JPH02290732A - Power train control device - Google Patents

Abstract

PURPOSE:To improve the slip convergence of a slipping wheel by preventing the increase in distributed torque by means of torque distribution control for a slip control target wheel when torque distribution control is going to be carried out for the wheel where slip control is being carrying out. CONSTITUTION:Propeller shafts 24, 26 for front and rear wheels are connected to the output side of an engine 12, in which a throttle valve 14 electrically driven and controlled is installed in an intake passage 16, through a transmission 22 and a center differential mechanism 23 to enable torque distribution quantities to respective shafts 24, 26 to be controlled. In such a device, a judging means which judges whether the torque transmitted, by action of the center differential mechanism 23, to the wheel where slip control is being carried out so that the slipping quantity of a slipping wheel may be below a prescribed level is increased or not is provided in a control 100. At the time of the judgment of YES, control is made so that the transmitted torque at least for a slip control target wheel may be decreased so as to restrain the transmitted torque to the wheel.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides torque distribution control that varies the amount of torque distribution to the front and rear wheels and left and right wheels in a four-wheel drive vehicle, or to the left and right wheels in a two-wheel drive vehicle. The present invention relates to a power train control device for a vehicle that has two functions: a slip control function and a slip control function that varies the braking force of each wheel according to the slip state of each wheel.

Conventionally, torque distribution control (or torque spur 7} control) and slip control (or traction control) have been performed in order to ensure running stability of a vehicle. The former is aimed at appropriately distributing engine torque applied to each wheel, mainly for the purpose of improving drivability when driving around curves or when starting. In other words, this torque distribution control performs torque distribution control in consideration of a change in the load on the wheels due to a change in the vehicle attitude caused by the driver's accelerator operation or steering operation.

Moreover, the latter slip control ensures an optimal slip state of the wheels. In other words, Slinop control is
This is to control wheel slip caused by causes independent of driver operations (for example, driving on a low resistance road).

In this way, both torque distribution control and slip control have been developed with their own unique challenges, and each control is performed by each system, but in the end, both control Since the drive torque to the wheels is controlled in a variable manner, control of one necessarily has an effect on the other.

Therefore, the powertrain control device of the present invention has been proposed with the aim of eliminating the adverse effects on vehicle running due to mutual interference between the two controls.

Hereinafter, the configuration, operation, and problems of various conventional techniques related to slip control or torque distribution control that have been disclosed or proposed so far will be explained, and then the specific details of the present invention will be explained. I will explain the problem or structure in detail.

(Prior art) Conventionally, for example, four-wheel drive vehicles (hereinafter referred to as 4WD vehicles)
Various technical ideas have been proposed in which different torques are distributed to each of the front, rear, left, and right wheels. for example,
As one example of this, as shown in the specification and drawings of JP-A-60-248440, the output from the engine is first distributed to each wheel by a center differential, and the braking force of the front, rear, left, and right wheels is mutually distributed. Braking means are provided individually so that they can be separated and controlled independently, and when slipping occurs in the left and right wheels on the front or rear wheels due to the road surface condition, the braking means will be applied to the specific wheel that is slipping. Technical means (wheel drive force control means) that applies braking force to the wheel to substantially reduce the drive force of the wheel is known. When a wheel that is slipping is braked in this manner, a torque difference occurs between the torque value of the other wheel, and as a result, it becomes possible to obtain appropriate driving force for each of the front, rear, left, and right wheels.

Originally, a vehicle is in contact with the ground through its four wheels, so its slip limit performance is uniquely determined by the product (μ・W) of the friction coefficient μ of the road surface and the load W on the tires (wheels). Limited by the frictional force of the tires. and,
The force applied to the tire includes various elements such as driving force, braking force, centrifugal force, etc., but if the value obtained by adding these vectorially is not within the above tire friction force value, the stability of the vehicle will be affected. You won't be able to get the driving performance that you expected.

By the way, regarding the load W applied to the tires mentioned above, when a load shift occurs due to each acceleration in the longitudinal direction and lateral direction of the vehicle body while driving, a load difference occurs between each of the four sets of front and rear wheels, thereby supporting the movement of the vehicle. There are also differences in the performance of tires. In particular, when the coefficient of friction μ with the road surface is low, the load W has a large influence on the running stability of the vehicle.

Therefore, in the above four-wheel drive vehicle, the load on each tire is reduced by appropriately distributing the drive torque to the four wheels as described above, and the friction coefficient μ of the road surface is reduced.
This ensures stable vehicle performance even on low road surfaces. However, in the above case, if the front, left, and right wheels are connected to each other by a center differential,
The same drive torque is inevitably distributed to the front and rear wheels.

As a result, slipping is more likely to occur on the wheel side with the lighter load, so the performance of the car is limited by the tire with the lowest capacity, while on the other hand, the wheel with the increased load...
There is a problem that this ability is not fully utilized.

On the other hand, if you take this situation into consideration and distribute torque differently between the front and rear wheels in a four-wheel drive vehicle like the one mentioned above, the road grip performance of the tires on each wheel will be more effectively demonstrated. However, if this torque distribution is changed by adjusting the degree of engagement (frictional force) of a clutch installed in the center differential, for example, a large engine output will inevitably be directly distributed. In addition, the structure of the clutch itself has become larger, which has increased mounting restrictions.
Naturally, therefore, the weight becomes heavy and the cost also increases.

However, as in the configuration of the prior art described above, the brake device is provided so that it can be operated independently for the front and rear wheels, and when a slip occurs in the front or rear wheel, the braking force is applied to the slipping wheel. For those that control to add,
A portion of the engine output is used for this braking force, causing the vehicle to decelerate, resulting in a decline in driving performance, especially acceleration performance.

Therefore, recently, the following torque split (distribution)
control is proposed. In other words, as mentioned above, the situation in which it is necessary to perform different torque distribution between the front and rear wheels or the left and right wheels is when the road surface has a low coefficient of friction μ, and when the vehicle is accelerating, the weight of the vehicle body shifts on the wheels as the vehicle accelerates. There are two main cases: when driving and when turning, where centrifugal force is applied to the same wheel in addition to the driving force.In these conditions, the engine output usually depends on the tire capacity. Since there is a large margin of torque that exceeds the limit, and a loss in engine output is tolerated to some extent, even if torque split control is performed, a deceleration state will hardly occur.

Therefore, it is not necessary to provide a mechanism such as a clutch in the torque transmission path to directly change the amount of transmission.

The torque split control device is used in a four-wheel drive vehicle configured to transmit engine output (engine torque) to the front, rear, left and right wheels respectively as described above, and includes, for example, engine output control means for variable control of engine output, A braking force (braking force) control means for variably controlling the braking force for the left and right wheels independently of each other is provided. The operations of the engine output control means and the braking force control means are controlled by the torque distribution changing means, and the braking force is applied to one of the front and rear wheels or the left and right wheels by the braking force control means and the braking force is applied by the engine output control means. The system is configured to change the amount of torque distribution to the front and rear wheels or the left and right wheels by increasing the engine output corresponding to .

In the above-mentioned torque split control device for a four-wheel drive vehicle, a braking force control means applies a predetermined amount of braking force to one of the front and rear wheels or left and right wheels whose torque is to be reduced, and at the same time, this braking force reduces the torque. Engine output corresponding to torque is distributed to other wheels by an engine output control means. As a result, the total value of engine output including this increase in engine output is appropriately distributed and transmitted to the front and rear wheels, respectively, but the torque transmitted to the wheel where braking force is applied is The torque that actually acts on the road surface from all wheels is reduced by the amount of braking force, and the torque that actually acts on the road side from all wheels is the same as before the change in the torque distribution amount, that is, before the braking operation, and only the torque that is transmitted to the wheels on the braking side. is reduced, and the torque of the non-braking side wheel is relatively increased.

As a result, the road surface grip of the wheels in a slipping state is improved, and this slipping state is prevented, so that the running stability of the vehicle is improved.

On the other hand, as a driving wheel control system for a four-wheel drive vehicle similar to the torque split control described above, there is a system called slip control (traction control), for example.

Generally, when a vehicle is running, if the amount of slip of the wheels on the road surface is large, the road surface will not run smoothly, and proper driving characteristics such as drift out due to wheelspin may not be obtained. I end up. Therefore, in such a case, the slip of the drive wheels on the road surface can be suppressed by operating the brake device installed in the vehicle in the same way as the torque blit control described above, or by reducing the engine output itself. A slip control device is used to perform the following control.

In order to suppress the Slinope phenomenon caused by the driving wheels against the road surface using such a Slissop control device, it is necessary to detect a state in which the driving wheels are slipping more than a predetermined level with respect to the road surface, and also to detect a state in which the driving wheels are slipping at a predetermined level or more with respect to the road surface. In order to set a target slip ratio, etc., which is a reference for the drive wheels that are causing the above-mentioned slip, it is first necessary to detect the vehicle speed. In the case of a two-wheel drive vehicle in which only one of the front wheels or rear wheels is driven, the vehicle speed can be detected relatively easily based on the circumferential speed of the driven wheel, which rarely causes slip on the road surface. As mentioned above, in a four-wheel drive vehicle in which both the front wheels and the rear wheels can be driven, when the vehicle is in the four-wheel drive state, there is no wheel that becomes a driven wheel. Therefore, its detection becomes difficult.

In order to solve the problem of slip rate detection in four-wheel drive vehicles, conventional methods such as Japanese Patent Laid-Open No. 6-2-2 have been proposed.
As shown in Publication No. 8,94,29, first, the circumferential speed of each wheel in a four-wheel drive vehicle is determined, and based on the circumferential speed, it is determined whether each wheel is slipping with respect to the road surface by a predetermined value or more. Along with detecting the condition,
A slip control device for a four-wheel drive vehicle has been proposed in which the vehicle speed is specifically estimated based on the minimum value of the circumferential speeds for each wheel.

As described above, in the slip control device for a four-wheel drive vehicle, which detects the state in which each wheel is slipping on the road surface and estimates the vehicle speed, it is possible to detect the slip state of each wheel on the road surface by a predetermined value or more. When a slip condition is detected, the slip rate of the wheel for which the slip condition is detected is normally applied to the wheel for which the slip condition is detected to be equal to or higher than the predetermined value in order to make the slip amount match a preset target value. Control is performed to reduce the driving torque. The target value in this control is set regardless of the number of wheels for which slip of the predetermined value or more is detected.

Generally, in a four-wheel drive vehicle, the number of wheels in which slip on the road surface is detected depends on the driving state of the vehicle and the road surface condition (road surface friction coefficient, etc.). The greater the number of wheels that are slipping at a predetermined level or higher, the greater the impact this has on the running stability of the vehicle. Therefore,
The greater the number of wheels for which slip of a predetermined level or higher is detected, the lower the target value of the slip rate (or slip amount) during slip control should be set, and priority should be given to ensuring the running stability of the vehicle. . Furthermore, the smaller the number of wheels for which slits and stubs of a predetermined level or higher are detected, the more
It is desirable to set a high target value for the slip rate or slip amount during slip control, and to prioritize ensuring vehicle driving characteristics such as acceleration and all-road performance.

For this reason, recently, for example, when a slip state of a predetermined level value or higher is detected for each wheel of a four-wheel drive vehicle, the slip rate or slip m of the detected wheel is adjusted to a set target value. In order to match, a torque control means is provided to change the driving torque acting on the wheel, and in this case, the slip ratio of the wheel to be controlled is determined depending on the vehicle running condition and road surface condition. Even high-precision slip control systems for four-wheel drive vehicles have been proposed, which are configured to obtain the desired driving characteristics under conditions where the driving stability of the vehicle is substantially ensured. There is.

The above is an overall overview of the prior art.

(Problems to be Solved by the Invention) As mentioned above, the drive wheel slip control (traction control) and torque distribution control (torque blit control) greatly contribute to the stability of the running condition of the vehicle, and improve the steering stability. , contributes to improving acceleration performance, but on the other hand, in a vehicle configured with these two systems, when both systems operate simultaneously, the following problems may occur.
The inventors of the present invention have found that there are cases where this occurs.

That is, even when performing torque distribution (split) control based on the momentum of the vehicle body or the amount of operation by the driver, for example, there are two cases: a case where the slip control is likely to be inhibited, and a case where it is not. Therefore, torque distribution control must be performed depending on the situation. In other words, if slip control is obstructed and the running stability of the vehicle is impaired, torque distribution control must necessarily be stopped, but even in cases where this is not the case, torque distribution control is stopped and only slip control is performed. Doing so will result in unnecessary deterioration of acceleration performance.

On the other hand, if torque distribution control is executed according to the amount of momentum of the vehicle body or the amount of operation by the driver as described above, it will be possible to make maximum use of the capacity of the tires on each of the front and rear wheels, as mentioned earlier. However, if the driving force increases beyond the tire capacity limit, which originally varies depending on the road surface condition (particularly the road surface μ), it is not possible to prevent wheelspin from occurring. For example, on a low μ road such as a snow-covered road, the difference in tire performance limits depending on vehicle motion conditions is small. Therefore, in such a case, there is a concern that increasing the distribution amount of the driving force itself may induce a spin phenomenon of the entire wheel, depending on the wheel position or the number of wheels.

Therefore, in such a case, it is naturally assumed that the above-mentioned slip control is carried out to reduce the torque acting on the wheels and prevent a spin state, but on the other hand, the above-mentioned torque distribution control is carried out. If the vehicle were to suddenly shift to slip control while the vehicle was running, the control force of the wheels on the road surface, which should have originally reduced the driving force, would be lost. Further, there are problems such as the vehicle body behavior becoming unstable due to sudden changes in the amount of driving force distribution.

(Object of the invention of claim 1) Thus, first of all, the object of the invention of claim 1 of the present application is to control the slip control target wheel when torque distribution control is to be performed on a wheel on which slip control is being performed. By preventing an increase in the distributed torque due to torque distribution control, the slip convergence of the slipping wheel is accelerated, and driving stability is quickly ensured.

(Means for solving the problem of the invention of claim 1) And, the structure of the problem-solving means of the invention of claim 1 of the same order for solving the above problem is to transmit an engine output of 1 lux to the wheels. A powertrain control device that controls the entire system includes a torque distribution means that independently distributes the output torque from the engine to each wheel while controlling the amount of distribution, and a means that detects the slip state of each wheel. In addition, a slip control means for controlling the slip so that the amount of slip of the detected slipping wheel becomes equal to or less than a predetermined level, and the torque distribution means further includes the above-mentioned torque distribution means for the wheel whose slip is being controlled by the slip control means. torque determining means for determining whether or not the torque transmitted to the wheel is increased when If this is the case, the slip control means or torque distribution means is controlled to at least reduce the torque transmitted to the wheel subject to slip control. The present invention is characterized by comprising: a torque suppressing means for suppressing the torque transmitted to the wheels;

(Operation of the means for solving the problem of the invention according to claim 1) Slip control (traction control) works to reduce the torque acting on the wheels to prevent the occurrence of a spin state.

