JPH054532A - Control device for vehicle - Google Patents

Abstract

PURPOSE:To improve the traveling stability and fuel consumption of a vehicle by setting at least either one of an inter-axle differential and inter-wheel differentials to the complete lock state, and releasing the set complete lock state when the vehicle travels at the preset speed or above. CONSTITUTION:In the power transmission system of a vehicle, a central differential 20 is arranged on a transfer 12, and front and rear differentials 21, 22 are arranged on front and rear axles 15, 17 respectively. The differentials 20-22 are controlled by a differential control unit 43 respectively based on input signals from a throttle sensor 32, a brake switch 31 and a manual switch 44. The differential control unit 43 sets at least either one of the inter-axle differential 20 and the inter-wheel differentials 21, 22 to the complete lock state, and it releases the set complete lock state when the vehicle travels at the preset vehicle speed or above.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle control system, and more particularly to a four-wheel drive vehicle control system having a differential limiting device.

[0002]

2. Description of the Related Art Generally, a four-wheel drive vehicle has a center differential between the axles of the front and rear wheels, a front differential between the front wheels, and a rear differential between the rear wheels in order to prevent slippage due to a difference in the trajectories of the front and rear wheels during turning. Are provided respectively. Such a four-wheel drive vehicle is described in, for example, Japanese Patent Laid-Open No. 62-166114. This publication discloses a four-wheel drive vehicle including a front differential, a rear differential, and a center differential whose operating states are locked and unlocked by hydraulic pressure.

In this conventional four-wheel drive vehicle, a wheel speed signal and a steering angle signal of each wheel are input to a control circuit, and rough road determination, straight traveling determination, acceleration determination and braking determination are performed based on these values. The operating states of the front differential, rear differential, and center differential are automatically set according to various driving conditions to improve steering stability, braking performance, and acceleration performance.

[0004]

However, in this conventional four-wheel drive vehicle, no consideration is given to the traveling speed of the vehicle. Therefore, how to control the vehicle based on the traveling speed of the vehicle is considered. Is not shown in the above publication. Therefore, an object of the present invention is to provide a control device for a vehicle, which improves traveling stability and fuel consumption of the vehicle by controlling the differential limiting device based on the traveling speed of the vehicle.

[0005]

In order to achieve the above object, the present invention relates to a vehicle control device having a differential limiting device for performing differential limiting with an inter-axle differential and an inter-wheel differential in a locked state. First differential limiting means provided on the differential, second differential limiting means provided on the inter-wheel differential, and the first
A lock state setting means for setting at least one of the differential limiting means and the second differential limiting means to a complete lock state, and a complete lock set by the lock state setting means when the vehicle travels at a predetermined speed or more. Differential limiting control means for canceling the state.

In the present invention thus constructed,
When at least one of the first differential limiting unit and the second differential limiting unit is completely locked by the lock state setting unit, the running stability of the vehicle is improved, and when the vehicle runs at a predetermined speed or higher, Since the complete lock state set by the lock state setting means is released by the differential limiting control means, when the vehicle turns, the differential limiting means operates, so that slip does not occur and the running resistance is reduced accordingly. The fuel efficiency can be improved.

Further, in the present invention, when the first differential limiting means and the second differential limiting means are set to the completely locked state by the locked state setting means, the vehicle is set to the first differential limiting means by the differential limiting control means. When traveling at a predetermined speed or faster
The locked state of the second differential limiting unit may be released when the locked state of the differential limiting unit is released and the vehicle travels at a second predetermined speed or slower than the first predetermined speed.

In the present invention thus constituted, the first differential limiting means, which has a great influence due to the running stability of the vehicle, is set in the completely locked state up to the first predetermined speed which is higher than the second predetermined speed. It also improves driving stability. Further, in the present invention, after the complete lock state is released by the differential limiting control means, the intermediate lock state or the unlock state may be automatically controlled according to the operating state of the vehicle.

