JP2007276575A - Controller of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller for a vehicle capable of preventing a coupling mechanism used in a driving force distributing device from being overheated by an increase of friction heat caused by an increase in the operating frequency of the coupling mechanism. <P>SOLUTION: The controller of the driving force distributing device for vehicle to transmit the output torque of a power source in distribution to different driving wheels by the coupling mechanism which can change the transmitted torque is equipped with a coupling temperature detection means to detect the temperature of the coupling mechanism (step S20) and a coupling overheat preventing means to prevent a temperature rise by reducing friction generated in the coupling mechanism (steps S30 and S40) when the temperature detected by the coupling temperature detection means has exceeded a prescribed value. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle control device equipped with a driving force distribution device using a coupling mechanism that distributes and transmits a driving force to each driving wheel.

  Use a coupling mechanism (or clutch mechanism) that can change the transmission torque for the differential that allows the differential between the front and rear wheels or the left and right wheels of the vehicle, and control the transmission torque of the coupling mechanism or By changing the driving force, the driving force distributed to each wheel is set in accordance with the traveling state of the vehicle and the road surface condition. As an example, Patent Document 1 discloses an invention relating to a driving force distribution control device for a four-wheel drive vehicle that distributes and transmits torque generated by an internal combustion engine to front wheels and rear wheels via a coupling.

  The driving force distribution control device for a four-wheel drive vehicle described in Patent Document 1 selects either the four-wheel drive state or the two-wheel drive state and drives the front wheels and the rear wheels in the four-wheel drive state. The power distribution rate (torque distribution rate) is controlled. Specifically, the four-wheel drive vehicle described in Patent Document 1 includes a wet multi-plate electromagnetic clutch mechanism having a plurality of clutch plates that are frictionally engaged with or separated from each other between a propeller shaft and a rear differential. The driving force transmission device (coupling) having the above is provided, and the driving force distribution control device controls the current supply / cutoff state and the current supply amount to the electromagnetic coil of the electromagnetic clutch mechanism. Yes. That is, when current is supplied to the electromagnetic coil of the electromagnetic clutch mechanism, the clutch plates are frictionally engaged with each other to transmit torque to the rear wheels, and when supply of current to the electromagnetic coil is interrupted, The clutch plates are separated from each other so that torque transmission to the rear wheels is interrupted.

  Patent Document 2 describes an invention related to a driving force distribution control device for a vehicle that distributes driving force by controlling a fastening force of a coupling mechanism to change a transmission torque. In the vehicle described in Patent Document 2, a transfer is integrally connected to a rear portion of a transmission connected to an output shaft of an engine. The transfer is composed of a planetary gear mechanism to which driving force from the transmission is input, and is connected to the planetary gear mechanism, and a center differential is formed by a transfer clutch (coupling mechanism) composed of a multi-plate clutch whose fastening torque is electronically controlled. Is configured. Then, after the engine output is converted to a predetermined torque by the transmission, the driving force is distributed to the front wheel side and the rear wheel side via the transfer and the center differential.

JP 2003-31294 A JP 2004-106793 A

  The driving force transmission device (coupling) provided with the electromagnetic clutch mechanism described in Patent Document 1 above, or the transfer clutch (coupling mechanism) including the electronically controlled multi-plate clutch described in Patent Document 2 By configuring the vehicle differential with a coupling mechanism such as the above, controlling to increase or decrease the engagement force (or fastening force, restraining force) of the coupling mechanism in accordance with the traveling state or road surface condition of the vehicle, That is, the engagement / disengagement state of the coupling mechanism can be controlled, and the driving force can be distributed to each wheel with an appropriate torque distribution according to the running state and the road surface condition.

  However, this occurs in the coupling mechanism when the frequency of coupling mechanism operation, that is, the frequency of controlling the engagement / release state of the coupling mechanism or the frequency of switching the power transmission / cutoff state of the coupling mechanism is high. The temperature of the coupling mechanism rises due to friction. For example, in the case where the coupling mechanism is configured by a multi-plate clutch, if the coupling mechanism is operated frequently, the clutch plates often come into contact with each other while sliding (half-engaged or slip-engaged state). And the temperature of each clutch plate rises due to the friction generated at that time. Further, when the operating frequency of the coupling mechanism is further increased, the clutch plates also become higher in temperature, and there is a possibility that the clutch plates are seized and fixed or fused.

