DEVICE FOR ESTIMATING TURBINE SPEED OF TORQUE CONVERTER

摘要

PROBLEM TO BE SOLVED: To estimate a turbine rotational speed of a torque converter even if the turbine rotational speed changes depending on operation conditions of a forward/backward switching mechanism in an automatic transmission.

SOLUTION: A device for estimating a turbine speed of a torque converter 6 is provided, the torque converter interposed between an engine 2 and a forward/backward switching mechanism 44 of an automatic transmission 4. The device for estimating a turbine speed includes: a hydraulic pressure estimating means 12 for estimating the hydraulic pressure P of working oil when a wet multi-disc clutch device 52 is engaged or disengaged; an engagement torque estimating means 14 for estimating the engagement torque TCLTof the wet multi-disc clutch device 52 on the basis of the hydraulic pressure P of the working oil estimated by the hydraulic pressure estimating means 12; and a turbine rotational speed computing means 16 for calculating a turbine rotational speed Nt of the torque converter 6 on the basis of the engagement torque TCLTestimated by the engagement torque estimating means 14 and of the rotational speed Ne of the engine 2 detected by a crank angle sensor 20a.

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