when the vehicle backward than when the vehicle travels forward is intended to reduce the predetermined value T _CU, by 4-wheel drive in a practical embodiment There is an advantage that the cruising distance when the vehicle moves backward can be extended as much as possible.

  Further, since the MG 14, which is the first electric motor, cannot generate electricity when the vehicle reverses, the cruising distance can be increased even when electric power is taken out from the power storage device 110 by the MG 14 when the vehicle reverses by four-wheel drive. There is an advantage that it can be extended as much as possible.

Further, it includes slip determination means 152 (S2) for determining whether or not the wheel slips between the traveling path of the vehicle, and the second motor operation control means 160 is positively determined by the slip determination means 152. In this case, since the output torque TRMG of the _RMG 18 is not limited, there is an advantage that sufficient four-wheel drive performance can be secured on a low μ road.

Further, the second electric motor operation control means 160, because when the outside air temperature _{T OA} is lower than the predetermined temperature _{T 1} of is not to limit the output torque _{T RMG} of the RMG18, outside air temperature _{T OA} is relatively low There is an advantage that sufficient four-wheel drive performance can be ensured when the road surface is expected to freeze.

Further, the second electric motor operation control means 160, since when the accelerator opening theta is the predetermined value theta ₁ or more is not to limit the output torque T _RMG of the RMG18, there is the vehicle start intention of the driver In this case, there is an advantage that sufficient four-wheel drive performance can be secured.

Further, the second electric motor operation control means 160, since the rotational speed _{N RMG} of the RMG18 is not to limit the output torque _{T RMG} that RMG18 if is less than the predetermined value _{N 1,} sufficient when the vehicle start 4 wheel drive performance can be secured, and there is an advantage that it is possible to avoid the vehicle starting failure due to the slip of the pair of front wheels 70.

  The preferred embodiments of the present invention have been described in detail with reference to the drawings. However, the present invention is not limited to these embodiments, and may be implemented in other modes.

  For example, in the above-described embodiment, the pair of front wheels 70 is driven by the main drive device 16 including the engine 12 and the MG 14, and the pair of rear wheels 78 is driven by the auxiliary drive device 20 including the RMG 18. However, the present invention is applied to a type of power transmission device in which the main drive device 16 drives the pair of rear wheels 78 and the auxiliary drive device 20 drives the pair of front wheels 70. It doesn't matter.

  In the above-described embodiment, the RMG 18 as the second electric motor is a motor generator that selectively functions as an electric motor that generates a driving force by electric energy and a generator that generates electric energy by receiving mechanical power. However, it may be an electric motor that functions only as an electric motor that generates driving force exclusively by electric energy.

  In the above-described embodiment, the power transmission device 10 includes the continuously variable transmission 24 in the power transmission path. However, the planetary gear type or the constantly meshing parallel twin-axis stepped transmission is used. It may be provided with.

  Further, in the above-described embodiment, the output torque control of the RMG 18 shown in FIGS. 6 and 7 is executed by the hybrid control device 104, but such control is executed by another control device. It doesn't matter.

  In addition, although not illustrated one by one, the present invention is implemented with various modifications within a range not departing from the gist thereof.

1 is a skeleton diagram illustrating a configuration of a power transmission device to which a drive device of a hybrid four-wheel drive vehicle that is an embodiment of the present invention is applied. FIG. It is a figure explaining the structure of the control apparatus provided in the power transmission device of FIG. FIG. 4 is a diagram showing a best fuel consumption rate curve which is a target of an engine operating point controlled by the control device of FIG. 3. 4 is a chart showing control modes selected by the hybrid control device of FIG. 3. It is a collinear diagram explaining the operation of the planetary gear device in the ETC mode controlled by the hybrid control device of FIG. It is a functional block diagram explaining the principal part of control functions, such as the hybrid control apparatus of FIG. 4 is a flowchart for explaining a main part of an RMG output torque control operation during four-wheel drive by the hybrid control device of FIG. 3 or the like.

Explanation of symbols

12: Engine (internal combustion engine)
14: Motor generator (first electric motor)
18: Rear motor generator (second electric motor)
70: Front wheel
78: Rear wheel (wheel)
152: Slip determination means 160: Second motor operation control means

Claims (7)

A control device for a hybrid four-wheel drive vehicle in which one of a front wheel and a rear wheel can be driven by an internal combustion engine and a first electric motor, and the other can be driven by a second electric motor,
A control device for a hybrid four-wheel drive vehicle, comprising: second motor operation control means for limiting an output torque of the second motor when the vehicle is moving backward. 2. The control device for a hybrid four-wheel drive vehicle according to claim 1, wherein the second motor operation control means reduces the output torque of the second prime mover when the vehicle is moving backward than when the vehicle is moving forward. 3. The control device for a hybrid four-wheel drive vehicle according to claim 1, wherein the first electric motor cannot generate power when the vehicle moves backward. Slip determining means for determining whether or not the wheel slips between the traveling path of the vehicle and the second electric motor operation control means is configured such that when the determination of the slip determining means is affirmed, The control device for a hybrid four-wheel drive vehicle according to any one of claims 1 to 3, wherein the output torque is not limited. The control device for a hybrid four-wheel drive vehicle according to any one of claims 1 to 4, wherein the second motor operation control means does not limit the output torque of the second motor when the outside air temperature is lower than a predetermined temperature. . The hybrid four-wheel drive vehicle control system according to any one of claims 1 to 5, wherein the second motor operation control means does not limit the output torque of the second motor when the accelerator opening is equal to or greater than a predetermined value. apparatus. The hybrid four-wheels according to any one of claims 1 to 6, wherein the second motor operation control means does not limit the output torque of the second motor when the rotation speed of the second motor is less than a predetermined value. Control device for driving car.

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