JP2008094123A - Vehicle controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a sound or vibration due to the rotation of a motor for selectively driving a wheel, and to extend the operating range of the motor. <P>SOLUTION: This four-wheel drive control system 50 for controlling the traveling of a four-wheel drive vehicle, equipped with front wheels 11 and 12 to be driven by an engine 20; rear wheels 14 and 15 to be driven by a motor 30 for operating with a power obtained by a power generator 31 exclusively for driving to be driven by the engine 20; and an electromagnetic clutch 34 for controlling the transmission/interruption of a power obtained by the motor 30 to the rear wheels 14 and 15, is configured so as to hold an electromagnetic clutch 34, in a fastened state within a predetermined time, after starting control so as to stop the driving of the motor 30. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle control device that drives and controls a four-wheel drive vehicle that drives main drive wheels with power obtained by an internal combustion engine and drives slave drive wheels with power obtained by an electric motor.

  Conventionally, as this type of technology, for example, those described in the following documents are known (see Patent Documents 1 and 2). Among these, in Patent Document 1, when a wheel different from the wheel driven by the power of the internal combustion engine is driven by the electric power of the electric motor, the output of the generator driven by the power of the internal combustion engine is supplied to the electric motor. A technique is disclosed in which output from a generator driven by the power of the internal combustion engine to the motor is stopped when a wheel different from the wheel driven by the power of the internal combustion engine is not driven by the electric power of the motor. Yes.

  On the other hand, in Patent Document 2, when a wheel different from a wheel driven by the power of the internal combustion engine is switched from a state driven by the electric power of the electric motor to a state not driven, the wheel driven by the power of the internal combustion engine. A technology that opens the clutch in a state where the motor-side acceleration and the wheel-side acceleration are almost the same, that is, in a torque state in which the electric force is zero, by interposing a clutch between the wheel and the electric power transmission path to the motor different from Is disclosed.

Further, in this technique, when a wheel different from a wheel driven by the power of the internal combustion engine is switched from a state where the wheel is not driven by the electric force of the electric motor to a state where the wheel is driven, The motor is driven so that the motor-side acceleration and the wheel-side acceleration substantially coincide with each other, and the clutch is engaged when they substantially coincide.
Japanese Patent Laid-Open No. 7-231508 JP 2004-88928 A

  In the above conventional vehicle control device, when the clutch interposed in the electric power transmission path between the electric motor and the wheel is released (non-engaged) from the engaged state, the electric motor has substantially the same rotational speed as the wheel side of the clutch. Since the motor is rotating, the electric motor loses its load by releasing the clutch, and the inertial force sometimes causes the rotation to continue and idle. When such rotation occurs, there is a possibility that sound and vibration may be generated from the electric motor and the mounting source. In addition, the bearings of the electric motor are worn and deterioration is accelerated, and when the electric motor is a brushed electric motor, the deterioration of the motor brush is also promoted.

  However, the above-mentioned patent document did not specify a technique for stopping such rotation.

  As a method for stopping the rotation of the motor due to no load, for example, a control in which a short-circuit current is generated in the armature and the rotation is stopped by the magnetic field, so-called motor (short-circuit) brake control is known. However, when the short-circuit current is passed through the armature, the motor generates heat or a high voltage is generated, and thus the above control may not be possible.

  In addition, when the clutch is reengaged after the clutch is changed from the engaged state to the non-engaged state due to a request for driving force to the driven wheels, there is a large difference in rotational speed between the motor side and the driven wheel side of the clutch. If it exists, it is necessary to synchronize the rotation speed of the motor side of a clutch and the driven wheel side by idling an electric motor. However, it is extremely difficult to control the rotational speed of the motor while the clutch is disengaged and the motor is idling in a no-load state, and much time is required for convergence of the synchronous rotational speed. For this reason, there has been a problem that it is difficult to widen the driving operation region of the electric motor.

  Therefore, the present invention has been made in view of the above, and an object of the present invention is to mitigate noise and vibration caused by rotation of an electric motor that selectively drives a wheel, and to set an operation driving area of the electric motor. The object is to provide an expanded vehicle control device.