  The present invention has been made paying attention to the above technical problem, and when the driving force is distributed and transmitted to each wheel by the driving force distribution device using the coupling mechanism, the operation of the coupling mechanism is performed. An object of the present invention is to provide a vehicle control device capable of preventing overheating of a coupling mechanism due to increased frequency and frictional heat.

  In order to achieve the above object, the invention according to claim 1 is a vehicle equipped with a driving force distribution device that distributes and transmits the output torque of a power source to each drive wheel by a coupling mechanism capable of changing the transmission torque. In the control device, coupling temperature detection means for detecting the temperature of the coupling mechanism, and friction generated in the coupling mechanism when the temperature detected by the coupling temperature detection means exceeds a predetermined value. And a coupling overheating preventing means for preventing the temperature from rising.

  According to a second aspect of the present invention, in the first aspect of the invention, the coupling mechanism distributes and transmits the output torque by changing the transmission torque by controlling the engagement / release state. A control coupling capable of executing control, wherein the coupling overheat prevention means includes means for reducing the friction and reducing the temperature rise by reducing the frequency of execution of the driving force distribution control. It is the control device characterized.

  The invention according to claim 3 is the invention according to claim 2, wherein the coupling overheat prevention means includes means for reducing the friction and preventing the temperature from rising by stopping the driving force distribution control. This is a control device characterized by that.

  According to a fourth aspect of the present invention, in the first aspect of the invention, the coupling overheat prevention means includes means for reducing the friction and reducing the temperature rise by reducing the vehicle speed. It is a control device.

  According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the coupling overheat prevention means reduces the friction by reducing the output torque and reducing the vehicle speed, thereby preventing the temperature from rising. A control device comprising means.

  According to a sixth aspect of the present invention, in the fourth aspect of the present invention, the power source includes an electric motor capable of executing power running / regenerative control, and the coupling overheat preventing means performs regenerative control of the electric motor for braking. A control device comprising means for reducing the friction by reducing the vehicle speed and preventing the temperature from rising.

  According to the first aspect of the present invention, the temperature of the coupling mechanism is monitored, and when the temperature exceeds a predetermined value, the vehicle is controlled so as to reduce the friction generated in the coupling mechanism. Therefore, for example, the frequency of switching the power transmission / cutoff state in the coupling mechanism or the frequency of controlling the coupling mechanism engagement / release state is increased, thereby increasing the frequency of the coupling mechanism. It is possible to prevent the coupling mechanism from overheating due to increased friction.

  According to the second aspect of the invention, the driving mechanism distributes and transmits the output torque of the power source to each drive wheel by changing the transmission torque by controlling the engaged / released state. When the control mechanism is configured by a control coupling and the temperature of the coupling mechanism exceeds a predetermined value, the frequency of execution of the driving force distribution control, that is, the engagement / release state of the coupling mechanism is By reducing the frequency of control, the vehicle is controlled to reduce the friction generated in the coupling mechanism. Therefore, it is possible to prevent overheating of the coupling mechanism due to an increase in the operating frequency of the coupling mechanism and an increase in friction in the coupling mechanism.

  According to the invention of claim 3, when the temperature of the coupling mechanism becomes higher than a predetermined value, the friction generated in the coupling mechanism is canceled by prohibiting or prohibiting the execution of the driving force distribution control. The vehicle is controlled to reduce. Therefore, it is possible to prevent overheating of the coupling mechanism due to an increase in the operating frequency of the coupling mechanism and an increase in friction in the coupling mechanism.

  According to the invention of claim 4, when the temperature of the coupling mechanism becomes higher than a predetermined value, the vehicle is reduced so as to reduce the friction generated in the coupling mechanism by reducing the vehicle speed. Be controlled. Therefore, it is possible to prevent overheating of the coupling mechanism due to an increase in the operating frequency of the coupling mechanism and an increase in friction in the coupling mechanism.

  Further, according to the invention of claim 5, when the temperature of the coupling mechanism exceeds a predetermined value, the output torque of the power source is decreased to reduce the vehicle speed, thereby generating in the coupling mechanism. The vehicle is controlled to reduce friction. Therefore, it is possible to prevent overheating of the coupling mechanism due to an increase in the operating frequency of the coupling mechanism and an increase in friction in the coupling mechanism.