On the other hand, torque distribution control (sprute control) controls the amount of torque distributed to each wheel according to the amount of momentum of the vehicle body or the amount of operation by the driver, and maximizes the capacity of the tires on each wheel. It can be used effectively.

However, when performing the above-mentioned slip control, spin occurs in one or two of the wheels, and torque distribution control is performed while only brake control is being performed, resulting in the amount of torque distribution to the controlled wheels being changed. If the size exceeds the limit of the tire's capacity, it becomes impossible to prevent wheel spin from occurring.

On the other hand, when the amount of torque distributed to the wheels to be controlled by the torque distribution control becomes smaller, on the other hand, the slip control can effectively prevent the occurrence of wheel spin.

Therefore, in the configuration of the power train control device according to the invention of claim 1, in addition to the torque distribution means for performing the torque distribution control and the slip control means for performing slip control, the transmission torque of the wheels subject to slip control and torque distribution control is provided. A torque determining means for determining an increasing state and a torque suppressing means for suppressing the amount of torque distributed from the torque distributing means to the controlled wheels according to the determination result of the torque determining means are provided, so that when the distributed torque increases, the torque is reduced. Torque distribution control by the distribution means is suppressed.

As a result, even if torque distribution control is started during slip control, if the amount of torque transmitted to the controlled wheel increases as a result, the torque distribution operation is automatically suppressed and It acts to suppress the occurrence of wheel spin.

(Effect of the invention of claim 1) Therefore, according to the power train control device according to the invention of claim 1 of the present application, slip control can be effectively utilized within the range of tire capacity, and the tire The slip state can be maintained at the optimum state for driving.

Further, even during slip control, sufficient torque distribution is possible as long as the tire capacity is reasonable, so it is possible to appropriately respond to the driver's acceleration request.

(Object of the invention of claim 2) Next, the object of the invention of claim 2 of the present application is to solve the above-mentioned problem when slip control is about to be performed in a state where torque distribution control is being performed. For wheels to which a small amount of distributed torque is distributed by torque distribution control, an increase in the distributed torque is also suppressed by slip control, thereby preventing new slips from occurring in the wheels to which the distributed torque is small.

(Means for solving the problem of the invention of claim 2) In order to achieve this object, the configuration of the means for solving the problem of the invention of claim 2 is to control the transmission of engine output torque to the wheels as a whole. 7 <The powertrain control device includes a torque distribution means that independently distributes the output torque from the engine to each wheel while controlling the amount of distribution, and a means for distributing the output torque from the engine to each wheel independently so as to keep the amount of slip of the wheels below a predetermined level. a slip control means for performing slip control; a first detection means for detecting a wheel to be controlled by the slip control means; and upon receiving the output of the first detection means, the torque distribution means is activated. a second detection means for detecting that the slip control means is about to perform slip control on the wheels to be controlled; and a second detection means for receiving the output of the second detection means. , a torque suppressing means for suppressing an increase in torque to the wheel subject to slip control when the torque to be distributed to the wheel subject to slip control exceeds a predetermined value. It is something.

(Operation of the means for solving the problem of the invention of claim 2) Torque distribution control (suburinoto control) is to control the torque distribution m to each wheel according to the momentum of the vehicle body or the driver's operation. The capacity of the tires can be utilized to the maximum extent possible.

Slip control (traction control) works to reduce the torque acting on the wheels to prevent the occurrence of a spin condition.

By the way, if torque distribution control is executed according to the momentum of the vehicle body or the driver's operation, as shown in -L, it will be possible to make maximum use of the capacity of the tires of each front and rear wheel. If the driving force increases to the point where it exceeds the tire capacity limit, which varies depending on the road surface condition (particularly the road condition), it is not possible to prevent wheel spin from occurring as described above. For example, when driving on a snow-covered road,
On the road, the difference in tire performance limits due to vehicle motion conditions is small. Therefore, in such a case, there is a concern that increasing the distribution amount of the driving force itself may induce a spin phenomenon of the entire wheel, depending on the wheel position or the number of wheels.

Therefore, in such a case, it is naturally assumed that the above-mentioned slip control is implemented to reduce the torque acting on the wheels and prevent a spin state, but on the other hand, the above-mentioned torque distribution control is If the slip control suddenly shifts to slip control while the vehicle is in operation, the control force of the wheels on the road surface, which should have originally reduced the driving force, will be lost and a new wheel spin will occur. Additionally, there were other problems such as the vehicle behavior becoming unstable due to sudden changes in the amount of driving force distribution.

Therefore, in the configuration of the power train control device according to the invention of claim 2, in addition to the torque distribution means and the sleeve control means, a first a detection means, and receives a detection output of the first detection means to detect that slip control is about to be performed on the slip control target wheel by the slip control means when the torque distribution means is operating. a second detection means for detecting; Upon receiving the output of this second detection means, when the torque to be distributed to the slip control target wheel exceeds a predetermined value, the slip control target wheel ＼
If sweep control is about to be applied to a predetermined wheel while torque distribution control is being performed by the torque distribution means, the control target wheel is An increase in the torque distribution amount of the torque distribution means is suppressed in accordance with the distribution torque value.

As a result, it becomes possible to prevent the generation of new spin-generating wheels during a switching transition in which slip control is applied to spin-generating wheels under torque distribution control.

(Effect of the invention of claim 2) Therefore, according to the power train control device of the invention of claim 2 of the present application, even if the slip control is executed during torque distribution control, the control control for the road surface of the wheels is stable. This also makes it possible to avoid changes in vehicle behavior.

(Example) Hereinafter, two examples of the power train control device of the present invention will be described.
Two examples (the basic first embodiment and the second embodiment, which is an improved version of the first embodiment) will be described in detail.

In each of these embodiments, the torque distribution control (torque sublime control) according to changes in the load distribution to the wheels is performed, for example, by increasing the amount of braking for the wheel whose torque is to be reduced. For each wheel where it is desired to increase the amount of braking, this is done by reducing the amount of braking. The engine torque lost due to the addition of braking force is compensated for by increasing the overall engine output.

In addition, slip control for optimizing the slip state of the wheels involves setting a target slip rate for each of the four wheels, and applying brake control to apply appropriate braking force to each wheel toward this target slip rate. The engine output is also controlled by engine torque control, which controls the wheel slip rate by controlling the engine output based on the difference between the engine output and the target slip rate.

In the control device of the first embodiment, torque split control in which the additional torque appropriately corresponds to changes in the load applied to the wheels and slip control (traction control) to prevent wheel slip are mutually independent. It is characterized by being carried out as follows, and improving the driving stability and acceleration of the vehicle.

On the other hand, in the control device of the second embodiment, since the slip control and the torque split control are performed independently in the control by the control device of the first embodiment, both controls end up interfering with each other. This was done with special consideration to the possibility that such a situation could occur. Such a situation is
There are mainly two situations as follows. That is, (2): When torque split (torque distribution) control is performed independently on a wheel that has caused slip and is subject to slip control by the control of the first embodiment, the torque split There may be cases where the drive torque is increased by control. Such an increase in drive torque further promotes slinop, so in order to prevent this, when such a situation is detected, an increase in torque is applied to the wheel subject to slip control by torque split control. It is something that we are trying to suppress.

In the description of the second embodiment, which will be explained in detail later, such an interference state will be referred to as a first interference state.

■2 In the torque suppression control described in ■ above, the increase in drive torque is suppressed for wheels that are subject to slip control,
It has the characteristic that the promotion of slippage is prevented.

However, for wheels that originally have a small amount of torque distribution, suppressing or prohibiting the torque distribution itself will lead to an increase in torque, and as a result, the wheels will receive excessive driving force that exceeds the tire's capacity. This could result in a dangerous drift-out. Therefore, in the second embodiment, even if the torque split control is stopped and the slip control is started as described above, the wheel to which the applied torque is actually decreasing may be affected by the wheel actually slipping. Whether or not it is done, torque splint control is performed to prevent new slip wheels from occurring.

Based on the above points, first of all, let us first discuss the first embodiment and the second embodiment.
After specifically explaining the configuration of the hardware section common to the power train control devices of each embodiment, the detailed control operations of each of the first and second embodiments will be sequentially explained. do.

<System configuration of the power train control device hardware section> First, FIG. It conceptually shows the basic vehicle structure of a four-wheel drive vehicle.

That is, as shown in FIG. 1, an in-line four-cylinder engine 12, for example, is mounted at the front of a vehicle body 10 of the four-wheel drive vehicle. This engine 12 has four cylinders 11,
II..., each of which has 94 m 1 1 . 1
1... is a mixture at a predetermined air-fuel ratio formed by the fuel supplied from the fuel supply system and intake air through the intake passage 16 provided with the throttle valve 14 that is electrically driven to open and close by the throttle actuator 13. Qi is supplied. The air-fuel mixture supplied into each gas cylinder 11 is combusted by the operation of an ignition system such as a spark plug, a distributor, an igniter, etc. (not shown), and then exhausted through the exhaust passage 17. The combustion of this air-fuel mixture causes the engine l2 to rotate, and the generated torque is transmitted to the transmission 22, center differential mechanism 23, propeller shaft 24 and differential mechanism 25 for the front wheels, and the blower shaft 2 for the rear wheels.
6 and the differential mechanism 27, the left front wheel 20L1 and the right front wheel 20
R, the left rear wheel 21L, and the right rear wheel 21R, respectively.

A brake control section 30 is provided in association with the front left wheel 20L, the front right wheel 20R1, the rear left wheel 21L, and the rear right wheel 21R. The brake control unit 30 is located at the front left @20
It has disc brakes 35A to 35D, each of which includes a disc 32 attached to each of the front right wheel 2OR, the rear left wheel 21L, and the rear right wheel 21R, and a caliber 34 provided with a brake lever throat that presses the disc 32. ing. Caliber 3 in each of the disc brakes 35A to 35D
4 is equipped with a wheel cylinder 36, and each wheel cylinder 36 has a conduit 3 extending from a hydraulic pressure adjustment section 40.
7a to 37d are connected to each other. Each caliper 3
4, when brake fluid pressure is supplied to the wheel cylinder 36 from the fluid pressure adjustment section 40 via the conduits 37a to 37d,
The brake pad is pressed against the disc 32 with a pressing force corresponding to the supplied brake fluid pressure, and the left front wheel 20 is
+, Braking of the front right wheel 2OR, the rear left wheel 21L, and the rear right wheel 21R is performed independently.

The hydraulic pressure adjusting unit 40 is supplied with hydraulic pressure corresponding to the depression operation of the brake pedal 4l from a power cylinder 43 attached to the brake pedal 41 through conduits 42a and 42b, and also supplied to the hydraulic pressure adjusting unit 40 through a pump 44 and a pressure regulating valve. 45
The hydraulic pressure generated by the hydraulic pressure is supplied through the conduit 46. During normal braking in which traction control, that is, slip control, is not performed, the hydraulic pressure adjustment unit 40 forms a brake hydraulic pressure according to the depression operation of the brake pedal 41, and transmits it to the disc brake 35 through conduits 37a to 37d.
Perform normal brake control operation to supply to A to 35D,
On the other hand, during slip control, built-in electromagnetic on-off valves 51 to 5
Disc brakes 35A to 35D depending on the operating status of 8.
The brake fluid pressures for the disc brakes 35A to 35D are individually formed and selectively supplied to the disc brakes 35A to 35D.

The electromagnetic on-off valves 51 to 58 are combined into pairs, respectively: electromagnetic on-off valves 51 and 52, electromagnetic on-off valves 53 and 54, electromagnetic on-off valves 55 and 56, and electromagnetic on-off valves 57 and 58. Front wheel 20L 1 right front wheel 2OR, left rear wheel 21L
and is involved in adjusting the brake fluid pressure for the disc brakes 35A to 35D provided on the right rear wheel 21R. One electromagnetic on-off valve 5 of each set
When valves 1, 53, 55 and 57 are opened and the other electromagnetic valves 52, 54, 56 and 58 are closed, the brake fluid pressure supplied to the disc brakes 35A to 35D is increased. and, conversely, one of the electromagnetic on-off valves 51, 53, 55 and 57 of each of the above sets.
When the disc brake 3 is in the idle state and the other electromagnetic on-off valves 52, 54, 56 and 58 are in the open state, the disc brake 3
When the brake fluid pressures supplied to disc brakes 5A to 35D are respectively reduced and all of the sets are idle, the brake fluid pressures supplied to disc brakes 35A to 35D remain at the current hydraulic pressure state. It is designed to be held in

The open/close states of each of these electromagnetic on-off valves 51 to 58 are appropriately controlled according to the control purpose by the illustrated control signal Ca=ch from the brake control section of the control unit lOO, as described later. There is.

That is, in addition to the above-mentioned configurations, this embodiment includes a brake control section for controlling the opening and closing of the electromagnetic on-off valves 51 to 58, a throttle control section for controlling the operation of the throttle actuator l3, and a control section for each wheel. A control unit 100 having a built-in torque distribution control section that performs torque distribution is provided. First, regarding slip control (traction control), the control unit 100 includes a left front M2.
OL, front right wheel 20R1, rear left wheel 21L, and rear right wheel 21R, respectively, obtained from the speed sensors 6l to 64 provided in relation to each of the front left wheel 20L1, the front right wheel 20R1, the rear left wheel 21L, and the rear right wheel 21H. Signals VFL, VF representing circumferential speed
R, VRL, VRR, the opening degree (θt) of the throttle valve 14 obtained from the throttle opening sensor 65, and the opening degree (θt) of the accelerator pedal 66 obtained from the accelerator distance sensor 67 provided in relation to the accelerator pedal 66. Left front wheel 20L and right front wheel 2OR obtained from the amount of depression θa and the steering angle sensor 69 provided in relation to the steering wheel 68
The steering angle signal θS and the like are respectively supplied and input.

The following table (Table 1) lists each data signal used for the following control.

(Table 1) - Outline of powertrain control in each embodiment (First embodiment) Next, first, an outline of the powertrain control performed in the first embodiment will be described.

The first control unit 100 receives the detection signal V
F L, V F R, V R L, V R R are specified (
The detected signals V F L, V F R, V R L, V R R are sequentially captured at the D circumference M. The estimated vehicle speed value and the circumferential acceleration value are calculated based on the circumferential velocity value of 21R, and each of the left front wheel 2OL, right front wheel 2OR, left rear wheel 21L, and right rear wheel 21R has a slip of a predetermined value or more. It is determined whether or not this has occurred by comparing the calculated values of each circumferential acceleration with a predetermined reference value Aa. Then, among the left front wheel 20L, the right front wheel 20R, the left rear wheel 21L, and the right rear wheel 21R, those whose circumferential acceleration values are determined to be equal to or higher than the reference value Aa are assumed to have experienced a slip of a predetermined level or higher. Sleeve/sleeve control is performed, and if it is determined that the circumferential acceleration values of the left front wheel 2OL, right front wheel 2OR, left rear wheel 21L, and right rear wheel 21R are less than the above reference value Aa, the normal throttle control is performed. Performs opening control.

