JP2649227B2 - Vehicle clutch control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method of a clutch means for controlling a transmission amount (a degree of transmission) of power transmitted from an engine to a wheel via a transmission.

(Prior Art) Various types of clutch means have conventionally been used, such as a type using a friction clutch disc.

As an example, there is a clutch device disclosed in Japanese Patent Application Laid-Open No. 56-95722. In this device, a short-circuit path is provided between two oil paths that form a closed circuit by connecting a hydraulic pump and a hydraulic motor. And a control device for controlling the operation of the clutch valve is provided with a first detecting means for detecting the engine speed, a throttle opening, The control device includes a control force proportional to the engine speed for driving the clutch valve in the closing direction, and a throttle opening degree for driving the clutch valve in the opening direction. And a control force proportional to the control force.

That is, in the clutch device, a target engine speed is set in accordance with the throttle opening, and the clutch opening is controlled so that the actual engine speed matches the target engine speed. ing.

Japanese Patent Publication No. 63-49090 discloses an apparatus for automatically controlling the operation of a friction clutch by a clutch actuator. In this device, a piston stroke of a clutch actuator is read from a clutch control map according to a driving state of a vehicle, and clutch operation is automatically controlled.

(Problems to be Solved by the Invention) By the way, in order to prevent the engine speed from increasing more than necessary due to the increase in the output of the engine when the vehicle starts, that is, to prevent the engine from blowing up, it is necessary to set the engine speed when the engine is idling. It is necessary to appropriately select and control the opening degree of the short-circuit path, that is, the opening degree of the clutch valve so that the initial addition is appropriate. However, when the vehicle is started by suddenly depressing the accelerator pedal, an increase signal of the throttle opening according to the amount of depression of the accelerator pedal is:
Although the signal is input to the control device promptly, the increase in the engine speed due to the opening of the throttle valve has a slight time delay, so the increase signal of the engine speed is input to the control device with a slight delay. You. So momentarily,
Although the throttle opening is large and the target engine speed is high, the engine speed has not yet risen,
In response to this, the opening degree of the short circuit is increased to control the clutch opening degree in the opening direction. As a result, the load on the engine becomes too small, and the engine speed exceeds the target engine speed and unnecessarily increases. In addition, when the increased engine speed is input to the control device, the clutch valve is suddenly operated in the closing direction, so that an appropriate half-clutch state cannot be obtained and hunting occurs. There is a problem that the smooth start of the vehicle is hindered.

The present invention has been made in view of the above problems, and has as its object to provide a clutch control method capable of smoothly starting and stopping a vehicle.

B. Configuration of the Invention (Means for Solving the Problem) As means for achieving the above object, in the control method of the present invention,
The target opening of the clutch means is set according to the vehicle speed of the vehicle and the accelerator opening (a value corresponding to the depression amount of the accelerator pedal or a throttle opening linked to the accelerator pedal), and the target engagement of the clutch means is set. Capacity (target opening)
Is set, and the degree of transmission by the clutch means is controlled so that the actual engagement capacity (actual opening degree) of the clutch means matches the target engagement capacity.

A deviation between the target engagement capacity and the actual engagement capacity is calculated, and a clutch control speed that increases as the difference increases in accordance with the difference is determined. Based on the clutch control speed, the transmission degree of the clutch means is determined. Preferably, control is performed.

(Operation) When the clutch engagement capacity is controlled using the control method having the above-described configuration, the clutch engagement control is performed by uniquely setting the target engagement capacity using only the accelerator opening and the vehicle speed as control information. However, since the engine speed with poor response is unnecessary as the clutch connection control information, an inappropriate engine speed due to a delay in increasing the engine speed when the accelerator pedal is suddenly depressed as described above. Clutch control (occurrence of hunting phenomenon of clutch opening) can be avoided. Further, if control is performed by setting the clutch control speed in accordance with the deviation between the target engagement capacity and the actual engagement capacity,
(In other words, if the clutch control gain is appropriately set), too fast closing control or too slow closing control can be reliably prevented. As a result, it is possible to prevent the engine speed from rising when the vehicle starts moving and the occurrence of hunting due to inappropriate setting of the half-clutch state.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a hydraulic circuit of a hydraulic continuously variable transmission whose clutch opening is controlled by the method of the present invention.
It has a constant discharge hydraulic pump P driven by an engine E via an input shaft 1 and a variable displacement hydraulic motor M having an output shaft 2 for driving wheels W. The hydraulic pump P and the hydraulic motor M are provided with a first oil passage La communicating the discharge port of the pump P and the suction port of the motor M and a second oil passage Lb communicating the suction port of the pump P and the discharge port of the motor M.
And a hydraulic closed circuit is formed by the two oil passages.

