Clutch Surface Temperature Measurements in a Controlled-Coupling Automatic Transmission

Clutch plate surface temperatures were measured with estimated accuracy of ± 10 F in a controlled-coupling automatic transmission. Power input to the transmission was from a 394 cu in. displacement engine, and power output was absorbed by a flywheel and dynamometer. Surface temperature as a function of time was obtained by incorporating a thermocouple into the surface of one of the steel clutch plates in the transmission.

Operating parameters studied with respect to their effect on clutch surface temperature were dynamometer load, engine throttle setting, and transmission sump temperature. Dynamometer load had little effect on maximum clutch surface temperatures during clutch engagement for all transmission sump temperatures investigated. On the other hand, maximum clutch surface temperatures were found to increase with increasing throttle opening. Results agree with calculations of energy dissipated by the clutch during clutch engagement.