KR101071695B1 - Method for diagnosing malfunction of damper clutch for auto transmission - Google Patents

Abstract

The present invention relates to a method for diagnosing a damper clutch failure of an automatic transmission, and in particular, in a line pressure variable control automatic transmission to which a variable pressure solenoid valve (VFS valve) is applied for variable line pressure control, the variable pressure control A first step (S10) for instructing the damper clutch in direct connection with the damper clutch in consideration of the failure of the valve, the TCU direct connection; A second step (S20) of increasing the damper clutch solenoid valve duty to directly connect the damper, and performing normal determination (S21) when the damper is directly connected under a specific duty condition; A third step (S30) of measuring and storing the slip amount (XSLIP = Ne-Nt) of the torque converter at a constant duty (DUTY_TGT) when the damper is not directly connected in the second step (S20); A fourth step (S40) of fixing the VFS valve duty to 100%, giving a damper release command, and increasing the VFS valve duty again when it is impossible to directly connect the damper even under a specific duty condition in the second step (S20); A fifth step S50 of measuring the slip amount XSLIP_new once again in the duty amount in which the slip amount is stored in the third step S30 and comparing it with the previous measurement value XSLIP; A sixth step S60 of making a VFS valve failure determination S61 when the comparison value exceeds a predetermined value ERR_MAX; When the comparison value does not exceed a certain value and is the specific duty condition, a seventh step S70 of lowering the damper clutch fault determination S71 is included to prevent deterioration of hardware due to damper clutch misdiagnosis. In addition, since accurate fault diagnosis is possible, post-service efficiency can be improved.

Line pressure, damper clutch, automatic transmission, VFS valve, diagnostics.

Description

Method for diagnosing damper clutch failure of automatic transmission {Method for diagnosing malfunction of damper clutch for auto transmission}             

1 is a hydraulic circuit diagram of an automatic transmission that does not control the conventional line pressure,

2 is a hydraulic circuit diagram of a conventional improved line pressure variable control automatic transmission;

3 is a flowchart showing an example of a failure diagnosis method of a conventional automatic transmission;

Figure 4 is an embodiment of a damper clutch failure diagnosis method of an automatic transmission of the present invention

Flowchart Indicating.

<Explanation of symbols for the main parts of the drawings>

S10: first step S20: second step

S30: third step S40: fourth step

S50: fifth step S60: sixth step

S70: seventh step

The present invention relates to a method for diagnosing a damper clutch failure of an automatic transmission, and in particular, in a line pressure variable control automatic transmission to which a variable pressure solenoid valve (VFS valve) is applied for variable line pressure control, the variable pressure control The present invention relates to a method for diagnosing a damper clutch failure of an automatic transmission to diagnose a failure of a damper clutch in consideration of a valve failure.

In the automatic transmission, a damper clutch is operated for fuel efficiency and engine brake operation. FIG. 1 is a hydraulic circuit diagram of a conventional automatic transmission which does not control the conventional line pressure, and FIG. 2 is a conventional improved line pressure variable control automatic transmission. As a hydraulic circuit diagram, a schematic damper clutch system is shown.

The role of the damper clutch solenoid valve 1 in the above circuit diagram is to divide the line pressure supplied from the oil pump 2 into the exhaust pressure and the control pressure according to the TMS command, and provide the desired control pressure to the clutch. In the same way, the VFS valve 3 provides a variable line pressure to each part of the automatic transmission.

The failure diagnosis for the conventional damper clutch shown in FIG. 1 largely examines the electrical disconnection short circuit (electronic check) of the damper clutch solenoid valve 1 and the disconnection / disconnection at the time of the mechanical damper release / connection command of the damper clutch. It is divided into rationality (mechanical) check.

Overview of the mechanical inspection of the damper clutch failure diagnosis method, as shown in Figure 3, the instruction step (S1) for directing the damper direct connection in the TCU, and the duty to increase the solenoid valve duty to directly connect the damper, if indicated Increasing step (S2), and the normal determination step (S3) is judged to be normal if the damper is directly connected before the 'continuity of 100% duty more than 4 seconds', and if the direct connection is impossible, the instruction step after the damper release command A return step (S4) to return after (S1), and a failure diagnosis step (S5) for lowering the damper clutch failure diagnosis when still impossible.

However, the conventional technique is a technique applied to an automatic transmission without a change in line pressure, and basically performs a failure diagnosis on the assumption that the line pressure supply is not a problem. Therefore, in the automatic transmission to which the variable line pressure control is applied, the line pressure may drop below the required pressure due to a malfunction of the VFS valve, which may cause the clutch to slip if the clutch control pressure is insufficient.

In this case, the damper clutch is determined to be released by the normal control (damper on) command of the solenoid. In the end, the damper clutch is misdiagnosed as a mechanical problem of the damper clutch. In proportion to this there was a problem that adversely affects the clutch durability.

