Patent ID: 6832978
Filing Date: 2004-12-21
Classification: B60W,F16H,Y10T

Abstract:
A method of controlling torque transferred across each of the two clutches of a dual clutch transmission during a gear shift, wherein the first of the two clutches is an off-going clutch and the second of the two clutches is an on-coming clutch, said method includes the steps of:determining when a shift has been commanded; sensing the speed of a driven member of the off-going clutch; determining a desired clutch torque and slip profile for the changeover of the clutches; sensing the speed of a driven member of the on-coming clutch; determining a target engine speed profile based on the speed of the driven member of the off-going clutch, the clutch torque and slip profile, and the speed of the driven member of the on-coming clutch; simultaneously controlling the torque transfer across each clutch so that a torque output of the transmission will be changed over from the off-going clutch to the on-coming clutch by linearly decreasing the torque transferred across the off-going clutch while linearly increasing the torque transferred across the on-coming clutch in an inversely proportional rate to follow the clutch torque and slip profile and to cause the engine to track the target engine speed profile; and varying the pressure applied to the on-coming clutch, once the on-coming clutch is transferring all of the output torque, to cause the engine to continue to track the target engine speed profile so that vehicle speed is maintained.