  According to the sixth aspect of the present invention, an electric motor capable of power running control and regenerative control is provided as a power source of the vehicle, and when the temperature of the coupling mechanism becomes higher than a predetermined value, the electric motor is By regenerative control to brake the vehicle and reduce the vehicle speed, the vehicle is controlled to reduce the friction generated in the coupling mechanism. Therefore, it is possible to prevent overheating of the coupling mechanism due to an increase in the operating frequency of the coupling mechanism and an increase in friction in the coupling mechanism.

  Next, the present invention will be described based on specific examples. FIG. 8 is a diagram schematically showing a power transmission path and a control system of the vehicle Ve to which the present invention is applied. First, a configuration example of a power transmission path of a four-wheel drive vehicle (vehicle) Ve to which the present invention is applied will be described. In FIG. 8, reference numeral 1 denotes a power source of the vehicle Ve. As the power source 1, for example, an engine such as a gasoline engine, a diesel engine, or an LPG engine, an electric motor (motor), or power running / regenerative control with the engine is possible. A hybrid system combined with a simple electric motor (motor / generator) is used. Here, an example will be described in which an engine 1 having an electronic throttle valve (not shown) as the power source 1 and capable of electrically controlling the output is used.

  A transmission 2 is connected to the output side of the engine 1. As this transmission 2, various known transmissions such as a selection gear type transmission, a planetary gear type transmission, a belt type or a toroidal type continuously variable transmission are used.

  A propeller shaft 4 is connected to the output side of the transmission 2 via a transfer gear 3. Left and right front drive shafts 6 and 7 are coupled to the front end of the vehicle shaft Ve (left side in FIG. 8) of the propeller shaft 4 via a front differential 5. Left and right front wheels 8, 9 are respectively attached.

  On the other hand, the front wheel side output shaft 10f of the driving force distribution device 11 configured by the coupling mechanism 10 capable of changing the transmission torque is coupled to the rear side of the vehicle Ve of the propeller shaft 4 (right side in FIG. 8). . Left and right rear drive shafts 13 and 14 are connected to the rear wheel side output shaft 10r of the driving force distribution device 11 via a rear differential 12, and the left and right rear wheels 15 are connected to the rear drive shafts 13 and 14, respectively. , 16 are attached. Therefore, the driving force distribution device 11 functions to distribute and transmit the torque of the engine 1 output via the transmission 2 to the front wheels 8 and 9 and the rear wheels 15 and 16.

  The coupling mechanism 10 constituting the driving force distribution device 11 is, for example, a control coupling capable of changing the transmission torque by controlling the engaged / released state, or a known viscous material utilizing the shear resistance of silicon oil. Coupling or the like can be used. As the control coupling, for example, a friction type electromagnetic clutch is provided, and an electronic control type control that can change the transmission torque by controlling the engagement / release state by controlling the current supplied to the electromagnetic clutch. Coupling or a hydraulically controlled control coupling that has an internal friction clutch that operates by hydraulic pressure, and that can control the engagement / release state by controlling the hydraulic pressure applied to the friction clutch. Can be used. Below, the example using the electronically controlled control coupling 10 as the coupling mechanism 10 is demonstrated.

  Next, a control system for the vehicle Ve to which the present invention is applied will be described. The vehicle Ve is provided with an electronic control unit (ECU) 17. For example, the ECU 17 detects a vehicle speed sensor 18 that detects the vehicle speed, an acceleration sensor 19 that detects the acceleration of the vehicle Ve, and a yaw rate of the vehicle Ve. Various sensors such as a yaw rate sensor 20, a steering angle sensor 21 for detecting the steering angle of the steering, and a coupling oil temperature sensor 22 for detecting the oil temperature of the control coupling 10 of the driving force distribution device 11 are connected. The output signals of these sensors are input as control data for controlling the running state of the vehicle Ve.

  The ECU 17 also includes an electronic throttle valve for controlling the output torque of the engine 1, a hydraulic control device (not shown) for executing the shift control of the transmission 2, and a braking device for each wheel 8, 9, 15, 16 ( The control signal is output to the control coupling 10 of the driving force distribution device 11 and the like.

