Patent ID: 6730000
Filing Date: 2004-05-04
Classification: B60W,F16H,Y10T

Abstract:
A process for controlling an engine and a transmission of a vehicle, said process comprising the steps of:determining when each of an output speed of the vehicle is less than a first predetermined value and a throttle position of said vehicle is lesser than a second predetermined value and brake pressure applied to said vehicle is greater than a third predetermined value; turning on an auxiliary pump to a maximum level to fill a first clutch element whenever each of said output speed is less than said first predetermined value and said throttle position is less than said second predetermined value and said brake pressure is greater than said third predetermined value for a first predetermined time and starting a timer stopping said engine; regulating a calculated duty cycle to achieve a predetermined percentage of normal line pressure in the transmission in order to turn on said first clutch element for a second predetermined time to thereby clamp an input shaft to a transmission case of said transmission during engine shut down and to minimize shutdown torque disturbances; stop said engine when said timer has reached a third predetermined time; decreasing the output from said auxiliary pump until the auxiliary pump output is a first predetermined pressure and maintaining said first predetermined pressure pump output in order to keep two friction elements of a first gear of said transmission applied while retaining a torque capacity of approximately zero so that torque transients at engine restart are not applied to driving wheels of said vehicle; determining whether a stop mode is enabled when at least one of brake pressure is less than said predetermined value and throttle position is greater than said second predetermined value and output speed is greater than said first predetermined value; cancel an enabled stop mode when throttle pressure is less than a fourth predetermined value and set a transmission regulated line pressure at a second predetermined pressure which is a minimum level and calculate a duty cycle required for said second clutch element to maintain a third predetermined pressure and apply said duty cycle to said second clutch element; increase the pressure on said second clutch element from said third predetermined pressure to a value necessary to obtain normal idle torque of said vehicle during a fourth predetermined time in order to avoid excess torque surge during engine restart and maintain a quick torque response; and maintain idle torque until throttle position is greater than a sixth predetermined valve or until a fifth predetermined time has elapsed and subsequently increase the idle torque to 100% of a torque value.