SUMMARY OF THE INVENTION The present invention has been made to solve the above drawbacks, and in the variable pressure automatic control of a variable pressure control valve (VFS valve) applying a variable pressure control valve (VFS valve) for variable line pressure control, the hardware of the damper clutch misdiagnosis In order to prevent deterioration and to accurately diagnose failures, the present invention aims to provide a damper clutch failure diagnosis method of an automatic transmission that can improve the efficiency of after-service.

The present invention, the first step of directing the damper direct connection in the TCU; A second step of increasing a damper clutch solenoid valve duty to directly connect a damper, and determining that the damper clutch solenoid valve is normal when the damper is directly connected at a specific duty condition; A third step of measuring and storing an amount of slip of the torque converter at a constant duty if the damper is not directly connected in the second step; A fourth step of fixing the VFS valve duty to 100%, giving a damper release command, and again increasing the damper clutch solenoid valve duty when the damper direct connection is impossible even under a specific duty condition in the second step; A fifth step of measuring the slip amount once again from a duty stored in the third step and comparing the slip amount with a previous measured value; A sixth step of making a VFS valve failure determination when the comparison value does not exceed a predetermined value; If the comparison value exceeds a certain value and is the specific duty condition, a seventh step of making a damper clutch failure determination is achieved.

An embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Figure 4 is a flow chart showing an embodiment of a damper clutch failure diagnosis method of the automatic transmission of the present invention, the present invention, the first step (S10) for directing the damper direct connection in the TCU; A second step (S20) of increasing a damper clutch solenoid valve duty to directly connect a damper, and performing normal determination (S21) when the damper clutch solenoid valve is directly connected to a damper under a specific duty condition; A third step (S30) of measuring and storing the slip amount (XSLIP = Ne-Nt) of the torque converter at a constant duty (DUTY_TGT) when the damper is not directly connected in the second step (S20); A fourth step (S40) of fixing the VFS valve duty to 100%, giving a damper release command, and increasing the damper clutch solenoid valve duty when the damper direct connection is impossible even under a specific duty condition in the second step (S20); A fifth step S50 of measuring the slip amount XSLIP_new once again in the duty amount in which the slip amount is stored in the third step S30 and comparing it with the previous measurement value XSLIP; A sixth step S60 of making a VFS valve failure determination S61 when the comparison value does not exceed a predetermined value ERR_MAX; When the comparison value exceeds a predetermined value and the specific duty condition, the technical characteristics include a seventh step S70 of lowering the damper clutch failure determination S71.

The specific duty condition is a state in which the duty state is 100% for 4 seconds or more. If the connection state is maintained even under these conditions, the VFS valve duty is fixed to 100% and a damper release command is issued. Proceeding to the fourth step (S40) or less to increase the solenoid valve duty, it is determined whether the VFS valve failure or the damper clutch failure.

Hereinafter, the operation and effect of the present invention having the configuration as described above with reference to FIG. 4 will be described.

The disadvantage of the conventional method is that there is no countermeasure against the case where direct connection is impossible when insufficient hydraulic pressure is supplied to the clutch in the line pressure variable control system in which two solenoid valves operate in one clutch control.

In this case, when the maximum line pressure is supplied to the damper clutch solenoid valve by the forced driving of the VFS, it is possible to determine whether the damper clutch is malfunctioning due to the failure of the VFS at least. The method is as follows.

When the damper clutch is normal and the line pressure control is abnormal, there is no change in slip amount at a certain operating point compared with the case where the line pressure control is not 100% and the line pressure control is 100%.

When the damper clutch is abnormal and the line pressure control is normal, comparing the case where the line pressure control is not 100% with the case where the line pressure control is 100%, at a certain operating point than when the line pressure control is not 100% The slip amount is small.

In these two situations, it is possible to determine whether the variable line pressure control is bad or the damper clutch is bad.

The above embodiment is an example for explaining the technical idea of the present invention in detail, and the scope of the present invention is not limited to the above drawings and embodiments.

As described above, the present invention provides a variable pressure control automatic transmission using a variable force solenoid valve (VFS valve) for variable line pressure control, to prevent deterioration of hardware due to damper clutch misdiagnosis, It is possible to improve the efficiency of the after-service because it can diagnose the failure.

Claims (2)

A first step of directing damper direct connection in the TCU; A second step of increasing a damper clutch solenoid valve duty to directly connect a damper, and determining that the damper clutch solenoid valve is normal when the damper is directly connected to a specific duty condition; A third step of measuring and storing an amount of slip of the torque converter at a constant duty if the damper is not directly connected in the second step; A fourth step of fixing the VFS valve duty to 100%, giving a damper release command, and again increasing the damper clutch solenoid valve duty when the damper direct connection is impossible even under a specific duty condition in the second step; A fifth step of measuring the slip amount once again from a duty stored in the third step and comparing the slip amount with a previous measured value; A sixth step of making a VFS valve failure determination when the comparison value does not exceed a predetermined value; And a seventh step of making a damper clutch fault determination when the comparison value exceeds a predetermined value and is a specific duty condition. The method of claim 1, wherein the specific duty condition is a condition in which the damper clutch of the automatic transmission is in a state in which the duty state is 100% or more.

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