When the control unit 100 performs the normal throttle opening control, a normal target throttle opening is set according to the amount of depression of the accelerator pedal 66 indicated by the accelerator depression point detection signal θa, The throttle valve is adjusted according to the difference between the normal target throttle opening and the opening of the throttle valve 14 so that the opening of the throttle valve l4 indicated by the throttle opening detection signal θt is brought close to the normal target throttle opening. A drive signal (feedback control signal) CL is formed and supplied to the throttle actiniator 13.

As a result, the throttle valve 14 is driven to open and close by the throttle actuator 13, and its opening degree is controlled to match the normal target throttle distance. Note that the normal target throttle opening degree is set so as to increase in a predetermined proportional relationship (linear characteristic) as the depression ffi of the accelerator pedal 66 increases.

When the control unit 100 performs the slip control, the left front wheel 20L,
The detected circumferential acceleration values for each of the front right wheel 20R, rear left wheel 21L, and rear right wheel 21R are used, and first, the wheels (hereinafter referred to as
Pickpocket. It is detected which of the four wheels (referred to as a knob wheel) is, and the number of slip wheels is detected, and the number of the detected slip wheels is detected. q
In the case of a number of slip wheels, the number of slip wheels that become slip wheels at approximately the same time among the plurality of slip wheels is detected, and based on the detection result, the number of slip wheels is determined as the target slip wheel. The estimated vehicle speed used when setting the slip rate is calculated and the slip control mode is set.

Estimation of vehicle speed>: In setting the estimated vehicle speed by the +7 torque unit 100, the above detection signal V taken in one cycle before is used.
FL, VFR, VR. Left front wheel 20 represented by L and VRR
The estimated vehicle speed value Vn-+ (where n is a positive integer) calculated based on the peripheral speeds of L, front right wheel 20R, rear left wheel 21L, and rear right wheel 21R is greater than or equal to a predetermined reference value vh. when traveling at high speed, and the estimated vehicle speed value Vn−,
is less than the reference value vh, and the steering angles of the left front wheel 20L and right front wheel 2OR represented by the steering angle signal θS are set to be less than the predetermined reference value θ. When driving straight at low speeds, the left front wheel 20L,
A predetermined correction coefficient α is applied to the lowest circumferential speed value of the front right wheel 20R, the rear left wheel 21L, and the rear right wheel 21R. (However, α. 1) is multiplied by the estimated vehicle speed value V
n is calculated (Vn-αoXMin(VF L, V
F R, V R L, V R Rl). In addition, when the estimated vehicle speed value Vn-, is less than the reference value vh, and the steering angle θS of the left front wheel 2OL and the right front wheel 20R is greater than or equal to the value θ, during low-speed turning, the detected slipping wheels and their number are Accordingly, the estimated vehicle speed is set under different setting modes based on the circumferential speed of wheels that do not slip more than a predetermined value with respect to the road surface (hereinafter referred to as non-slinop wheels). .

When setting the estimated vehicle speed during low-speed turning, the left turning state of the vehicle is detected based on the steering angles of the front left wheel 2OL and the front right wheel 20R when zero or one slipping wheel is detected. When the left front wheel 20L and the right rear wheel 21R are non-slip wheels, a predetermined correction coefficient α1 is set to the average value of the circumferential speed of the left front wheel 20 and the circumferential speed of the right rear wheel 21R. The estimated vehicle speed value Vn is calculated by multiplying the estimated vehicle speed.
When a left turn of the vehicle is detected with at least one of the wheels being a slipping wheel, the peripheral speed of the right front wheel 20R, which is a non-slip wheel, and the left rear wheel 2
The average value with the peripheral speed of 1L is multiplied by the correction coefficient α1,
An estimated vehicle speed value Vn is calculated. On the other hand, when the right turning state of the vehicle is detected with zero or one slipping wheel detected, if the front right wheel 20R and the rear left wheel 21L are non-slip wheels, ,
The estimated vehicle speed value Vn is calculated by multiplying the average value of the circumferential speed of the right front wheel 20R and the circumferential speed of the left rear wheel 21L by a correction coefficient α1. When a right turn of the vehicle is detected when one of the wheels is detected to be a slipping wheel, the average value of the circumferential speed of the left front wheel 20L and the circumferential speed of the right rear wheel 2LR, which are non-slip wheels, is detected. Each estimated vehicle speed value Vn is calculated by multiplying by a correction coefficient α.

Furthermore, when two slip wheels are detected, the non-slip wheels are the left front wheel 2OL and the right front wheel 20R.
1 If << is the left rear wheel 21L and right rear wheel 21R, then the average value of the circumferential speed of the left front wheel 20L and the circumferential speed of the right front wheel 20R, or the circumferential speed of the left rear wheel 21L and the right rear wheel 21R.
The estimated vehicle speed value Vn is calculated by multiplying the average value with the circumferential speed by a predetermined correction coefficient α. In addition, when the non-slip wheels are the left front wheel 20L and the left rear wheel 21L1 or the right front wheel 20R and the right rear wheel 21R, the wheel that takes the trajectory closest to the trajectory of the center of gravity of the vehicle among the non-slip wheels. The estimated vehicle speed value Vn is calculated by multiplying the circumferential speed by the correction coefficient α. Specifically, when the non-slip wheels are the left front wheel 2OL and the left rear wheel 21L, and the vehicle is turning to the right, a correction coefficient α is applied to the peripheral speed of the left front wheel 2OL.
, and when the vehicle is turning left, the peripheral speed of the left rear wheel 21L is multiplied by a correction coefficient α.

On the other hand, when the left slip wheels are the right front wheel 20R and the right rear wheel, and the vehicle is turning right, the right front wheel 20R
The estimated vehicle speed value Vn in each case is calculated by multiplying the circumferential speed of the vehicle by a correction coefficient α, and when the vehicle is turning left, multiplying the circumferential speed of the right rear wheel 21R by a correction coefficient α. Ru.

On the other hand, the non-slip wheels are the left front wheel 20L and the right rear wheel 21R.
1 or if there are a right front wheel 20R and a left rear wheel 21L, the average value of the circumferential speed of the left front wheel 20L and the circumferential speed of the right rear wheel 21R, or the circumferential speed of the right front wheel 20R and the left rear wheel 21L.
The estimated vehicle speed value Vn is calculated by multiplying the average value with the circumferential speed by a correction coefficient α.

Further, when it is detected that there are three slip wheels, the circumferential speed of the remaining one non-slip wheel is multiplied by the correction coefficient α3 to calculate the estimated vehicle speed value Vn.

Furthermore, when it is detected that the front left wheel 20L1, the front right wheel 2OR, the rear left wheel 2IL, and the rear right wheel 21R are all slip wheels, the estimated vehicle speed value Vn calculated immediately before the slip wheels are detected. is the estimated vehicle speed value Vn at that time.

Note that the above-mentioned correction coefficients α, , α, and α3 are calculated as It is desirable that the values be set successively smaller so that the value becomes smaller.

In this way, the estimated vehicle speed is set based on the setting mode according to the determination results such as which of the four wheels is the slipping wheel (wheel position) and the number of slipping wheels. For example, without using an expensive ground vehicle speed sensor, etc., the actual driving condition of the vehicle is taken into account with a relatively simple configuration, and the speed is set to a value that is appropriate for control purposes and does not deviate significantly from the actual vehicle speed. It turns out.

<Slip Control> Under the condition in which the estimated vehicle speed is set as described above, the control unit 100 performs slip control on the slip wheels according to the number of slip wheels and information on which wheel is slipping. The following is performed according to a predetermined control mode. That is, in the slip control by the control unit 100, first, the number of slipping wheels (stored in the Slinop wheel number counter SN) and four flags (SFFR, SFFL, SFFL, S
FRR), the brake control hydraulic circuit section 30 includes a left front wheel 20L and a right front wheel 20L.
Brake control (variable braking force control) that applies braking force to each of the left rear wheel 21L and right rear wheel 21R, and throttle control that reduces engine output by decreasing the opening degree of the throttle valve 14. (variable engine torque control) is selectively performed.

Further, the target slip ratio TGBR introduced for the above-mentioned brake control is determined by three predetermined control constants TGI~
It is set to the smallest value TGI of TG3 (O<TC;1<TG2<TG3). Further, the target slip ratio TGTR introduced for the throttle control is selected and set to one of the values TGI to TG3. Note that the slip rate here is (wheel speed - vehicle body speed)
/ is defined by wheel speed.

Then, a correction coefficient γ stored in a built-in memory preset for each number of slip wheels is added to each value of the target slip ratio TGBR in brake control and target slip ratio TGTR in throttle control set in this way. The target slip ratios TGBR and TGTR are corrected by being multiplied by the number of slipping wheels at that time. Then, the target slip rate T
The correction coefficient γ multiplied by each of GTR and target slip rate TGTR is 1 when there is one slip wheel.
, and the larger the number of slip wheels, the smaller the value.

In this way, as the number of slip wheels increases, the correction coefficient γ is set to a smaller value, so that the values of the target slip ratios TGBR and TGTR corrected by multiplying by the correction coefficient γ can be set specifically for the vehicle. It depends on the driving conditions and road surface conditions (especially road surface resistance μ).

In addition, when performing the above-mentioned brake control and throttle control, the estimated vehicle speed value Vn calculated as described above is used to control the left front wheel 2OL, right front wheel 20R, left rear wheel 21L, and The actual slippage ratios SFL, SFR, SRL and SRR for each of the right rear wheels 21R are expressed by the following formula: SFL=(VFLn - Vn)/V F Ln,
SRL = (VFRn-Vn)/VFRn,
SRL=(VRLn-Vn)/VRLn, and SRR=
It is calculated by (VRRn-Vn)/VRRn.

When brake control is actually performed, the actual slip rate SF calculated for each wheel as described above is
L. Based on the comparison between SFR, SRL, and SRR and the corrected target slip ratio TGBR multiplied by the correction coefficient γ, the drive signal Ca=Ch is selectively formed by the control unit 100. It is supplied to the electromagnetic on-off valves 51 to 58 for variable braking force described above. As a result, the disc brakes 35A~ attached to the left front wheel 2OL, the right front wheel 20R, the left rear wheel 21L, and the right rear wheel 21R
The brake fluid pressure for 35D is adjusted, and the slip rate of the Slinop wheel is controlled to match the corrected target slip rate TGBR by being multiplied by the correction coefficient γ.

On the other hand, when throttle control is performed, the actual slip rates SFL, SFR, and
Based on the comparison between SRL and SRR and the corrected target slip ratio TGTR value multiplied by the correction coefficient γ, the control unit 100 forms a throttle valve drive signal Ct, which is used as a throttle actuation signal for variable engine torque control. It is supplied to the coator 13. Thereby, the opening degree of the throttle valve 14 is adjusted and the torque is controlled.
The actual slip rate of the slipping wheel is controlled to match the corrected target slip rate TGTR by being multiplied by the above-mentioned correction coefficient γ. However, during this throttle control, if the opening degree θt of the throttle valve l4 is larger than the normal target throttle opening degree set according to the depression amount θa of the accelerator pedal 66, such throttle control is stopped. Normal throttle opening control is started.

Control Pattern> With reference to FIG. 2, control modes in the first and second embodiments will be described.

(a) When there is one slipping wheel As mentioned above, brake control and throttle control in slip control are performed selectively depending on the number of slipping wheels and the combination of slipping wheels, but when there is only one slipping wheel, When something is detected, only brake control is performed.

(b) When there are two slipping wheels Also, when it is detected that there are two slipping wheels, two of the four wheels (i@) are selected according to each of six combinations. This is performed according to one of predetermined control modes. That is, when the left rear wheel 21L and the right rear wheel 21R are slip wheels, only brake control is performed.

On the other hand, when the front left wheel 20L and the front right wheel 20R are slip wheels, the influence exerted on the running stability of the vehicle is greater than when the rear left wheel 2LL and the rear right wheel 21R are slip wheels. Therefore, in addition to brake control, the target slip rate TGTR is set to the above set value TG3.
is multiplied by the correction coefficient γ and throttle control is performed when set to the corrected value, and if the slip wheels are the left front wheel 20L and the left rear wheel 21L, then << is the right front wheel 20R and the right rear wheel 21R. In this case, the vehicle has a tendency to generate yaw motion, so in addition to brake control, the target slip ratio TGTR is set to a value corrected by multiplying the set value TG2 by the correction coefficient γ. throttle control is performed. When the slipping wheels are the front left wheel 20L and the rear right wheel 21R, or the front right wheel 20R and the rear left wheel 21L, only brake control is performed.

In this way, when two slipping wheels are detected, it is considered that the effect on the running stability of the vehicle is relatively small, and only brake control is performed, so the engine output is reduced. This prevents the wheel drive torque from being reduced more than necessary, and the reduction in driving characteristics originally required of the vehicle, such as acceleration and running performance, is suppressed. In addition, when the impact on the running stability of the vehicle is likely to be large, throttle control is performed in addition to brake control, which effectively prevents the occurrence of yaw movement that affects the running stability of the vehicle. Avoided.

(c) When there are three slipping wheels If there are three slipping wheels detected and each of them is slipping at a predetermined value or more at almost the same time,
Since it is recognized that the vehicle is in an extremely unstable running state, the target slip ratio TGTR is set to a value corrected by multiplying the set value TG2 by the correction coefficient γ. Only 7 Torr control is performed. In addition, if the three slip wheels do not slip more than a predetermined value at almost the same time, in addition to the brake control described above, the target slip rate TGTR is set by multiplying the set value TO2 by the correction coefficient γ. Throttle control is performed under the corrected value.

(d) When there are four slipping wheels Furthermore, if it is detected that there are four slipping wheels (all wheels), brake control is stopped, the target slip rate TGTR is set to zero, and the throttle is Throttle control is performed to bring the valve 14 into a fully idle state. Then, with the throttle valve 14 in a fully idle state, in order to determine whether or not each of the four wheels has been converted to a substantially non-slip state, the circumferential speed average value VAV is calculated using the formula: VAV= (
VFLn+V F Rn×V R Ln×V R Rn
)/4. Then, using the calculated circumferential velocity average value VAV, the total deviation value ε is calculated using the formula; ε=(VF
Ln-VAV)”+(VFRn-VAV)+(VRL
n-VAV)'+(VRRn-VAV)"l, and it is further determined whether this deviation value ε is less than or equal to a predetermined value Za. Then, the total deviation value ε is set to a predetermined setting value. If it is determined that it is larger than Za (ε〉Za), it means that all four wheels are not free of slinop, so the throttle valve 1 is
The total quiet state of 4 is maintained.

On the other hand, if it is determined that the total deviation value ε is less than or equal to the value Za (ε≦Za), it is assumed that all four wheels are substantially free of slip, and the slip control for each wheel is performed. It will be restarted.