  Then, the ECU 17 performs arithmetic processing based on various control data relating to the running state of the vehicle Ve input to the ECU 17 as described above, and performs an electronic throttle valve of the engine 1, a hydraulic control device of the transmission 2, each wheel 8, Control for outputting a control signal to the braking devices 9, 15, 16 and the control coupling of the driving force distribution device 11 to maintain the running stability of the vehicle Ve in an appropriate state, for example, VDM (Vehicle Dynamics Management) ) The vehicle motion control referred to as control or the like can be executed.

  As VDM control, for example, output control of the engine 1, brake control of each braking device, etc. are executed in a coordinated manner when turning, running on a slope, or when slipping occurs on a rough road. This includes control for avoiding a side slip or slip of the vehicle Ve by controlling the device 11 to control the driving force distribution between the front wheels 8 and 9 and the rear wheels 15 and 16 to an appropriate state.

  As described above, according to the present invention, for example, when the VDM control as described above is performed, the driving force distribution device 11 using the coupling mechanism 10 causes the front wheels 8 and 9 and the rear wheels 15 and 16 to be applied. An object of the present invention is to prevent overheating of the coupling mechanism 10 due to an increase in the frictional heat when the driving force is distributed and transmitted and the frictional heat increases. Is configured to execute the following control.

(First control example)
FIG. 1 is a flowchart for explaining a first control example in the control device of the present invention, and the routine shown in this flowchart is repeatedly executed every predetermined short time. In FIG. 1, first, a current value Ct to be supplied to the control coupling 10 of the driving force distribution device 11 is calculated based on the target front / rear driving force command of the VDM control (step S10). Specifically, the target value (target distribution) of the driving force distribution to the front and rear wheels, the actually measured driving force distribution to the front and rear wheels (actual distribution), and the front wheel side output of the control coupling 10 Based on the rotational speed Ncf of the shaft 10f and the rotational speed Ncr of the rear wheel side output shaft 10r, a current value (target current value) Ct supplied to the control coupling 10 is calculated as a target longitudinal driving force command.

  Subsequently, the temperature (coupling oil temperature) Tr of the coupling oil in the control coupling 10 is detected by the coupling oil temperature sensor 22 (step S20). Then, the magnitudes of the coupling oil temperature Tr and the oil temperature threshold value Tt are compared. That is, it is determined whether or not the coupling oil temperature Tr is higher than the oil temperature threshold value Tt (step S30). Here, the oil temperature threshold value Tt takes into account a predetermined safety factor with respect to the oil temperature Tmax at which a friction member such as a clutch plate (coupling plate) constituting the control coupling 10 is fixed or fused. The oil temperature is set in advance as a threshold value for determining whether or not there is a possibility that a malfunction such as sticking or fusion occurs in the control coupling 10 at a temperature lower than the oil temperature Tmax.

  When the detected coupling oil temperature Tr is higher than the oil temperature threshold value Tt, if the determination in step S30 is affirmative, the process proceeds to step S40, and the current command to the control coupling 10 in the coupling protection mode is performed. A value is calculated and output. When the coupling oil temperature Tr becomes higher than the oil temperature threshold value Tt, there is a possibility that problems such as sticking and fusion occur in the control coupling 10, so that the friction generated in the control coupling 10 is reduced. The control coupling 10 is controlled in a state where the coupling protection mode is controlled as described above.

  The control content for calculating the current command value of the control coupling 10 in the coupling protection mode executed in step S40 described above, that is, the subroutine in step S40 is shown in the flowchart of FIG. In FIG. 2, first, it is determined whether or not the difference between the target distribution ratio and the actual distribution ratio is greater than or equal to a threshold value Dt (step S41). The distribution ratio is a value indicating the ratio between the driving force distributed to the front wheels 8.9 and the driving force distributed to the rear wheels 15 and 16. The target distribution ratio is the front / rear wheel distribution ratio based on the target front / rear driving force command calculated in step S10, and the actual distribution ratio is the front / rear wheel actually measured at that time. It is a distribution ratio based on the driving force.

