JPH06100111B2 - Vehicle skid control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a skid control device for a vehicle, and more particularly to a device capable of preventing wheel spin from occurring at the time of starting.

[Prior art]

High-output engines tend to be mounted on recent vehicles, and along with this, it is important to efficiently transmit the driving force from the engine to the road surface. Of course, vehicles are also used on slippery roads such as snowy roads, icy roads and mud roads, but when traveling on such a road surface, the driving force applied to the wheels is the grip force, that is, between the road surface and the driving wheels. The frictional resistance may be greater than the frictional resistance, so that a so-called skid in which the drive wheel spins is liable to occur, which makes it difficult to start the vehicle on such a slippery road surface.

Therefore, conventionally, in order to solve the problem of such a reduction in gripping force, improvement in terms of hardware such as making a vehicle into four-wheel drive type, mounting high-performance tires, and improving roll rigidity has been studied.

Further, as a means that can solve the problem of skid from the aspect of software, there is a skid control device described in Japanese Patent Laid-Open No. 59-202963, which is a left or right driving wheel of a vehicle. The rotational speed of the driven wheels is detected to obtain the rotational speed difference between the two wheels, and when the rotational speed difference exceeds a predetermined value, either the accelerator or the clutch is controlled to prevent the occurrence of wheel spin. It was something that was done. However, in this conventional device,
It simply controls either the accelerator or the clutch so that the driving force is reduced. For example, since there is no specific control target value for how much the driving force should be reduced, the control accuracy is low, and in the end this conventional device The effect of preventing skid generation was not so great.

[Object of the Invention]

The present invention has been made in such a conventional situation,
Provided is a skid control device for a vehicle, which can grasp a road surface condition at an early stage, that is, at the time of starting, can obtain a driving force that does not cause spin in the road surface condition, and can reliably prevent occurrence of wheel spin at the time of starting. Is intended.

[Structure of Invention]

The present inventor diligently studied the mechanism of wheel spin generation at the time of starting the vehicle, and found the following points. Here, FIG. 4 shows the change characteristics (curves A, B) of the rotational speeds of the driving wheels and the driven wheels at the time of starting, and FIG. 5 shows the driving wheels after the driving wheels started to rotate, which were obtained by experiments. There shows the characteristic between the delay time T _D and the road surface friction coefficient mu until the start of rotation, as is apparent from the figure, and the delay time T _D and the coefficient of friction mu, as T _D is larger mu is There is a certain relationship such as becoming smaller. From this point of view, when performing skid control with the slip ratio S as a target value, if the road surface with a large T _D is controlled near the limit slip ratio, the limit will be exceeded due to road surface irregularities, fluctuations in control output, etc. , The target slip ratio S _T due to the risk of wheel spin.
As shown in the T _D -S characteristic of FIG. 6, it was thought that the larger the delay time T _{D, the} smaller the value should be.

That is, the present invention relates to a skid control device for a vehicle, including the first
As shown in the functional block diagram in the figure, the first and second rotation sensors
8, 9 detect the start of rotation, the timer unit 10 measures the delay time T _D of the rotation start between the driving wheel and the driven wheel from the outputs of both sensors, and the slip ratio setting unit 11 determines the delay time T _D. The slip ratio S corresponding to the delay time T _D is set as the target slip ratio S _T by utilizing the fact that there is a certain relationship between the slip ratio S and the slip ratio S (see FIG. 6). 12 is the target slip ratio S _T
Therefore, in the present invention, the road surface condition is grasped at an early stage, that is, at the time of starting, and the vehicle starts with an acceleration that does not cause spin in the road surface condition.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

2 and 3 show an embodiment of the present invention, in which 1 is a front-wheel drive type vehicle, 2 is its body, 3 is an engine, and a throttle valve 3b is attached to its intake passage 3a. ing. Reference numeral 4 is a clutch for connecting or disconnecting the output of the engine 3 to the transmission 5, and 6 is a front wheel as a driving wheel, which is driven by the output of the engine 3 via the clutch 4 and the transmission 5.
Reference numeral 7 is a rear wheel as a driven wheel, which is driven through the vehicle body 2 by the forward movement of the automobile 1 due to the rotation of the front wheel 6. Further, 8 is a front wheel sensor as a first rotation sensor for detecting the rotation speed of the front wheel 6, 9 is a rear wheel sensor as a second rotation sensor for detecting the rotation speed of the rear wheel 7, and 21 and 22 are accelerator pedal positions, An accelerator and a clutch sensor that detect the clutch pedal position.

Reference numeral 15 is a clutch actuator as a driving force control unit, which is for making and closing the clutch 4 to drive it, that is, for controlling the position of the clutch 4, and which is a complete cut-off position from a complete disengagement position to a complete meet point. The clutch 4 is moved to the connection position.

FIG. 3 shows a throttle actuator 14 which is another drive force control unit, 16 is a hydraulic cylinder, and a piston rod 16a of the hydraulic cylinder is provided with a drive wire 16b for the intake passage.
The throttle valve 3b is connected to the throttle valve 3b of 3a, and the retracted position of the piston rod 16a is detected by a throttle valve sensor 16c which is a feedback positioner. Reference numeral 17 denotes a servo valve provided in a hydraulic pressure supply passage 20 that communicates the cylinder 16 with the hydraulic pump 18, which serves to control the switching of the hydraulic oil supply to the hydraulic cylinder 16, and 19 A reducing valve for reducing the discharge pressure of the hydraulic pump 18 to a predetermined value.