When slip control is restarted, for example (second
Brake control is not performed until a predetermined period Tx has elapsed from the time when the deviation value ε becomes less than or equal to the value Za (as shown in the figure), and the target slip ratio TGTR is set by multiplying the set value TGI by the correction coefficient γ. Throttle control is performed only under the corrected value. However, when such throttle control is performed, the opening degree θt of the throttle valve 14 is larger than the normal target throttle opening degree Tk that is set according to the depression amount θa of the accelerator pedal 66 (θt> Tk), the throttle/torque control is stopped and the normal throttle distance control is started. In other words, it is prohibited to perform throttle control at a level higher than the driver's request because it causes the driver to feel uneasy.

In this way, when it is detected that all four wheels have slipped more than a predetermined value with respect to the road surface, the brake control is stopped until the four wheels are returned to a state where there is substantially no slip. The throttle valve 14 is maintained in a fully idle state so that the engine output is quickly reduced. This control reliably and quickly avoids a situation that affects the running stability of the vehicle, and also reliably and quickly returns the four wheels to a state in which no slip occurs. Therefore, even if a slip of a predetermined level or more occurs in the four wheels, a running state in which the estimated vehicle speed and the actual vehicle speed are equal or substantially equal can be obtained in a very short time.

Furthermore, after the four wheels are returned to a state where there is substantially no slip, there is a high possibility that slip will occur again in the four wheels until the period Tx has elapsed. 2
As shown in Figure B, during this period, only throttle control is performed to suppress the occurrence of slip exceeding the predetermined value, so that the four wheels are in a state in which slip does not substantially occur. The running stability of the vehicle immediately after the vehicle is turned on is ensured.

Also, when slip control is performed as described above,
Since the values of the target slip ratios TGBR and TGTR are corrected according to the number of slip wheels, and the slip ratio of the slip wheels is controlled to match the corrected values of the target slip ratios TGBR and TGTR, the vehicle Appropriate slinop control is performed according to the driving conditions and road surface conditions, making it possible to substantially ensure the driving stability of the vehicle and to obtain desired driving characteristics.

<Torque split control> -4. A control signal from the torque distribution control section is output to the throttle control section O and the brake control section of the control unit 100. This torque distribution control section includes, for example, an acceleration signal I)tra from a longitudinal acceleration sensor,
Lateral acceleration signal DL from the lateral acceleration sensor, Steering angle from the steering angle sensor 69 {i No. θs1 Throttle opening signal θt from the throttle opening sensor 65, Boost pressure detection signal from the boost pressure sensor B1 Accelerator opening sensor 67
The accelerator opening detection signal θa is inputted, and the amount of torque distribution to each wheel between the front and rear wheels and the left and right wheels is appropriately controlled during acceleration and cornering, for example.

The torque distribution control section controls the front wheel 2 when there is a load shift between the rear wheels 21L and 21R, such as during start acceleration.
By applying braking force to the disc brakes 35A and 35B of OL and 2OR, and increasing the engine torque corresponding to this braking force, the wheels 2OL, 2OR, and 21L as a whole are
, 2 Torque split control is performed so that the driving torque acting on the road surface from 1R is the same, but the amount of torque distribution is different. In addition, when driving around a corner, the disc brakes 35A on the front wheels 20L and 20R side are used when entering a corner.
, 35B. On the other hand, when exiting a corner, braking force is applied to the disc brakes 35G and 35D on the rear wheels 21L and 2lR, respectively, and when turning left, the brakes are applied to the right front and rear wheels 20R.
Since there is a load shift on the 2lR side, the left front and rear wheels 20L, 2
Apply braking force to the brakes 35A and 35V on the L side. In addition, when turning right, the brake 3 on the right front and rear wheels 20R and 21R side
Braking force is applied to each of 5B and 35D, and the engine torque corresponding to the torque lost due to each braking force is controlled to be increased on the other side, thereby changing the amount of torque distribution acting on each wheel. ing.

Details of Control Operation of First Embodiment The slip control (traction control) and torque distribution control (torque distribution control) described above are both based on the operation of each control section of the microcomputer built in the control unit 100. Although it is done,
The specific individual control programs (basic system) executed by this microcomputer will first be described in detail regarding slip control with reference to the flowcharts of FIGS. 3 to 10.

First, the flowchart in FIG. 3 shows the main program (main routine) of the slip control.

After starting the control operation, each part is initialized in step SI01, followed by step S. , in addition to the detection signals VFL, etc. mentioned above, θt, θaθS
etc. are sequentially imported to create necessary data, and the subsequent process steps S1.3 to S. In this step, slip determination, vehicle speed constant control mode setting, target slip ratio correction, throttle control, and brake control are executed in sequence, and the process returns to step 102.

For example, as shown in the flowchart of FIG. 4, the slip determination program executed in step S3 in the flowchart of FIG. Set to zero and step S Il1
, the value V of the peripheral speed of the left front wheel 20L one cycle before
F L n-+ is placed in the register VWo, and the value VFLn of the circumferential speed of the left front wheel 20L at that time is placed in the register V.
Put it on WN. In addition, the front wheel slip/zob flag SFFL held in the previous cycle is saved in SFQ, and in step S113, the slip detection program shown in FIG. 5 is executed.

In the slip detection program shown in FIG. 5, after the start, in step Slffl, the circumferential velocity value ■W○ of the previous cycle is deleted from the circumferential velocity value VWN of the current cycle, and the circumferential acceleration of the left front wheel 2OL is calculated. Calculate Δ■W, and calculate the circumferential acceleration ΔVW at the following step S, 3.
It is determined whether or not is greater than or equal to a predetermined set value Aa. If it is determined that the circumferential acceleration Δ■W calculated above is equal to or greater than the set value Aa, the left front wheel 20L has a slippage greater than or equal to the predetermined value.
, is determined to have occurred, and in step S, 3, the slip wheel determination flag SFQ indicating this is set to l? (slip occurrence). At the same time, 1 is added to the slip wheel counting counter SN to update the count value of the counter SN. If it is determined in step S132 that the circumferential acceleration ΔVW is less than the reference value Aa, the slip detection program is ended without going through step S133. After the program shown in FIG. 5 is completed, in step S114 in the flowchart shown in FIG. 4, the left front wheel slippage/blur flag SFFL is replaced with a slipping wheel determination flag SFQ, and the process proceeds to the next step Sllfi.

Hereinafter, step S I ls = S I 1? Then, for the left front car, 3 1111~S1■ is for the left rear wheel,
SI again! ! ~S1 and S4 perform slip determination for each of the right rear wheels.

Furthermore, in step S Its, the left front wheel slip flag SFFL, the right front wheel slip flag SFFR1, the left rear wheel slip flag SFRL, and the right rear wheel slip flag S
By adding each FRR, the slip wheel count counter SN calculates the number of slip wheels? save. Next step S
At +ms, it is determined whether or not the accelerator pedal 66 is in the released state (driver's throttle fully closed request state). In the case of YES determination, which means that the accelerator pedal 66 is in the released state, in the final step S In the case of No in S1■, where it is determined that the accelerator pedal 66 is not in the released state, step SL! ? This slip determination program ends without going through.

On the other hand, Step 3 in the flowchart of FIG.
For example, as shown in the flowchart of FIG. 6, the vehicle speed estimation executed in step 104 is performed in step S140 after the start, when the estimated vehicle speed value Vl-1 set one cycle earlier is equal to or higher than the reference value vh. If it is determined that the estimated vehicle speed value Vn is equal to or higher than the reference value vh (YES), in the next step S141, the estimated vehicle speed value \Jh is set to the left front wheel 20L. , right front wheel 2
0R1 Circumferential speed values VFLn, VFRn, VRLn, and VRRn for the left rear wheel 21L and right rear wheel 21H, respectively.
The correction coefficient α is set to the smallest one. The vehicle speed estimation program is then completed. on the other hand,
Step S14 above. , the estimated vehicle speed value Vn-
, is determined to be less than the above reference value vh,
On the other hand, in step S142, it is determined whether the steering angles of the front left wheel 20L and the front right wheel 20R, which are indicated by the steering angle detection signal θS, are greater than or equal to the set value θ. The steering angle is the same set value θ.
If it is determined that it is less than
41 is executed in the same manner as described above, and this vehicle speed estimation program is ended. On the other hand, in the case of YES in step S14, where it is determined that the steering angle θS is greater than or equal to the set value 08, it is determined in step S143 whether the slip wheel counting counter SN is zero or 1, and the slip It is determined that the wheel count counter SN is 0 or 1. If the
Based on the steering angle θ, it is first determined whether the vehicle is in the right turn state. If it is determined that the vehicle is turning to the right, then in the next step S, 4, it is determined whether the right front wheel slinop flag SFFR is zero. As a result, if it is determined that the right front wheel slip flag SFFR is zero, it is further determined in step S148 whether or not the left rear wheel slip flag SFRL is zero, and the left rear wheel slip flag SFRL is set to zero. If it is determined that is zero, in step S1.7, the estimated vehicle speed value vn is calculated using the formula: Vn-{(VFRn+VRLn)/
2) Calculate using Xα1 and end this estimated vehicle speed setting program. On the other hand, the steps S14 and . 4, if it is determined that the front right wheel slip flag SFFR and the rear left wheel slip flag SFRL are not zero, the estimated vehicle speed value Vn is calculated in step S148 by the formula: Vn=={(VFLn+VRRn)/21Xα, The vehicle speed estimation program is then completed.

On the other hand, if it is determined in step S144 that the vehicle is not turning to the right, then in step S, 1, it is determined whether or not the front left wheel slip flag SFFL is zero, and the front left wheel slip flag SFFL is set to zero. If it is determined that the right rear wheel slip flag SFRR is zero, it is determined in step S ISt whether or not the right rear wheel slip flag SFRR is zero. As a result, if it is determined that the right rear wheel slip flag SFRR is zero, the estimated vehicle speed value Vn is calculated using the formula; Vn=[(VFLn+V
RRn)/2}×α1, this vehicle speed estimation program is terminated, and the steps S+61 and .
If it is determined in lI1 that the front left wheel slip flag SFFL and the rear right wheel slip flag SFRR are not zero, in step 81.4, the estimated vehicle speed value Vn is calculated using the formula; Vn= ((V F Rn + V R Ln )
/21Xα1, and this vehicle speed determination program is ended.

On the other hand, if it is determined in step S143 that the slip wheel count counter SN is not zero or l, then in step S155, it is determined whether the slip wheel count counter SN is 2 or not, and If it is determined that the counting counter SN is 2, it is determined in the following step Slsa whether or not the right front wheel slip flag SFFR is zero, and if it is determined that the right front wheel slip flag SFFR is not zero. for,
In step S167, the right rear wheel slip flag SF
Determine whether RR is zero. And as a result,
If it is determined that the right rear wheel slip flag SFRR is not zero, steps S1, . , it is determined whether the vehicle is in a right-turning state. If it is determined that the vehicle is turning right, step S1
In 511, the estimated vehicle speed value Vn is calculated using the formula; v1=VFL
nXα2, and this vehicle speed estimation program is ended. Further, if it is determined in step S+ss that the vehicle is not in a right-turning state, step S
+60, the estimated vehicle speed value Vn is calculated using the formula: Vn=VR
LnXα, and this vehicle speed estimation program is ended.

On the other hand, what if it is determined in steps S1 and 7 that the right rear wheel slip flag SFRR is zero? In step S1■, it is determined whether or not the left front wheel slip flag SFFL is zero, and the left front wheel slip flag SFF is set.
If L is determined to be zero, step S Ill! , the estimated vehicle speed value Vn is expressed as; Vn={(VF Ln
10 VRRn)/21 The value Vn is expressed as: Vn=f(VRRn+VRLr+)/2)
The calculation is performed using Xα*, and this program ends.

Further, if it is determined that the right front wheel slip flag SFFR is zero in step s + se, step S l? . , left front wheel slip flag SFFL
is zero, and sets the left front wheel slip flag SF.
If it is determined that FL is zero, step S16
4, the estimated vehicle speed value Vn is calculated using the formula; Vn= ((V
F Rn+V F Ln)/2)
If it is determined that L is not zero, step S18,
At , it is determined whether the left rear wheel lever knob flag SFRL is zero. And the left rear wheel slip flag SFR
If L is determined to be zero, then step S,6
6, the estimated vehicle speed value Vn is calculated using the formula; Vn=t(V
F Rn+V R Ln)/21Xa, and this vehicle speed estimation program is ended. On the other hand, step S
If it is determined in Ill5 that the left rear wheel slip flag SFRL is not zero, in step 8 187 it is determined whether the vehicle is in a right-turning state,
If it is determined that the vehicle is not in a right-turning state, in step SlB11, the estimated vehicle speed value Vn is calculated using the formula: ■
n=VRRnXα, and this vehicle speed estimation program is terminated, and if it is determined in step S lat that the vehicle is in a right-turning state, step Sl. . The estimated vehicle speed value Vn is calculated using the formula; vn=VFR
．． nXα, and then ends this vehicle speed estimation program.

Furthermore, in step SIIIS, Sri. If it is determined that the slip wheel count counter SN is not 2, it is determined in step S1,1 whether the slip wheel count counter SN is 3, and if the slip wheel count counter SN is 3. If it is determined, step S
1,! In step S173, it is determined whether or not the right front wheel slip flag SFFR is zero, and if it is determined that the right front wheel slip flag SFFR is zero, in step S173, the estimated vehicle speed value Vn is calculated using the formula: V11= VFRnXα,
The vehicle speed estimation program is then completed.

Further, in step S11, the right front wheel slip flag S
If it is determined that FFR is not zero, step S
1-4, it is determined whether the left front wheel slip flag SFFL is zero, and if it is determined that the left front wheel slip flag SFFL is zero, the estimated vehicle speed value Vn is determined in step S1. Formula: Vy1=VFLnXα,
The estimated vehicle speed setting program is then completed. If it is determined in step S194 that the left front wheel slip flag SFFL is not zero, then in step S178 it is determined whether or not the right rear wheel slip flag SFRR is zero, and the right rear wheel slip flag SFR is
If it is determined that R is zero, step S1, ?
, the estimated vehicle speed value Vn is expressed by the formula; v1=VRRnXα
, and terminate this vehicle speed estimation program,
Further, in step S176, if it is determined that the right rear wheel slip flag SFRR is not zero, step S176
I7. , the estimated vehicle speed value vn is expressed as; Vn=VR
LnXα, and this vehicle speed estimation program is ended.

On the other hand, if it is determined in step S171 that the value of the slip/slip wheel counting counter SN is not 3, this vehicle speed estimation program is immediately terminated.

Next, in the flowchart of FIG.
. The control mode setting program executed in , for example, as shown in FIG. 7A, after the control operation starts,
First, in steps S, . . . , it is determined whether a four-wheel slip control flag CF4, which will be described later, is zero indicating a steady state, and the four-wheel slip control flag CF4 is set to zero.
If it is determined that is zero (Y E S ), step S Il+. At , it is determined whether the slip wheel counter SN is 1 or not. If it is determined that the slip wheel count counter SN is 1 (YE
S), in step S1, 1, the brake control execution flag EBF is set to 1, and the throttle control execution flag ETF is set to zero, and in step S181, the target slip rate TG for throttle control is set.
TR is set to constant TG2, and in step S+113, target slip ratio TGBR for brake control is set to constant TGI, and this control mode setting program is ended.