If the difference between the target distribution ratio and the actual distribution ratio is greater than or equal to the threshold value Dt, if the determination in step S41 is affirmative, the process proceeds to step S42, and the target current value Ct calculated in step S10 described above is obtained. It is corrected. That is, when the correction coefficient is A, the corrected target current value Ct ′ is
Ct ′ = Ct × A
Is calculated as The correction coefficient A can be obtained based on a map related to the coupling oil temperature, for example, as shown in FIG. That is, the correction coefficient A is set as a value in the range from 0 to 1 according to the coupling oil temperature Tr.

  When the target current value Ct 'is calculated, a current command value based on the target current value Ct' is output (step S43).

  Then, returning to the flowchart of FIG. 1, the driving force distribution control is executed to control the engagement / release state of the control coupling 10 based on the target current value Ct ′ to set the driving force distribution to the front and rear wheels. (Step S50) Then, this routine is once complete | finished. As described above, the driving force distribution control is executed by the target current value Ct ′ corrected by the correction coefficient A that takes a value in the range from 0 to 1 according to the coupling oil temperature Tr, so that the normal correction is not performed. Compared with the case where the driving force distribution control is performed with the target current value Ct, the execution frequency of the driving force distribution control is reduced.

  On the other hand, if the difference between the target distribution ratio and the actual distribution ratio is less than the threshold value Dt and a negative determination is made in step S41, the process proceeds to step S44, where the target current value Ct is 0. After that, in step S43, a current command value based on the target current value Ct ′ is output.

  And it returns to the flowchart of FIG. 1, and driving force distribution control is performed (step S50). That is, in this case, the driving force distribution control is stopped or prohibited. Thereafter, this routine is once terminated.

  As described above, when the coupling oil temperature Tr becomes higher than the oil temperature threshold value Tt, the control coupling is controlled by the coupling protection mode, thereby reducing the execution frequency of the driving force distribution control, or The driving force distribution control is stopped or prohibited, and as a result, the friction generated in the control coupling 10 can be reduced.

  On the other hand, if the coupling oil temperature Tr is equal to or lower than the oil temperature threshold value Tt, a negative determination is made in step S30 described above, the process proceeds to step S60, and the control coupling 10 in the normal mode that is not the coupling protection mode. Current command value based on the target current value Ct is output.

  In this case, since there is no risk of problems such as sticking and fusion occurring in the control coupling 10, normal driving force distribution control is executed based on the target current value Ct calculated in step S10 described above ( Step S50), and then this routine is temporarily terminated.

(Second control example)
FIG. 3 is a flowchart for explaining a second control example in the control apparatus of the present invention. Like the first control example, the routine shown in this flowchart is repeated every predetermined short time. Executed. In the second control example, when the coupling oil temperature Tr becomes higher than the oil temperature threshold value Tt, the output torque of the engine 1 is reduced and the vehicle speed is reduced as compared with the first control example. This is an example of the control in which the friction generated in the control coupling 10 is reduced by reducing the friction. Therefore, the second control example shown in the flowchart of FIG. 3 is an addition or change to the first control example shown in the flowchart of FIG. Steps having the same control content are denoted by the same reference numerals as those in FIG. 1 and detailed description thereof is omitted.

  In FIG. 3, when the coupling oil temperature Tr detected in step S20 is higher than the oil temperature threshold value Tt and a positive determination is made in step S30, the process proceeds to step S70 to reduce the vehicle speed. The control for reducing the output of 1, that is, the control for reducing the output torque is executed. Specifically, correction for reducing the output torque of the engine 1 is performed with respect to the target throttle opening degree θt for the electronic throttle valve of the engine 1 set based on the driver's required drive amount. The output of the engine 1 is controlled based on the target throttle opening θt ′.

For example, if the correction coefficient for the throttle opening target value θt is B, the target throttle opening θt ′ is
θt ′ = θt × B
Is calculated as The correction coefficient B can be obtained based on a map related to the coupling oil temperature, for example, as shown in FIG. That is, the correction coefficient B is set as a value in the range from 0 to 1 according to the coupling oil temperature Tr. When the target throttle opening degree θt ′ is calculated, the output of the engine 1 is controlled based on the target throttle opening degree θt ′.

  When the control for reducing the output torque of the engine 1 is executed, the driving force distribution control is executed based on the target current value Ct calculated in step S10 (step S50), and then this routine is temporarily terminated. To do.

