JPS60192155A - Slip preventing device for car - Google Patents

Abstract

PURPOSE:To prevent a slip without deteriorating exhaust gas by changing a speed change ratio of a stepless speed change gear in such a manner as to lower the turning force of a driving wheel while the driving wheel slips. CONSTITUTION:A driving wheel is provided with slip detecting means, whereby the speed change ratio of a stepless speed change gear is changed in such a manner as to lower the turning force of the driving wheel while the driving wheel slips. Thus, the turning force is lowered until the slip of the driving wheel is removed, so that a slip can be prevented without deteriorating the exhaust gas of a car and without an actuator and complicated coupling mechanism for controlling a throttle.

Description

[Detailed description of the invention] Technical field The present invention relates to a slip prevention device for a vehicle.

Prior art When a vehicle starts or is running, especially when the road surface is covered with snow or ice, the drive wheels of the vehicle often slip, and in such cases, the vehicle cannot run normally. . In response to this, a slip prevention method has been considered that suppresses ignition of fuel in the engine combustion chamber or suppresses the throttle operation amount while the slip of the vehicle drive wheels is detected. However, in the method of preventing pickpocket knobs by suppressing ignition, unburned components of fuel are discharged.
Vehicle exhaust emissions are a major drawback.

In addition, in a system that prevents slippage by suppressing the amount of throttle operation, an actuator that drives the slip nottle toward the isle side and a complicated connection mechanism that connects the actuator and the slip nottle are required. Therefore, the structure is complicated and expensive.

Purpose of the Invention The present invention has been made against the background of the above circumstances,
The purpose is to provide a slip prevention device for a vehicle that can prevent slips without deteriorating heavy exhaust force and without using an actuator or complicated connection mechanism to suppress the throttle. be.

Structure of the Invention In order to achieve the above object, the gist of the present invention is to provide a vehicle equipped with a heavy-duty continuously variable transmission that continuously changes the speed of the engine and transmits it to the drive wheels. slip detection means for detecting a slip knob on the drive wheel;
) Gear ratio changing means for changing the gear ratio of the continuously variable transmission in a direction to reduce the rotational force of the drive wheel while the slip lever knob of the drive wheel is detected by the slip detection means. That's true.

Effects of the Invention With this arrangement, as shown in the diagram corresponding to the claims in FIG. 1, while the slip detection means detects the slip of the drive wheels, the gear ratio changing means reduces the rotational force of the drive wheels. The gear ratio of the continuously variable transmission is changed in the direction. Therefore, the rotational force of the driving wheels is reduced until the slippage of the driving wheels disappears, so that the slipping of the driving wheels of the vehicle is automatically prevented, and at the same time, the exhaust of the vehicle is not worsened, and the throttle is suppressed. There is no need for an actuator for driving in this direction or a complicated connection mechanism for connecting the actuator and the throttle.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

In FIG. 2, a vehicle engine 10 includes a clutch 12 such as a powder type electromagnetic clutch, a fluid clutch, a centrifugal clutch, etc.
A Held type continuously variable transmission 14 is connected through the Held type continuously variable transmission 14, and after the rotation of the engine 10 is continuously changed by the Held type continuously variable transmission 14, it is connected to a drive wheel (not shown). .

