Study on the Effect of Clutch Hydraulic System Hysteresis on Intermittent Clutch Pedal Stuck Concern

The clutch pedal in manual transmission plays a significant role in defining the comfort of driver as it is a direct customer interfaces in the vehicle. Clutch & its hydraulic release system in manual transmission are the significant components which affects the maneuverability of the vehicle and the driver comfort.The clutch pedal characteristics optimization is one of the vital parameters are involving various parameters like pedal effort, pedal travel, hump, engagement and disengagement travel, modulation travel & pedal return curve min load. Normally the clutch pedal characteristics has a hysteresis between the forward and return curve (depress and release of the clutch pedal). The hysteresis is the component of mechanical friction like clutch pedal, clutch cover, and hydraulic seal friction. For an optimum clutch pedal feel, free play, peak effort, max. travel, hump and return load are the major functional parameters.This paper focus on study of the clutch pedal stuck intermittently while releasing the clutch pedal after gear shift close to the free play zone. The Clutch pedal return curve profile plays a major role for smooth pedal returnability. In this case the return curve load at 20 mm of pedal travel was lesser which eventually leading to clutch pedal stuck. CMC seal Friction plays a vital role for clutch pedal to return its home position while engaging the clutch which is controlled by optimum hysteresis in the system. The optimum hysteresis can be maintained by fine tuning the friction of clutch master cylinder seal contact profile, which having relative motion with clutch master cylinder piston while engage and disengage the clutch. The design simulation and experimental DOE is done with different seal lip profile to evaluate the friction variation and its impact on the overall hysteresis in the clutch pedal characteristics.


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Filing Info

  • Accession Number: 01879832
  • Record Type: Publication
  • Source Agency: SAE International
  • Report/Paper Numbers: 2023-01-0462
  • Files: TRIS, SAE
  • Created Date: Apr 19 2023 4:34PM