A charge pump 10 driven by the engine E
Is connected to a closed circuit via a charge oil passage Lh having a check valve 11 and a third oil passage Lc having a pair of check valves 3, 3, and is discharged from an oil sump 15 by a charge pump 10 to charge. The operation of the hydraulic oil check valves 3, 3 regulated by the pressure relief valve 12 supplies the oil to the lower pressure side of the two oil passages La, Lb. In addition, high and low pressure relief valves 6,
Fifth and sixth oil passages L having 7 and leading to oil sump 15
A fourth oil passage Ld having a shuttle valve 4 to which e and Lf are connected is connected to the closed circuit. This shuttle valve 4
Is a two-port three-position switching valve, and includes first and second oil passages.
The first and second oil passages La and Lb operate in response to a difference in hydraulic pressure between La and Lb.
The oil passage on the high pressure side of Lb is communicated with the fifth oil passage Le, and the oil passage on the low pressure side is communicated with the sixth oil passage Lf. Thereby, the relief oil pressure of the high pressure side oil passage is adjusted by the high pressure relief valve 6, and the relief oil pressure of the low pressure side oil passage is adjusted by the low pressure relief valve 7.

Further, between the first and second oil passages La and Lb, a seventh oil passage Lg for short-circuiting the two oil passages is provided.
Is provided with a clutch valve 5 comprising a variable throttle valve for controlling the degree of opening of the oil passage. For this reason, by controlling the throttle amount of the clutch valve 5, it is possible to perform clutch opening control for controlling transmission of the driving force from the hydraulic pump P to the hydraulic motor M.

Further, the hydraulic pump P is driven by the engine E, and the hydraulic motor M is rotated by the hydraulic pressure from the hydraulic pump P, and the rotation is transmitted to the wheels W via the output shaft 2,
The wheels W are driven, but the hydraulic motor M
For example, it is a swash plate axial piston motor, and by controlling the angle of the swash plate, the speed ratio of the transmission T can be changed steplessly. The description of the control of the swash plate angle is well known and will not be repeated.

On the other hand, the operation control of the clutch valve 5 is performed by a clutch servo valve 80.
The operation of is controlled by a pair of solenoid valves 155 and 156 whose duty ratio is controlled in response to a signal from the controller 100. Signals indicating the vehicle speed V, the engine speed Ne, the throttle opening θth, the swash plate inclination angle θtr of the hydraulic motor M, and the clutch opening θcl are input to the controller 100. Based on these signals, desired signals are obtained. A signal for controlling each of the above-mentioned solenoid valves is output so that the traveling control is performed.

Hereinafter, the structure and operation of the clutch servo valve 80 will be described in detail with reference to FIG.

The valve 80 includes a cylinder member 81 and a piston member 82 which is slidably inserted into the cylinder member 81 left and right in the drawing.
, A cover member 85 attached to cover the cylinder chamber in which the piston member 82 is inserted, and a spring 87 for urging the piston member 82 leftward in the figure. The piston 82a of the piston member 82 divides the above-mentioned cylinder chamber into
3 and 84, and ports 86a and 8 are connected to both cylinder chambers 83 and 84.
The hydraulic lines 110, 112 are connected via 6b.

The hydraulic pressure of the hydraulic line 110 is such that hydraulic oil pressure of discharge oil of the charge pump 10 adjusted by the charge pressure relief valve 12 is led through the hydraulic line 101, and the hydraulic pressure of the hydraulic line 112 is Forked orifice
This is a hydraulic pressure obtained by controlling the hydraulic pressure of the hydraulic line 111 having 111a by two solenoid valves 155 and 156 whose duty ratio is controlled. The solenoid valve 156 controls the flow of hydraulic oil from the hydraulic line 111 having the orifice 111a to the hydraulic line 112 according to the duty ratio. The solenoid valve 155 is connected to the hydraulic line 113 branched from the hydraulic line 112 and the orifice. The hydraulic fluid is disposed between the hydraulic line 114 and the hydraulic line 114 communicating with the drain via the hydraulic line 114a. The hydraulic oil flows out of the hydraulic line 113 to the drain side according to a predetermined duty ratio.