  In order to achieve the above object, an invention according to claim 1 is a slave drive driven by an electric motor operating with electric power obtained by a main drive wheel driven by an internal combustion engine and a generator driven by the internal combustion engine. In a vehicle control device for controlling traveling of a four-wheel drive vehicle comprising a drive wheel and a clutch that transmits / cuts off the power obtained by the electric motor to the slave drive wheel by being engaged or disengaged. And motor control means for controlling driving / stopping of the electric motor, and clutch control means for holding the clutch in an engaged state after starting control for stopping the driving of the electric motor by the motor control means. And

  According to the first aspect of the present invention, when the driven wheel is decelerating, the electric motor can quickly reduce the rotational speed in synchronization with the rotation of the driven wheel. Thereby, generation | occurrence | production of the sound and vibration resulting from rotation of an electric motor can be reduced.

  According to a second aspect of the present invention, in the vehicle control device according to the first aspect, the clutch control means holds the clutch in an engaged state when a preset operation requirement of the electric motor is satisfied. It is characterized by that.

  According to the second aspect of the present invention, it is possible to prevent the motor from overheating, the deterioration of the motor due to the generation of a high voltage, and the malfunction of the vehicle control device.

  According to a third aspect of the present invention, in the vehicle control device according to the first or second aspect, the electric motor control unit restarts the electric motor after the electric motor control unit starts a control for stopping the driving of the electric motor by the electric motor control unit. Re-estimating means for estimating whether or not the motor is re-established, and the clutch control means holds the clutch in an engaged state when the re-driving estimating means estimates that the motor is re-driven. It is characterized by doing.

  According to the third aspect of the present invention, when it is estimated that the electric motor is re-driven, it is not necessary to control the clutch to engage the motor and the rotational speed of the driven wheel. . As a result, the vehicle can be quickly shifted to the four-wheel drive state.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS The best embodiment for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of a four-wheel drive vehicle equipped with a vehicle control apparatus according to Embodiment 1 of the present invention. In FIG. 1, a front wheel axle 13 serving as a first axle is rotatably supported on the front side of a vehicle body 10 in a four-wheel drive vehicle 100. Front wheels 11 and 12 are attached to both ends of the front wheel axle 13. A front wheel differential gear 23 that is a differential power transmission mechanism is provided at the center of the front wheel axle 13.

  In the front wheels 11 and 12, the rotational power of the engine 20, which is an internal combustion engine, is shifted by an automatic transmission including a torque converter 21 and a transmission mechanism 22 and transmitted to the front wheel side differential gear 23, and the front wheel side differential gear is transmitted. By being transmitted from 23 to the front wheel axle 13, it is driven in the entire traveling range of the vehicle.

  That is, the power system including the automatic transmission including the engine 20, the torque converter 21 and the transmission mechanism 22 and the front wheel side differential gear 23 has the same configuration as a so-called front wheel drive vehicle, and constitutes the main drive system. is doing. The automatic transmission may be either multi-stage or continuously variable.

  A rear wheel axle 16 serving as a second axle is rotatably supported on the rear side of the vehicle body 10. Rear wheels 14 and 15 are attached to both ends of the rear wheel axle 16. A rear wheel differential gear 35 that is a differential power transmission mechanism is provided at the center of the rear wheel axle 16.

  In the rear wheels 14 and 15, the rotational power of the electric motor 30 is decelerated by the speed reducer 33 and is transmitted to the rear wheel side differential gear 35 through the electromagnetic clutch 34, and is transmitted from the rear wheel side differential gear 35 to the rear wheel axle 16. Thus, the vehicle is driven during a part of the vehicle travel, for example, from the start of the vehicle until the travel speed is reached by driving only the front wheels 11 and 12 (only driving the engine 20). The rear wheels 14 and 15 are also driven when a slip occurs on the front wheels 11 and 12. That is, the power system composed of the electric motor 30, the speed reducer 33, the electromagnetic clutch 34, and the rear wheel side differential gear 35 constitutes a slave drive system. The reduction gear 33 and the electromagnetic clutch 34 may be provided integrally with the rear wheel side differential gear 35.

