JPH0718460B2 - Control method for starting clutch - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a starting clutch which is provided between an engine and a transmission and which automatically performs starting control.

Conventional technology and its problems Conventionally, automatic clutches such as electromagnetic clutches and fluid clutches are generally known as start clutches for automatically performing start control, and fluid clutches are most preferable in terms of smooth startability, In the case of a fluid clutch, there are drawbacks such as creeping when in neutral and poor efficiency during normal running.

Therefore, if a general friction clutch is used as the starting clutch and the starting characteristics similar to those of the fluid clutch can be obtained by hydraulically controlling this clutch, the configuration will be extremely simple and the above-mentioned drawbacks can be eliminated. is there.

From such a viewpoint, a clutch disconnection hydraulic circuit, a coupling hydraulic circuit, a hydraulic control valve provided in the coupling hydraulic circuit, and a valve control circuit that performs duty control of the hydraulic control valve according to a clutch operation command. It has been proposed that the valve control circuit duty-controls the hydraulic control valve at a duty ratio according to the throttle opening (JP-A-59).
-217043). In this case, after the half-clutch state, the clutch is driven in the connecting direction quickly when the throttle opening is large and gradually when the throttle opening is small.

However, in this control method, since the clutch is controlled only by the throttle opening, it does not correspond to the actual change in the engine speed, and it is difficult to obtain a smooth starting characteristic like a fluid clutch. .

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a starting clutch control method capable of obtaining a smooth starting characteristic similar to that of a fluid clutch by using a wet clutch.

To achieve the above object, the present invention provides a wet starting clutch, a hydraulic control valve for controlling clutch hydraulic pressure to the starting clutch, a solenoid valve for controlling the hydraulic control valve, and a duty control for the solenoid valve. In the control device for the starting clutch including the control circuit, by comparing the difference between the input rotational speed Ni and the output rotational speed No of the starting clutch with the set value δ, the step of determining the engagement state of the starting clutch,
When it is determined in the determination step that the starting clutch is in the half-clutch state, the step of obtaining the duty ratio D for obtaining the clutch torque according to the input rotation speed Ni and the duty ratio D obtained in the above step are The method includes a step of correcting the input rotation speed Ni toward the set input rotation speed N _R set according to the throttle opening θ, and a step of outputting the corrected duty ratio signal to the solenoid valve.

That is, first, if the duty ratio D for obtaining the clutch torque according to the input rotation speed Ni is obtained and this duty ratio is output to the solenoid valve, normally, a smooth clutch engagement such as a fluid clutch is possible. Is. However, in reality, due to various factors, the relationship between the input rotational speed and the clutch torque is inconsistent with the target engagement characteristic. Therefore, in the present invention, the duty ratio D is corrected so that the input rotation speed approaches the set input rotation speed set according to the throttle opening, and the solenoid valve is controlled by this corrected duty ratio. In other words, by feedback controlling the duty ratio through the input speed,
It is possible to prevent the shift of the engagement characteristic due to various factors and realize an ideal starting characteristic.

Description of Embodiments FIG. 1 shows an example of a control system for a starting clutch for carrying out the present invention, in which the piston 2 is moved leftward to press the clutch plates 3 and 4 into contact with each other to disconnect the power. Friction start clutch to perform, 5 is an input shaft directly connected to the engine, 6 is an output shaft, 10 is a hydraulic control valve, 40 is a solenoid valve,
50 is a control circuit.

The hydraulic control valve 10 has a spool 12 that is slidable in the valve body 11, and a spring 13 that constantly biases the spool 12 to the left. An oil passage 30 is provided in a port 14 of the valve body 11. Line pressure is introduced from a hydraulic pressure supply source (not shown) via the
Opened and closed by 15. Oil passage 31 branched from the above oil passage 30
The small diameter formed at the right end of the valve body 11 is connected to the right end chamber 16, and the needle 41 of the solenoid valve 40 is connected to this oil passage 31.
An opening 32 that is opened and closed by is provided. Therefore, the solenoid pressure controlled by the solenoid valve 40 acts on the right end chamber 16 to push the land 17 on the right side of the spool 12 to the left.

A port 18 adjacent to the right side of the port 14 is connected to the piston chamber 7 of the starting clutch 1 via an oil passage 33, and a left end chamber 20 of the valve body 11 via a communication hole 19 formed inside the spool 12. Is in communication with. Therefore, the leftmost chamber 20
The hydraulic pressure of the piston chamber 7 of the starting clutch 1 (clutch hydraulic pressure) acts on the spool via the oil passage 33 and the communication hole 19.
The land 15 on the left side of 12 is pressed to the right. In addition, spool
Instead of the communication hole 19 formed inside the valve 12, another oil passage 34 for connecting the oil passage 33 and the left end chamber 20 may be provided in the valve body 11 as shown by a broken line in FIG.

A drain port (oil drainage port) 21 is formed on the valve body 11 adjacent to the right side of the port 17, and the drain port 21 is opened and closed by a land 22 at the center of the spool 12.

The outside diameter a of the land 15 on the left side of the spool 12 is larger than the outside diameter b of the land 17 on the right side, the clutch hydraulic pressure acting on the land 15 is P _C , the solenoid pressure acting on the land 17 is P _S , the spring of the spring 14 is If the force is F, The clutch hydraulic pressure P _C is controlled so that the relationship of 1 is established.

The control circuit 50 includes an input speed Ni, an output speed N _O and an oil passage 33.
The clutch hydraulic pressure P _C and the line pressure P _{L of the} oil passage 30 are input as electric signals, and the solenoid valve 40 is duty-controlled based on these signals. That is, from the control circuit 50 to the solenoid valve 40, as shown in FIG.
A signal of a constant cycle T ₀ including the ON time T ₁ and the OFF time T ₂ is input, and by changing the ratio (duty ratio D%) of the ON time T _{1 to} the cycle T ₀ of the signal, the solenoid pressure is changed. P _S can be changed proportionally as shown in FIG.

In general, when the engine and the fluid clutch are combined, the engine matching characteristics of the fluid clutch can be best matched at the positions connecting the vertices of the performance curves shown by the solid lines in FIG. 4, and are shown by the broken lines. Clutch torque T is equal to engine speed (equal to input speed)
The relationship is proportional to the square of. When this matching characteristic curve is replaced with the relationship between the input speed and the throttle opening, it becomes as shown in FIG. Therefore, if the input rotational speed is set in advance according to each throttle opening as shown in FIG. 5 and the actual input rotational speed Ni is controlled so as to match the set input rotational speed N _R , friction start With the clutch 1, it is possible to obtain a starting characteristic similar to that of the fluid clutch.

By the way, a relational expression of T = K × μ × P _C (2) (K: proportional constant, μ: friction coefficient) is established between the clutch torque T and the clutch hydraulic pressure P _C, and the clutch hydraulic pressure P _C The above equation (1) is established between the solenoid pressure P _S and the solenoid pressure P _S.
Since the duty ratio D is directly proportional to the duty ratio D as shown in FIG.
After all, if the duty ratio D is set to a relationship proportional to the square of the input rotation speed Ni as shown in FIG. 6, the matching characteristic is theoretically similar to that of the fluid clutch, in other words, it matches the curve of FIG. It is possible. Note that the relationship in FIG. 6 is the case where the line pressure applied to the oil passage 30 is constant regardless of the change in the input rotation speed Ni, and when the line pressure increases as the input rotation speed Ni increases, the line pressure For example, the relationship shown by the broken line in FIG. 6 may be changed according to the rate of increase.

However, the relationship between the duty ratio D and the solenoid pressure P _S cannot be uniquely determined due to the influence of the viscosity change due to the oil temperature, and the relationship between the solenoid pressure P _S and the clutch oil pressure P _C is also the spring force of the spring 13. Because it changes due to variations,
Even if the relationship between the input rotational speed Ni and the duty D is set as shown in FIG. 6, the desired matching characteristic (FIG. 5) cannot be obtained.

In the present invention, in order to eliminate the problem caused by such an unstable element, the throttle opening θ is detected, and the preset input rotational speed N _R and the actual input rotational speed Ni corresponding to the throttle opening are preset. The duty ratio of the solenoid valve is corrected by comparing the above, and the solenoid valve 40 is duty-controlled so that the input rotation speed Ni matches the set input rotation speed N _R quickly and accurately.

Here, the control of the present invention by the control circuit 50 will be described with reference to FIG.
It will be described with reference to FIG.

When the basic routine shown in FIG. 7 starts, first, the A value is set to the initial value (= 0%). This A value is added to the duty ratio D and added as a signal to the solenoid valve 40. The initial value is 0% and is corrected by the interrupt routine of FIG. After setting the A value to the initial value, the actual input rotation speed Ni and the output rotation speed N _O are input, and the input rotation speed Ni is compared with the preset initial rotation speed N _C. This initial rotational speed N _C is the minimum rotational speed at which the starting clutch 1 should be disengaged, and is set slightly higher than the idle rotational speed. When Ni <N _C, the engine will stop if the starting clutch 1 is engaged, so the solenoid valve 40
Is turned off (duty ratio D = 0%), and the starting clutch 1 is disengaged. On the other hand, when Ni ≧ N _C , the difference between the input rotation speed Ni and the output rotation speed N _O is compared with the predetermined value δ. This value δ is a reference for determining whether the starting clutch 1 is in the engaged state or the semi-engaged state, and is, for example, 200 rpm.
It is set to a degree.

If | Ni−N _O | ≦ δ, it means that the start has been completed, so the solenoid valve 40 is turned on (duty ratio D = 100
%) And connect the starting clutch 1.