The belt-type continuously variable transmission TA14 includes an input shaft 16 connected to the clutch 12, a variable pulley 18 with a variable effective diameter attached to the input shaft 16, an output shaft 20, and an effective pulley 18 attached to the output shaft. A variable pulley 22 whose diameter is variable, and a conduction heald 24 that is hooked between the variable pulleys 18 and 22.
and hydraulic cylinders 26 and 28 that change the V-groove widths of variable pulleys 18 and 22 to change their effective diameters. The variable pulleys 18 and 22 are fixed rotating bodies 3 fixed to the input shaft 16 and the output shaft 20, respectively.
0 and 32, and movable rotary bodies 34 and 36, which are respectively attached to the input shaft 16 and the output shaft 20 so as to be movable in the axial direction and non-rotatable about the axes. By being driven in the axial direction by hydraulic pressure applied to the spaces within the hydraulic cylinders 26 and 28, the hanging diameter (effective diameter) of the transmission heald 24 is continuously changed. That is, the cold line oil pressure is applied to the hydraulic cylinder 28, and the volume of hydraulic oil in the hydraulic cylinder 26, in other words, the hydraulic pressure, is adjusted by the gear ratio control valve device 38 connected via the oil path 48. By doing so, the balance of forces acting on the movable rotors 34 and 36 is changed, and the gear ratios of the input shaft 16 and output shaft 20 of the continuously variable transmission 14 are changed. The pressure-receiving area of the movable rotating body 34 is set larger than that of the movable rotating body 36, and the gear ratio can be changed both in the direction of increasing from 1 and in the direction of decreasing. It has become.

The line oil pressure is obtained by adjusting the hydraulic oil pressure-fed from the oil pump 40 by the pump 42 by the pressure regulating valve 44, and is supplied to the gear ratio control valve device 38 and the hydraulic cylinder 28 via the line oil passage 46. There is. The pressure regulating valve 44 includes, for example, a linear solenoid and a valve element driven by the linear solenoid, and the linear solenoid is driven by a pressure regulating signal SP, which will be described later, to return hydraulic oil pumped from the pump 42. By adjusting the amount of relief to the oil passage 50, the line oil pressure is changed.

For example, the gear ratio control valve device 38 operates at an operating position where line hydraulic pressure supplied via a line oil passage 46 is supplied to the hydraulic cylinder 26 and where the working hydraulic pressure within the hydraulic cylinder 26 is released, in accordance with a shift direction control signal SH to be described later. The shift direction switching valve is equipped with a two-position shift direction switching valve that is driven between an operating position for discharging oil into an oil path, and a linear solenoid and a valve element that is driven by the linear solenoid. The shift speed switching valve controls the amount of hydraulic oil supplied from the hydraulic cylinder 26 into the hydraulic cylinder 26 or the amount of hydraulic oil discharged from the hydraulic cylinder 26 to the shift direction switching valve.

That is, the speed ratio control valve device 38 controls the direction and speed of change of the working oil pressure in the hydraulic cylinder 26, thereby controlling the direction and speed of change of the speed ratio.

On the other hand, an accelerator pedal 52 is attached to the intake pipe of the engine 10.
A throttle valve 54 connected to the
A valve position sensor 56 is attached to the 'throttle valve 54. The valve position sensor 56 converts a throttle opening signal VC representing the opening degree θ of the throttle valve 54 into an A/D converter.
Converter 58 is supplied. Further, rotation sensors 62 and 64 are provided for detecting the rotation of fixed rotating bodies 30 and 32 fixed to the input shaft 16 and the output shaft 20, and the rotation sensor 62 detects the rotation of the crankshaft of the engine 1o. The rotation sensor 64 supplies the rotation signal MsE of the corresponding frequency to the input cover sofa circuit 66, and the rotation sensor 64 supplies the rotation signal SC of the frequency corresponding to the rotation of the drive wheel (not shown) to the input cover sofa circuit 66. Δ/D converter 58
The input cover sofa 66 supplies signals thereto in response to commands from the CPU 60. The CPU 60 is equipped with a ROM and a RAM, and the CPU 60 uses the primary storage function of the RAM according to a program stored in advance in the ROM, while also controlling the A/D converter 58 and the large power buffer 6.
6, a shift direction control signal S H and a shift speed control signal SV for adjusting the gear ratio of the continuously variable transmission 14 and a pressure regulation signal SP for adjusting the line oil pressure. is output to the speed ratio control valve device 38 and the pressure regulating valve 44 via the buffer 68. The above CPU60, A/D converter 58. Hippo sofa 68
constitutes a so-called electronic control unit 1- (ECU) for controlling the gear ratio of the continuously variable transmission 14.