Also, step S. . In step S, if it is determined that the slip wheel count counter SN is not 1, step S
．． ．． In step S18, it is determined whether the slip wheel counter SN is 2, and if it is determined that the slip wheel counter SN is 2, the right front wheel slip flag SFFR is set to zero in step S18. Determine whether or not.

If it is determined that the right front wheel slip flag SFFR is zero, it is determined in step S86 whether or not the left front wheel slip flag SFFL is zero, and the left front wheel slip flag SFFL is determined to be zero. If it is determined that the rear left wheel 21L and the rear right wheel 21R are slipping more than a predetermined value on the road surface, step SI is performed.
．． ? , the brake control execution flag EBF is set to 1 (brake control execution), and the throttle control execution flag E is set to 1 (brake control execution).
Set each TF to zero and proceed to STEP S+at, STEP, PU S le? The subsequent processes are sequentially executed in the same manner as described above, and this control mode setting program is ended.

On the other hand, if it is determined in step S188 that the left front wheel slip flag SFFL is not zero, then in step S+se the left rear wheel slip flag SFFL is
Determine whether or not is zero. Left rear wheel slip flag S
If it is determined that FRL is not zero, the left front wheel 20L
And since the left rear wheel 21L is causing more than a predetermined amount of friction with the road surface? At step S18fl, the target slip rate TGTR is set to the set value TG2 and the process proceeds to step S1114. If it is determined in step S1116 that the right front wheel slip flag SFFR is not zero, then in step S1110 it is determined whether the right rear wheel slip flag SFRR is zero, and the right rear wheel slip flag SFFR is determined to be non-zero. If the slip flag SFRR is determined, it is determined in step S1111 whether or not the left front wheel slip flag SFFL is zero, and if it is determined that the left front wheel slip flag SFFL is not zero, the left front wheel Since the 2OL and right front wheel 20R are slipping more than a predetermined value on the road surface, step Sl■
, the target slip rate TGTR is set to the set value TG3 and SteSob SI! ．． Proceed to. Furthermore, step S
If it is determined in I9G that the right rear wheel slip flag SFRR is not zero, this means that the right front wheel 20R and the right rear wheel 21R are slipping with respect to the road surface by a predetermined value or more. , the target slip ratio TGTR is set to the set value TG2 and the process proceeds to step S1.4. In step S184, both the brake control execution flag EBF and the throttle control execution flag ETF are set to 1, and then in step S183, the target slip ratio TGBR is set to the set value TGI, and this control mode setting program is terminated. do. moreover,
Step 3 At 1118 left rear wheel Slinop flag S
If it is determined that FRL is zero, the left front wheel 2OL
If it is determined in step S1111 that the front left wheel slip flag SFFL is zero, the front right wheel 2OR and the rear left wheel 21L are slipping by a predetermined value or more. In this case, the process proceeds to the other step Sll17, and the process proceeds to step Sll17. Each process after 87 is executed in the same manner as described above, and this control mode setting program is ended.

On the other hand, if it is determined in step S184 that the slip wheel count counter SN is not 2, then in steps S1 and 6, the slip wheel count counter S
Determine whether N is 3 or not? If it is determined that the lip wheel count counter SN is 3, step S1
．． At step 7, it is determined whether the three-wheel simultaneous slip occurrence flag CF3 is zero. If it is determined that the three-wheel simultaneous slip occurrence flag CF3 is zero, step S8
At the same time, it is determined whether or not the slip count counter SSN is 3. If it is determined that the slip count counter SSN is not 3, at step S1■,
The target slip rate TGTR is set to the set value TG2, and both the brake control execution flag EBF and the throttle control execution flag ETF are set to 1, and step SII
At l3, the target slip ratio TGBR is set to the set value TGI, and this program is ended. Also, if it is determined that the three-wheel simultaneous slip occurrence flag CF3 is not zero in step S187, and if the three-wheel simultaneous slip occurrence flag CF3 is determined to be not zero,
1, if it is determined that the slip count counter SSN is 3 at the same time, step S. . , set the target slip rate TGTR to a set value TG2,
Both the brake control execution flag EBF and the throttle control execution flag ETF are set to 1, and the three-wheel simultaneous slip occurrence flag CF3 is set to 1, and the stenop S1 is set.

, in the same manner as above, and end this program.

On the other hand, step S1. ．． If it is determined that the slip wheel count counter SN is not 3 in step S of FIG. 7B. , it is further determined whether or not the slip wheel counting counter SN is 4, and if it is determined that the slip wheel counting counter SN is 4, the process continues as it is. , proceed to . Also, on the other hand, step S
Also when it is determined in step 1711 that the four-wheel slip control flag CF4 is not zero, step S. , and proceed to step S,. , it is determined whether the four-wheel slip control flag CF4 is 2, which indicates a slip convergence state. If it is determined that the four-wheel slip control flag CF4 is not 2, step S. 3, it is determined whether the four-wheel slip control flag CF4 is zero, which indicates a steady state.

In the case of a steady state in which the four-wheel slip control flag CF4 is determined to be zero, step S. 4, the target slip rate TGTR is set to zero and the brake control execution flag EB is set to zero.
F is set to zero, throttle control execution flag ETF is set to 1, and four-wheel slip control flag CF4 is set to 1 representing the slip convergence process. , proceed to . On the other hand, Step S! . , if it is determined that the four-wheel slip control flag CF4 is not zero, the process continues at step S.

, proceed to .

Step S. , the circumferential velocity average value VAV is first calculated by adding the circumferential velocity values VFLn, VFRn, VRLn, and VRRn and dividing by 4, as described above. In the following step S2as, the total deviation value ε is calculated using the above formula; ε=(VFLnVAV)”+(V
FRn-VAV)”+(VRLn-VAV)”10(VR
Rn-VAV)'' is calculated, and in the subsequent step S, it is determined whether the calculated total deviation value ε is less than or equal to a predetermined value Za, and it is determined that the total deviation value 8 is not less than or equal to the value Za. If so, proceed to step S18.
Step S1. , operation (T G B R
←TG 1) The above steps? S, ■+ S II4T
SI@8+ S 1. . Exit this program as you would for . Step S20 to the other? In step S, if it is determined that the total deviation value ε is less than or equal to the set value Za. At step 8, the target slip ratio TGTR is set to the set value TGI, the four-wheel slip control flag CF4 is set to 2, and the built-in timer is started to start measuring the elapsed time T. Then, in the following step S11G, it is determined whether the elapsed time T is equal to or greater than the predetermined time length Tx, and if it is determined that the elapsed time T is less than the time length TX, the steno knob S L183 is moved as described above. Execute the same procedure to terminate this program.

If it is determined that the elapsed time T is greater than or equal to the time length TX, in step S1, the brake control execution flag EBF, the throttle control execution flag ETF, the three-wheel simultaneous slip occurrence flag CF3, and the four-wheel slip control flag are set. C
F4 and slip wheel counting counter SH are set to zero, the built-in timer is reset, and step S183 is executed in the same manner as described above, and then this program is terminated. Also, step S, above. 1, even if it is determined that the slip wheel count counter SN is not 4, steps S, 13 and step Sl! 13
Execute as above and return.

On the other hand, in the target slip ratio correction program at step 3 111118 in the flowchart shown in FIG. 3, as shown in FIG. A correction coefficient γ corresponding to the value of the number of slip wheels SN represented by SN is read out. γ is S
It is a constant that takes a large value when N=O and decreases as SN increases. In steps S,..., a new target slip ratio TGBR is set by multiplying the target slip ratio TGBR by the correction coefficient γ read out in step S2+6, and in step S21? In step S
! 1, the correction coefficient γ read out is set as the target slip ratio TG.
A new target slip rate TGTR is set by multiplying by TR, and this program ends.

Furthermore, step S in the flowchart of FIG.

For example, as shown in FIG. 9, the throttle control program No. 7 executes step S.7 after the start of the control operation.
. , it is determined whether or not the throttle control execution flag ETF is zero, and the throttle control execution flag ETF is set.
If it is determined that is zero, step S. At step 1, a normal throttle opening control program is executed and this program is terminated. On the other hand, step S,,.

In step S ttt, if it is determined that the throttle control execution flag ETF is not zero,
It is determined whether or not the target slip rate TGTR is zero, and if it is determined that the target slip rate TGTR is zero, step S! At step 24, a throttle valve drive signal Ct is sent to the throttle actuator 13 to completely idle the throttle valve l4, and this control program is ended.

Also, Step S! T! , the target slip rate T
If it is determined that GTR is not zero, Stenop S
At tts, the opening degree θL of the throttle valve 14 is set according to the amount of depression of the accelerator pedal 66. It is determined whether the opening degree θL of the throttle valve 14 is equal to or less than the normal target throttle opening degree Tk.
In the case of No, which is determined to be larger, step S
At ttl, the normal throttle distance control program is executed and the program is terminated. Further, in step S■, YE is determined that the opening degree θt of the throttle valve l4 is equal to or lower than the normal target throttle opening degree Tk.
In the case of S, in step S tea, the above-mentioned estimated vehicle speed value (vehicle speed) Vn is used to detect the slip of the left front wheel 20L1 right front wheel 2OR, left rear wheel 21L, and right rear wheel 21R with respect to the road surface by a predetermined value or more. The average slip ratio SAV of the slip ratio SAV which is occurring is calculated, and the difference ΔS is calculated by subtracting the average slip ratio SAV from the target slip ratio TGTR in step S2. And then the continuation 《Step S. ．． In order to make the average slip ratio SAV match the target slip ratio TGTR, the throttle valve drive signal (feedback control signal) Ct is adjusted according to the difference ΔS.
and sends it to the throttle actuator l3 to end this control program.

Furthermore, the brake control program in step S108 in the flowchart of FIG.
As shown in the flowchart of FIG. In step S231, it is determined whether the brake control execution flag EBF is zero, and if it is determined that the brake control execution flag EBF is zero, the above-mentioned drive signal Ca=Ch
The above-mentioned disc brakes 35A to 3
After setting the 5D to the released state, exit this program.

On the other hand, the above-mentioned Stenop S. . If it is determined that the brake control execution flag EBF is not zero, it is determined in step S131 whether the left front wheel slip flag SFFL is zero. If it is determined that the left front wheel slip flag SFFL is not zero, then in step S3, the actual slip rate SFL of the left front wheel 20'L is calculated using the estimated vehicle speed value Vn using the formula; L
= (VF Ln-Vn)/VFLn, and in the subsequent step S114, the actual slip rate SFL
In order to match the actual slip ratio SFL and the target slip ratio TGBR, the drive signals Ca and cb are applied to the electromagnetic on-off valves 51 and 52 based on the comparison between the actual slip ratio SFL and the target slip ratio TGBR.
The process then proceeds to step S, . Also,
At step 3t, left front wheel slip flag S
Even if it is determined that FFL is zero, step S!
Proceed to 3. In step S, 35, it is determined whether or not the right front wheel slip flag SFFR is zero. If it is determined that the right front wheel slip flag SFFR is not zero, in step S, 36, the quasi-constant vehicle speed value Vn is determined. The actual slip rate SFFR of the right front wheel 2OR is calculated using the formula; S
Calculate by FR=(VFRn-Vn)/VFRn, followed by step S! 37, in order to match the actual slip rate SFR and the target slip rate TGBR, the actual slip rate SFR and the target slip rate TG are adjusted.
Drive signals Cc and Cd are selectively sent to the electromagnetic on-off valves 53 and 54 based on the comparison with BR, and step StS.

Proceed to. Also, if it is determined in step S35 that the right front wheel slip flag SFFR is zero, the process proceeds to step Stsa. In this step S tss, it is determined whether or not the left rear wheel slip flag SFRL is zero. If it is determined that the left rear wheel slip flag SFRL is not zero, the estimated vehicle speed is determined in step S t38. Using the value Vn, calculate the actual slip rate SRL of the left rear wheel 2l using the formula: SRL = (VRLn - Vn) / VR
Calculated by Ln, in the following Stenobu 3 24G,
The actual slip ratio SRL and the target slip ratio TGBR should be matched. Based on the comparison between the actual slip ratio SRL and the target slip ratio TGBR, the drive signals Ce and Of are selectively applied to the electromagnetic on-off valves 55 and 56. The process then proceeds to step St4. Also, if it is determined in step S, 36 that the left rear wheel slip flag SFRL is zero, the process proceeds to step S, 41. Step S f
In fi41, it is determined whether or not the right rear wheel slip flag SFRR is zero, and the right rear wheel slip flag SFR
If it is determined that R is not zero, step s t4
At t, the actual slip rate SRR of the right rear wheel 21R is calculated using the estimated vehicle speed value vn using the formula; SRR=(VRRn-V
n)/VRRn, followed by step 3 143
, the actual slip rate SRR and the target slip rate T
In order to match the actual slip ratio SRR with the target slip ratio TGBR, the drive signal Cg is
and ch are selectively sent to the electromagnetic on-off valves 57 and 58, and this program ends. Also, step S! 4,
In step S, if it is determined that the right rear wheel slip flag SFRR is zero. , in the same manner as above to terminate this program.

On the other hand, this first one. In addition to the slip control (traction control) described above, as is clear from the explanation of the configuration of the control 22, l-100, the power train control device of the embodiment also performs torque distribution control (torque split control). ) means are provided at the same time and are adapted to be combined with the slip control system as required.

First, in order to make the explanation easier to understand, the control contents (basic program) of the torque distribution control system alone will be explained, and then the control contents (correlation control program) in combination with the above-mentioned slip control will be specifically explained. I decided to.

The flowcharts in FIGS. 11A and 11B show the control details of the torque distribution control (torque split control).

First, after starting the control, in step 3 301, it is determined whether the measurement timing has arrived at every predetermined cross-clock time, and when the measurement timing arrives (YES), the vehicle's longitudinal acceleration, lateral acceleration, and Parameters such as engine accelerator opening, boost pressure value, and steering angle are measured based on signals from each sensor (step S
3. ,).

And then Stethop S. , it is determined whether or not the steering angle θS is greater than or equal to a predetermined value θb.
In the case of o, in step 3 304, the basic distribution ratio of torque distribution, that is, the distribution ratio Ka between the front and rear wheels, is set to 0.5, and the left and right distribution ratio Y is set to 0.5, so that each wheel is equally distributed between the front, rear, left and right wheels. Set it so that

On the other hand, if the determination result in step S sos is YES and the turning is in progress, step S is performed corresponding to the turning state.

, determine the front/back distribution ratio K8. This front-rear distribution ratio K8 is calculated as Ka"0.7 when entering a corner, and the rear wheels 21L, 2
Increase the torque distribution amount for 1R, and increase the torque distribution during turning.
．． = 0. 5 to equalize the front and rear wheels, and when exiting a corner, set KB=0.3 to increase the amount of torque distributed to the front wheels. This improves turning performance by increasing the driving force on the rear wheels at the beginning of a turn, while increasing the driving force on the front wheels at the end of a turn to improve straight-line performance.As a result, overall good turning performance is achieved. The purpose is to obtain the following.