  The engine 20 is mechanically coupled with a drive generator 31 that exclusively generates electric power consumed by the electric motor 30. It operates by receiving the rotational power of the engine 20 and generates electric power according to the driving state of the vehicle. The drive generator 31 is disposed in the engine room together with the engine 20. The drive generator 31 is mechanically coupled to the engine 20 by a single pulley belt 25 being hung between the pulley 24 of the engine 20 and the pulley 32 of the drive generator 31. Can receive the power of

  In the present embodiment, since the drive-dedicated generator 31 is provided as a drive power source for the electric motor 30, a dedicated large-capacity battery for driving the electric motor 30 is not mounted, and the in-vehicle space can be used effectively accordingly. . In other words, the vehicle-mounted space for the drive-only battery for the electric motor 30 can be eliminated. In addition, in this embodiment, a large and expensive device such as a propeller shaft is not required as compared with a conventional mechanical four-wheel drive vehicle (a vehicle in which front and rear wheels are driven by an engine). In this embodiment, the power system of the rear wheels can be configured easily and inexpensively.

  The electric motor 30 is composed of, for example, a field winding type AC electric motor, is installed in a narrow space under the floor from the rear seat of the vehicle to the trunk room, and is arranged in the vicinity of the rear wheel side differential gear 35. In the present embodiment, a case where a field winding type AC motor is used as the motor 30 will be described as an example. In addition, as the electric motor 30, you may use the direct current machine provided with the field winding in the stator (field).

  When an AC motor is used, an inverter device (converter that converts DC power into AC power) is provided for driving the AC motor, and the DC power output from the drive generator 31 is the same as that of the AC motor. It is directly supplied to an electric motor unit equipped with an inverter device, and is directly input to the input side (DC side) of the inverter device. By using this electric motor, a driving force larger than that of the DC electric motor can be output. Moreover, the output of the rotation speed higher than a direct current motor can be output, and a rear wheel can be driven to the traveling speed larger than the time of a direct current motor.

  Inside the four-wheel drive vehicle 100, a plurality of in-vehicle control devices including a four-wheel drive control device 50, an engine control device 51, a transmission control device 52, and an antilock brake system control device 53 are provided. The plurality of in-vehicle control devices are electrically connected by an in-vehicle communication network (not shown), and are configured to be able to share information owned by each control device with each other by signal transmission.

  The engine control device 51 controls the power output from the engine 20 by controlling the operation of engine devices such as a throttle valve and a fuel injection valve mounted on the engine 20. The transmission control device 52 is for controlling the operation of the transmission mechanism 22 of the automatic transmission to control the power transmitted from the automatic transmission to the front wheel side differential gear 23. The anti-lock brake system control device 53 controls the braking force of the front wheels 11 and 12 and the rear wheels 14 and 15, and operates an anti-lock brake system (not shown) that avoids locking of each wheel due to strong depression of the brake pedal. Is for controlling.

  The four-wheel drive control device 50 controls the operation of the voltage regulator of the drive-only generator 31 and controls the field winding of the drive-only generator 31 from the battery, the on-vehicle electrical generator 40, or a part of the self-generated power generation current. A function for controlling the field current supplied to the wire and controlling the power output from the in-vehicle electrical generator 40 and the operation of the H-bridge circuit or half-bridge circuit to control the battery or in-vehicle electrical power generation The function for controlling the field current supplied from the machine 40 to the field winding of the electric motor 30 and the excitation supplied from the battery or the on-vehicle electrical generator 40 to the excitation coil by controlling the operation of the voltage regulator And a function for controlling the current and controlling the engagement state (complete engagement, slip engagement, disengagement (release)) of the electromagnetic clutch 34.