Hereinafter, the operation of this embodiment will be explained according to the flowchart shown in FIG.

First, step S1 is executed to read the throttle opening signals VC2, rotation signs SE and SC, and step S2 is executed to calculate the throttle opening θ and the actual rotational speed Ni of the engine 10 based on these signals. , the rotational speed No. of the output shaft 20 (rotational speed Vw of the driving wheels), and the vehicle speed V are calculated. Then, the following step S3 is executed, and the acceleration* of the driving wheels and the gear ratio r (=Ni/N) are determined based on the rotational speed Ni and the rotational speed NO.

) is calculated. The acceleration Q of the driving wheels is calculated based on, for example, the difference between the speed value calculated in the previous control cycle and the speed value calculated in the current control cycle, and the execution time interval of the control cycle. Therefore, steps S3 also serve as means for detecting the acceleration Vw of the driving wheels.

In step S4, a target rotational speed Ni' of the engine 10 is determined. The target rotational speed N t I is set such that the optimum fuel efficiency and suitable vehicle drivability are obtained.
It is determined based on the throttle opening θ and the vehicle speed V from a data map or relational expression that is stored in advance. Next, step S5 is executed to determine whether or not the content of the slip flag FS is 1. If it is 1, in other words, if a slip is occurring, step S6 is executed. After that, step S7 is executed, but if the content is O, in other words, if the step has not occurred, step S6 is skipped and step S7 is directly executed. In step S6, the target rotational speed Ni is determined according to equation (1).
° is corrected.

N t l ← J (Ni' - K) ... (1) The correction using the above formula (1) reduces the rotational force of the drive wheel to the extent that slip does not occur when the drive wheel slips. The constants J and K are set to such values. Here, J is a constant number less than or equal to 1,
For example, it is set to about 0.7. Further, K is also a constant, and is set to about 1100 rp, for example.

In step S7, the acceleration α of the vehicle is determined based on the throttle opening θ and the gear ratio r from a predetermined relationship or a data map based thereon. The above relational expression is determined, for example, as follows. The acceleration performance of a vehicle is generally a value obtained by dividing its margin driving force by its inertial weight, and the acceleration α is expressed by equation (2).

However, F max is the maximum driving force, Ro is the running resistance, W is the vehicle weight, and φ is the increase in rotating portion.

On the other hand, the driving force F of the vehicle is expressed by equation (3), and the running resistance Ro of the vehicle is expressed by equation (4).

Rt x (μtm x i Diff) (kg)...
(31 However, i tm is the gear ratio of Nidoran Smith, i Diff is the gear ratio of the differential.

Rt: Tire effective radius, 'I'e: Engine output torque, η tm: ) Transmission transmission efficiency, ηDi
ff: differential transmission efficiency.

Ro−μrxW+μ2 XAXV” +WXsin θ (kg) ---141However, A:
Vehicle overall projected area, V: Vehicle speed W; Vehicle gross weight, sin
θ Road surface gradient, μ2: Windage loss coefficient, μr: Rolling resistance coefficient Here, the transmission efficiency of the transmission and differential gear is approximately 1, and the vehicle speed is 0. Assuming that the road surface slope is 0, the driving force F and the running resistance RO are respectively Rt Ro = μRXW. From these and the above equation (2), the vehicle acceleration α
becomes -Te-r-L (5). However, in k1+Ll and L, L is a constant. Here, since the engine torque Te is a function of the throttle opening degree θ, the above equation (5) is expressed as α=f(θ.

r). That is, the vehicle acceleration is expressed as a function of the throttle opening θ and the speed ratio r of the continuously variable speed ratio 14. Therefore, in step s7 as the vehicle acceleration determining means, the vehicle acceleration α is calculated using the relational expression (5), or (5)
The data map shown in Table 1 prepared in advance based on the formula is used to determine the acceleration α (unit: G) of the vehicle.

