JP4254428B2 - Driving force distribution control device for four-wheel drive vehicles - Google Patents

Description

The present invention relates to a driving force distribution control device for a four-wheel drive vehicle that controls torque distribution to front and rear wheels by electronic control.

A conventional driving force distribution control device for a four-wheel drive vehicle has control region map setting means divided into a driving force distribution control region and a differential rotation control region according to the accelerator opening and the vehicle speed, and the detected accelerator opening and When the driving point based on the vehicle speed is the driving force distribution control area on the control area map, the driving force distribution control is executed by the large torque command, and the driving point is the differential rotation control area on the control area map. A technique for executing differential rotation control based on a torque command corresponding to a speed difference between a main drive wheel and a sub drive wheel is known (see, for example, Patent Document 1).
JP 2001-225658 A

  However, the conventional driving force distribution control device for a four-wheel drive vehicle has a configuration in which the control specifications are determined only by the accelerator opening and the vehicle speed. Even in a driving scene that does not require continuous large torque transmission, as long as the operating point exists in the driving force distribution control region, the driving force distribution control is continuously executed, and the sliding engagement is performed with high torque. There is a problem that the durability and reliability (for example, unit oil temperature and gear system fatigue strength) of the torque distribution actuator is reduced.

  The present invention has been made paying attention to the above problems, and provides a driving force distribution control device for a four-wheel drive vehicle capable of ensuring both start performance and improving the durability and reliability of a torque distribution actuator. The purpose is to provide.

In order to achieve the above object, in the present invention,
Four wheels equipped with a driving force distribution controller that determines the torque transmitted to the auxiliary driving wheels via a torque distribution actuator provided in the engine drive system by means selected from a plurality of preset driving force distribution control means In the driving force distribution control device for driving vehicles,
As the driving force distribution control means, torque corresponding driving force distribution control means for determining the transmission torque to the auxiliary driving wheel according to the engine torque equivalent value, and accelerator corresponding to the front and rear wheel driving force distribution control according to the accelerator opening speed. Driving force distribution control means ,
The driving force distribution controller prohibits determination of torque transmitted to the auxiliary driving wheel by the torque corresponding driving force distribution control means when the vehicle speed is equal to or higher than a predetermined value , and the accelerator corresponding driving force distribution control means applies the auxiliary driving wheel to the auxiliary driving wheel. The transmission torque is determined .

  Here, the “torque-adaptive driving force distribution control means” means, for example, feedforward control based on a target transmission torque characteristic set by an engine torque equivalent value such as an accelerator opening, a transmission output shaft torque, and an engine output shaft torque. Thus, means for outputting a command for transmitting a large torque to the auxiliary drive wheels for the purpose of securing the starting performance.

  Therefore, in the driving force distribution control device for a four-wheel drive vehicle according to the present invention, in the driving force distribution controller, when the vehicle speed is equal to or higher than a predetermined value, the transmission torque to the auxiliary driving wheel is determined according to the engine torque equivalent value. Torque-related driving force distribution control is prohibited, so starting performance is ensured by torque-compatible driving force distribution control in a starting region where the vehicle speed is less than a predetermined value, and torque is generated by suppressing unnecessary torque transmission in a traveling region where the vehicle speed is a predetermined value or more. It is possible to improve the durability and reliability of the distribution actuator.

  Hereinafter, the best mode for realizing a driving force distribution control device for a four-wheel drive vehicle according to the present invention will be described based on a first embodiment shown in the drawings.

First, the configuration will be described.
FIG. 1 is an overall system diagram showing a four-wheel drive vehicle based on a rear wheel drive to which a drive force distribution control device for a four-wheel drive vehicle according to a first embodiment is applied.

As shown in FIG. 1, the drive system of the four-wheel drive vehicle includes an engine 1, an automatic transmission 2, a rear propeller shaft 3, a rear differential 4, rear drive shafts 5 and 6, a left rear wheel 7, a right rear wheel 8, A truss clutch 9 (torque distribution actuator), a front propeller shaft 10, a front differential 11, front drive shafts 12 and 13, a left front wheel 14 and a right front wheel 15 are provided.
The left and right rear wheels 7 and 8 correspond to main drive wheels, and the left and right front wheels 14 and 15 correspond to auxiliary drive wheels.