Next, the torque distribution to the left and right wheels during this turn is set in step sson, and is determined so that the greater the lateral acceleration of the vehicle, the greater the left and right distribution ratio Y. And further step 3 3Q.
It is determined whether the lateral acceleration DL is positive (left turning) or not. If the result is YES and the turning is to the left, the turning flag F1 is set to 1 (step S308), and if the result is NO and the turning is to the right, the turning flag F1 is set to 1 (step S308). resets the turning flag Fl to 0 (Stenop S3
. s).

Next, the steering knob Sj10 determines the rear wheel distribution ratio K0 in accordance with the longitudinal acceleration DFR, and the larger the acceleration of the vehicle, the larger the amount of torque distributed to the rear wheels 21L and 21R. And this rear wheel distribution ratio K. According to the step S, l04 or S3. , the front and rear distribution ratio K.
is corrected (Stennob S3,,), and the distribution ratio KF to the rear wheels is finally determined. Then, the amount of torque distributed to the rear wheels is controlled to be large during acceleration, regardless of whether the vehicle is turning or not.

Further, the steno knob S,1, is used to calculate the current engine generated torque Ps, and is determined based on the engine boost pressure value B1, throttle opening TVO, or accelerator distance ACC. After that, Stenop S3, 3 determines whether the longitudinal acceleration DFR is smaller than 0.5 (equally divided value), and if this judgment is No and 0.5 or more, the amount of torque distributed to the rear wheels is larger than the front wheels. In this case, the acceleration flag FO is reset to O in step S314, and the above determination result is Y.
Less than 0.5 in ES? If the amount of torque distributed to the front wheels is larger than that to the rear wheels, step S3. to set the acceleration flag Fo to 1
At the same time, in step 3 3+11, the front and rear distribution ratio k is converted to a value larger than 1-k, which is 0.5.

Subsequently, in step S317 of FIG. 11B, the required torque Pr required to realize the above-mentioned front-rear distribution ratio Kr and left-right distribution ratio Y is calculated. This required torque Pr is calculated by multiplying the distributed torque PSXKFXY for the wheel with the largest torque distribution by 4. The above required torque Pr
is the engine's maximum torque Pl. It is determined whether or not it is smaller than IAx (step S, +8), and when it is determined YES that there is a margin in the engine torque, the throttle opening degree is increased and controlled so that the engine torque becomes the above-mentioned required torque Pr (
Stenobu S3,. ). Then, in step S3tQ, it is determined whether or not the acceleration flag FO is set to 1, and since there is a load shift to the rear wheels during acceleration when it is reset to O, in step S3■, the torque on the front wheels is In order to reduce this, the disc brakes 35A and 35B of the left and right front wheels 20L and 20R apply braking force to the front wheels 20L and 2OR so that the braking force is applied to the front wheels 20L and 2OR so that the brake force is applied to the front wheels 20L and 2OR so that the brakes correspond to half of the difference between the front and rear torque distributions from equal distribution. I do. On the other hand, the above-mentioned step S32. If the determination is YES and the acceleration flag FO is set to 1, the front wheel 20
Since there is a load shift on the L, 20Y< side, step S
321 has disc brakes 35G on the left and right rear wheels 21L and 21R to reduce the torque on the rear wheels 21L and 21R.
At 35D, control is performed to apply braking force to the rear wheels so that the braking force is applied to the rear wheels so that the braking force corresponds to half of the difference between the front and rear torque distributions.

Furthermore, in step 3 3I3, the turning flag Fl is set to Fl.
= 1 is set, and when turning left when it is set to 1, there is a load shift to the right front and rear wheels 2OR and 2lR, so the left front and rear wheels 2OL are set to 1 with Stenop S and 4.
, 21L side torque should be reduced [left front and rear wheels 2OL, 2
Control is performed to apply braking force to the left wheel side so that the 1L disc brakes 35A and 35C each apply braking force equivalent to half of the difference between the left and right torque distributions.

? On the other hand, step S3. If the judgment is No, the acceleration flag F1 is O.
When turning to the right, the left front and rear wheels 2OL, 2 are reset to
Since there is a load shift on the lL side, step s sts
In order to reduce the torque on the right front and rear wheels, the right front and rear wheels 2OR,
Control is performed to apply braking force to the right wheel side so that the brakes 35B and 35D of 21R perform braking for a torque corresponding to half of the difference between the left and right torque distributions from equal distribution.

Moreover, on the other hand, the above step S3. ．． The judgment result is NO,
The required torque Pr is the engine's maximum torque P. If the required torque Pr is larger than the maximum torque P of the engineering engine, the required torque Pr is calculated when the left and right distribution is stopped and the left and right distribution ratio Y is set to 0.5 in steps S3 and 8. l
Determine whether it becomes smaller than AX (step S32
7). And the maximum torque PM is smaller than κ.
At the time of ES determination, the throttle opening degree is controlled so that the engine torque becomes the required torque Pr (step S se
e). Furthermore, the above step S3'to-33■
Similarly, in steps s3te to S3,1, depending on the state of the acceleration flag FO for the magnitude of the front/rear distribution ratio Y,
During acceleration, braking force is applied to the front wheels, while during deceleration, braking force is applied to the rear wheels.

Furthermore, if the determination in step S3 above is No and the requested torque Pr is greater than the maximum engine torque PMAx even if the left-right distribution is canceled, the process proceeds to step S3fft to determine whether the acceleration flag FO is set to 1 or not. At the time of acceleration, which is reset to 0, step S33
At step 4, the engine torque is set to the maximum torque PMAX, and control is performed to apply braking force to the front wheels so as to brake the torque equivalent to half of the increased torque. On the other hand, during deceleration when the acceleration flag FO is set to 1, the engine torque is set to the maximum torque P l4AX in step S33.
At the same time, control is performed to apply braking force to the rear wheels so as to apply braking to a torque equivalent to half of the increased torque.

The above torque distribution amount is changed so that, for example, if the vehicle is running with a drive torque of 50 Kg-m for the front wheels and rear wheels, the current gear ratio of the transmission will equalize the wheel drive force. The corrected engine generated torque Ps is 100K
g-m. If we apply a total of 30 kg-m of braking torque to the left and right front wheels in response to the acceleration state, and compensate for the drive torque lost due to this braking torque by increasing the engine output, the required engine The output torque Pr is 130Kg-1. 65Kg before and after this
Since the final distributed torque is distributed equally in m increments, the front wheels receive 6
5-30 = 35Kg-m, the rear wheel becomes 65Kg-m,
In the end, the rear wheel torque distribution ratio k becomes 0.65.

Modifications to the first embodiment> (Modifications to slip control) In the first embodiment described above, the slip wheels are
When the vehicle is a vehicle, a first control mode in which only brake control is performed and a second control mode in which throttle control is performed in addition to brake control are adopted depending on the combination of the slip and pull wheels. In the second control mode, if the left front wheels or the left and right rear wheels are slipping wheels, which tend to affect the running stability of the vehicle, then the other two wheels are slipping. Although the system is configured such that a control mode with a different target slip rate is taken depending on whether the wheel is a wheel or not, the four
The slip control device of a wheel drive vehicle does not necessarily have to be configured in this way; for example, when the target slip rate in brake control and throttle control is set to the same value,
The brake control and the throttle control are performed together, and the ratio of the decrease in the drive torque acting on the slipping wheel due to the brake control and the decrease due to the throttle control is equal to It goes without saying that the slip control may be configured to be performed according to control modes that differ depending on the combination of wheels.

Further, in the above-described embodiment, a specific slip rate value is calculated for a specific wheel for which a slip state of a predetermined value or more is detected, and the calculated slip rate is made to match a set target value. However, the slip control device for a four-wheel drive vehicle according to the present invention does not necessarily have to do so. By subtracting the estimated vehicle speed value from the circumferential speed value of a specific wheel for which a slip condition has been detected, the slip amount for that specific wheel is calculated, and the calculated slip amount is made to match the target value. It may also be configured to change the drive torque acting on a particular wheel.

Furthermore, in the embodiments described above, the output torque of the engine during the sleeve/brake control is configured to be variably adjusted by changing the throttle opening, but it is not necessary to do so. Instead, it is configured to be variably adjusted, for example, by changing the air-fuel ratio, ignition timing, exhaust gas recirculation amount, intake/exhaust valve opening/closing timing, boost pressure, fuel injection timing, etc. instead of the throttle opening. Of course it's a good thing.

Furthermore, in the embodiments described above, the powertrain control system is applied to a full-time four-wheel drive vehicle that is always in four-wheel drive mode, but the present invention is in no way limited to this. For example, 4
Needless to say, the present invention can also be applied to so-called part-time four-wheel drive vehicles in which a wheel drive state and a two-wheel drive state can be arbitrarily and selectively selected.

<Modification of Torque Distribution Method> In the configuration of the above embodiment, the braking force is configured to be able to be changed independently for each of the front, rear, left, and right wheels, so that the torque distribution to each wheel can be changed. Needless to say, the braking force may be varied independently for the side and rear wheels, and the torque distribution may be changed only between the front and rear wheels, or the torque distribution may be changed only between the left and right wheels.

Second Embodiment> Overview By the way, according to the control of the first embodiment described above, the slip control (traction control) and the torque distribution control (torque split control) of the drive wheels each stabilize the running state of the vehicle. However, as already mentioned in relation to the conventional technology, when these two controls operate simultaneously, the following problems occur between the two controls: This may lead to interference problems. The inventors categorized this interference problem into two types,
The second embodiment specifically proposes control measures for each of these improvements.

The first interference problem occurs when the need for Torx blit control arises during slip control. For example, assume that you are starting or turning on a road with low frictional resistance. As shown in FIG. 12A, in such a case, slip control due to slip occurrence and torque split control due to non-uniform distribution of load between wheels are required at the same time. , torque may be increased by torque blit control. In the above example, if slip occurs in the rear wheels at the time of starting, the torque will be increased by torque spurinoto control on the rear wheels subject to slip control, and this will make it difficult to converge the slip state. That is, in this case, superimposed control of slip control and Torxbrinoto control causes inconvenience.

On the other hand, if slip occurs in the front wheels when starting, increasing the torque distribution ratio to the rear wheels using torque split control when performing slip control on the front wheels will not only improve starting performance. First, if turning is performed at the same time as starting, there is an effect of improving turning performance at the initial stage of turning.

Furthermore, the reduction in front wheel torque through torque split control brings about early convergence of slip. Like this, the same,
Even when starting on a low-resistance road surface such as a snow-covered road, torque split control increases the amount of driving force distributed depending on the location of the slippage and the number of slipping wheels. There are cases where it has a positive effect on sexuality and cases where it has a negative effect.

Therefore, in this second embodiment, special control measures are taken so that the torque applied to the wheels subjected to the above-mentioned slip control is not increased by the torque split control. The details of this control device will become clear from the explanation of the control procedure shown in FIG. 15 below.

Further, in the second embodiment, further control measures have been added. That is, the following must be considered as the second interference problem.

This second interference problem occurs when the need for slip control occurs during torque split control, contrary to the first interference condition. Now, let us assume, for example, a situation where a turning operation is performed on a road with large changes in road resistance. in this case,
1st. 2 As shown in Figure B, when lateral acceleration is detected during a right turn, torque blit control is executed as the load shifts, and the engine output torque is appropriately distributed to provide multiple outputs to the outside wheels (FL, RL). of torque is distributed. At this time, the road surface changes and the left rear wheel (R
When slipping occurs in wheel L), as explained in the first interference problem above, it is necessary to stop increasing the torque by torque split control on the left rear wheel RL, which is the outer wheel that is slipping. However, if the Torx blit control is simply stopped, the following problems will occur. In other words, not all wheels are slipping. In the above example, at the moment when slinop occurs on the left rear wheel RL, the torque is
L), the torque applied to the inner wheel is small. In order to reduce the torque applied to the outer wheel where slipping has occurred, it is easy to stop the torque split control, but if the torque split control is stopped, the torque will be distributed evenly, so The inner wheels (FR, RR) to which only a small amount of torque had been applied until then suddenly experience an excessive increase in torque, and there is a risk that new slip will occur in the inner wheels (FR, RR). Or, even if no slipping occurs, the outer wheel of the turning wheel that is slipping will exert a small amount of force on the vehicle body, and the inner wheel, which is given too much torque to turn, will exert a turning force on the vehicle body. As a result, the turning performance of the vehicle is reduced, and the behavior of the vehicle body becomes unstable.

Therefore, in order to avoid the inconvenience caused by this second interference state, the following control measures are taken in this second embodiment. In other words, if a slip occurs in a wheel while Torque Split control is being executed and Torque Split control must be stopped, first stop Torque Split control instead of immediately stopping Torque Split control. In this case, it would be possible to detect a wheel where the applied torque suddenly increases, and perform slip control on such a wheel, regardless of whether or not slip actually occurs on that wheel. This prevents a sudden increase in applied torque.

The control procedure for avoiding this second interference condition will be explained in detail later in connection with the flowchart of FIG. 14.

(Details of power train control in the second embodiment) FIGS. 13 to 19 show details of the power train control operation in the second embodiment. Among the control procedures of this second embodiment, FIG. 13 shows the main program, and FIGS. 14 to 19 show various subroutines used for controlling the second embodiment. As mentioned above, in both Torx blit control and slip control, the direct control target is the engine output (i.e., the above-mentioned throttle opening control signal Ct), and the brake control of each wheel (i.e., the actuator control signal). Ca-Ch).

The various signals used in the control according to the second embodiment are shown in the table below (Table 2).

(Table 2) That is, first, in step S4C)O of FIG. 13, it is determined whether the measurement timing of various input signals has arrived. If YES, the measurement timing has arrived,
The various input signals shown in Table 2 are read from each sensor. Furthermore, in step S402 and step S403,
Based on these human input signals, slip determination and vehicle speed estimation are performed. Since the determination of the slip state in step S401 is the same as that of the first embodiment, the flowchart of FIG. 4 of the first embodiment is used as the control procedure. Then, in step S402, the slip state of each wheel is flagged as flags SF F L, SFFR, SF.
In RL and SFRR, the cumulative number of wheels that have slipped is in the counter SN, and the number of wheels that have occurred at the same time is in the counter SSN.
stored respectively. In addition, the vehicle body speed V in step S403
Since the estimation control of n is the same as that of the first embodiment, the flowcharts of FIGS. 6A and 6B of the first embodiment are used as the control procedure.

(Slip Control Parameter Settings) Next, in step S404, various parameters used for slip control in this embodiment are set.