  Further, in the four-wheel drive control device 50, an accelerator opening signal, which is a driver's request value for the vehicle, is sent from the engine control device 51, and an A / T shift signal indicating the position of the shift lever is sent from the transmission control device 52. Wheel speed signals indicating wheel speed values of the front wheels 11 and 12 and the rear wheels 14 and 15 are input from the antilock brake system control device 53, respectively. The four-wheel drive control device 50 calculates control values necessary for controlling each control target of the drive-only generator 31, the motor 30, and the electromagnetic clutch 34 based on these input signals, and responds to each control target. Output control value (control signal). In the control value calculation, in addition to the calculation with respect to the control target, whether or not the rotating electric motor 30 to be described later is allowed to perform motor brake control based on the input signal, and whether or not there is a possibility of driving again after the motor driving is finished. Is also estimated.

  Next, with reference to the flowchart of FIG. 2, a procedure for driving and controlling the electric motor 30 will be described.

  In FIG. 2, first, based on the input signal to the four-wheel drive control device 50, the drive determination of the motor 30 is performed, and the motor drive request is made (step S101). The drive determination of the electric motor 30 is performed by, for example, inputting wheel speed signals indicating the wheel speed values of the front wheels 11 and 12 and the rear wheels 14 and 15 from the anti-lock brake system control device 53 and based on the wheel speed signals. When it is determined that the speed is higher than the rear wheel speed and the front wheel is slipping, it is determined that the electric motor 30 is driven in order to apply driving force to the rear wheel.

  Alternatively, an accelerator opening signal, which is a driver's request value for the vehicle, is input from the engine control device 51, and when starting or acceleration is requested by the driver based on the accelerator opening signal, start / acceleration stability (front wheel) It is determined that the motor 30 is driven in order to increase the driving force so as to increase the starting and acceleration while suppressing the slip that may occur.

  When driving of the electric motor 30 is requested, electric motor control means included in the four-wheel drive control device 50 starts driving the electric motor 30.

  Next, the four-wheel drive control device 50 determines whether or not the rotation speed of the electric motor 30 is synchronized with the rotation speed of the rear wheels 14 and 15 by the electromagnetic clutch 34 (substantially the same rotation or converges to the same rotation after a certain time). Is determined (step S102). At this time, when the motor speed sensor is attached to the motor 30, the motor side speed of the electromagnetic clutch 34 is calculated in consideration of the reduction ratio of the speed reducer 33 between the motor 30 and the electromagnetic clutch 34. To do.

  As a result of the determination in the previous step S102, when it is determined that they are not synchronized, the motor control means of the four-wheel drive control device 50 changes the motor-side rotation speed of the electromagnetic clutch 34 to the slave-drive wheel-side rotation speed. In order to synchronize, the motor 30 is driven (motor reconnection control) (step S103). At this time, the electric motor 30 has no load, and the rotational drive of the electric motor 30 is controlled while converging the range of the rotational speed that rises and falls while repeating the determination processing of the previous step S102 with respect to the rotational speed of the driven wheel.

  On the other hand, if it is determined as a result of the determination that the electromagnetic clutch 34 is open, the clutch control means included in the four-wheel drive control device 50 engages the electromagnetic clutch 34 if the electromagnetic clutch 34 is released. Furthermore, the electric motor control means of the four-wheel drive control device 50 drives the electric motor 30 (step S103).

  Next, based on the input signal to the four-wheel drive control device 50, it is determined whether or not the motor 30 is stopped (step S104). For example, when it is determined that the front wheel side wheel speed is equal to the rear wheel side wheel speed based on the wheel speed signal given from the anti-lock brake system control device 53, that is, the front wheels 11 and 12 slip. If it is determined that the motor 30 has not been driven, it is not necessary to apply a driving force to the rear wheels 14 and 15, and therefore it is determined that the driving of the electric motor 30 is stopped. Further, when it is determined that the driver stops or accelerates (accelerator is turned off) based on the accelerator opening signal given from the engine control device 51, it is determined that the driving of the electric motor 30 is stopped.