  The engine 1 is subjected to fuel injection control or the like according to a command from the engine controller 16, and the automatic transmission 2 is subjected to gear shift control or the like according to a command from the automatic transmission controller 17.

  The front / rear differential limiting system that controls the engagement of the transfer clutch 9 includes a front / rear differential limiting actuator 19 and a differential limiting controller 20 (torque distribution controller) that outputs a fastening command or a release command to the front / rear differential limiting actuator 19. ).

  As the transfer clutch 9, for example, a hydraulic multi-plate clutch, an electromagnetic multi-plate clutch, or the like is applied, and it has a front-rear differential limiting function that limits the differential between the left and right rear wheels 7 and 8 and the left and right front wheels 14 and 15 by fastening. . That is, the left and right rear wheels 7 and 8 and the left and right front wheels 14 and 15 are driven by a torque distribution action in which the driving torque is transmitted from the left and right rear wheels 7 and 8 to the left and right front wheels 14 and 15 by fastening the transfer clutch 9. Limit 15 differentials.

  Information from an accelerator opening sensor 21 (accelerator opening detecting means), a longitudinal acceleration sensor 22, a mode changeover switch 23, and the like is input to the differential limiting controller 20. The mode changeover switch 23 is means for manually switching between the 2WD fixed mode, the 4WD fixed mode, and the auto mode. When the 4WD fixed mode of the mode switch 23 is selected, the differential limiting action for the front and rear wheels is strongest. When the auto mode of the mode changeover switch 23 is selected, for example, if the clutch engagement torque applied according to the front-rear wheel rotational speed difference, the accelerator opening speed, or the like is large, the differential allowance between the front and rear wheels is small and strong differential. The limiting effect is exhibited, and the differential allowable amount of the front and rear wheels gradually increases as the clutch engagement torque decreases.

  As shown in FIG. 1, an anti-lock brake system that brakes the wheels 7, 8, 14, and 15 with brake hydraulic pressure includes a brake pedal 30, a booster 31, a master cylinder 32, master cylinder hydraulic pipes 33 and 34, ABS actuator 35, left rear wheel wheel cylinder hydraulic pipe 36, right rear wheel wheel cylinder hydraulic pipe 37, left front wheel wheel cylinder hydraulic pipe 38, right front wheel wheel cylinder hydraulic pipe 39, left rear wheel wheel cylinder 40, right A rear wheel wheel cylinder 41, a left front wheel wheel cylinder 42, a right front wheel wheel cylinder 43, and a brake controller 44 are provided.

  The ABS actuator 35 is constituted by an oil pump, a hydraulic pressure control valve, and the like, and during normal braking, each wheel 7, via two brake hydraulic pressure systems divided corresponding to the master cylinder hydraulic pressure pipes 33, 34. Brake fluid pressure is supplied to 8,14,15. At the time of ABS operation, the brake fluid pressure is controlled by three modes of pressure reduction, holding, and pressure increase so as to suppress braking lock of each wheel 7, 8, 14, and 15.

  The brake controller 44 includes a brake lamp switch 45, a left front wheel speed sensor 46 (vehicle speed detection means), a right front wheel speed sensor 47 (vehicle speed detection means), a left rear wheel speed sensor 48, a right rear wheel speed sensor 49, and the like. Information is entered.

  The engine controller 16, the automatic transmission controller 17, the differential limit controller 20, and the brake controller 44 are connected to each other by a bidirectional communication line 50 for exchanging information. It is supplied to the differential limiting controller 20 via the directional communication line 50.

  Next, the operation will be described.

[Torque distribution control processing]
FIG. 2 is a flowchart showing the flow of torque distribution control processing executed at predetermined control cycles by the differential limiting controller 20 of the first embodiment. Each step will be described below.

In step S1, the accelerator opening degree ACC and the vehicle speed V are read, and the process proceeds to step S2.
Here, the accelerator opening ACC is calculated based on a sensor signal from the accelerator opening sensor 21. The vehicle speed V is calculated from an average value of the left front wheel speed and the right front wheel speed based on sensor signals from the left front wheel speed sensor 46 and the right front wheel speed sensor.

In step S2, whether or not the operating point based on the accelerator opening ACC and the vehicle speed V exists in the driving force distribution control region on the control region map divided into the driving force distribution control region and the differential rotation control region shown in FIG. If YES, the process proceeds to step S3. If NO, the process proceeds to step S6.
Here, the control area map shown in FIG. 3 is stored and set in advance in the memory of the differential limiting controller 20 (control area map setting means).

In step S3, it is determined whether or not the vehicle speed V is equal to or higher than a predetermined value. If YES, the process proceeds to step S4. If NO, the process proceeds to step S5.
Here, the “predetermined value” is set to a boundary region where the vehicle starts and moves to steady running, for example, a vehicle speed of 40 km / h to 60 km / h.

In step S4, if the vehicle speed V is greater than or equal to a predetermined value in the determination in step S3, the torque command value to the sub drive wheel by feedback control according to the speed difference between the main drive wheel and the sub drive wheel (the differential rotation compatible drive). Force distribution control means), the torque command value to the auxiliary drive wheel by feedforward control according to the accelerator opening speed and the command value by the select high of (acceleration corresponding driving force distribution control means) are set as the target transmission torque, A command for obtaining the target transmission torque is commanded to the front-rear differential limiting actuator 19 and the process proceeds to the end.
Here, the control according to the accelerator opening speed is obtained by calculating the accelerator opening speed by time differentiation processing of the accelerator opening ACC, and as shown in FIG. 4, the larger the determined accelerator opening speed, the larger the torque command value. Trr_ctrl is set, and the driving force distribution amount to the front wheels 14 and 15 is increased.

In step S5, when the vehicle speed V is less than the predetermined value in the determination in step S3, the torque command value to the auxiliary driving wheel by feedback control according to the speed difference between the main driving wheel and the auxiliary driving wheel, and the engine torque equivalent value The command value by the select high of the torque command value to the auxiliary driving wheel by the feedforward control according to the torque and the (high torque corresponding driving force distribution control means) is set as the target transmission torque, and the command to obtain this target transmission torque is set to the front-to-back difference. A command is given to the motion limiting actuator 19 to shift to the end.
Here, the “engine torque equivalent value” refers to, for example, the accelerator opening, the transmission output shaft torque, the engine output shaft torque, and the like, and the “torque command value to the sub drive wheels by feedforward control” Based on the target transmission torque characteristic set by the engine torque equivalent value, it refers to a command for transmitting a large torque to the sub drive wheels for the purpose of securing the starting performance.

  In step S6, if the operating point based on the accelerator opening ACC and the vehicle speed V in step S2 exists in the differential rotation control region on the control region map divided into the driving force distribution control region and the differential rotation control region shown in FIG. If it is determined, it is determined whether or not the vehicle speed V is equal to or higher than a predetermined value. If YES, the process proceeds to step S7, and if NO, the process proceeds to step S8.

  In step S7, if the vehicle speed V is greater than or equal to a predetermined value in the determination in step S6, the torque command value for the auxiliary driving wheel by the feedback control according to the speed difference between the main driving wheel and the auxiliary driving wheel, and the accelerator opening speed The command value by the select high of the torque command value to the auxiliary drive wheel by the feedforward control according to and the command value by the selection high is set as the target transmission torque, and the command to obtain this target transmission torque is commanded to the front-rear differential limiting actuator 19 and the end Migrate to

  In step S8, when the vehicle speed V is less than the predetermined value in the determination in step S6, the torque command value to the auxiliary driving wheel by the feedback control according to the speed difference between the main driving wheel and the auxiliary driving wheel is set as the target transmission torque. Then, a command for obtaining the target transmission torque is commanded to the front-rear differential limiting actuator 19 and the process proceeds to the end.

[Torque distribution control function]
The torque distribution control action is based on the time chart shown in FIG. 4, taking as an example the case where the vehicle has entered a curve after running continuously uphill after starting on a slope with a tight mountain road. explain.

  First, when the accelerator is depressed and the vehicle starts at time t0, the flow proceeds from step S1 to step S2 to step S3 to step S5 in the flowchart of FIG. Front / rear wheel torque distribution control is executed in which the command value based on the select high between the transmission torque at the torque and the transmission torque in the torque corresponding driving force distribution control is the target transmission torque.

  In step S3, until the time point t1 when the vehicle speed V is determined to be equal to or higher than the predetermined value, the flow of steps S1 → step S2 → step S3 → step S5 is repeated in the flowchart of FIG. Front / rear wheel torque distribution control is executed using a command value based on a selection high between the transmission torque in the rotation-compatible driving force distribution control and the transmission torque in the torque-compatible driving force distribution control as the target transmission torque.