Further, the first differential limiting means and the second differential limiting means may have electromagnetic clutches. In this case, the completely locked state of the first differential limiting means and the second differential limiting means is released by the electromagnetic clutch, whereby the power consumption in the electromagnetic clutch is reduced, power saving is achieved, and fuel consumption is improved. To do. Further, the present invention is a differential limiting device for a vehicle, which performs differential limiting with a center differential provided between axles, a rear differential provided between rear wheels, and a front differential provided between front wheels being locked. A first differential limiting means provided on the center differential, a second differential limiting means provided on the rear differential, a third differential limiting means provided on the front differential, and the first differential limiting means. A lock state setting unit that sets the differential limiting unit, the second differential limiting unit, and the third differential limiting unit to a completely locked state, and the lock state setting unit when the vehicle travels at a predetermined speed or more. A differential limiting control means for releasing the completely locked state, and the vehicle runs at a first predetermined speed or higher by the differential limiting control means. When the first differential limiting means locked state is released and the vehicle travels at a second predetermined speed or slower than the first predetermined speed, the second differential limiting means locked state is released, and the vehicle moves to the second When the vehicle travels at a third predetermined speed or slower than the predetermined speed, the third differential limiting device is unlocked by releasing the locked state.

In the present invention thus constructed,
Further, when the vehicle travels at the third predetermined speed or lower, which is slower than the second predetermined speed, the third differential limiting device is unlocked by releasing the locked state, so that the operability is improved.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram showing an overall configuration of a vehicle control device of the present invention. First, the power transmission system of the vehicle shown in FIG. 1 will be described. 10 is an engine, and a transmission 11 is connected to the engine 10.
A transfer 12 is connected to the transmission 11. This transfer 12 has an engine 1
A front propeller shaft 13 for transmitting the output from 0 to the front wheel side and a rear propeller shaft 14 for transmitting the output to the rear wheel side are respectively connected. A front wheel 16 is connected to the front propeller shaft 13 via a front axle 15. A rear wheel 18 is connected to the rear propeller shaft 14 via a rear axle 17. In addition, the transfer 12
Differential 20 (hereinafter referred to as center differential),
The front axle 15 is provided with a front differential 21 (hereinafter referred to as front differential), and the rear axle 17 is provided with a rear differential 22 (hereinafter referred to as rear differential).

A wheel speed sensor 30 for detecting the wheel speed of each wheel is attached to each front wheel 16 and each rear wheel 18. Reference numeral 31 is a brake switch, and the brake switch 31 detects ON / OFF of the brake. Reference numeral 32 denotes a throttle sensor, which detects the throttle opening of the engine 10.

Reference numeral 40 denotes an engine control unit, and the throttle opening is input from the throttle sensor 32 to the engine control unit 40. Reference numeral 41 is a control unit for an anti-skid brake device (hereinafter referred to as an ABS control unit), and each wheel speed is input from the wheel speed sensor 30 to the ABS control unit 41. Reference numeral 43 denotes a differential control unit. The differential control unit 43 is connected with a manual switch 44 and a battery 45 for selecting a diff lock mode to be described later. The differential control unit 43 includes a throttle opening from the throttle sensor 32, a brake signal from the brake switch 31, an ABS signal from the ABS control unit 41 indicating whether the anti-skid brake device is in operation, and each wheel. The wheel speed and the mode signal are input from the manual switch 44, respectively. Based on each of these input values, the differential control unit 43
To the center differential 20, the front differential 21 to the front differential current, and the rear differential 22 to the rear differential current. Based on these current values, the center differential 20, the front differential 21, and the rear differential 22 are in the unlocked state, the intermediate differential state, and the intermediate differential state. Locked and completely locked. Control unit 4 for differential
3 to ABS control unit 41, ABS
A prohibition signal is output.

FIG. 2 is a sectional view showing an electromagnetic multi-plate clutch provided on the center differential. The center differential 20 is provided with an electromagnetic multi-plate clutch 50, and the electromagnetic multi-plate clutch 50 brings the center differential 20 into an unlocked state, an intermediate locked state, and a completely locked state. The electromagnetic multi-plate clutch 50 may be of any type as long as it can limit the differential between the front propeller shaft 13 and the rear propeller shaft 14. An example thereof is shown in FIG. In FIG. 2, the electromagnetic multi-plate clutch 50 is composed of a clutch plate 51 composed of a plurality of inner discs and an outer disc, and an actuator 52 for generating a pressing force on the clutch plate 51. 53 is a bearing,
Reference numeral 54 is a transmission member that is transmission-connected to one propeller shaft, and 55 is a transmission member that is transmission-connected to the other propeller shaft. The actuator 52 uses the magnetic force generated when a current flows through the solenoid 56 to cause the armature 5 to move.
7 is configured to press the clutch plate 51.
In this electromagnetic multi-plate clutch 50, the solenoid 56
Is proportional to the pressing force for frictionally engaging the clutch plate 51, that is, the torque generated by the electromagnetic multi-plate clutch 50, the operating speed of the center differential 20 can be continuously changed by increasing or decreasing the current. it can.