  Thus, when the coupling oil temperature Tr becomes higher than the oil temperature threshold value Tt, the control for reducing the output torque of the engine 1 to reduce the vehicle speed is executed, whereby the front wheel of the control coupling 10 is executed. The rotational speed difference between the rotational speed Ncf of the side output shaft 10f and the rotational speed Ncr of the rear wheel side output shaft 10r can be reduced, and as a result, the friction generated in the control coupling 10 can be reduced.

  On the other hand, when the coupling oil temperature Tr is equal to or lower than the oil temperature threshold value Tt, when a negative determination is made in step S30, the process proceeds to step S80, and normal control that does not decrease the output of the engine 1 is executed. .

  In this case, since there is no risk of problems such as sticking and fusion occurring in the control coupling 10, normal driving force distribution control is executed based on the target current value Ct calculated in step S10 (step S50). Thereafter, this routine is once terminated.

(Third control example)
FIG. 4 is a flowchart for explaining a third control example in the control device of the present invention. Like the first and second control examples described above, the routine shown in this flowchart is performed for a predetermined short time. Repeated every time. This third control example is a control example for a configuration in the case where a hybrid system 1 in which an engine and a motor / generator are combined is adopted as the power source 1 of the vehicle Ve, and is the second control example described above. On the other hand, when the coupling oil temperature Tr exceeds the oil temperature threshold value Tt, regenerative braking is performed by the motor / generator of the hybrid system 1 to reduce the vehicle speed, thereby generating the control coupling 10. It is an example of control which reduced friction. Therefore, the third control example shown in the flowchart of FIG. 4 is an addition / change to the first and second control examples shown in the flowcharts of FIGS. 2, steps having the same control contents as the control shown in the flowchart of FIG. 2 are denoted by the same reference numerals as in FIGS. 1 and 2, and detailed description thereof is omitted.

  In FIG. 4, when the coupling oil temperature Tr detected in step S20 is higher than the oil temperature threshold value Tt and a positive determination is made in step S30, the process proceeds to step S90, where the hybrid speed is decreased. Automatic regenerative control is performed in which the motor / generator of the system 1 is regeneratively controlled and braked.

  Specifically, the automatic regeneration amount R is set according to the coupling oil temperature Tr, and the automatic regeneration control of the motor / generator is executed based on the automatic regeneration amount R. Here, the automatic regeneration amount R can be obtained based on a map related to the coupling oil temperature, for example, as shown in FIG. That is, the automatic regeneration amount R is set as a value that changes according to the coupling oil temperature Tr.

  When the automatic regeneration control of the motor / generator is executed, thereafter, the driving force distribution control is executed based on the target current value Ct calculated in Step S10 (Step S50), and then this routine is temporarily ended.

  As described above, when the coupling oil temperature Tr becomes higher than the oil temperature threshold value Tt, the motor / generator is regeneratively controlled, and the vehicle Ve is braked to execute the control to reduce the vehicle speed. The rotational speed difference between the rotational speed Ncf of the front wheel side output shaft 10f of the coupling 10 and the rotational speed Ncr of the rear wheel side output shaft 10r can be reduced, and as a result, the friction generated in the control coupling 10 is reduced. Can be made.

  On the other hand, when the coupling oil temperature Tr is equal to or lower than the oil temperature threshold value Tt, if a negative determination is made in step S30, the process proceeds to step S100, and normal control that does not execute automatic regeneration control is executed.

  In this case, since there is no risk of problems such as sticking and fusion occurring in the control coupling 10, normal driving force distribution control is executed based on the target current value Ct calculated in step S10 (step S50). Thereafter, this routine is once terminated.

  As described above, according to the control device according to the present invention, the temperature Tr of the coupling oil of the control coupling 10 constituting the driving force distribution device 11 is detected, and the coupling oil temperature Tr sets the oil temperature threshold Tt. If it exceeds the upper limit, the vehicle Ve is controlled so as to reduce the friction generated in the control coupling 10. That is, when the temperature of the control coupling 10 exceeds a predetermined value, the target current value Ct for controlling the engaged / released state of the control coupling 10 is corrected, and the driving force distribution control is executed. The friction generated in the control coupling 10 is reduced by reducing the frequency, that is, the frequency at which the engagement / release state of the control coupling 10 is controlled, or by stopping or prohibiting the execution of the driving force distribution control. Thus, the vehicle Ve is controlled. Therefore, for example, the operation frequency of the control coupling 10 which is a frequency for controlling the engagement / release state of the control coupling 10 is increased, and the control coupling 10 is overheated due to an increase in friction in the control coupling 10. Can be prevented.

