Foley & Lardner LLP
Hydraulic switch malfunction assessment device
A hydraulic switch malfunction assessment device includes a solenoid valve disposed in a hydraulic circuit of an automatic transmission and having a characteristic such that a hydraulic pressure supplied to a frictional engagement element changes due to a change in an electric current supplied to the solenoid valve, and a hydraulic switch interposed between the solenoid valve and the frictional engagement element and configured to output an ON signal when the hydraulic pressure is higher than or equal to a threshold value and output an OFF signal when the hydraulic pressure is less than the threshold value. Also provided is a controller configured to control the supplied current to a prescribed current value or less when a predetermined running condition has been met, and then assess a malfunction of the hydraulic switch, based on a state of operation of the solenoid valve and the signal from the hydraulic switch.
JATCO LTD
F F F F
F16H F16H F16H F16H
inventional inventional additional additional
Takamitsu Youji
Shimazu Itou