Method and apparatus for diagnosing a malfunction of a clutch actuator

• US 6,752,743 B2
• Filed: 02/27/2003
• Issued: 06/22/2004
• Est. Priority Date: 08/30/2000
• Status: Expired due to Fees

• Current Assignee: Schaeffler Technologies AG & Co.KG (INA-Holding Schaeffler GmbH & Co. KG)
• Original Assignee: Alexander Schweizer, Jäger, Thomas, Jürgen Eich, Küpper, Klaus, Martin Vornehm, Ralf Enderlin
• Inventors: Jäger, Thomas, Schweizer, Alexander, Eich, Jürgen, Küpper, Klaus, Enderlin, Ralf, Vornehm, Martin
• Primary Examiner(s): Lewis, Tisha D
• Application Number:
  US10/375,821
• Publication Number:
  US 20030130092A1
• Time in Patent Office: 481 Days
• Field of Search: 477/175, 477/179, 477/180, 477/181, 477/902, 477/906, 701/63, 701/67, 701/68
• US Class Current: 477/175
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• CPC Class Codes: B60W 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 10/11 Stepped gearings
• CPC Class Codes: B60W 2050/0031 Mathematical model of the vehicle
• CPC Class Codes: B60W 2050/021 Means for detecting failure or malfunction
• CPC Class Codes: B60W 2510/0225 Clutch actuator position
• CPC Class Codes: B60W 2510/0652 Speed change rate
• CPC Class Codes: B60W 2510/0657 Engine torque
• CPC Class Codes: B60W 2540/16 Ratio selector position
• CPC Class Codes: B60W 30/18 Propelling the vehicle
• CPC Class Codes: B60W 30/1819 Propulsion control with control means using analogue circuits, relays or mechanical links
• CPC Class Codes: F16D 2500/1088 CVT
• CPC Class Codes: F16D 2500/3026 Stroke
• CPC Class Codes: F16D 2500/3065 Torque of the engine
• CPC Class Codes: F16D 2500/3069 Engine ignition switch
• CPC Class Codes: F16D 2500/30806 Engaged transmission ratio
• CPC Class Codes: F16D 2500/3166 Detection of an elapsed period of time
• CPC Class Codes: F16D 2500/5108 Failure diagnosis
• CPC Class Codes: F16D 2500/70454 Engine speed
• CPC Class Codes: F16D 48/06 Control by electric or electronic means, e.g. of fluid pressure
• CPC Class Codes: Y02T 10/40 : Engine management systems
• CPC Class Codes: Y10S 477/906 : Means detecting or ameliorating the effects of malfunction or potential malfunction

Abstract

In a method and apparatus for diagnosing a malfunction in a clutch actuator of a motor vehicle, the actual position of the clutch actuator is measured by a position sensor. Simultaneously, an estimated position of the clutch actuator is calculated by an emulation unit that emulates the function of the clutch actuator. Malfunctions of the clutch-actuator are diagnosed by comparing the actual, measured position to the estimated position.

Claims

1. A method of diagnosing a malfunction of a clutch actuator that actuates the engagement and disengagement of a clutch of a motor vehicle with a transmission and a control unit, comprising the steps of:

a) feeding an input command signal representing a desired amount of clutch engagement from the control unit to the clutch actuator;

b) measuring the clutch-actuator position and generating an actual position signal corresponding to the actually measured clutch-actuator position;

c) feeding the actual position signal to a processor unit for the function of the clutch and a dynamic behavior of an engine, which generates an actual rpm signal based on an rpm-sensor input, representing a measured engine rpm-rate;

d) simultaneously with step c), feeding the actual position signal to a calculator unit which calculates a theoretically estimated engine rpm-rate based on the estimated position signal and a current engine torque and generates an estimated rpm signal representing the theoretically estimated engine rpm-rate;

e) feeding the actual rpm signal and the estimated rpm signal to a comparator unit which, in turn, generates a comparison signal representing the result of a comparison of actual and estimated rpm signals;

f) based on said comparison signal, making a conclusion about the condition of the clutch.

2. The method of claim 1, wherein the comparison signal is returned from the comparator unit through a feedback line to the calculator unit, so that the calculator unit can apply a correction to keep the actual rpm signal and the estimated rpm signal from drifting apart.