The front differential 21 and the rear differential 22 are also provided with an electromagnetic multi-plate clutch, but the description thereof is omitted because it has the same structure as that shown in FIG. Next, the control contents in each mode selected by the manual switch 44 will be described with reference to Table 1.

[0016]

[Table 1]

As shown in Table 1, in the "AUTO (A mode)" of the manual switch 44, the front differential 21 is in the unlocked state, and the center differential 20 and the rear differential 22 are in the automatic mode control. "C (C mode)"
In the above, the front differential 21 is unlocked, the center differential 20 is completely locked, and the rear differential 22 is in automatic mode control. In "R (R mode)", the front differential 21 is unlocked, and the center differential 20 and the rear differential 22 are completely locked. In "F (F mode)", the front differential 21 and the center differential 20
Also, all of the rear differential 22 are completely locked. Here, If is the front differential current, Ic is the center differential current, Ir is the rear differential current, and the numerical values are the current values thereof. The electromagnetic multiple disc clutches provided in each differential are provided with the differential current of these values. By being supplied, each differential is brought into a completely locked state.

Each of these modes is arbitrarily selected by the driver. In A mode, front differential 2
Since No. 1 is in the unlocked state, it has little influence on the drivability and is excellent in operability, and is suitable for on-road traveling on a normal road such as an urban area. On the other hand, "F mode"
In, since the front differential 21, the center differential 20, and the rear differential 22 are all completely locked,
Operability is reduced, but driveability is excellent, making it suitable for off-road traveling on rough roads. The “C mode” and the “R mode” have characteristics between them and are selected according to the driver's preference.

Next, the control contents of the differential control unit 43 will be described with reference to FIGS. In these figures, the symbol P indicates each step in the flowchart. FIG. 3 is a flowchart showing a vehicle body speed calculation routine in the "A mode" automatic mode control. As shown in FIG. 3, at P10, the wheel speeds Nfr, Nfl, Nrr, Nrl are input. here,
Nfr represents the wheel speed of the right front wheel, Nfl represents the wheel speed of the left front wheel, Nrr represents the wheel speed of the right rear wheel, and Nrl represents the wheel speed of the left rear wheel. Next, at P11, these wheel speeds Nfr,
The minimum value of Nfl, Nrr, and Nrl is defined as the vehicle body speed Vsp.

FIG. 4 is a flow chart showing a center differential differential rotation speed calculation routine in the automatic mode control of the "A mode". As shown in FIG. 4, the wheel speeds Nfr, Nfl, Nrr, and Nrl are input at P20. Then P21
At, the center differential differential rotation speed ΔNc, which is the rotation difference, is obtained. FIG. 5 is a flowchart showing a rear differential differential rotation speed calculation routine in the automatic mode control of the “A mode”. As shown in FIG. 5, at P30, the wheel speeds Nrr and Nrl of the rear wheels are input. Next, at P31, the rear differential differential rotation speed ΔNr is obtained.