  Therefore, from the start until the vehicle speed reaches a predetermined value, for example, the larger the accelerator opening ACC, the larger the transmission torque is transmitted to the left and right front wheels 14 and 15, which are auxiliary drive wheels, and the engine torque is transferred to the four wheels 7, 8, 14 , 15 can be distributed on the road up and down continuously with high driving performance that suppresses the driving slip of the left and right rear wheels 7, 8.

  Next, when it is determined that the vehicle speed V is greater than or equal to a predetermined value at the time t1, the flow proceeds to step S1, step S2, step S3, step S4 in the flowchart of FIG. Front-and-rear wheel torque distribution control is executed with a command value based on select high between the transmission torque in the corresponding driving force distribution control and the transmission torque in the accelerator-compatible driving force distribution control as the target transmission torque.

  Then, in step S3, as long as the vehicle speed V is equal to or higher than a predetermined value, step S1 in the flowchart of FIG. 2 is determined until it is determined that the accelerator is released at time t2 immediately before entering the curve on the steep mountain road. Step S2 → Step S3 → Step S4 is repeated, and the command value based on the selection high between the transmission torque in the differential rotation corresponding driving force distribution control and the transmission torque in the accelerator corresponding driving force distribution control is set as the target transmission torque. The front and rear wheel torque distribution control is executed.

  Therefore, unlike the conventional control specification in which the driving force distribution control is continued until time t3, the driving force distribution control mode is switched at time t1, and the accelerator opening speed is zero from t1 to t2. Therefore, as long as there is no differential rotation between the main drive wheel and the sub drive wheel, the torque transmitted to the left and right front wheels 14, 15 is reduced to zero. For this reason, for example, when the transfer clutch 9 is a hydraulic clutch unit, an excessive increase in the oil temperature is prevented, and a gear, a chain, or the like is provided in the unit torque transmission path to the left and right front wheels 14 and 15. The fatigue strength is ensured, and the durability and reliability of the transfer clutch 9 can be improved.

  Next, in the flowchart of FIG. 2, the flow from step S1 → step S2 → step S6 → step S7 is repeated in the flowchart of FIG. The front and rear wheel torque distribution control using the command value by the select high of the transmission torque in the differential rotation corresponding driving force distribution control and the transmission torque in the accelerator corresponding driving force distribution control as the target transmission torque is continued.

  Therefore, in the traveling section from t2 to t3, since the accelerator opening speed is zero, the torque transmitted to the left and right front wheels 14 and 15 as long as there is no differential rotation between the main drive wheel and the sub drive wheel. The torque distribution control for the front and rear wheels, where the torque is reduced to zero, will continue as it is from the point of time t1, large torque transmission to the sub drive wheels will be suppressed, and the durability and reliability of the transfer clutch 9 will be improved. Can do.

  Next, when the accelerator is depressed again in the section from the time point t3 to the time point t4 after exiting the curve, the flow proceeds to step S1, step S2, step S6, step S7 in the flowchart of FIG. In S7, front and rear wheel torque distribution control is executed in which the command value based on the select high of the transmission torque in the differential rotation corresponding driving force distribution control and the transmission torque in the accelerator corresponding driving force distribution control is set as the target transmission torque.

  Therefore, in the travel section from t3 to t4, since the accelerator opening speed is high, a high torque is temporarily transmitted to the left and right front wheels 14 and 15, and the acceleration performance after the curve is lost is ensured.

  Furthermore, after t4, when the accelerator depression operation is finished and maintained at a high accelerator opening, the accelerator opening speed is zero, so the right and left are not affected unless there is a differential rotation between the main drive wheel and the sub drive wheel. Front and rear wheel torque distribution control is executed in which the torque transmitted to the front wheels 14 and 15 is reduced to zero.

  [Contents of torque distribution control]

The torque distribution control contents of the first embodiment are as shown in the control area map of FIG.
(1) TA1 area When the driving point of the vehicle is in the driving force distribution control area and the vehicle speed V <the TA1 area where the vehicle speed V <predetermined value, in step S5 in FIG. The torque command value based on the torque corresponding driving force distribution control and the command value based on the select high are set as the target transmission torque.
(2) TA2 region When the driving point of the vehicle is in the driving force distribution control region and the vehicle speed V is equal to or greater than the predetermined value TA2, the torque command value by the differential rotation corresponding driving force distribution control is set in step S4 of FIG. Then, the torque command value by the accelerator corresponding driving force distribution control and the command value by the select high are set as the target transmission torque.
(3) When the operating point of the DA1 area vehicle is in the differential rotation control area and the vehicle speed V <the DA1 area where the vehicle speed V <predetermined value, the target torque command value by the differential rotation corresponding driving force distribution control is set in step S8 of FIG. The transmission torque.
(4) In the DA2 region where the driving point of the DA2 region vehicle is in the differential rotation control region and the vehicle speed V ≧ predetermined value, in step S7 of FIG. The torque command value by the accelerator corresponding driving force distribution control and the command value by the select high are set as the target transmission torque.

  In other words, although there are four control modes on the control area map, the same control is performed in the TA2 area and the DA2 area. There are three control modes: a mode, a control mode corresponding to differential rotation in the DA1 area, and a control mode based on differential rotation corresponding to the TA2 + DA2 area and a control mode corresponding to the accelerator.

  Here, from the three control modes, excluding the differential rotation support control that feedback controls the torque distribution of the front and rear wheels to suppress drive slip, the torque support control mode in the TA1 region and the accelerator support in the TA2 + DA2 region It can be seen that the control mode is divided according to the vehicle speed condition. The reason will be described below.

(1) Reason for Switching between Torque-Compatible Control Mode and Accelerator-Compatible Control Mode by “Vehicle Speed” Necessary auxiliary driving wheel torque in a traveling scene where the vehicle speed is high is not so much required as compared to when starting. That is, in order to achieve both the 4WD performance and the improvement of component durability reliability, the switching determination condition is the vehicle speed.

(2) Reasons to set the accelerator control mode when the vehicle speed is higher than the specified value Unnecessary command torque is applied in a driving scene where the accelerator pedal is continuously depressed even if the vehicle is not accelerating, such as on a continuous uphill road. It was inspired by the desire to cut. That is, in a traveling scene such as a continuous uphill road, in the conventional technique, an unnecessary torque is commanded even when the vehicle speed exceeds a predetermined vehicle speed. However, as described above, in the first embodiment, the accelerator is operated when the vehicle speed exceeds a predetermined value. If the corresponding control mode is set, the transmission torque can be suppressed in a traveling scene in which the accelerator pedal is continuously depressed, and the durability reliability of the parts is reliably improved.

(3) Reason why the vehicle speed should be less than the predetermined value and the torque corresponding control mode should be set. This is to ensure the start performance as in the prior art. When the accelerator-compatible control mode is applied when the vehicle speed is less than a predetermined value, for example, the accelerator pedal is depressed at the time of starting uphill, but after that, when the accelerator opening is constant, 4WD does not become 4WD. Performance cannot be secured.

Next, the effect will be described.
In the driving force distribution control device for a four-wheel drive vehicle according to the first embodiment, the following effects can be obtained.

  (1) Provided with a driving force distribution controller that determines torque transmitted to the sub drive wheels via a torque distribution actuator provided in the engine drive system by means selected from a plurality of preset driving force distribution control means In the four-wheel drive vehicle driving force distribution control device, the driving force distribution control means is provided with torque corresponding driving force distribution control means for determining the transmission torque to the sub driving wheel according to the engine torque equivalent value, and the driving force When the vehicle speed is equal to or higher than a predetermined value, the distribution controller prohibits the determination of the torque transmitted to the auxiliary drive wheels by the torque-compatible driving force distribution control means, so that the torque-compatible driving force distribution control in the starting region where the vehicle speed is less than the predetermined value. The durability and reliability of the torque distribution actuator is ensured by ensuring start performance by driving and suppressing unnecessary torque transmission in the driving range where the vehicle speed exceeds the specified value. It is possible to achieve the above, the compatibility of.

  (2) As the driving force distribution control means, provided is an accelerator corresponding driving force distribution control means for performing front and rear wheel driving force distribution control according to the accelerator opening speed, and the driving force distribution controller includes the torque corresponding driving force distribution control. When the vehicle speed is about to be accelerated by the accelerator depressing operation in the traveling region where the vehicle speed is equal to or higher than the predetermined value in order to determine the transmission torque to the auxiliary driving wheel by the accelerator-corresponding driving force distribution control means. Acceleration can be improved by suppressing the occurrence of wheel drive slip.

  (3) The accelerator-adaptive driving force distribution control means increases the amount of driving force distribution to the auxiliary driving wheel as the accelerator opening speed increases, so the driving performance increases as the driver's acceleration intention appears in the accelerator depression speed. be able to.

  (4) As the driving force distribution control means, provided is a differential rotation-compatible driving force distribution control means for determining a transmission torque to the auxiliary driving wheel according to a speed difference between the main driving wheel and the auxiliary driving wheel, and the driving force distribution controller When the torque corresponding driving force distribution control is prohibited, the driving force distribution is controlled by selecting high between the transmission torque by the accelerator corresponding driving force distribution control means and the transmission torque by the differential rotation corresponding driving force distribution control means. When the torque corresponding driving force distribution control is not prohibited, the driving force distribution is controlled by selecting high between the transmission torque by the torque corresponding driving force distribution control means and the transmission torque by the differential rotation corresponding driving force distribution control means. Ensuring start performance in the stop-low speed range, improving the durability and reliability of the torque distribution actuator in the mid-high speed range, and suppressing drive slip in all vehicle speed ranges , It can be achieved together.

  (5) Vehicle speed detecting means for detecting the vehicle speed, accelerator opening detecting means for detecting the accelerator opening, and control in which the driving force distribution control area and the differential rotation control area are set according to the relationship between the vehicle speed and the accelerator opening. An area map setting means, wherein the driving force distribution controller is configured such that the vehicle speed is a predetermined value when the driving point of the vehicle based on the vehicle speed detection value and the accelerator opening detection value exists in the driving force distribution control area on the control area map. When the vehicle speed is less than a predetermined value, control is performed by selecting high between the transmission torque by the differential rotation-compatible driving force distribution control means and the transmission torque by the accelerator-compatible driving force distribution control means. The driving force distribution is controlled by selecting high between the transmission torque by the distribution control means and the transmission torque by the torque corresponding driving force distribution control means, and the vehicle speed detection value and the accelerator opening detection When the driving point of the vehicle is present in the differential rotation control region on the control region map, when the vehicle speed is a predetermined value or more, the transmission torque by the differential rotation corresponding driving force distribution control unit and the accelerator corresponding driving force distribution control unit When the vehicle speed is less than a predetermined value, the driving force distribution is controlled by the transmission torque by the differential rotation corresponding driving force distribution control means. While using the control region map based on the relationship as it is, the optimum driving force distribution control can be executed in each region divided on the control region map simply by adding the switching determination condition based on the vehicle speed on the control region map. .

  As mentioned above, although the drive force distribution control apparatus of the four-wheel drive vehicle of this invention has been demonstrated based on Example 1, it is not restricted to this Example 1 about a concrete structure, Each of Claims Design changes and additions are permitted without departing from the scope of the claimed invention.

  For example, in the first embodiment, when the torque corresponding driving force distribution control is prohibited, the example is switched to the accelerator corresponding driving force distribution control. However, when the torque corresponding driving force distribution control is prohibited, the torque distribution actuator is released, It is good also as an example which transfers to a two-wheel drive state.

  In the first embodiment, an example in which a vehicle speed threshold value (predetermined value) is given by a fixed value as a vehicle speed condition that is a switching determination condition. However, by a manual switching operation by a driver's preference or an automatic switching operation by a vehicle state or the like, A vehicle speed threshold value (predetermined value) may be given by a variable value.

  The driving force distribution control device for a four-wheel drive vehicle according to the present invention is not limited to an application example to a four-wheel drive vehicle based on a rear wheel drive, but can also be applied to a four-wheel drive vehicle based on a front wheel drive base.

1 is an overall system diagram illustrating a driving force distribution control device for a four-wheel drive vehicle according to a first embodiment. 6 is a flowchart illustrating a flow of torque distribution control processing executed by the differential limiting controller according to the first embodiment. It is a figure which shows the control area map set to the differential limiting controller of Example 1. FIG. It is a figure which shows the sub drive wheel transmission torque characteristic with respect to the accelerator opening speed used by accelerator corresponding driving force distribution control. It is a time chart which shows the torque distribution control effect | action performed with the differential limiting controller of Example 1 at the time of an uphill traveling with a strong gradient.

Explanation of symbols

1 Engine 2 Automatic transmission 3 Rear propeller shaft 4 Rear differential 5, 6 Rear drive shaft 7 Left rear wheel 8 Right rear wheel 9 Truss clutch (torque distribution actuator)
DESCRIPTION OF SYMBOLS 10 Front propeller shaft 11 Front differential 12, 13 Front drive shaft 14 Left front wheel 15 Right front wheel 16 Engine controller 17 Automatic transmission controller 19 Front-back differential limiting actuator 20 Differential limiting controller (torque distribution controller)
21 Accelerator opening sensor (accelerator opening detector)
22 Longitudinal acceleration sensor 23 Mode changeover switch 44 Brake controller 46 Front left wheel speed sensor (vehicle speed detection means)
47 Front right wheel speed sensor (vehicle speed detection means)
48 Left rear wheel speed sensor 49 Right rear wheel speed sensor

Claims (4)

Four wheels equipped with a driving force distribution controller that determines the torque transmitted to the auxiliary driving wheels via a torque distribution actuator provided in the engine drive system by means selected from a plurality of preset driving force distribution control means In the driving force distribution control device for driving vehicles,
As the driving force distribution control means, torque corresponding driving force distribution control means for determining the transmission torque to the auxiliary driving wheel according to the engine torque equivalent value, and accelerator corresponding to the front and rear wheel driving force distribution control according to the accelerator opening speed. Driving force distribution control means ,
The driving force distribution controller prohibits determination of torque transmitted to the auxiliary driving wheel by the torque corresponding driving force distribution control means when the vehicle speed is equal to or higher than a predetermined value , and the accelerator corresponding driving force distribution control means applies the auxiliary driving wheel to the auxiliary driving wheel. A driving force distribution control device for a four-wheel drive vehicle, wherein the transmission torque of the vehicle is determined . In the drive force distribution control device for a four-wheel drive vehicle according to claim 1 ,
The driving force distribution control device for a four-wheel drive vehicle, wherein the accelerator-compatible driving force distribution control means increases the amount of driving force distribution to the auxiliary driving wheels as the accelerator opening speed increases. In the driving force distribution control device for a four-wheel drive vehicle according to claim 1 or 2 ,
As the driving force distribution control means, provided is a differential rotation-compatible driving force distribution control means for determining the transmission torque to the auxiliary driving wheel according to the speed difference between the main driving wheel and the auxiliary driving wheel,
When the driving force distribution controller prohibits the torque corresponding driving force distribution control, the driving force distribution controller is driven by selecting high between the transmission torque by the accelerator corresponding driving force distribution control means and the transmission torque by the differential rotation corresponding driving force distribution control means. When the force distribution is controlled and the torque corresponding driving force distribution control is not prohibited, the driving force is selected by selecting high between the transmission torque by the torque corresponding driving force distribution control means and the transmission torque by the differential rotation corresponding driving force distribution control means. A driving force distribution control device for a four-wheel drive vehicle, characterized by controlling the distribution. The drive force distribution control device for a four-wheel drive vehicle according to any one of claims 1 to 3 ,
Vehicle speed detection means for detecting the vehicle speed;
An accelerator opening detecting means for detecting the accelerator opening;
A control region map setting means for setting a driving force distribution control region and a differential rotation control region according to the relationship between the vehicle speed and the accelerator opening; and
The driving force distribution controller, when the vehicle operating point based on the vehicle speed detection value and the accelerator opening detection value is present in the driving force distribution control region on the control region map, when the vehicle speed is equal to or greater than a predetermined value, When the vehicle speed is less than a predetermined value, the transmission torque by the differential rotation correspondence driving force distribution control means and the torque are controlled by selecting high between the transmission torque by the force distribution control means and the transmission torque by the accelerator correspondence driving force distribution control means. When the driving force distribution is controlled by selecting high with the transmission torque by the corresponding driving force distribution control means, and the driving point of the vehicle based on the vehicle speed detection value and the accelerator opening detection value exists in the differential rotation control region on the control region map, When the vehicle speed is equal to or higher than a predetermined value, the transmission torque by the differential rotation corresponding driving force distribution control means and the transmission torque by the accelerator corresponding driving force distribution control means Of controlled by select-high, the vehicle speed is the differential speed corresponding driving force distribution of a four-wheel-drive vehicle and controls the driving force distribution by the torque transmitted by the control means the driving force distribution control apparatus when less than the predetermined value.

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