  Further, when the coupling oil temperature Tr becomes higher than the oil temperature threshold value Tt, the vehicle speed is reduced by reducing the output torque of the engine 1 or by performing regenerative braking with the motor / generator of the hybrid system 1. By lowering, the vehicle Ve is controlled so as to reduce the friction generated in the coupling mechanism 10. Therefore, it is possible to prevent overheating of the coupling mechanism 10 due to an increase in the frequency of operation of the coupling mechanism 10 and an increase in friction in the coupling mechanism.

  Here, the relationship between the above-described specific example and the present invention will be briefly described. The functional means in step S20 described above corresponds to the coupling temperature detecting means of the present invention. Moreover, the functional means of steps S30, S40, S70, and S90 correspond to the coupling overheat preventing means of the present invention.

  The present invention is not limited to the specific example described above. In the specific example, a control coupling capable of controlling the engagement / release state is shown as the coupling mechanism. Thus, for example, the case where viscous coupling is used can be set as a control target. In this case, as in the above second and third control examples, the output torque of the engine is reduced, or by regenerative braking by the motor / generator to reduce the vehicle speed, It is possible to control the friction generated in the coupling mechanism to be reduced by reducing the frequency at which the shut-off state is switched.

It is a flowchart for demonstrating the 1st control example by the control apparatus of this invention. In the first control example, it is a flowchart for explaining the control content in the coupling protection mode. It is a flowchart for demonstrating the 2nd control example by the control apparatus of this invention. It is a flowchart for demonstrating the 3rd control example by the control apparatus of this invention. In the first control example, it is an example of a map for obtaining a correction coefficient A for correcting a target current value. In a 2nd control example, it is an example of the map for calculating | requiring the correction coefficient B which correct | amends the output torque of an engine. In a 3rd control example, it is an example of the map for calculating | requiring the automatic regeneration amount R in the case of performing automatic regeneration control. It is a conceptual diagram which shows typically the power transmission path | route and control system of a vehicle which can apply the control apparatus of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Power source (engine, hybrid system), 2 ... Transmission, 8, 9, 15, 16 ... Wheel, 10 ... Coupling mechanism (control coupling), 11 ... Driving force distribution device, 17 ... Electronic control device ( ECU), 22 ... coupling oil temperature sensor, Ve ... vehicle.

Claims (6)

In a vehicle control device including a driving force distribution device that distributes and transmits output torque of a power source to each driving wheel by a coupling mechanism capable of changing transmission torque,
Coupling temperature detecting means for detecting the temperature of the coupling mechanism;
Coupling overheat preventing means for reducing friction generated in the coupling mechanism and preventing the temperature from rising when the temperature detected by the coupling temperature detecting means exceeds a predetermined value. A control device for a vehicle. The coupling mechanism is a control coupling capable of executing a driving force distribution control for distributing and transmitting the output torque by controlling the engagement / release state and changing the transmission torque.
2. The vehicle according to claim 1, wherein the coupling overheat prevention means includes means for reducing the friction and reducing the temperature rise by reducing an execution frequency of the driving force distribution control. Control device.   3. The vehicle control device according to claim 2, wherein the coupling overheat preventing means includes means for reducing the friction and preventing the temperature from rising by stopping the driving force distribution control.   2. The vehicle control apparatus according to claim 1, wherein the coupling overheat prevention means includes means for reducing the friction by reducing a vehicle speed to prevent the temperature from rising.   5. The vehicle according to claim 4, wherein the coupling overheat prevention means includes means for reducing the friction by reducing the output torque and reducing the vehicle speed to prevent the temperature from rising. Control device. As the power source, an electric motor capable of executing power running / regenerative control is provided,
5. The coupling overheat preventing means includes means for reducing the friction and preventing the temperature from rising by regeneratively controlling the electric motor to perform braking and reduce a vehicle speed. Vehicle control device.

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