Patent ID: 7925407
Filing Date: 2011-04-12
Classification: F16H,Y10T

Abstract:
1. An adjustment method for a vehicle automatic transmission that is provided with a hydraulic control circuit including linear solenoid valves which control supply pressures that are supplied to hydraulically-driven friction engagement elements; and a valve control unit that outputs drive currents to drive the linear solenoid valves, the adjustment method being used to calculate correction values that are applied to control command values used to adjust the drive currents so that correlations between the drive currents and effective pressures exhibit nominal characteristics, comprising: measuring valve characteristics of the linear solenoid valves when the linear solenoid valves are fitted to the hydraulic control circuit, and estimating linear valve characteristics of the linear solenoid valves in isolation state based on the measured valve characteristics using predetermined correlations; calculating estimated linear piston-end pressures of the hydraulically-driven friction engagement elements immediately before the hydraulically-driven friction engagement elements are engaged based on the estimated linear valve characteristics, and calculating the correction values that are applied to the control command values to adjust the drive currents supplied from the valve control unit to the linear solenoid valves based on differences between the estimated linear piston-end pressures and nominal piston-end pressures; and outputting the calculated correction values, wherein: