1992-11-01

Clutch Engagement Simulation: Engagement with Throttle 922483

The present paper is a continuation of engineering efforts devoted mathematical modeling and computer simulation presented in [1]. The modeling and study is extended on starting a vehicle with use of a throttle. The basic mathematical model utilized in [1] has had to be modified because clutch engagement with throttle make investigators consider new human factors contributing strongly to starting conditions. In particular, not only the clutch release but also the accelerator pedal are controlled by a vehicle operator. This has made the authors modify the definition of an ideal engagement and incorporate both the throttle level and the throttle lead time to the mathematical model. Moreover, the model has been adjusted to consolidate dissimilar low range characteristics for diesel and gas engines.
Utilizing the loading rate of clutch facings as a controlled (command) parameter, the model and computer simulation program are used to determine, for various loading and starting conditions, the sliding velocity, torque transmitted through the clutch, instantaneous engine torque, and the rate at which energy is dissipated during engagement. Also, they are used to calculate lock-up parameters such as slip time, damper twist angle, vehicle speed and acceleration, and total energy dissipated during a single engagement.
The discussion of various simulation cases and results of extensive studies for various clutch parameters (such as the plate bad, facing materials, pressure, damper size, damper stiffness, number of plates, etc.), engine parameters (the minimum speed, slop angle of the low rate of characteristic, throttle level, throttle lead time, engine inertia, etc.), and truck parameters (the payload size, surface rolling conditions, gear ratios, etc.) are presented. Important extreme cases are examined to determine when the clutch lock-up cannot be accomplished or the engine cannot be killed.
As a result of this research program, design recommendations for clutch and truck manufacturers are formulated. They point out how, by the proper clutch engagement design, the engagement quality can be enhanced and life of engine and driveline components can be extended.

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