JPS629030A - Control method for starting clutch - Google Patents

Abstract

PURPOSE:To enable easy coincidence of starting characteristics with a ideal value, by a method wherein a duty ratio added to a solenoid valve is corrected through feedback of a clutch oil pressure controlled by a hydraulic control valve. CONSTITUTION:A line pressure PL of an oil passage 30 is inputted to a control circuit 50, and a set oil pressure PcR, proportioning to the square of the number Ni of input revolutions in response to the number Ni of input revolutions, is read out from a data map stored in a circuit 50 to compute a duty ratio D, and the signal of the duty ratio D is outputted to a solenoid valve 40. Since an actual clutch oil pressure Pc is prohibited against coincidence to a set oil pressure PcR by the influence of an unstable factor, e.g., a change in an oil temperature, unevenness in a spring force, a factor A, serving to compute the duty ratio D, is inputted to the circuit 50 through detection of the actual clutch oil pressure Pc, and is corrected according to a difference between the set oil pressure PcR and the clutch oil pressure Pc. The correcting value is returned to a fundamental routine to orderly repeat correction of the duty ratio D.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for controlling a starting clutch that is provided between an engine and a transmission and that automatically controls starting.

Conventional technology and its problems Conventionally, automatic clutches such as electromagnetic clutches and fluid clutches have been known as starting clutches that automatically perform starting control, and fluid clutches are most preferable in terms of smooth starting performance. Fluid clutches have the drawbacks of creep when in neutral and low efficiency during normal driving.

Therefore, it would be best if a general friction clutch could be used as the starting clutch and this clutch could be hydraulically controlled to obtain the same starting characteristics as a fluid clutch, since the configuration would be extremely simple and the above drawbacks could be overcome. be.

OBJECTS OF THE INVENTION The present invention has been made with attention to this point of view, and its purpose is to provide a control method for a starting clutch that can obtain ideal starting characteristics using a friction clutch.

Structure of the Invention In order to achieve the above object, the present invention includes a hydraulic control valve that controls clutch hydraulic pressure to a starting clutch, a solenoid valve that controls the hydraulic control valve, and a control circuit that controls the duty of the solenoid valve. The control circuit detects the clutch oil pressure applied to the starting clutch, and corrects the duty ratio of the solenoid valve according to the difference between the clutch oil pressure and a preset oil pressure set in accordance with the input rotation speed.

That is, by feeding back the clutch oil pressure controlled by the oil pressure control valve and correcting the duty ratio applied to the solenoid valve, it is possible to easily match the ideal starting characteristics.

DESCRIPTION OF THE EMBODIMENTS FIG. 1 shows an example of a control device for a starting clutch for carrying out the present invention, in which the piston 2 moves to the left to press the clutch plates 3.4 into contact with each other to interrupt the power. 5 is an input shaft directly connected to the engine, 6 is an output shaft, IO is a hydraulic control valve, 40 is a solenoid valve, and 50 is a control circuit.

The hydraulic control valve 10 has a spool 12 that is slidable within the pulp body 11 and a spring 13 that always biases the spool 12 to the left. Hydraulic supply source (not shown)
The boat 14 is opened and closed by a land 15 on the left side of the spool 12. An oil passage 31 branched from the oil passage 30 is connected to a small diameter right end chamber 16 formed at the right end of the valve body 11.
1 is provided with an opening 32 that is opened and closed by a needle 41 of a solenoid valve 40. Therefore, the rightmost chamber 1
A solenoid pressure controlled by a solenoid valve 40 acts on the land 17 on the right side of the spool 12 to the left.

The boat 18 adjacent to the right side of the boat 14 has an oil passage 3
3 to the piston chamber 7 of the starting clutch 1,
The spool 12 also communicates with the left end chamber 20 of the valve body 11 via a communication hole 19 formed inside the spool 12 . Therefore, the oil pressure (clutch oil pressure) of the piston chamber 7 of the starting clutch 1 acts on the left end chamber 20 through the oil passage 33 and the communication hole 19, and presses the land 15 on the left side of the spool 12 to the right. Note that instead of the communication hole 19 formed inside the spool 12, another oil passage 34 is provided to connect the oil passage 33 and the left end chamber 20 to the valve body 11, as shown by the broken line in FIG.
Even if it is provided, the same function can be achieved.

