Patent attributes
An automatic transmission controller has an electronic control circuit, an electromagnetic valve, and a pressure control valve. The electronic control circuit generates a control current. The electromagnetic valve regulates a command pressure in accordance with the control current. The pressure control valve has a spool and is formed with a spool hole. The spool reciprocates in the spool hole in accordance with the command pressure to regulate a pressure supplied to a friction element of an automatic transmission. In a standby state, when the friction element is in a disengaged state, the electronic control circuit generates an oscillating current as the control current so that the electromagnetic valve generates a standby command pressure that makes the spool reciprocate in a range in which no pressure is supplied to the friction element.