  As a result of the determination, when it is determined that the driving of the electric motor 30 is to be stopped, the control range of the electric motor 30 is subsequently determined (step S105). The determination of the control range of the electric motor 30 is performed in the subsequent control whether or not the control can be performed within the range of the allowable rotation speed of the electric motor 30, whether the electric motor 30, the drive dedicated generator 31, and the four-wheel drive control device 50. It is determined whether or not can be controlled without high voltage or high temperature.

  The determination as to whether or not the motor 30 can be controlled within the allowable rotational speed range is based on, for example, calculating the wheel acceleration based on the wheel speed signal given from the antilock brake system control device 53 and based on the obtained wheel acceleration. This is performed by estimating whether or not the electric motor 30 can be controlled at an allowable rotational speed or less until a predetermined time set in advance elapses. This predetermined time is the motor stop when the drive of the motor 30 is stopped during the processing time for performing the processing of Step S107 to Step S111 selectively executed after Step S106 and then returning to the processing of Step S106 again. It is set as a time to which a control delay time in processing is added. In addition, when the electromagnetic clutch 34 is engaged, the rotational acceleration of the electric motor 30 is estimated based on the wheel acceleration in consideration of the gear ratio of the rear wheel side differential gear 35, and a similar operation is performed based on the rotational acceleration. Estimate whether control is possible.

  On the other hand, the determination as to whether or not the electric motor 30, the drive-only generator 31 and the four-wheel drive control device 50 can be controlled without a high voltage exceeding a preset allowable value is made first by, for example, the electric motor 30. The field quantity of the motor 30 and the electric motor based on the number of rotations of the electric motor 30 given from the revolution number sensor (not shown) attached to the motor and the field current given from the field current sensor (not shown). The induced voltage of the electric motor 30 generated according to the rotation amount of 30 is estimated. Thereafter, the estimated induced voltage does not exceed a voltage that can cause deterioration of the electric motor 30, the dedicated drive generator 31, or the four-wheel drive control device 50 within the predetermined time used in the estimation process of the previous step S106. This is done by judging whether or not. That is, if it exceeds, it is determined that the voltage is high, and it is determined that control is not possible. On the other hand, if it does not exceed, it is determined that the voltage is not high and control is possible.

  The induced voltage of the electric motor 30 may exceed the voltage that can be deteriorated by the electric motor 30 or the drive-only generator 31 due to the fluctuation of the amount of rotation of the electric motor 30 and the fluctuation of the magnetic field due to the delay of the field current control. Further, when the four-wheel drive control device 50 is electrically connected to a portion where the induced voltage of the electric motor 30 is generated, there is a possibility that the voltage that can be deteriorated by the four-wheel drive control device 50 may be exceeded at the connection portion. .

  On the other hand, whether or not the electric motor 30 and the drive-only generator 31 can be controlled without reaching a high temperature that is equal to or higher than a preset allowable value is used in the estimation process of the previous step S106. The amount of heat generated within a predetermined time is estimated, and based on the obtained amount of heat generated and the current temperature, it is determined whether or not the allowable temperature is not exceeded within the predetermined time. That is, if the temperature does not exceed the allowable temperature, it is determined that the motor and the drive generator 31 can be controlled by assuming that they do not reach a high temperature. Judge.

  The temperature of the electric motor 30 or the drive-only generator 31 is measured by a temperature sensor (not shown) attached to each of them, or the field current and the armature current of the electric motor 30 and the flow time thereof and the resistance value of the electric motor 30 Based on the above.

  As described above, when maintaining the engaged state of the electromagnetic clutch 34, it is determined whether or not the above-described requirements are satisfied, and only when the requirements are satisfied, the engaged state is set, so that the electric motor 30 is overheated or high voltage is generated. Deterioration of the electric motor 30 and adverse effects on the four-wheel drive control device 50 can be prevented.