On the other hand, if | Ni−N _O |> δ, it means that the starting clutch 1 is in the semi-engaged state, that is, in the middle of starting. Therefore, from FIG. Read the duty ratio D corresponding to the number Ni,
A value (initial value = 0%) is added to the duty ratio D and output to the solenoid valve 40.

If there is no unstable element such as a change in oil temperature or a variation in spring force of the spring, it is possible to obtain an ideal matching characteristic by the duty ratio D. However, as described above, there is a difference between the clutch torque actually generated by the duty ratio D due to the influence of the instability factor and the clutch torque preset with the ideal fluid clutch. It is necessary to correct the A value by the interrupt routine.

That is, the actual throttle opening θ is input, the set input rotation speed N _R corresponding to the throttle opening θ is read from FIG. 5, and the difference between the input rotation speed Ni and the set input rotation speed N _R (| Ni− N
_R |) is compared with the value β. This β is a reference value for determining whether or not the input rotation speed Ni is substantially in the same range as the set input rotation speed N _R, and is set to, for example, about 0 to 1000 rpm. If | Ni−N _R | ≦ β, there is almost no influence of the unstable element, which means that the target matching characteristic is obtained, and therefore the A value is not corrected.

In the case of | Ni−N _R |> β, it means that the input rotation speed Ni is far from the target set input rotation speed N _R.
Next, the input rotation speed Ni and the set input rotation speed N _R are compared.
When Ni ≧ N _R , it means that the coupling of the starting clutch 1 is insufficient as compared with the target matching characteristic, so the A value is corrected to a higher value by A = A + γ, and this correction value is Return to the basic routine as shown in FIG. As a result, the duty ratio applied to the solenoid valve 40 increases and the starting clutch 1 is urged in the connecting direction, so that the increase in the input rotational speed Ni is suppressed.

On the other hand, when Ni <N _R , it means that the coupling of the starting clutch 1 is excessive. Therefore, the A value is corrected to a low value by A = A−γ, and this correction value is shown in FIG. To return to the basic routine. As a result, the duty ratio of the solenoid valve 40 decreases and the starting clutch 1 is urged in the disengagement direction, so that the input rotational speed Ni increases.

In the above control, the value of γ may be a constant,
Alternatively, it may be variable according to the difference between the input rotation speed Ni and the set input rotation speed N _R.

As described above, the duty ratio applied to the solenoid valve 40 is corrected by the magnitude relationship between the set input rotation speed N _R corresponding to the throttle opening θ and the actual input rotation speed Ni. The input speed Ni can be made to match the set input speed N _R without being affected by unstable factors such as changes. Therefore, it is possible to obtain the smooth startability similar to that of the fluid clutch.

In the above embodiment, the relationship between the throttle opening and the set input rotational speed N _R is set as shown in FIG. 5 in order to obtain a smooth startability similar to that of the fluid clutch, but the present invention is not limited to this. Various controls are possible according to the purpose such as startability with emphasis on fuel consumption performance.

EFFECTS OF THE INVENTION As is clear from the above description, according to the present invention, the duty ratio for obtaining the clutch torque according to the input rotation speed is obtained, and this duty ratio is set according to the input rotation speed according to the throttle opening. Since the solenoid valve is controlled with this corrected duty ratio, the clutch engagement characteristics are idealized without being affected by unstable factors such as changes in oil temperature. It is possible to obtain the ideal starting characteristics.

[Brief description of drawings]

FIG. 1 is a block diagram of a control device for a starting clutch for executing the control method according to the present invention, FIG. 2 is a signal waveform diagram of an example of duty control, and FIG. 3 is a relationship between duty ratio and solenoid pressure. FIG. 4 is a diagram showing a relationship between engine speed and engine torque and clutch torque, and FIG.
The figure shows the relationship between the throttle opening and the set input speed. Fig. 6 shows the relationship between the input speed and the duty ratio. Fig. 7 shows the basic operation of the control circuit. Fig. 8 shows the interrupt routine. FIG. 1 ... Starting clutch, 10 ... hydraulic control valve, 40 ... solenoid valve, 50 ... control circuit, D ... duty ratio, .theta.
Throttle opening, Ni …… input speed, N _R …… set input speed.

Claims (1)

[Claims] 1. A starting clutch including a wet starting clutch, a hydraulic control valve for controlling a clutch hydraulic pressure to the starting clutch, a solenoid valve for controlling the hydraulic control valve, and a control circuit for duty-controlling the solenoid valve. In the control device, a step of determining the engagement state of the starting clutch by comparing the difference between the input rotational speed Ni and the output rotational speed No of the starting clutch with a set value δ; When it is determined that the state is the state, the step of obtaining the duty ratio D for obtaining the clutch torque according to the input rotation speed Ni and the duty ratio D obtained in the above step are compared with the input rotation speed Ni.
Is the set input speed set according to the throttle opening θ
A method for controlling a starting clutch, comprising: a step of correcting in a direction approaching N _R; and a step of outputting a corrected duty ratio signal to a solenoid valve.