Table 1 Next, step S8 is executed, and the actual acceleration α of the vehicle is
It is determined whether or not is larger than the coefficient of friction μ between the tires of the driving wheels and the road surface. If it is, step S9 is executed and the contents of the acceleration α are replaced with μ, but if it is not, step S9 is executed. S9 is skipped and step 310 is executed.

The driving force of the drive wheels is limited by the slip limit driving force μW, which depends on the friction coefficient μ between the tires and the road surface.
Equation (6), in which the extra horsepower in Equation (2) is replaced with μW, represents the maximum acceleration at the slip limit.

μ on a general dry asphalt road surface is 0.6 to 0.7
Therefore, even if the vehicle engine has a high output, its maximum acceleration is limited to 0.7 to 0.6. In step S9, the calculated value of the vehicle acceleration α is saturated to the maximum value μ, but in this embodiment, the throttle opening is low.

μ is set small during low to medium acceleration in the medium gear ratio region, improving controllability.

In step $10, which forms a slip determination means together with step S12, which will be described later, it is determined whether the acceleration ΩW of the driving wheels calculated in step S3 is larger than the actual acceleration α of the vehicle calculated in step S7. , if it is large, step 311 is executed and the contents of the slip flag SF are set to 1, but if it is not large, the execution of step 311 is skipped and the next step 312 is executed. In step S12, it is determined whether or not the acceleration Vw of the driving wheels is smaller than α-Δα. If it is smaller, step 313 is executed and the contents of the slip flag SF are set to 0, but if it is not smaller, then In this case, the execution of step S13 is skipped and the next step 314 is executed. That is, step 33. And steps S7 to 313 form a slip detection means. Step S12 is to prevent fluctuation in determination of slip of the drive wheels,
Δα is a small value determined to provide the hysteresis necessary for stable slip determination.

In step 314, the actual rotational speed Ni of the engine calculated in step S2 and step S
In other words, the gear ratio of the continuously variable transmission 14 is adjusted so that the actual rotation speed Ni of the engine 10 coincides with the target rotation speed Ni' so that the difference from the target rotation speed Ni' determined in step 4 becomes smaller. A shift direction control signal S1 (and a shift speed control signal SV) for changing the shift direction is determined.

When the signals SH and SV are supplied to the solenoid of the shift direction switching valve and the solenoid of the shift speed switching valve in the gear ratio control valve device 38, hydraulic oil is supplied to the hydraulic cylinder 26 by the shift direction switching valve. At the same time, the linear solenoid flows the hydraulic oil at a flow rate according to the control voltage represented by the signal SV, and the actual state of the engine 10 is changed. Rotational speed Ni
is made to match the target rotational speed Ni°.

Next, in step S15, from a predetermined relationship, the actual torque Te of the engine 10 is determined by the throttle opening θ.
and the rotation a degree Ni of the engine 10, and in step 816, the pressure regulation signal SP is determined based on the engine torque Te and the gear ratio r of the continuously variable transmission 14 from a predetermined relationship. . Therefore, the pressure regulation signal sp corresponding to the line oil pressure is transmitted to the pressure regulation valve 44.
Since the line oil passage 46 is supplied to the linear solenoid of
The line hydraulic pressure within the transmission heald 24 is maintained at the minimum pressure within the range where slippage does not occur, preventing power loss due to excessive line hydraulic pressure, and increasing the durability of the transmission belt 24 and variable pulleys 18, 22. is prevented.

In the situation where the above control cycle is repeatedly executed, the presence or absence of slip of the drive wheels is determined in step S5 for each control cycle, and while the slip of the drive wheels is occurring, the target rotational speed is determined in step S6. Ni
° is corrected to a smaller value. As a result, in the steering knob S14, the continuously variable transmission 1
4 gear ratio is changed. In other words, the rotational force of the drive wheels is controlled to be reduced until the slip is eliminated. Therefore, when slipping of the driving wheels occurs when the vehicle starts on a snowy road, the rotational force of the driving wheels is immediately reduced and the slipping is automatically prevented. Here, steps 35, 36. S14 constitutes a gear ratio changing means.