  Next, when it is determined that the result of the previous step S106 is outside the control range of the electric motor 30, a series of processing is executed to stop the electric motor 30. In this process, the drive of the motor 30 is first controlled so that the acceleration on the side of the motor 30 and the acceleration of the rear wheels 14 and 15 substantially coincide (synchronize) in the electromagnetic clutch 34 in the same manner as the operation conventionally performed ( Step S107). After both are synchronized, the electromagnetic clutch 34 is released (step S108).

  Thereafter, it is determined whether motor brake control is possible (step S109). Whether the motor brake control is possible or not is determined, for example, by the temperature of the motor 30 measured by a temperature sensor attached to the motor 30 withstanding the heat generated by the armature current generated by the motor brake control to be performed. It is performed by estimating whether or not the temperature is lower than the allowable heat resistant temperature.

  That is, when it is estimated that the temperature of the electric motor 30 is equal to or lower than the heat-resistant temperature, the motor brake control is executed and the electric motor 30 is stopped (step S110). On the other hand, when it is estimated that the temperature of the electric motor 30 exceeds the heat-resistant temperature, this determination process is continued, and after the motor brake control becomes possible, the motor brake control is executed and the electric motor 30 is stopped. (Step S110).

  Alternatively, for example, the number of rotations of the motor 30 measured by a rotation sensor attached to the motor 30 is such that an armature current or a voltage increase generated by motor brake control to be performed will deteriorate the four-wheel drive control device 50. This is performed by estimating whether the rotation speed is less than the number of revolutions at which no high voltage or high current is generated. That is, when it is estimated that the rotation speed of the electric motor 30 is equal to or less than the rotation speed at which high voltage and high current are not generated, the previous step S110 is executed. Execute.

  Next, if it is determined in step S106 that the electric motor 30 is within the control range, then the electric motor 30 is re-driven based on an input signal to the four-wheel drive control device 50. It is estimated whether or not (step S111).

  The estimation as to whether or not the electric motor 30 is redriven is performed by performing, for example, the following three determination processes. First, it is determined whether or not it is immediately after the driving force of the electric motor 30 becomes unnecessary. That is, after starting the drive stop control by determining the drive stop of the electric motor 30, it is determined whether or not there is a drive request for the electric motor 30, and if there is a request, a series of operations until the drive of the electric motor 30 is restarted. Considering the response delay time of the process, it is estimated that there is a very high possibility that the motor 30 will be re-driven during the response delay time from the drive stop determination (no motor driving force is required).

  Next, when it is determined that the road surface condition is low μ (the road surface friction is low), it is estimated that the electric motor 30 is redriven. For example, when it is detected in the previous step S101 that the front wheels 11 and 12 are slipping and the driving of the electric motor 30 is started, there is a high possibility that the road surface is freezing and slippery, for example. It is possible to estimate that there is a high possibility that the driving will be re-requested (re-driving estimation). For this reason, it is presumed that the re-driving of the electric motor 30 is required until the accelerator is turned off or the vehicle stops (an operation state in which the possibility of occurrence of front wheel slip is eliminated). Note that the outside air temperature may be measured, and when the measured outside air temperature is lower than a threshold temperature indicating the possibility of freezing, it may be determined that the road surface is frozen and slippery.

  Next, when the front wheels 11 and 12 of the main drive wheels are kept in the slip state, it is estimated that the electric motor 30 is redriven. For example, when the threshold value of the front / rear wheel speed difference when performing the slip determination of the front wheels 11 and 12 in the drive request determination of the motor 30 is large and the above threshold value in the drive stop determination of the motor 30 is large, When the difference is small and the front wheels 11 and 12 are slightly slipping, it is determined that the front and rear wheel speed difference exceeds the threshold value and the front wheels 11 and 12 are in the slipping state, and the motor 30 is re-driven. Estimated. That is, it is estimated that the electric motor 30 is re-driven until the front-rear wheel speed difference becomes completely zero.

  Next, based on the result of the process executed in the previous step S111, it is determined whether or not the electric motor 30 is redriven (step S112). As a result of the determination, when it is determined that the electric motor 30 is to be driven again, the engagement state of the electromagnetic clutch 34 is continued by the clutch control means provided in the four-wheel drive control device 50 (step S113). In a state where the electromagnetic clutch 34 is engaged, the electric motor 30 becomes a load on the rear wheels 14 and 15 of the driven wheels and is rotated around the rear wheels 14 and 15.