A drain boat (oil drain port) 21 is formed in the valve body 11 adjacent to the right side of the boat 18, and this drain boat 21 is connected to the land 22 in the center of the spool 12.
It is opened and closed by

The outer diameter a of the land 15 on the left side of the spool 12 is larger than the outer diameter of the land 17 on the right side. When F, clutch oil pressure Pc is controlled so that the following relationship holds true.

The control circuit 50 has an input rotation speed N (and an output rotation speed N), a clutch oil pressure PC in the oil passage 33, and a line pressure PL in the oil passage 30.
are input as electrical signals, and the solenoid valve 40 is duty-controlled based on these signals. That is, the solenoid valve 40 has a control circuit 50.
As shown in FIG. 2, a signal with a constant period T0 including an ON time open and an OFF time T2 is input, and of this signal, a period T of an ON time open. (Duty ratio D%
), the solenoid pressure PS can be changed proportionally as shown in FIG.

-m, the engine matching characteristic of the starting clutch is such that the best matching can be achieved when the torque is proportional to the square of the rotational speed, as in the case of a fluid clutch. Therefore, in order to obtain starting performance similar to that of a fluid clutch, the clutch torque T of the starting clutch 1 may be set in a relationship proportional to the square of the input rotational speed (engine rotational speed) NL, as shown in FIG. Here, the relational expression T = K Hydraulic P. is uniquely determined by Also, clutch oil pressure P. The above equation (1) holds true between P and solenoid pressure PS, and furthermore, solenoid pressure P and duty ratio are
As shown in the figure, it is directly proportional, so if the duty ratio is set in a relationship proportional to the square of the input rotation speed N+ as shown in Figure 5, matching characteristics similar to those of a fluid clutch can theoretically be obtained. Is possible.

However, the relationship between the duty ratio and the solenoid pressure ps cannot be determined uniquely due to the influence of viscosity changes due to oil temperature, and the relationship between the solenoid pressure Ps and clutch oil pressure PC also changes due to variations in the spring force of the spring 13. Therefore, even if the relationship between the input rotational speed N1 and the duty D is set as shown in FIG. 5, the desired matching characteristics cannot be obtained.

In the present invention, in order to eliminate problems caused by such unstable factors, the actual clutch oil pressure P. is detected, and the solenoid valve 40 is activated so that this clutch oil pressure P0 quickly and accurately matches the clutch oil pressure (hereinafter referred to as set oil pressure PC,l) for obtaining the target clutch torque T.
This is to control the duty.

Here, the control of the present invention by the control circuit 50 will be explained with reference to FIGS. 7 and 8.

When the basic routine shown in FIG. 7 starts, first, a coefficient A for calculating the duty D is set to an initial value,
Next, input the input rotation speed N (and output rotation speed N), and compare the input rotation speed N[ and the preset initial rotation speed Nc. This is the rotation speed and is set slightly higher than the idle rotation speed.The input rotation speed N+ is the initial rotation speed N.When it is lower, the engine will stop if the starting clutch l is connected as it is, so the solenoid valve 40 is turned off. (
duty ratio D=0%), and the starting clutch lt is disconnected. On the other hand, when the input rotation speed N is higher than the initial rotation speed Nc, the input rotation speed N and the output rotation speed N. The difference is compared with a predetermined value δ. This value δ is a reference value for determining whether the starting clutch 1 is in the engaged state or in the semi-engaged state, and is set to, for example, about 20 Orpm.

If IN+Nol≦δ, it means that the start has been completed, so the solenoid valve 40 is turned on (duty ratio D=100%) and the start clutch 1 is connected. on the other hand,
If IN--Nol>δ, this means that the starting clutch 1 is in a half-engaged state, that is, the vehicle is in the middle of starting, so the following starting control is performed.