Therefore, the charge pressure regulated by the charge pressure relief valve 12 acts on the right cylinder chamber 52 via the hydraulic line 110. From the hydraulic line 112, the two solenoid valves 155 and 156 operate to operate. A pressure lower than the charge pressure is supplied to the left cylinder chamber 83. Here, since the pressure receiving area of the right cylinder chamber 84 is smaller than the pressure receiving area of the left cylinder chamber 83, the force received by the piston member 82 by the hydraulic pressure in the left and right cylinder chambers 83, 84 takes into account the urging force of the spring 87. The hydraulic pressure in the left cylinder chamber 83 is lower than the hydraulic pressure P1 in the right cylinder chamber 84 by a predetermined value P2 (P1> P
2) is balanced when. For this reason, if the hydraulic pressure supplied from the hydraulic line 112 to the left cylinder chamber 83 is controlled by the solenoid valves 155 and 156 to be greater than the predetermined value P2, the piston member 82 can be moved rightward, and the left cylinder chamber 83 Is controlled to be smaller than P2, the piston member 82 can be moved to the left.

The movement of the piston member 82 in the left-right direction is performed by a link mechanism.
Via 88, it is transmitted to the clutch valve 5. Clutch valve 5
Is composed of a fixed member 5a having a first valve hole 5b and a rotating member 5c having a second valve hole 5d rotatably disposed in the fixed member 5a, and an arm 5e connected to the rotating member 5c.
Are connected to the link mechanism 88, and the rotating member 5c is rotated with the movement of the piston member 82. Rotating member
When 5c is rotated, the communication opening degree of the first and second valve holes 5b and 5d changes from fully open to fully closed. As shown in the figure, when the piston member 82 is moved to the left as far as possible, the communication opening in the clutch valve 5 is fully opened, and thereafter, as the piston member 82 is moved to the right, the communication opening is fully closed. It changes gradually until.

Here, the first valve hole 5b communicates with the first oil passage La that forms a closed circuit of the continuously variable transmission T, and the second valve hole 5d communicates with the second oil passage La.
Lb, the first and second valve holes 5
By changing the communication opening degree of b, 5d, the opening degree of the seventh oil path Lg, which is a short-circuit path of the first and second oil paths La, Lb, can be changed. Done. That is, the clutch opening degree control is performed by controlling the duty ratio of the solenoid valves 155 and 156 based on the signal from the controller 100.

Regarding the method of controlling the opening of the clutch valve 5 by controlling the duty ratio of the solenoid valves 155 and 156,
A specific description will be given based on the flowchart in FIG.

This control is started by reading the accelerator opening θacc from the depression amount of the accelerator pedal or the throttle opening of the engine and reading the vehicle speed V. Subsequently, the target clutch opening θclo corresponding to the accelerator opening θacc is calculated from the graph of FIG. 4th
In the figure, a target clutch opening θclo is set in advance for each accelerator opening θacc (1)... Θacc (n) corresponding to the vehicle speed V, and when the vehicle speed V and the accelerator opening θacc are read, the target clutch opening θclo corresponds to these. It is possible to calculate the target clutch opening θclo for performing smooth clutch connection. The accelerator opening θacc (1) is in the fully closed state of the throttle, and the opening is sequentially increased as the number increases, θacc (n) indicates the fully opened state of the throttle, and the target clutch opening θclo is The value is maximum at 90 ° when fully closed, changes to the open side as this value decreases, and is 0 ° when fully open.