FIG. 6 is a flow chart showing a center differential current setting routine in the automatic mode control of the "A mode". As shown in FIG. 6, at P40, the center differential current Ic is set. This center differential current Ic
Is calculated from the center differential differential rotation speed ΔNc and the throttle opening TVO. FIG. 7 is a diagram showing the relationship between the current value I ₁ and the center differential differential rotation speed ΔNc, and FIG. 8 is a diagram showing the relationship between the current value I ₂ and the throttle opening TVO. That is, when either the center differential differential rotation speed ΔNc or the throttle opening TVO reaches the maximum current value Imax, the center differential current Ic is set to “Ic = Imax”. When both the center differential differential rotation speed ΔNc and the throttle opening TVO are equal to or less than the maximum current value Imax,
Based on the current value I ₁ and the current value I ₂ at that time, the center differential current Ic is calculated using a predetermined arithmetic expression. Then P41
At, it is determined whether the center differential current Ic has the maximum current value Imax, and the center differential current Ic has the maximum current value Im.
When it is different from ax, that is, when it is smaller than the maximum current value Imax, "Ic = Ic" is set in P42. At this time, the center differential 20 is in an intermediate locked state, and in the case of "Ic = 0", it is in an unlocked state.
When the center differential current Ic is the maximum current value Imax, P4
The timer is set at 3 and the center differential current Ic is set at "Ic = Imax" at P44. At this time, the center differential 20 is completely locked. Then P4
In 5, the timer is counted up, and in P46, it is judged whether or not a predetermined time has elapsed. That is, when the center differential differential rotation speed ΔNc suddenly increases due to slip or the like, the center differential 20 is kept in a completely locked state for a predetermined time.

FIG. 9 is a flowchart showing a rear differential control current value setting routine in the automatic control in the "AUTO mode". The rear differential control current value setting routine is basically the same as the above center differential control current value setting routine. That is, as shown in FIG. 9, the rear differential current Ir is similarly set at P50. Next, in P51, it is determined whether or not the rear differential current Ir has the maximum current value Imax. If the rear differential current Ir is smaller than the maximum current value Imax, "Ir = Ir" is set in P52. At this time, the rear differential 22 is in the intermediate lock state,
Further, in the case of "Ic = 0", the unlocked state is set. When the rear differential current Ir has the maximum current value Imax, the timer is set at P53 and the rear differential current I is set at P54.
Set r as “Ir = Imax”. At this time, the rear differential 22 is completely locked. Next, in P54, the timer is counted up, and in P56, it is determined whether or not a predetermined time has elapsed. That is, when the rear differential differential rotation speed ΔNr rapidly increases due to slippage or the like, the rear differential 22 is held in the completely locked state for a predetermined time.

Next, the control contents when the brake switch and the ABS device are operated will be described with reference to Table 2.

[0024]

[Table 2]

The ABS device detects the skid state of each wheel based on the vehicle body speed and each wheel speed, and controls the braking force of each wheel according to the skid state so as to cancel the locking tendency of the wheel during braking. is doing. However, in a vehicle having the front differential 21, the center differential 20, and the rear differential 22, it is impossible to estimate the vehicle speed when any of these is completely locked, so that it is difficult to perform appropriate ABS control. Becomes Therefore, in the embodiment of the present invention, when the brake switch 31 and the ABS device are activated, the control shown in Table 2 is performed.

First, in the "A mode", when the brake operates, that is, when the brake signal is ON, "I"
f = 0, Ic = 0, Ir = 0 ", and all the front differential 21, the center differential 20, and the rear differential 22 are unlocked. In the "C mode", if the brake signal is ON, "If = 0, Ic = 0.8 (within 0.2 seconds), Ir = 0" is set, and the front differential 21 and the rear differential 22 are unlocked. , The intermediate limiting state is set within 0.2 seconds after the center differential 20 is turned on to reduce the differential limiting force. Further, when the ABS device operates, that is, when the ABS signal is ON, “If =
0, Ic = 0 (within 0.2 seconds), Ir = 0 ”,
All of the front differential 21, the center differential 20, and the rear differential 22 are unlocked.

In the "R mode", the brake signal O
In the case of N, “If = 0, Ic = 0.8, Ir = 1.2”
Then, the front differential 21 is unlocked, the center differential 20 and the rear differential 22 are in an intermediate locked state, and the differential limiting force is reduced. If the ABS signal is ON,
"If = 0, Ic = 0, Ir = 0" is set, and all of the front differential 21, the center differential 20, and the rear differential 22 are unlocked.

In the "F mode", ABS control is not performed. Here, FIG. 10 shows the ABS in the “F mode”.
It is a flow chart which shows a control prohibition routine. Figure 10
Enter the mode at P60 as shown in
It is determined whether or not the mode input in is the "F mode". If the mode is other than the "F mode", ABS control is enabled in P62, and in the "F mode", the A mode is selected in P63.
BS control is prohibited.

