Patent ID: 6579207
Filing Date: 2003-06-17
Classification: F16H,Y10T

Abstract:
A hydraulic pressure control method of an automatic transmission provided with a hydraulic pump and a plurality of friction engagement elements that are engaged by the supply of a hydraulic pressure, comprising the operations of:detecting a supply state of the hydraulic pressure; estimating, based on said detected supply state of the hydraulic pressure, whether or not the hydraulic pressure for the friction engagement elements in the engagement state becomes deficient, when the hydraulic pressure is supplied to the friction engagement elements in the release state in order to discharge air from a hydraulic path; supplying the hydraulic pressure to the friction engagement elements in the release state to discharge the air from the hydraulic path, provided that it is estimated that the hydraulic pressure for the friction engagement elements that are in the engagement state does not become deficient; and suspending the supply of the hydraulic pressure for discharging the air when it is estimated that the hydraulic pressure for the friction engagement elements in the engagement state becomes deficient.