Control system for an automatic transmission having a neutral coast and idle feature

摘要

A control circuit for an automatic power transmission mechanism for use with an internal combustion engine in a vehicle driveline including fluid pressure operated clutches and brakes that are applied selectively to effect various ratio changes, a forward clutch being applied to effect a forward driving mode and being released to effect a neutral condition, and a clutch pressure regulator valve assembly for controlling distribution of actuating pressure to the forward clutch whereby the clutch pressure is regulated at a threshold value to effect minimum frictional engagement during coasting operation of the vehicle and during engine idling wherein provision is made for quickly increasing the pressure in the forward clutch to establish a maximum torque capacity when the coasting and idling mode is interrupted at the onset of driving torque delivery through the driveline thereby effecting a smooth transition from the coasting and idling condition to the driving mode.