In the control shown in Table 2 described above,
In the "A mode", "C mode", and "R mode", when the brake signal is ON, the control contents are unlocked or each diff that is in auto mode control is unlocked, and the control contents are The differential, which is in a completely locked state, is in an intermediate locked state. afterwards,
When the ABS signal is turned on, all of the front differential 21, the center differential 20, and the rear differential 22 are unlocked. Therefore, even if all the differentials are in the unlocked state when the ABS device is operating, the operation limiting force of each differential is lowered in advance when the brake is activated, so that the responsiveness of the ABS control can be improved. In the "F mode", the differential control is prioritized over the ABS control.
The driver can obtain the desired driving force.

Next, referring to Table 3, power saving control during high speed traveling will be described.

[0031]

[Table 3]

Table 3 is a flow chart showing the power saving control during high speed running. First, "C mode", "R mode"
Further, in the "F mode", as shown in Table 2, the center differential 20 is forcibly set to the completely locked state. In each of these modes, the center differential 20 is set to the vehicle speed Vsp.
When the speed is 100 km / h or less, it is held in a completely locked state, and when it is 100 km / h or more, "auto mode control"
Switch to. Similarly, in the "R mode" and the "F mode", the rear differential 22 is forcibly put into a completely locked state. In the rear differential 22, the vehicle speed Vsp is 50k.
When it is less than m / h, it is kept in a completely locked state and 50 km
If / h or more, switch to "auto mode control".
In the "F mode", the front differential 21 is forcibly set to the completely locked state, and the vehicle speed Vsp is 30 km /
In case of h or less, it is held in a completely locked state and 30 km /
If h or more, the state is switched to the unlocked state.

The operation of the power saving control during high speed traveling will be described. In "C mode", "R mode" and "F mode", the vehicle speed Vsp is 100 km / h
In the above case, there is almost no possibility that each wheel will slip even during acceleration, and the vehicle will not travel off-road. Therefore, there is no problem even if the center differential 20 is switched from the completely locked state to the "auto mode control". Further, by switching to the "auto mode control", the unlocked state, the intermediate locked state, or the completely locked state is set under the predetermined condition as described above. Therefore, the electromagnetic multi-plate provided on the center differential 20 except when necessary. The clutch does not operate, which saves power and improves fuel efficiency. Further, in the case other than the completely locked state, when the vehicle turns, the center differential 20 operates and slip does not occur, so that the running resistance is reduced and fuel consumption is improved. Again 100
Since the center differential 20 is set to the "auto mode control" when traveling at a high speed of km / h or more, stability at a high speed can be obtained.

In the "R mode" and the "F mode", when the vehicle speed Vsp is 50 km / h or more, the rear differential 22 is similarly switched to the "auto mode control". Also in this case, similarly to the above, the fuel consumption can be improved by the power saving and the reduction of the running resistance, and the stability at high speed can be obtained. In "F mode", the front differential 21 is 30
The operability is improved by switching to the unlocked state in the case of km / h or more. Further, similarly, fuel efficiency can be improved by saving power.

In this power saving control during high speed running,
The vehicle speeds that are the standard for switching each diff from the forced complete lock state to the "auto mode control" or the unlock state are different. The reason for this is as follows. When the vehicle is traveling, it is necessary to reliably transmit the driving force from the engine to each wheel. Therefore, the center differential 20 close to the engine side is completely locked up to a relatively high speed of 100 km / h. In the rear differential 22 and the front differential 21, which affect only each wheel, the rear differential 22 is unlocked at a relatively low speed of 50 km / h or 30 km / h or more to save power. Improves fuel efficiency. Since the front diff 21 has a great influence on the operability, the front diff 21 is unlocked at a lower speed to improve the operability. Further, it is determined that the vehicle will not be driven off-road at a speed of 30 km / h or more, which requires the front differential 21 to be completely locked.