As described above, according to the present embodiment, drive wheel slip is detected, and while the drive wheel is slipping, the target rotational speed N i I of the engine 10 is corrected to be small. This immediately prevents the engine from slipping, and there is no need for an actuator or complicated connection mechanism to reduce the amount of throttle operation, and there is no deterioration of exhaust gas.

Further, according to this embodiment, the acceleration α of the vehicle is
7, and the slip is detected based on this, which has the advantage that an accelerometer for detecting the acceleration of the vehicle is not required. Moreover, compared to the case where the slip of the drive wheels is detected based on the rotation difference between the front and rear wheels, there is an advantage that a rotation speed detection device for wheels other than the drive wheels is not required.

Although the embodiment of the present invention has been described above based on the drawings, the present invention can also be applied to other aspects.

For example, although the belt-type continuously variable transmission 14 is described in the above embodiment, other types of continuously variable transmissions may be used. Furthermore, the shift speed control valve of the gear ratio control valve device 38 is configured to operate between two positions: a position that allows supply of hydraulic oil to the hydraulic cylinder 26 and discharge of hydraulic oil discharged from the cylinder 26, and a position that suppresses the supply of hydraulic oil to the hydraulic cylinder 26 and the discharge of hydraulic oil discharged from the cylinder 26. It may also be constituted by a controlled shift speed switching valve device. In such a case, the shift speed can be changed continuously by duty-controlling the shift speed switching valve.

Although the gear ratio of the continuously variable transmission 14 is controlled by so-called feed-hack control in which the rotational speed Ni of the engine 10 is made to match the target rotational speed Ni', so-called open-loop control may also be used. In short, it is only necessary to control the gear ratio of the continuously variable transmission 14 so as to reduce the driving force of the drive wheels while the slip of the drive wheels is being detected.

In addition, in the above-mentioned embodiment, the vehicle acceleration α is calculated by executing step 7, step 7, all 7, but an acceleration needle is provided on the vehicle, and the actual The acceleration α may also be measured. In addition, the slip detection means includes a rotation speed detection means for detecting the rotation speed of the front wheel or the rear wheel when the drive wheel is either the front wheel or the rear wheel, and a rotation speed detection means for detecting the rotation speed of the front wheel or the rear wheel. A determining means may be provided that determines that the drive wheels are slipping when the speed exceeds the speed by a certain amount or more.

The above-mentioned embodiment is merely one embodiment of the present invention, and various modifications may be made to the present invention without departing from the spirit thereof.

[Brief explanation of the drawing]

FIG. 1 is a diagram corresponding to claims of the present invention. FIG. 2 is a configuration diagram of a continuously variable transmission for a vehicle to which an embodiment of the present invention is applied. FIG. 3 is a flowchart illustrating the operation of the embodiment of FIG. 2. 10: Engine 14: Belt type continuously variable transmission (slip detection means) Step S5. S6. Sl 4. : Gear ratio changing means 1st
Figure 2

Claims (2)

[Claims] (1) In a vehicle equipped with a vehicular continuously variable transmission that continuously changes the speed of the engine and transmits the rotation to the drive wheels, the slip detection means detects the slip of the drive wheels, and the slip detection means drives the drive wheels. A slip prevention device for a vehicle, comprising: a gear ratio changing means for changing the gear ratio of the continuously variable transmission in a direction to reduce the rotational force of the drive wheel while wheel slip is detected. Device. (2) The slip detecting means detects the acceleration of the vehicle based on the required load of the engine and the gear ratio of the continuously variable transmission based on a predetermined relationship with the acceleration detecting means that detects the actual acceleration of the drive wheel. vehicle acceleration determining means for determining acceleration; when the acceleration of the drive wheel exceeds the acceleration of the vehicle;
The slip prevention device for a vehicle according to claim 1, further comprising a slip determining means for determining whether the driving wheels are slipping.