Reference numeral 25 is a control unit composed of an interface 26, a CPU 27 and a memory 28, and the memory 28 has a CPU 2
7 calculation processing program, delay time T _D −slip rate S
A map (see FIG. 6) and the like are stored. Also above CP
U27 calculates the delay time T _D0 which is the time elapsed from the rotation start time of the front wheels 6 to the rotation start time of the rear wheels 7 and
_{From the} DS map, the slip rate corresponding to this delay time T _D0
S ₀ is read and the throttle actuator 14 and the clutch actuator 15 are controlled by using S ₀ as the target slip ratio.

Further, in the present embodiment, the CPU 27 in the above-mentioned configuration is used by the timer unit 10, the slip ratio setting unit 11, and the acceleration control unit 12 of FIG.
It realizes the function of.

Next, the function and effect will be described.

Here, FIG. 7 shows a flow chart of the skid control program of the CPU 27. When the skid control program starts, the CPU 27 determines whether or not it is the measurement timing (step 51). At 54, it is detected whether the vehicle is starting. That is, the above CP
The U27 determines that the vehicle is traveling when output signals from both the front and rear wheel sensors 8 and 9 are present, and determines that the vehicle is not traveling otherwise (step 52), and the clutch 4 is disengaged. When the clutch 4 is further engaged, the start is detected (steps 53, 54). When the vehicle is traveling, that is, when the vehicle is not starting, the throttle valve opening corresponding to the accelerator pedal position is calculated (step 65).

Next, in steps 55 to 59, the delay time T _D0 is calculated. That is, when the output signal from the front wheel sensor 8 is input, the CPU 27 determines that the front wheel 6 has started to rotate, that is, the rotation of the front wheel 6 has risen (see the curve A in FIG. 4), and thereby the timer is activated. When the output signal from the rear wheel sensor 9 is input after starting (steps 55 and 56), it is determined that the rotation of the rear wheel 7 has risen (see curve B in FIG. 4), and the timer is stopped accordingly. Then, the time from the start of the timer to the stop is calculated as the delay time T _D0 (steps 57 to 59).

Further, when the delay time T _D0 is calculated, the target slip ratio S _T is set. That is, the CPU 27 reads the slip ratio S ₀ corresponding to the delay time T _D0 from the T _D -S map shown in FIG. 6 (step 60) and stores this in the target value register as the target slip ratio S _T (step). 61).

Finally, the CPU 27 calculates the throttle valve opening and the clutch position for realizing the target slip ratio S _T (step 62), and determines the throttle valve opening and the clutch position as the current throttle valve opening and the clutch position. The throttle valve and the clutch servo valve control signal are created by comparison, and the throttle valve control signal and the clutch position control signal are output to the throttle and the clutch actuators 14 and 15 (steps 63 and 64). Actuator 1
The throttle valve 3a and the clutch 4 are driven by 4, 15 so as to obtain the target slip ratio S _T.

As described above, in this embodiment, first, the delay time T _{D0 of the} start of rotation of the front wheels 6 and the rear wheels 7 is measured when the automobile 1 starts, and the target slip ratio S _T is map-calculated from this delay time T _D0. Therefore, the road surface condition can be grasped at an early stage, and the opening degree of the throttle valve 3b and the position of the clutch 4 are controlled according to the calculated slip ratio S _T , that is, the acceleration that does not spin on the road surface. Therefore, the occurrence of spin can be reliably prevented, and the vehicle can easily start even on a slippery road surface. Further, at this time, since the acceleration control is performed with a specific control target value, control accuracy can be improved.

In the above embodiment, the case where both the throttle valve 3b and the clutch 4 are controlled in order to achieve the target slip ratio S _T has been described, but it is possible to control either one of them. Good.

〔The invention's effect〕

As described above, according to the vehicle skid control device of the present invention, the delay time of the rotation start of the driving wheels and the driven wheels is measured, the target slip ratio is set according to this delay time, and this slip ratio is set. Since the fuel amount and the clutch position are controlled with the target value as the target value, the road surface condition can be grasped at an early stage, the acceleration that does not cause the spin is obtained in the road surface condition, and the spin is prevented from occurring even on the slippery road surface. It has the effect of making it easy to start.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing the configuration of the present invention, FIG. 2 is a configuration diagram of a skid control device for a vehicle according to an embodiment of the present invention, FIG. 3 is a configuration diagram of its throttle actuator portion, and FIGS. FIG. 7 is for explaining the operation, FIG. 4 is a wheel rotation speed-time characteristic diagram, FIG. 5 is a delay time-road surface friction coefficient characteristic diagram, and FIG. 6 is a delay time-slip ratio characteristic diagram. FIG. 7 is a flow chart showing the contents of the kid control by the CPU. 1 ... automobile (vehicle), 3 ... engine, 4 ... clutch, 6 ... front wheel (driving wheel), 7 ... rear wheel (driven wheel),
8 ... front wheel sensor (first rotation sensor), 9 ... rear wheel sensor (second rotation sensor), 10 ... timer section, 11 ... slip ratio setting section, 12 ... acceleration control section, 14, 15 ... ... Throttle, clutch actuator (driving force control unit).

 ─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A-60-157053 (JP, A) JP-A-51-14591 (JP, A) JP-A-60-165554 (JP, A)

Claims (1)

[Claims] 1. A first rotation sensor for detecting a rotation speed of a driving wheel of a vehicle, a second rotation sensor for detecting a rotation speed of a driven wheel, and a start signal output from the first and second rotation sensors. And a slip ratio setting unit that sets a target slip ratio according to the delay time from the timer unit, and a delay unit that measures the delay time from the start of rotation of the drive wheels to the start of rotation of the driven wheels. A vehicle comprising: a drive force control unit that controls the drive force of the drive wheels; and an acceleration control unit that controls the drive force control unit with the target slip ratio from the slip ratio setting unit as a target value. Skid control device.