Next, the overall control contents of the vehicle control system according to the embodiment of the present invention will be described with reference to FIG. FIG. 11 is a flowchart showing the overall control contents of the vehicle control device according to the embodiment of the present invention. First, in P100, the center differential current value Ica and the rear differential current values Ira, A in the "auto mode control" are set.
BS signal, brake signal, mode signal, and vehicle speed Vsp
Enter. Next, in P102, it is determined whether or not it is the "A mode". In the case of the "A mode", it is determined in P104 whether or not the brake is on, based on the brake signal. If not, the process proceeds to P106. In P106, “If = 0, Ic = Ica, Ir = Ira” is set, the front differential is in the unlocked state, and the center differential and the rear differential are in “auto mode control”. When the brake is turned on in P104, "If =
0, Ic = 0, Ir = 0 ”, and all the differentials are unlocked.

When it is determined in P102 that the mode is not the "A mode", it is determined in P110 whether the mode is the "C mode". In the case of "C mode", it is determined in P112 whether or not the brake is on, and if not, the process proceeds to P114. Vehicle speed Vsp is 1 at P114
It is determined whether or not it is 100 km / h or more. If it is not 100 km / h or more, in P116, “If = 0, Ic = 2.
2, Ir = Ira ", the front differential is unlocked, the center differential is completely locked, and the rear differential is" auto mode control ". Vehicle speed Vsp is 100km /
If h or more, in P118, “If = 0, Ic
= Ica, Ir = Ira ", the front differential is in the unlocked state, and the center differential and the rear differential are in the" auto mode control ". When it is determined that the brake is on in P112, the ABS is detected in P120 based on the ABS signal.
Determine if the device is differential. When the ABS device is not differential, in P122, “If = 0, I
c = 0.8, Ir = 0 ”, the front differential and the rear differential are unlocked, and the center differential is intermediately locked. When it is determined in P120 that the ABS device is differential, in P124, “If = 0, Ic =
0, Ir = 0 ”, and all the differentials are unlocked.

When it is determined in P110 that the mode is not the "C mode", it is determined in P126 whether the mode is the "R mode". In the case of the "R mode", it is determined in P128 whether or not the brake is on, and if not, the process proceeds to P130. Vehicle speed Vsp is 1 at P130
It is determined whether or not it is 00 km / h or more, and if it is not 100 km / h or more, it is determined in P132 whether or not it is 50 km / h or more. If it is not 50 km / h or more, in P134, “If = 0, Ic = 2.2, Ir = 4.1” is set, and the front differential is in the unlocked state, and the center differential and the rear differential are in the completely locked state. If it is 50 km / h or more, in P136, “If = 0, Ic = 2.
2, Ir = Ira ", the front differential is unlocked, the center differential is completely locked, and the rear differential is" auto mode control ". If it is 100 km / h or more, in P138, “If = 0, Ic = Ica, I
"r = Ira" is set, the front differential is in the unlocked state, and the center differential and the rear differential are in the "auto mode control".

If it is determined at P128 that the brake is on, at P140, A is determined based on the ABS signal.
It is determined whether the BS device is differential. If the ABS device is not differential, in P142, “If =
0, Ic = 0.8, Ir = 1.2 ", and the front differential is in the unlocked state, and the center differential and the rear differential are in the intermediate locked state. If it is determined in P140 that the ABS device is differential, in P144, “If =
0, Ic = 0, Ir = 0 ”, and all the differentials are unlocked.

When it is determined in P126 that the mode is not the "R mode", this case corresponds to the remaining "F mode", and the process proceeds to P146. Not more than 100 km / h at P146, not more than 50 km / h at P148, P150
When it is determined that each is not 30 km / h or more,
In P152, “If = 2.1, Ic = 2.2, I
r = 4.1 "is set, and all the differentials are completely locked. When it is determined at P150 that the speed is 30 km / h or more, at P154, “If = 0, Ic =
2.2, Ir = 4.1 "is set, and the front differential is unlocked and the center differential and the rear differential are completely locked. When it is determined in P148 that the speed is 50 km / h or more, in P156, “If = 0, Ic =
2.2, Ir = Ira "is set, the front differential is unlocked, the center differential is completely locked, and the rear differential is in" auto mode control ". 100 on P146
If it is determined to be equal to or higher than km / h, in P158, “If = 0, Ic = Ica, Ir = Ira” is set, the front differential is unlocked, and the center differential and the rear differential are set to “auto mode control”. .

