Patent ID: 7322903
Filing Date: 2008-01-29
Classification: B60K,B60L,B60W,F16D,Y02T,Y10T

Abstract:
1. A method for controlling rate of flow of cooling oil for a pressure-actuated friction clutch in a torque delivery path for a transmission in a powertrain for an engine-driven vehicle, the method comprising the steps of: measuring cooling oil temperature; measuring friction clutch slip speed; determining desired cooling oil temperature as a function of the slip speed for a given value of measured cooling oil temperature; converting the desired cooling oil temperature to a first cooling oil pressure; developing the clutch pressure; converting the clutch pressure to the clutch torque; multiplying clutch torque and clutch slip speed to obtain a clutch power loss; converting the clutch power loss to a second cooling oil pressure; combining the first and second cooling oil pressures to obtain a total cooling oil pressure; and converting the total cooling oil pressure to an electrical current for a cooling oil flow control valve whereby the cooling oil flow rate is increased when the cooling oil temperature is increased and is decreased when the cooling oil temperature is decreased.