First, the line pressure PL of the oil passage 30 is input to the control circuit 50, and then the set oil pressure PCI+ corresponding to the input rotation speed N is read out from the data map stored in the control circuit 50. In order to obtain matching characteristics similar to those of a fluid clutch, this data map is based on the input rotation speed N, as shown in FIG.
A set oil pressure PcR is set in proportion to the square of PcR. The duty ratio is calculated from the read set oil pressure PCI+, the initial value of the coefficient A, and the line pressure PL using the following equation.

CRC If there are no unstable factors such as changes in oil temperature or variations in spring force, it is possible to obtain ideal matching characteristics using the duty ratio determined by the above formula. However, if the above-mentioned coefficient A is set to an unchanging value, the actual clutch oil pressure pc and the set oil pressure PcR will not match due to the influence of unstable factors as described above. Therefore, the value of the coefficient A is changed by the interrupt routine shown in FIG. Needs to be corrected.

That is, the actual clutch oil pressure P. and inputs this clutch oil pressure PC as an electric signal to the control circuit 50,
The coefficient A is corrected according to the difference between the set oil pressure PCR and the clutch oil pressure pc using the following formula.

xPL After correcting the A value using the above formula, this correction value is expressed as ■ in Figure 7.
Return to the basic routine as shown in , and repeat the same operation while sequentially correcting the duty ratio.

As mentioned above, the actual clutch oil pressure PC and the set oil pressure PC
By correcting the duty ratio according to the difference from 1I, it is possible to quickly and accurately match the clutch oil pressure Pc to the set oil pressure P without being affected by unstable factors such as changes in oil temperature. . Therefore, it is possible to obtain smooth starting performance similar to that of a fluid clutch.

In addition, in the above embodiment, an example was shown in which a wet type clutch was used as the starting clutch 1, but a dry type clutch may also be used. It is.

In addition, in the above embodiment, in order to obtain matching characteristics similar to those of a fluid clutch, the set oil pressure PCR was set as a quadratic function of the input rotation speed Nl as shown in FIG. It may also be set in a relationship.

Effects of the Invention As is clear from the above explanation, according to the present invention, the duty ratio of the solenoid valve is corrected by feedbanking the actual clutch oil pressure, thereby eliminating the influence of unstable factors such as changes in oil temperature. The clutch oil pressure can be quickly and accurately matched to the set oil pressure without learning, and ideal starting performance can be easily obtained.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of a control device for a starting clutch for carrying out 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 diagram showing the relationship between duty ratio and solenoid pressure. Figure 4 is a diagram showing the relationship between input rotation speed and clutch torque, Figure 5 is a diagram showing the relationship between input rotation speed and duty ratio, and Figure 6 is a diagram showing the relationship between input rotation speed and duty ratio. FIG. 7 is a diagram showing the relationship between rotational speed and set oil pressure, FIG. 7 is a basic operation diagram of the control circuit, and FIG. 8 is an operation diagram of the interrupt routine. 1... Starting clutch, 10... Hydraulic control valve, 40...
...Solenoid valve, 50...Control circuit, D...Duty ratio, P,...Solenoid pressure, PC...Clutch oil pressure, PcR...Setting oil pressure, P,...Line pressure,
Nl...Input rotation speed, A...Coefficient. Applicant Daihatsu Motor Co., Ltd. Agent Patent Attorney Hidetaka Tsutsui Figure 1 Figure 2 Figure 4 Figure 7

Claims (1)

[Claims] (1) A hydraulic control valve that controls the clutch hydraulic pressure applied to the starting clutch, a solenoid valve that controls the hydraulic control valve, and a control circuit that controls the duty of the solenoid valve, and the control circuit controls the clutch hydraulic pressure applied to the starting clutch. A method for controlling a starting clutch, comprising detecting the clutch oil pressure and correcting the duty ratio of a solenoid valve according to the difference between the clutch oil pressure and a preset oil pressure set in accordance with the input rotation speed.