Controller for an automatic transmission

摘要

In gear-shift control performed during normal travelling, a drive frequency of each solenoid valve is set to a higher one to suppress fluctuations or changes of a quantity or speed of a flow of a hydraulic oil concerned when the solenoid current is turned on/off to suppress fluctuations of the output hydraulic pressure. In start selection, the drive frequency of the solenoid valve is set to a lower one to reduce the number of times a plunger and a ball hit each other within the solenoid valve to reduce a sound produced by the operation of the solenoid.