Next, the actual clutch opening θcl is read, and an opening difference Δθcl (= θclo−θcl) between the calculated target clutch opening θclo and the actual clutch opening θcl is calculated. Then, the clutch opening control speed is calculated from the graph of FIG. 5 based on the opening difference Δθcl. As is clear from FIG. 5, the control speed is determined by the opening degree difference Δθ.
When cl is positive, that is, when the target clutch opening Δclo is larger than the actual clutch opening θcl (the target clutch opening θcl
o is on the closing side), the clutch having a size proportional to the magnitude of the opening degree difference Δθcl is closed (turned on).
When the control speed in the direction is given and the opening degree difference Δθcl is negative, that is, when the target clutch opening degree θclo is smaller than the actual clutch opening degree θcl (when the target clutch opening degree θclo is on the release side). Releases the clutch having a magnitude proportional to the magnitude of the absolute value of the opening difference Δθcl (OF
Control speed in the direction of F) is given.

The opening / closing control of the latch valve 5 is performed based on the calculated speed. When the actual clutch opening θcl is far away from the target clutch opening θclo, the actual clutch opening The opening control is performed at a high control speed so that θcl rapidly approaches the target clutch opening θclo, and when both approaches, the control speed becomes slower, and the actual clutch opening θcl gradually approaches the target clutch opening θclo. .

When the control is performed as described above, the engine speed is not used as the control information. Therefore, the control is not affected by the delay of the increase in the engine speed as in the conventional control. Also, smooth ON / OFF operation of the clutch can be performed.

In the above-described embodiment, a description will be given of a method of controlling the opening of a clutch valve in which the opening of a short circuit that short-circuits a closed circuit is controlled in a hydraulic transmission including a hydraulic pump and a hydraulic motor. However, the control method of the present invention is not limited to such a method, and is applied to a clutch device using a friction clutch disc as in other types of transmissions such as a gear type transmission conventionally used. Can also be used.

C. Effect of the Invention As described above, according to the method of the present invention, the target engagement capacity of the clutch means is set in accordance with the accelerator opening and the traveling speed of the vehicle, and the actual engagement capacity of the clutch means is set to this value. Since the degree of power transmission by the clutch means is controlled so as to match the target engagement dose, the engine speed, which is not very responsive, is unnecessary as control information for clutch engagement control, and the accelerator pedal is not required. In the event that the engine is suddenly depressed, inappropriate clutch control due to a delay in the increase in engine speed can be avoided.
As a result, it is possible to prevent the engine speed from rising when the clutch is engaged at the time of starting and the occurrence of hunting due to an inappropriate half-clutch.

If the clutch engagement control speed is set and controlled according to the deviation between the target engagement capacity and the actual engagement capacity of the clutch means, the clutch control can be performed more accurately.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram of a continuously variable transmission in which the clutch opening is controlled by the method of the present invention. FIG. 2 is a cross-sectional view of a clutch servo valve for controlling the clutch opening of the continuously variable transmission. 3 is a flowchart showing the contents of clutch opening control according to the present invention, FIG. 4 is a graph showing the relationship between vehicle speed and target clutch opening for each accelerator opening, and FIG. It is the graph which showed the relationship with opening control speed. 4. Shuttle valve, 5 ... Clutch valve 10 ... Charge pump 80 ... Clutch servo valve 155, 156 ... Solenoid valve 100 ... Controller, E ... Engine T ... Continuously variable transmission, W ... Wheel

Claims (3)

(57) [Claims] A transmission for shifting the engine output to a wheel to drive the wheel; and a clutch means for controlling a degree of transmission of the engine output transmitted to the wheel via the transmission. A target engagement capacity of the clutch means is set in accordance with an accelerator opening and a traveling speed of the vehicle, and the actual engagement capacity of the clutch means is made to coincide with the target engagement capacity. Controlling the degree of transmission by the clutch means. 2. A method for calculating a deviation between the target engagement capacity and the actual engagement capacity, obtaining a clutch control speed that increases in accordance with the difference, and obtaining a clutch control speed based on the clutch control speed. The vehicle clutch control method according to claim 1, wherein the degree of transmission is controlled by means. 3. A hydraulic system in which the transmission comprises a hydraulic pump and a hydraulic motor, and a hydraulic closed circuit formed by connecting the discharge and suction ports of the hydraulic pump and the hydraulic motor with two oil paths. A continuously variable transmission, wherein the clutch means comprises a clutch valve disposed on a short-circuit path directly connecting the two oil paths to adjust an opening degree of the short-circuit path; 3. The vehicle clutch control method according to claim 1, wherein the transmission degree is controlled by adjusting an opening degree.