Claims:We Claim

1. A method for detecting if a degree of clutch wear of an automobile is above a threshold level of clutch wear by an engine control unit, said method comprising:
determining an actual engine speed oscillation (10) based on an engagement of a specific vehicle gear and a specific vehicle speed by the engine control unit;
comparing the actual engine speed oscillation (10) with an actual engine speed oscillation (14) by the engine control unit, wherein the actual engine speed oscillation (14) is a theoretical engine speed oscillation that is based on the specific vehicle gear and the specific vehicle speed;
determining if the actual engine speed oscillation (10) that is based on the engagement of the specific vehicle gear and the specific vehicle speed is greater than the theoretical engine speed oscillation that is based on the specific vehicle gear and the specific vehicle speed by the engine control unit; and
transmitting an output alert signal (16) by the engine control unit if the actual engine speed oscillation (10) that is based on the engagement of the specific vehicle gear and the specific vehicle speed is greater than the theoretical engine speed oscillation that is based on the specific vehicle gear and the specific vehicle speed.
, Description:Complete Specification:

The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed.
Field of the invention
[0001] This invention relates to a method for determining a degree of clutch wear of an automobile and more specifically to a method for determining a degree of clutch wear of an automobile via non-destructive testing techniques.

Background of the invention
[0002] US 5181593 A describes an apparatus for automatically sensing when the friction elements of a clutch are excessively worn and for generating a signal in response thereto is disclosed. The clutch includes a bearing housing which is adapted to be moved between engaged and disengaged positions. A shift assembly is provided for moving the bearing housing to the disengaged position. The shift assembly includes a pair of fingers which are normally spaced apart from the bearing housing when the clutch is engaged and the friction elements are not worn. However, when the friction elements become worn, the bearing housing engages the fingers of the shift assembly when the clutch is in the engaged position. A sensor is mounted in the bearing housing for generating a signal when the fingers are in contact therewith. The signal may be an electrical signal which is transmitted to a control circuit. The control circuit includes a timing and comparison circuit which activates an alarm device only when the signal from the sensor has been continuously generated for a predetermined period of time.

Brief description of the accompanying drawing
[0003] Figure 1 illustrates a schematic diagram of a method for detecting a degree of clutch wear of an automobile.

Detailed description of the embodiments
[0004] Figure 1 illustrates a schematic diagram illustrating a method for detecting a degree of clutch wear of an automobile. The method comprises detecting if a degree of clutch wear of the automobile is above a threshold level of clutch wear by an engine control unit. The method comprises determining an actual engine speed oscillation 10 based on an engagement of a specific vehicle gear and a specific vehicle speed by the engine control unit, and comparing the actual engine speed oscillation 10 with a actual engine speed oscillation 14 by the engine control unit, wherein the actual engine speed oscillation 14 is a theoretical engine speed oscillation that is based on the specific vehicle gear and the specific vehicle speed. The method further comprises determining if the actual engine speed oscillation 10 that is based on the engagement of the specific vehicle gear and the specific vehicle speed is greater than the theoretical engine speed oscillation that is based on the specific vehicle gear and the specific vehicle speed by the engine control unit, and transmitting an output alert signal 16 by the engine control unit if the actual engine speed oscillation 10 that is based on the engagement of the specific vehicle gear and the specific vehicle speed is greater than the theoretical engine speed oscillation that is based on the specific vehicle gear and the specific vehicle speed.

[0005] The method for detecting clutch wear of an automobile comprises determining if a level of clutch wear of the automobile is above a threshold level of clutch wear by an engine control unit. More specifically, in the exemplary embodiment, the method comprises determining an actual engine speed oscillation 10 based on an engagement of a specific vehicle gear and a specific vehicle speed by the engine control unit. The engine control unit determines the specific vehicle gear that is engaged by means of a signal that is received from a gear position sensor at a pre-determined engine operating point. In addition, the engine control unit determines the specific vehicle speed of the vehicle by a signal that is received from a vehicle speed sensor at the pre-determined engine operating point. Finally, the engine control unit determines an actual engine speed at the pre-determined engine operating point by means of an engine speed sensor.
[0006] The engine control unit now retrieves a two dimensional map from its memory unit. The two dimensional map comprises a theoretical vehicle speed along its x-axis and the corresponding theoretical engine speed oscillation along its y-axis for a specific gear position (e.g. first gear). Each two dimensional map corresponds to a different gear position. Each map for a given gear position contains the vehicle speed that is plotted along the x-axis and the engine speed oscillation that is plotted along the y-axis. A plurality of curves are plotted for different values of theoretical vehicle speed and theoretical engine speed oscillations, with each curve representing a different level of wear of the clutch. More specifically, for a specific gear position, (i.e. first gear) a plurality of curves are plotted with theoretical vehicle speed along its x-axis, and the corresponding theoretical engine speed oscillation along the y-axis, with each curve corresponding to a known level of wear of the clutch.

[0007] For a pre-determined gear position, for a pre-determined engine operating point, and for a pre-determined vehicle speed, the theoretical engine speed oscillation as determined is plotted on the graph containing the plurality of curves corresponding to different levels of wear of the clutch. Therefore, the coinciding point of the actual engine speed oscillation 10 for an actual gear position, for the actual engine operating point, and for the actual vehicle speed with the corresponding curve on the graph that is related to the pre-determined level of wear of the clutch is determined. The correlation of the actual engine speed oscillation 10 with the corresponding curve that is related to the actual level of wear of the clutch is used to determine the actual level of wear of the clutch of the automobile. If the actual level of wear of the clutch is greater than a predetermined threshold, an error signal is generated by the engine control unit.

[0008] A working of the method for detecting clutch wear of an automobile is described as an example. The method comprises detecting if a clutch wear of an automobile is above a threshold level of clutch wear by an engine control unit. More specifically, the method comprises determining an actual engine speed oscillation 10 based on an engagement of an actual vehicle gear and an actual specific vehicle speed by the engine control unit. The engine control unit now retrieves a two dimensional map from its memory unit comprising the theoretical vehicle speed along its x-axis and the corresponding theoretical engine speed oscillation along its y-axis for a specific gear position (e.g. first gear). A plurality of curves are plotted for different values of vehicle speeds and engine speed oscillations, with each curve representing a different level of mechanical wear of the clutch. Therefore, for an actual gear position, for an actual engine operating point, and for an actual vehicle speed, the engine speed oscillation as determined is plotted on the graph containing the plurality of curves corresponding to different levels of wear of the clutch. Therefore, the coinciding point of the actual engine speed oscillation 10 for an actual gear position, for the actual engine operating point, and for the actual vehicle speed with the corresponding curve that is related to the known degree of wear of the clutch is determined. The correlation of the actual engine speed oscillation 10 with the corresponding curve that is related to the known degree of wear of the clutch is used to determine the actual degree of wear of the clutch of the automobile. If the actual level of wear of the clutch of the automobile is greater than a threshold level of wear of the clutch, an error signal is generated by the engine control unit thereby notifying a user to replace the clutch.

[0009] It must be understood that the embodiments explained above are only illustrative and do not limit the scope of the disclosure. Many modifications in the embodiments with regard to dimensions of various components are envisaged and form a part of this invention. The scope of the invention is only limited by the scope of the claims.