[0041]

As described above, according to the present invention, by controlling the differential limiting device based on the traveling speed of the vehicle, the traveling stability and fuel consumption of the vehicle can be improved.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an overall configuration of a vehicle control device of the present invention.

FIG. 2 is a cross-sectional view showing an electromagnetic multi-disc clutch provided on a center differential.

FIG. 3 is a flowchart showing a vehicle body speed calculation routine in "A mode" automatic mode control.

FIG. 4 is a flowchart showing a center differential differential rotation speed calculation routine in “A mode” auto mode control.

FIG. 5 is a flowchart showing a rear differential differential rotation speed calculation routine in the automatic mode control of “A mode”.

FIG. 6 is a flowchart showing a center differential current setting routine in the automatic mode control of “A mode”.

FIG. 7 is a diagram showing a relationship between a current value I ₁ and a center differential differential rotation speed ΔNc.

FIG. 8 is a diagram showing a relationship between a current value I ₂ and a throttle opening TVO.

FIG. 9 is a flowchart showing a rear differential control current value setting routine in the automatic mode control of “A mode”.

FIG. 10 is a flowchart showing an ABS control prohibition routine in “F mode”.

FIG. 11 is a flowchart showing the overall control contents of the vehicle control device according to the embodiment of the present invention.

[Explanation of symbols]

16 front wheel 18 rear wheel 20 center differential (center differential) 21 front differential (front differential) 22 rear differential (rear differential) 30 wheel speed sensor 31 brake switch 32 throttle sensor 41 anti-skid braking device control unit 43 differential control・ Unit 44 Manual switch 50 Electromagnetic multi-plate clutch

Claims (8)

[Claims] 1. A control device for a vehicle having a differential limiting device for limiting a differential by setting an inter-axle differential and an inter-wheel differential in a locked state, and a first differential limiting means provided in the inter-axle differential and an inter-wheel differential. A second differential limiting means provided differentially, a lock state setting means for setting at least one of the first differential limiting means and the second differential limiting means in a completely locked state, and a vehicle having a predetermined speed or more. And a differential limiting control unit for releasing the complete lock state set by the lock state setting unit when traveling in the vehicle. 2. When the first differential limiting means and the second differential limiting means are set to the completely locked state by the lock state setting means, the vehicle is operated at a first predetermined speed or higher by the differential limiting control means. When traveling, the locked state of the first differential limiting means is released, and when the vehicle travels at a second predetermined speed lower than the first predetermined speed, the second differential limiting means is unlocked. The control device for a vehicle according to claim 1, wherein the control device is a vehicle. 3. The control of the vehicle according to claim 1, wherein after the complete lock state is released by the differential limiting control means, the intermediate lock state or the unlock state is controlled according to the operating state of the vehicle. apparatus. 4. The first differential limiting means and the second differential limiting means have electromagnetic clutches.
The vehicle control device described. 5. The vehicle control device according to claim 1, wherein the inter-wheel differential is a rear differential provided between rear wheels. 6. A differential limiting device for a vehicle that performs differential limiting with a center differential provided between axles, a rear differential provided between rear wheels, and a front differential provided between front wheels being locked. In the center differential, the first differential limiting means and the second differential limiting means provided in the rear differential.
Differential limiting means, third differential limiting means provided on the front differential, first differential limiting means, second differential limiting means
A lock state setting means for setting the differential limiting means and the third differential limiting means in a completely locked state, and when the vehicle travels at a predetermined speed or more, the complete locked state set by the lock state setting means is released. A differential limiting control means, wherein the differential limiting control means releases the first differential limiting means locked state when the vehicle travels at a first predetermined speed or more, and the vehicle is at the first predetermined speed. When traveling at a lower speed than a second predetermined speed, the second differential limiting means is unlocked, and when the vehicle travels at a third predetermined speed which is lower than the second predetermined speed, the third differential restriction. A control device for a vehicle, characterized in that a means locked state is released to an unlocked state. 7. The differential limit control means releases the complete lock state of the first differential limit means and the second differential means, and then controls to an intermediate lock state or an unlock state according to the driving state of the vehicle. The control device for a vehicle according to claim 6, wherein: 8. The first differential limiting means and the second differential limiting means have electromagnetic clutches.
The vehicle control device described.