The setting operation of this parameter is the slip state flag (S
Flags EBF and E are used to determine whether or not to perform brake control and throttle control for slip control based on the slip wheel count counter SN, etc.
Setting and holding TF and target slip rate (TGB
The content is to set the R, TGTR). Also, monitoring the four-wheel slip state is one of the operations in step S404. Step S for setting various parameters used for slip control
Since the details of the procedure in step 404 are the same as those of the first embodiment described above, the flowcharts of FIGS. 7A and 7B of the first embodiment described above are used as the control procedure.

Thus, by this control parameter setting routine, the states of the brake control execution flag EBF, the throttle control execution flag ETF, and the target slip rate TGBR in brake control for slip control are determined, for example, in the control manner shown in the control table of FIG. 2A. , the target slip rate TGBR in throttle control for slip control, etc. are set according to the number of slip wheels SN, the number of simultaneous slip wheels SSN, and the position of the slip wheels (S F F R etc.).

By the way, if slipping occurs in the four wheels (SN = 4)
) slip convergence monitoring control will first be explained in detail. Each state of control from the occurrence of four-wheel slip until its resolution is tracked, for example, by the value of status counter C F 4. At the beginning of the four-wheel slip, CF4=O, and then CF. = changes from 1 → 2 → 0.

Now, immediately after slipping occurs in the four wheels, as shown in Figure 7B,
Step S201 → Step S202 → Step S20
3→Step S204, and in this step S204,
In order to stop brake control, EBF=O.

Further, although throttle control is performed, in order to fully open the throttle valve, EFT=l and TGTR=O. Further, in step S204, the status indicating that control to converge the four-wheel slip state has been started is CF. =1.

In step S205, the average vehicle speed VAV is estimated from the following equation, and SteSob S206 estimates the circumferential speed of the four wheels (V F
Calculate the variation ε of L, V F R, V R L, V R R).

Until it is detected that this ε has become equal to or less than a predetermined threshold value Za, the control procedure continues from step S201 to step S2.
02→Step S203→Step S205→Step S206→Step S207→Step 8183 are repeated, and during that time, the CF. =1, EBF=O, ETF=
1, TGTR=0, TGBR=TG, are maintained.

Eventually, the slip between each wheel converges and the peripheral speed variation ε becomes Za (ε≦Za), step S207.
When detected, the stethoscope 8208 changes the target slip rate TGTR of throttle control to TG1 (T G T
R = T G , )L, the throttle tends to open slightly from full open. Also, a timer for period Tx is started, and CF. 2
Change to

Step S210 indicates that this timer has timed out.
Until the detection is made, the control procedure is step S201 → step S202 → step S210 → steno knob 8183.
is repeated, during which time CF. =2,EBF=O,ET
F=1, TGTR=TG, TGBR=TG, are maintained.

Eventually, when a preset time TX has passed in which the four-wheel slip state will be sufficiently converged, step S is performed.
213, CF4, CF. ,EBF,ETF,SN,S
FFL, SFFR, SFRL, SFRR=2, EBF=
Reset O, ETF = 1.

Returning to the explanation of FIG. 13. In step S405, the target slip rate TGTR, TG set in step S404 is
BR is modified. That is, by multiplying TGBR and TGTR by a coefficient γ that changes depending on the value of the number of slip wheels SN, TGBR=TGBRxγ (Step S218) TGTR=TGTRxγ (Step S21?) The number of slip wheels at that time The target value of slip ratio is corrected to be suitable for

(Torx bullet control parameter setting) Steno knob 8
Details of the Torx blit control parameter setting routine 406 are shown in FIG. Step S423
Then, it is determined from the steering angle signal OS whether or not the vehicle is currently turning.

If the vehicle is not turning, in step S424, the basic torque distribution rate Ke to the two rear wheels is set to 0.5, and the torque distribution rate Y to the two right wheels is set to 0.5. That is, the distribution ratio is determined so that the torque distribution is uniform between the front, rear, left, and right wheels.

On the other hand, if it is determined in step S423 that the vehicle is turning, in step S425, the basic torque distribution ratio K8 is set to 0.5 in order to increase the rear wheel torque at the start of a turn that requires turning performance. At the end of a turn where straight-line performance is required, the basic torque distribution ratio KB is set to 0.3 in order to increase the driving force on the front wheel side. In this way, cornering performance is improved by selecting an appropriate rear wheel torque distribution ratio at each stage of the corner.

Regarding the left and right wheels, the torque distribution ratio (absolute value) Y to the right wheel is expressed as the lateral rotational acceleration Dt. absolute value ID of
According to Ll, acceleration Dt. The larger the value, the more 0
．． Set the amount to a value greater than 5. Even if the torque distribution rate Y to the right wheel is an absolute value, there is no problem because the flag F stores whether the vehicle is turning to the right or to the left depending on the sign of the lateral acceleration DL. That is, in the case of a left turn where the acceleration DL is positive, that is, when a large amount of torque must be distributed to the right wheel, "l" is set in the flag F in step S428.
In the case of a right turn where the acceleration DL is negative, that is, if a large amount of torque must be distributed to the left wheel, the flag F1 is set to "O" in step S429.

In this way, when the basic torque distribution rate Ka to the rear wheels and the torque distribution rate Y to the right wheel are calculated, Stesobu S430
- In step S436, the final rear wheel torque distribution ratio K+- is determined. That is, in step S430, a correction coefficient Ko is determined according to the longitudinal acceleration DFR, and in step S431, the final distribution ratio Kr is determined as follows: KF=(KBXKo)/0. Calculate from 5. The numerator of 0.5 is to normalize the contribution of the corrected KO to KF. By comparing this KF with 0.5, it can be determined whether the vehicle body is accelerating or not. Steno knob S432 determines engine generated torque Ps based on engine boost pressure B1 throttle opening θt or accelerator opening θa.

Steps 8433 to S436 are steps for determining acceleration. In step S433, acceleration or deceleration is determined by checking the sign of the longitudinal acceleration. If it is determined that the acceleration is not accelerating (DFR>0), the flag FO is set in step S435 to indicate that the acceleration is not accelerating. is set, and if it is determined that the vehicle is being accelerated (DFI1-0), the flag FO is reset in step S434 to remember that the vehicle is being accelerated.

Note that the rear wheel distribution ratio K2 and the right wheel distribution ratio Y obtained by the control procedure shown in FIG. 14 are not necessarily "accurate" values, and at this stage, K! l and Y may also include a front wheel distribution rate and a left wheel distribution rate, respectively. It is Kr. When calculating Y, step S 4 3 0 and step 84 in FIG.
26, the correction constants Ko and Y are determined by the absolute value of the longitudinal acceleration DFR and the absolute value of the lateral acceleration DL, respectively. Corrections for K, , Y to accurately reflect the rear wheel distribution ratio and right wheel distribution ratio are performed in steps 8500 to S503 in FIG. 19, which will be described later.

In this way, various parameters for Torx blit control (rear wheel torque distribution ratio KFI, right wheel torque distribution ratio Y) are
The determination is made appropriately depending on whether the turning is in progress, or whether it is at the beginning of the turn, in the middle of the turn, or at the end of the turn.

(Slip control, Torx blit control) Next, the 13th
Based on the control procedure shown in step 8407 to step S416 in the figure and the various control parameters determined in FIGS. 15 to 19 above, the slip control of the second embodiment,
A specific control process in which torque split control is actually performed will be explained in detail.

As mentioned above, each of the torque split control and the Slinop control of the present invention is an engine torque control (throttle control) at the embodiment level. ! : Consists of flake control. Engine torque control for torque split control and slip control is performed in step S41 in FIG.
The details of step S415 are shown in FIG. In FIG. 17, steno knob 8521 to step S526 are engine torque control for torque blit control, and step 8527 to step S532
is engine torque control for slip control. On the other hand, brake control for torque split control and slip control is executed in step S416 in FIG. 13, the details of which are shown in FIG. 18. In FIG. 18, step S480 (details thereof are shown in FIG. 19) performs brake control for Torx blit control in step S480 (details thereof are shown in FIG. 19).
Steps 481 to 8484 show brake control for slip control. Table 3 below shows the mutual relationship between the above controls.

(Table 3) Steps 8407 to S414 in FIG. This is a procedure for adapting and correcting the above-mentioned two interference conditions. In particular, the control for dealing with the first interference condition is mainly carried out in the flowchart of FIG.
In addition, the control for dealing with the second interference condition is mainly
This is shown in Figure S. The following Tables 4 and 5 each divide the above two interference states into cases in more detail and briefly describe the countermeasure control for each case.

(Table 4) When torque splint control becomes necessary during slip control (Table 5) Further, steps 3407 to S416 will be explained in detail according to the attached drawings.

First, in step S407, it is determined whether or not Torx blit control is necessary. This can be recognized by determining whether the rear wheel torque distribution ratio K and the right wheel torque distribution ratio Y are both 0.5. If it is determined that KF=Y=0.5, the process advances to step S415. Stenobu S4
15 is engine torque control, the details of which are shown in FIG. 17.

(When Torque Split Control is Not Necessary) Here, engine torque control in the same case will be explained by explaining the engine torque control shown in FIG. 17 when there is no need to perform torque split control. First, in step S520 of FIG.
Determine whether the execution flag ETF is 0 or not. EFT
= 0, that is, the case where there is no need to perform throttle control for slip control will be explained. When EFT=O, for example, the number of slipping wheels is one, as shown in FIG. 2A. In such a case, step S
Proceeding to step 521, first, the driver's required torque Pr is calculated. This Pr is the engine generated torque depending on the accelerator distance θt, the boost pressure B, etc. Next, step S
At 522, the torque Ps required for making the torque distribution judgment is determined.
Calculate.

Pr-4 ・Ps-K+-・Y Torque split control is not performed K F= Y =
0. In the case of 5, Pr=Ps.

Incidentally, as already explained in the flowchart of Fig. 11,
At present, K, and Y do not represent the rear wheel torque distribution ratio and the right wheel torque distribution ratio, respectively.

That is, if there is an unevenness between the rear wheel torque distribution rate and the front wheel torque distribution rate, KF means the larger distribution rate. Y also means the larger of the right wheel distribution rate and the left wheel distribution rate. Therefore, when Torx blit control is substantially performed (K,≠0.5, Y +
0. 5), Pr=4・Ps-KF-Y is
Torque refers to the maximum torque required to perform blit control and slip control.

Next, in step S523, the torque Pr required for the engine and the maximum torque P MA that the engine can generate are determined.
Check the size of X. If the requested torque Pr is less than P MAX (P r < P , 4AX), the engine has a margin, so the throttle opening that generates the torque equivalent to this Pr is calculated in step S525, or the requested torque is Torque Pr is PMAX or more (Pr≧P.
AX), the engine cannot output more than P MAX, so the Stenop S524TEP
MAX, and then set the throttle opening to generate a torque corresponding to Pl4AX in step S5.
Calculate by 25. In step 8526, the control signal Ct corresponding to this opening degree is sent to the slot/nottle acticoator 13.
Output to.

Next, a case where engine torque control for slip control is performed in step S520 (ETF=1) will be described. Such a case is, for example, a case where slip occurs only in the left and right front wheels. In this case, step S52
Proceed to step 7 to check whether the value of the target slot/nottle slip rate TGTR is zero. The case where it is zero is the case where slip occurs in the four wheels, as shown in FIG. 2A.

If TGTR is zero, the throttle valve is fully closed in step S528. If TGTR is not zero, the process proceeds to step S530, and the average value SΔV of the slip and slip rates of each wheel is calculated.
Calculate. For example, if slipping occurs in the front left wheel and the front right wheel, S A V = 1/2 ((V
FLn4n)/(VFLn+ VFRn-Vn)/VF
Calculated by Rnl. Next, this average slip rate SAV
The deviation ΔS between the target slip rate TGTR and the target slip rate TGTR by throttle control is calculated using the steno knob S531 from ΔS=TGTR−SAV. In the steno knob S532, the throttle valve control signal Ct corresponding to this ΔS is sent to the actuator 1.
Output to 3. This control signal Ct is applied to the actuator 13.
When the signal Ct is outputted, the opening degree of the throttle valve is controlled in accordance with the signal Ct, the engine torque is reduced, and as a result, the slip rate of the wheels is controlled.

The above is the explanation of engine torque control (FIG. 17).

That is, steps 3521 to S526 are engine torque control for torque split control, and steps 8527 to S532 are engine torque control for slip control.

Returning to the explanation of the flowchart in FIG. 13. Step S4
When the torque control of step S416 is completed, the brake control of step S416 is executed. The details of this brake control are explained in Part 1.
This is shown in Figure 8. First, in step 8480, the brake torque TBST (TBSTFR, TBST) for torque split control for each wheel is calculated.
F L, T B S T R R, T B STR
Calculate L). Details of this calculation routine are shown in FIG.

The procedures from step 8500 to step S503 in FIG. 19 were introduced because the braking force (torque) for torque split control to be applied to each wheel was defined in step 8508 by the following equation.

TBSTFR=Ps/4-(Ps・(1-Kr)・Y)
TBSTFL=Ps/4-tPs・(t-Kr)(1-
Y) ITBSTRR=Ps/4-tPs-KF-Y)T
BSTRL; Ps/41Ps4r{l-Y)1 Ps/4, the first term on the right side of each of the above equations, is the value requested by the driver (re
Quest) This is the torque when the engine torque Pr is distributed on average to one wheel. Furthermore, the second term is the amount of torque to be distributed to each wheel according to the parameters K and Y in FIG. 14. By subtracting the second term from the first term, the brake force TBST for each wheel for torque split control is calculated as shown in the above equation.

? However, in the KF, Y calculation in Figure 14, K
,,Y are treated as positive numbers. For example, when exiting from the last corner, K should be smaller than 0.5 to indicate that a large amount of torque should be distributed to the front wheels, but in step S430 of FIG. , since the correction constant KF is determined by the absolute value of the longitudinal acceleration D■, even if the conditions are the same, KP is 0.5
A value larger than 1 is calculated in step S432. The same situation applies to the right wheel distribution ratio. Therefore,
In steps 8500 to S503 in FIG. 19, it is necessary to correct KIT and Y so that they correctly represent the distribution ratio in the acceleration state and in the turning direction.

Based on the torque distribution ratio corrected in this way, the brake force for torque blit control is determined in the steps starting from step 8504.

That is, in step S504, it is first confirmed that the torque Pr requested of the engine during the current operation is smaller than the maximum torque P MAX that the engine can generate, that is, it is possible to control the increase in torque. . If Pr<PM, that is, if there is still room in the engine output, the process advances to step 8508, and T B
S T F R, T B S T FL, T BSTRR
, TBSTRL.

On the other hand, if it is determined in step S501 that P r>P NAX, the process advances to step S505. Here, in order to equalize the torque distribution ratio between the left and right wheels, set the distribution ratio Y to Y
= 0.5, and calculate the engine required torque Pr"2・PS-KF. Then, in step S506, the engine with the left and right distribution ratios made equal is calculated. It is determined whether the requested torque Pr is smaller than the maximum torque P WAX of the engine.

If a No determination is obtained in step S506 that the requested engine torque Pr does not become smaller than the maximum torque PMAX even if the torque distribution to the left and right wheels is made equal, in step S506, KF=f is determined in step S506. (PsAx-Ps)/(Pr-Ps)) ・
Calculate as (K, -0.5)+0.5. What this formula means is that the distribution ratio K, is the value of KF, which is the difference between the engine required torque Pr and the generated torque Ps (Pr - Ps),
The torque is reduced by 0.5 based on the ratio between the maximum torque PMAX and the difference (P.AX-Ps) between the maximum torque Ps and the engine generated torque Ps.

Returning to the explanation of FIG. 18. When the brake force calculation in step 3480 is completed, the process advances to step S481. In steps 8481 to 484, the brake force TBTR (TBTRFL, TBTRFR, TBT) for slip control is
RRL, TBTRRR) are calculated. Next, Stenobu S
481 to 484 will be explained in detail.

In step 8481, it is determined whether brake control for slip control should be performed based on the value of flag EBF. No brake control (EBF=O)
If so, in step S484, TBTRFL=O, TB
TRFR=O, TBTRRL=O, and TBTRRR=0. When performing brake control (EBF=1),
Proceeding to step 8482, a correction value MBTR is calculated. That is, if a is a predetermined constant, MBTRFL=a {
SFL-TGBR)MBTRFR=a ・(SFR-T
GBR)MBTRRL=a ・(SRL-TGBR)M
BTRRR=a·(SRR−TGBR). Furthermore, in step 8483, the brake torque TBTR is updated.

TBTRFL=TBTRFL1MBTRFLTBTRF
R=TBTRFR1MBTRFRTBTRRL=TBT
RRL+MBTRRLTBTRRR=TBTRRR+M
BTRRR Thus, the brake force TBTR for slip control is calculated.

Subsequently, the process proceeds to step 8485, where a comparison is made to see which of the brake force TBST for torque spring control and the brake force TBTR for slip control is greater. TBST<
In the case of TBTR, priority is given to slip control in step 8486, and the braking force of each wheel is set to the calculated value TBTR.
Brake control is performed so that Conversely, TBST>T
In the case of BTR, on the other hand, priority is given to torque split control, and brake control is performed so that the braking force of each wheel becomes TBST.

Note that step 8485 calculates TBST and T for each military ring.
This shows that the magnitude relationship with BTR is determined, and as a result, while brake control for Torx blit control is performed between different wheels, at the same time brake control for slip control is performed for the other wheel. There may also be cases where control is provided. For example, for the right front wheel, it is determined that TBSTFR>TBTRFR, and the brake control for torque blit control is performed for this right front wheel, and for the right rear wheel, it is determined that TBSTRR<TBTRRR, Brake control for slip control is performed on this right rear wheel.

(When only torque split control is executed) When only torque split control is executed, the number of slip wheels SN is zero, and brake control and torque control for slip control are not performed, so ETF=EBF
=O. In addition, K2≠0.5 and/or Y≠0.5 to accommodate the uneven load distribution applied to each wheel. Therefore, after various parameters are set in step S404 and step 8406, the process proceeds to step S407, where a negative determination is made. Next, in step 8408, to check whether the number of slip wheels is increasing, S N > S N T
Determine whether the following holds true. Here, SNT is a register for temporarily comparing the number of slipping wheels when the number is increasing. Steps 6409 to S411 are steps for detecting the occurrence of the second interference state. Since it is now assumed that there is no slip, a NO judgment is made in step S408, and the process does not proceed to step S409, and the step S411 (d) is performed.
The process proceeds to step S412. Furthermore, since it is currently assumed that ETF=O, a YES determination is made in step S412. Then, a routine for determining whether or not torque distribution should be stopped in step S414 (see FIG. 16 for details) is executed.

In the control means of FIG. 16, a slip determination flag (S
(FFR, etc.) is zero, so this subroutine does virtually nothing, and steps S41.
5. Return to step S416 and execute these steps in order. That is, in the engine torque control in FIG. 17, steps 8521 to S526 are executed, and in FIG. 18, the brake force of the torque split control is calculated in the step knob 8480. On the other hand, since EBF=O, in step S484, since TBTR=O, brake control for torque split control in step 8487 is performed.

(When the second interference state occurs) For convenience of explanation, the case where the second interference state occurs will be described first. As explained in relation to FIG. 12B, this second interference state is such that when the occurrence of a slip wheel is detected during execution of torque split control, torque split control is immediately stopped and slip control is executed. Refers to a situation in which it is necessary to judge whether it is okay to do something.

As an example, as shown in FIG. 12B, assume that slip occurs in the outer left front wheel and the left rear wheel during a right turn.

In such a case, step S in the flowchart of FIG.
402, in steps S404 and S406, SFFL=SFRL=1 SFFR=SFRR=O SN=2 EBF=ETF=1 TGTR=TG, xγ TGBR=TG. The parameters should have been determined. Also, in the same step 3406 (Fig. 14), for example, a parameter K F = 0. 5, Y=0.3 F=0 is set. Furthermore, by torque split control (step S508, Fig. 19), TBSTFR=T
BSTRR=O. lPsTBSTFL=TBSTRL=
-0. It is calculated as IPs.

Next, since Torx blit control is being performed, a negative determination is made in step S407. Also, since SN>SNT, step 3408 yields YE.
After determination S is made, the process advances to step S409. In step S409, the SNA is updated, and then the slip flag resetting routine (FIG. 15) of step S410 is performed.

In other words, since SFFR=SFRR=O, the 15th
In steps 8440 to S451 in the figure, the two right wheels are likely to undergo parameter setting changes. That is, for the right front wheel, step S44
0=O Proceeding to step S441, (1.KF)·Y=0.15 is calculated, and the judgment of the steno knob S441 becomes YES. Therefore, in step S442, SFFR=1, TBTRFR=TBSTFR=0. IPs are executed. What this step S442 means is that a wheel that is not actually slipping is assumed to be slipping, and the brake power TBSTFR that should be applied to the right front wheel for torque split control is changed for Slinop control. Brake power TBTR to be applied to the same wheel
It is considered as FR. Regarding the right rear wheel that is not actually slipping, Steno knob 8447 ~ Step 8448
The same operation as above is performed.

Thus, when spin is detected in any wheel while torque split control is being performed, firstly, the torque split control will distribute less than 25% of the engine's output torque. For such a wheel, the brake force TBST for torque split control set in the previous control cycle is changed to the brake force for slip control. This is the content of the slip flag resetting routine in step S410.

After completing the calculation in step S410, next step S410 is completed.
In step 412, it is checked whether engine torque control for slip/slip control should be performed (ETF=1).

In the specific example currently being explained, for slip control,
A case is assumed in which engine torque control and brake control should be performed together (ETF=EBF=1), and slipping occurs in the left front wheel and the left rear wheel. Therefore, since ETF=1, the control proceeds from step S412 to step S413, where the torque blit control is stopped by setting K,=Y=0.5. That is, by KF=Y=0.5,
TBST calculated in step 8508 is zero. Thus, as shown in Table 5, a case where slip occurs during Torx blit control will be explained as an example. From the table in FIG. 2A, when only one wheel slips, only brake control is performed (EBF=1) and engine torque control is not performed (ETF 10). In this case, Stenop S4
10 (Fig. 15), for wheels whose distributed torque is less than 25%, a slip flag (S F F R, etc.) is set and TB1R = TBST, regardless of whether the wheel is slipping or not. , the wheel to be subjected to slip control is subjected to brake control (step 3485. 18th
Figure) is carried out. Here, the "wheels subject to slip control" in Table 5 refer to the wheels for which slip was first detected and the wheels for which slip flags were forcibly set. In other words, Torx blit control continues. This control is the content of (a) in Table 5.

Next, the meaning of (c) in Table 5 is as follows. Engine torque control is not performed by slip control (E
TF=0), that is, when only brake control is performed, the control shown in FIG. 16 is performed in step S414, and if the slip flag is set for any one of the four wheels, and When the engine torque applied to the engine exceeds 25% of the total engine torque, the Torque Coupon control is discontinued. However, as shown in Table 5 (
In case of c), 25% on one of the wheels subject to slip control.
Even if torque blit control is canceled because there is a wheel to which a torque exceeding = 0, the brake force for slip control is maintained.

(Occurrence of first interference state) The first interference state means that slip has occurred and slip control is being performed on the slipping wheel, and at that time, Torx blit control is being performed and the relevant When torque increase control is to be performed on a slipping wheel, torque split control is to be canceled. As shown in Table 4, there are two ways to stop this Torx blit control: ((b) and (C).

An example of the control in Table 4 (b) is shown in FIG. 20B. Slip control is performed on the left front wheel FL only by brake control (ETF=0), and the torque applied to at least one slip control target wheel (Fl, ) is 2
If there is a possibility that it exceeds 5%, Torx blit control will be canceled. The wheels subject to slip control are wheels that are slipping or are at risk of slipping, so if there is a risk that a large torque will be applied to even one of these wheels, even if engine torque control is not being performed. Even in the case (ETF=O), the torque split control is stopped to suppress the throttle knob condition at an early stage.

In FIG. 20, the wheels are hatched to indicate that they are wheels subject to slip control. Furthermore, the 20th
The left rear wheel RL in FIGS. A and 20B is forcibly determined to be a slipping wheel in the slip flag resetting routine of FIG. 15.

In addition, (c) in the same table corresponds to Figure 20C, and when engine torque control is executed in slip control (ETF = 1), what is the torque distribution ratio by torque split control? Even if there is, Torx blit control will be completely stopped.

The control in (a) of Table 4 corresponds to FIG. 20A.

A case is shown in which, when Torx blit control becomes necessary during slip control, Torx blit control is executed in response to the request.

In this case, the torque applied to all wheels subject to slip control is less than 25%.

In the example of FIG. 20A, the slip control target wheels (FL, RL
) are all less than 25% of the torque applied. In such a case, Torx blit control is executed because there is no risk of generating a new slip or aggravating the previous slip. In the control shown in Table 4 (a), even if more than 25% of torque is applied to wheels other than the wheels subject to slip control, it is thought that no slip problem will occur, so torque split control is performed as requested. Execute.

Furthermore, Table 4 shows (a). The step numbers that are the points at which each of the controls in (b) and (c) are executed are listed.

In addition, (a
), the control in step 34 is performed for a wheel that is forcibly determined to be slipping by the control shown in FIG.
42 etc., and TBTR=TBST is set. As a result, in the control mode shown in Table 4 (a), brake control for slip control and brake control for torque split control coexist;
At step 8485 in FIG. 8, the brake control that has the greater braking force between TBTR and TBST is adopted.

Modifications of the Present Invention> It goes without saying that the present invention can be modified in various ways without departing from the spirit thereof.

For example, the above 1. In the second embodiment, a method of varying the braking force of each of the disc brakes 35A to 35D was adopted as a means for controlling torque distribution, but the method is not limited to this. Friction clutches may be provided in the left and right output shafts of the front and rear differential mechanisms 25, 27 and the propeller shafts 24, 26, respectively, and the engagement force between these clutches may be controlled individually. Needless to say.

It goes without saying that the present invention can be further modified, and such modifications and equivalents are included within the scope of the present invention.
The invention of the present invention should of course be determined by the above claims.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a control system diagram showing the overall configuration of the control system of the power train control device according to the first and second embodiments of the present invention, FIG. 2A, and FIG. 2B. 3 is a control table showing the number of slipping wheels and control contents in the slip control of the first embodiment and a time chart of the control operation, and FIG. 3 is a main diagram of the slip control (traction control) system of the embodiment device shown in FIG. Flowchart showing the routine, FIG. 4 is a flowchart of the subroutine showing the slip determination operation of the slip control system, FIG. 5 is a flowchart of the subroutine showing the slip detection operation of the slip control system, FIGS. 6B is a flowchart of a subroutine showing the vehicle speed estimation operation of the slip control, and FIGS. 7A and 7B are a flowchart of the subroutine showing the control mode setting operation of the slip control.
The figure is a flowchart of a subroutine showing the target slip ratio correction operation of the slip control, FIG. 9 is a flowchart of a subroutine showing the throttle control operation of the slip control, and FIG. 10 is the brake control operation of the slip control. The flowchart of the subroutine, FIGS. 11A and 11B, is the flowchart of the torque distribution control (torque split control) system of the above-described embodiment apparatus,
2A and 12B are explanatory diagrams explaining the problems to be solved by the second embodiment, FIG. 13 is an overall view of the main flowchart of the control procedure of the second embodiment of the present invention, and FIG.
15 is a flowchart of the subroutine for resetting the slip flag in the second embodiment. FIG. 16 is a flowchart of the subroutine for resetting the slip flag in the second embodiment. 17 is a flowchart of the engine torque control subroutine in the second embodiment, FIG. 18 is a flowchart of the brake control subroutine in the second embodiment, and FIG. 19 is a flowchart of the brake control subroutine in the second embodiment. Flowchart of the brake force calculation subroutine in the second embodiment, Fig. 20A, Fig. 2
FIG. 0B and FIG. 20C are explanatory diagrams for explaining the second interference state in the second embodiment. IO...Car body 11...Cylinder 12...Engine 13...Throttle actuator 14●Fist●
・Throttle valve 2OL ・ ・ 2OR ・ ・ 21L ・ ・ 21R ・ ・ 22 ・ ・ ・ 23 ・ ・ ・ 30 ・ ・ 35A ~ 35B ・ +00 ・ ・ ・ Left front wheel ・ Right front wheel ・ Left rear wheel ・ Right rear wheel ・ Shifting Machine/Center differential mechanism ●Brake control section/Disc brake control unit

Claims (2)

[Claims] (1) In a powertrain control device that controls overall transmission of engine output torque to wheels, a torque distribution means that independently distributes output torque from the engine to each wheel while controlling its distribution amount. and a slip control means that detects the slip state of each wheel and performs slip control so that the amount of slip of the detected slip wheel becomes equal to or less than a predetermined level; and wheels that are subjected to slip control by the slip control means. a torque determining means for determining whether or not the torque transmitted to the wheel is increased when the torque distributing means further acts on the torque distributing means; When the torque transmitted to the wheel is to be increased, at least the slip control means or the torque distribution means is controlled to reduce the torque transmitted to the wheel subject to slip control, and the torque is transmitted to the wheel. A powertrain control device comprising: a torque suppression means for suppressing torque; and a powertrain control device. (2) In a powertrain control device that controls overall transmission of engine output torque to wheels, a torque distribution means that independently distributes output torque from the engine to each wheel while controlling the distribution amount. a slip control means for performing slip control so that the amount of slip of the wheel is equal to or less than a predetermined level; a first detection means for detecting a wheel subject to slip control to be controlled by the slip control means; a second detection means that receives the output of the detection means and detects that the slip control means is about to perform slip control on the slip control target wheel when the torque distribution means is operating; , a torque suppressing means that receives the output of the second detection means and suppresses an increase in torque to the wheel subject to slip control when the torque to be distributed to the wheel subject to slip control exceeds a predetermined value; A powertrain control device comprising: