METHOD FOR DETERMINING A STATE OF A TORSIONAL VIBRATION DAMPER OF A VEHICLE

Abstract

A failure state of a torsional vibration damper is analyzed by means of an acoustic sensor. The acoustic sensor may be present in the vehicle for other reasons, such as a knock sensor of a gasoline engine or an injection sensor of a diesel engine. Fault images of the torsional vibration damper are determined for specified operating points of the vehicle during vehicle operation. The fault monitoring can be carried out easily while the vehicle is being driven and replaces a visual check in the workshop.

Claims

1. A method for determining the state of a torsional vibration damper of a vehicle, with which a state is detected by detecting structure-borne sound waves, wherein the structure-borne sound waves are analyzed according to the operating point using an image of the structure-borne sound that is acquired while the vehicle is being driven.

2. The method of claim 1, wherein for determining the state of the torsional vibration damper the image of the structure-borne sound of a sensor positioned at a distance from the torsional vibration damper is analyzed.

3. The method of claim 2, wherein the image of the structure-borne sound of an acoustic sensor that is present in the vehicle is analyzed.

4. The method of claim 3, wherein a knock sensor that is disposed on a gasoline engine is used as a sensor that is present in the vehicle.

5. The method of claim 3, wherein an injection amount determining sensor of a diesel engine is used as a sensor that is present in the vehicle.

6. The method of claim 1, wherein a method of analyzing the image of the structure-borne sound is determined depending on the operating point of the vehicle.

7. The method of claim 6, wherein as the analysis method an amplitude of a sensor signal of the sensor is analyzed at a specified frequency.

8. The method of claim 6, wherein a frequency modulation analysis or a sideband analysis is used as the analysis method.

9. The method of claim 1, wherein a wear state of the torsional vibration damper is concluded if a parameter to be analyzed exceeds a parameter threshold value.

10. The method of claim 1, wherein an analysis method for determining the state of the torsional vibration damper is integrated within an existing engine sensing arrangement analysis method.

11. A method for determining the state of a torsional vibration damper of a vehicle, the method comprising: using a sensor to detect knock of a gasoline powered engine; while the vehicle is being driven at a predetermined operating point, detecting structure-borne sound waves using the sensor; analyzing an image of the structure-borne sound to diagnose a failure state of the torsional vibration damper.

12. The method of claim 11, wherein analyzing an image of the structure born sound comprises analyzing an amplitude of a sensor signal at a specified frequency.

13. The method of claim 11, wherein analyzing an image of the structure born sound comprises performing a frequency modulation analysis.

14. The method of claim 11, wherein analyzing an image of the structure born sound comprises performing a sideband analysis.

15. The method of claim 11, wherein the failure state of the torsional vibration damper is a torn rubber.

16. The method of claim 11, wherein the failure state of the torsional vibration damper is a missing roller.

17. The method of claim 11, wherein the failure state of the torsional vibration damper is a jamming material.

18. A method for determining the state of a torsional vibration damper of a vehicle, the method comprising: using a sensor to an injection amount of a diesel engine; while the vehicle is being driven at a predetermined operating point, detecting structure-borne sound waves using the sensor; analyzing an image of the structure-borne sound to diagnose a failure state of the torsional vibration damper.

19. The method of claim 11, wherein the failure state of the torsional vibration damper is a torn rubber.

20. The method of claim 11, wherein the failure state of the torsional vibration damper is a missing roller.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The disclosure enables numerous embodiments. One of these will be described in detail using the figures represented in the drawing.

[0019] In the figures:

[0020] FIG. 1 shows a first exemplary embodiment of the method,

[0021] FIG. 2 shows a second exemplary embodiment of the method.

DETAILED DESCRIPTION

[0022] In FIG. 1 a first exemplary embodiment of the method is represented, with which inadequate functionality of a torsional vibration damper is detected using acoustic detection of structure-borne sound. During this, an acoustic image of the structure-borne sound that is output by the structure-borne sound sensor that is attached to the engine is analyzed, with which an acoustic amplitude is represented by means of a number of different measurements. For an amplitude of 0.2 a standard deviation of the acoustic amplitude is indicated as the threshold value S. The measurement results that lie below said standard deviation indicate that the measured component is in order. The components with acoustic amplitudes exceeding said threshold value S, which forms the standard deviation, stand out from the tolerance-related focus. Thus, a measurement point A at about 0.46 of the acoustic amplitude has been determined, whereas a second measurement point B at 0.82 of the acoustic amplitude has been detected. The measurement result A is a torn rubber in the path of the torsional vibration damper, whereas the measurement result B indicates that a roller is missing in the torsional vibration damper.

[0023] Such an analysis is possible because certain defects of the torsional vibration damper occur at different operating points of the vehicle. Thus, while the vehicle is travelling corresponding faults can be identified from the image of the structure-borne sound from the knock sensor. An analysis can in particular identify whether a stop buffer or a rubber of the torsional vibration damper is defective at low engine revolution rates, advantageously when idling. The rubbers can have become brittle or can have completely failed here. In the case of the partially loaded vehicle, for example when starting, where a rise in the revolution rate occurs, it can be particularly simply detected from the image of the structure-borne sound whether a roller of the torsional vibration damper is missing. A jamming material, as represented in FIG. 1, can be particularly advantageously determined when the vehicle is under full load.

[0024] The corresponding analysis method is also selected depending on the operating point of the vehicle. Thus for example, as already described the amplitude can be analyzed for defined frequencies. At other operating points, analysis methods such as frequency modulation, the envelope of the frequency or a sideband analysis are to be used. The analysis methods are not limited only to the method mentioned in this section in this case.

[0025] In FIG. 2, an analysis method is illustrated, with which an output signal of the structure-borne sound sensor is represented against time. The graph IO shows only slight fluctuations in this case, for which reason proper operation of the component is concluded. The graph NIO shows a defective component because of a missing stop element, in particular because level peaks occur with a certain periodicity. Said level peaks represent a large rotary oscillation amplitude and are caused by a defective torsional vibration damper.

[0026] With the present solution, a wear state of a torsional vibration damper can be analyzed by means of an acoustic sensor. During this, fault images of the torsional vibration damper are determined for specified operating points of the vehicle, wherein at least one specified analysis method is used for each fault recognition. The fault monitoring can be carried out easily while the vehicle is being driven and replaces a visual check in the workshop. Thus, this results in very rapid and inexpensive identification of any signs of wear in the torsional vibration damper.