  Next, in a state where the electric motor 30 is rotated as a load on the rear wheels 14 and 15, the accelerations of both the electric motor 30 side and the rear wheels 14 and 15 side of the electromagnetic clutch 34 are made closer to each other. The electric motor 30 is controlled (step S114). Thereby, generation | occurrence | production of the vibration by the play which can generate | occur | produce in the mechanical connection part between the electric motor 30 and the rear-wheels 14 and 15 can be suppressed. Note that this control may be omitted when the load on the rear wheels 14 and 15 of the motor 30 is small or when the vibration is small.

  Next, based on the input signal to the four-wheel drive control device 50, it is determined whether or not there is a request to redrive the electric motor 30 (step S115). As a result of the determination, if it is determined that there is no re-drive request, the process returns to the previous step S106 to determine again whether or not the electric motor 30 is within the control range.

  On the other hand, if it is determined that there is a re-drive request, the process returns to the previous step S102, and the synchronization between the electric motor 30 and the rear wheels 14, 15 is determined again. At this time, since the electromagnetic clutch 34 is in the engaged state and the motor 30 has been rotated by the rear wheels 14 and 15 until then, if the rotational speeds of the motor 30 and the rear wheels 14 and 15 are substantially the same, it is promptly determined. To be judged. For this reason, it is not necessary to perform an operation (reconnection control) that synchronizes the rotation speed between the two, and the driving force of the electric motor 30 is quickly applied to the rear wheels 14 and 15 so that the rear wheels 14 and 15 It becomes a drive state, and it becomes possible to quickly shift the four-wheel drive vehicle 100 to a stable four-wheel drive state.

  FIG. 3 shows temporal changes in the wheel speeds of the rear wheels 14 and 15 and the rotation speed of the electric motor 30 when the electric motor 30 and the electromagnetic clutch 34 are controlled as described above. In FIG. 3, when the rear wheels 14 and 15 are driven by the electric motor 30 and the wheel speed of the rear wheels 14 and 15 is increased according to the rotation speed of the electric motor 30, the driving force of the electric motor 30 becomes unnecessary. Conventionally, since the electromagnetic clutch 34 is opened and the motor and the rear wheel are separated from each other, as shown in FIG. 3, the motor 30 idles and the number of revolutions rapidly increases.

  Thus, if the clutch is released as in the prior art, the motor 30 loses its load and the rotational speed increases rapidly. Therefore, when the driving force of the motor 30 is required again in such a state, the motor 30 3 and the rotation speed of the rear wheels 14 and 15 are not synchronized. Therefore, as shown in FIG. 3, the rotation speed of the electric motor 30 is increased or decreased while approaching the rotation speed of the rear wheels 14 and 15. It is necessary to perform reconnection control to synchronize between them.

  On the other hand, in this embodiment, if the electric motor 30 can be controlled as described above, the electromagnetic clutch 34 is brought into the engaged state, so that the electric motor 30 and the rear wheels 14 and 15 are substantially synchronized. deep. Thus, even if the driving force of the electric motor 30 becomes unnecessary, such a state is set, and when the driving force of the electric motor 30 becomes necessary again, the rotation speed of the electric motor 30 is the wheel of the rear wheels 14 and 15. Ascends quickly in sync with speed. Thereby, the reconnection control of the electromagnetic clutch 34 becomes unnecessary, and the operation drive region of the electric motor 30 can be expanded.

  Returning to FIG. 2, when it is determined that the electric motor 30 is not redriven in the determination result of the previous step S <b> 112, processing for stopping the driving of the electric motor 30 is started. First, based on the input signal to the four-wheel drive control device 50, it is determined whether or not the rear wheels 14 and 15 are decelerating (step S116). As a result of the determination, if the vehicle is not decelerating, the control at the time of releasing the electromagnetic clutch 34 is performed by executing the processing shown in the previous step S107.

