Toyota Jidosha Kabushiki Kaisha

Hideo Masaki

Toshio Sugimura

Tatsuya Kawamura

An ECU executes a program that includes a step of determining whether an output shaft rotation speed NOUT is equal to or greater than a reference rotation speed at which determining regions with all of the gear speeds in a stepped automatic transmission do not overlap, a step of determining that there is an abnormality in the gear speed by dividing the turbine rotation speed NT by the output shaft rotation speed NOUT if the output shaft rotation speed NOUT is not equal to or greater than that reference rotation speed, and a step of determining that there is an abnormality in the gear speed by subtracting a value, which is obtained by multiplying the output shaft rotation speed NOUT by the gear ratio, from the turbine rotation speed NT if the output shaft rotation speed NOUT is equal to or greater than that reference rotation speed.

Abnormality determining apparatus and method for automatic transmission

An ECU executes a program that includes the steps of setting an abnormality flag when a hydraulic pressure switch is on even though a lock-up clutch is in a lock-up OFF state, forcing an SLU off when the lock-up clutch is on and the abnormality flag is on, determining that there is an SLU failure when the lock-up clutch is still in a lock-up ON state after a predetermined period of time has passed, and determining that there is a hydraulic pressure switch failure when the lock-up clutch is not in the lock-up ON state after the predetermined period of time has passed.

Growing community of inventors

Toyota, Japan

Hideo Masaki