  On the other hand, when the rear wheels 14 and 15 are decelerating, the engagement state of the electromagnetic clutch 34 is continued (step S117). As a result, the electric motor 30 is caused to rotate with the rear wheels 14 and 15 as a load on the rear wheels 14 and 15, and the rotation of the electric motor 30 is decelerated. As a result, the rotational speed of the electric motor 30 can be reduced and the rotation of the electric motor 30 can be stopped as the rear wheels 14 and 15 are decelerated.

  By adopting such a method, as shown in FIG. 4, it is determined that the driving force of the electric motor 30 is unnecessary, and at the same time, the rotation of the electric motor 30 is reduced compared to the conventional method in which the electromagnetic clutch 34 is released. It can be quickly stopped and the sound and vibration caused by the rotation of the electric motor 30 can be suppressed. This is effective when the motor brake control described above cannot be performed.

  Returning to FIG. 2, it is determined whether or not the electromagnetic clutch 34 is to be released by determining whether or not the rotational speed of the electric motor 30 has decreased to a rotational speed that does not cause excessive rotation when the electromagnetic clutch 34 is subsequently released. Judgment is made (step S118).

  As a result of the determination, if it is determined that the motor 30 does not over-rotate even when the rotational speed of the motor 30 is sufficiently reduced and the electromagnetic clutch 34 is released, the process shown in the previous step S108 is executed to perform the electromagnetic The clutch 34 is released. On the other hand, when it is determined that the rotational speed of the electric motor 30 has not sufficiently decreased and there is a possibility that the electric motor 30 may over-rotate when the electromagnetic clutch 34 is released in this state, the process returns to the process shown in the previous step S116. The rotational speed of the electric motor 30 is reduced with the electromagnetic clutch 34 engaged.

It is a figure which shows the structure of the four-wheel drive vehicle containing the vehicle control apparatus which concerns on Example 1 of this invention. It is a flowchart which shows the processing operation which concerns on Example 1 of this invention. It is a figure which shows the change of the rotation speed of the electric motor at the time of re-driving an electric motor. It is a figure which shows the change of the rotation speed of the electric motor at the time of stopping an electric motor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Vehicle body 11, 12 ... Front wheel 13 ... Front wheel axle 14, 15 ... Rear wheel 16 ... Rear wheel axle 20 ... Engine 21 ... Torque converter 22 ... Transmission mechanism 23 ... Front wheel side differential gear 24, 32 ... Pulley 25 ... Pulley belt DESCRIPTION OF SYMBOLS 30 ... Electric motor 31 ... Drive-only generator 33 ... Reduction gear 34 ... Electromagnetic clutch 35 ... Rear wheel side differential gear 40 ... On-vehicle electrical generator 50 ... Four-wheel drive control device 51 ... Engine control device 52 ... Transmission control device 53 ... Anti-lock brake system controller 100 ... 4-wheel drive vehicle

Claims (3)

Main drive wheels driven by an internal combustion engine;
A driven wheel driven by an electric motor that operates with electric power obtained by a generator driven by the internal combustion engine;
In a vehicle control device that controls the traveling of a four-wheel drive vehicle including a clutch that transmits / cuts off the power obtained by the electric motor to the slave drive wheels by being in a fastened state or a non-fastened state,
Motor control means for controlling driving / stopping of the motor;
A vehicle control apparatus comprising: clutch control means for holding the clutch in an engaged state after starting control for stopping driving of the motor by the motor control means. The vehicle control device according to claim 1, wherein the clutch control means holds the clutch in an engaged state when a preset operation requirement of the electric motor is satisfied. The electric motor control means includes a redrive estimation means for estimating whether the electric motor is redriven after starting control for stopping the driving of the electric motor by the electric motor control means,
3. The vehicle according to claim 1, wherein the clutch control unit holds the clutch in an engaged state when the redrive estimation unit estimates that the electric motor is redriven. Control device.

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