Patent ID: 8100802
Filing Date: 2012-01-24
Classification: F16H,Y10T

Abstract:
1. A method of controlling a lockup clutch of a hydrodynamic torque converter having a speed ratio and being operable for transmitting torque between an engine and a transmission, the transmission having a first gear and at least one higher gear, the method comprising each of: fully releasing the clutch without controlling a slippage level of the clutch when the speed ratio is below a threshold speed ratio and the transmission is in the first gear; partially engaging the clutch when the speed ratio rises above the threshold speed ratio without controlling said slippage level while still operating in said first gear; fully engaging the clutch and controlling said slippage level across the clutch when the transmission exits said first gear and is operating in a steady-state within said at least one higher gear; and fully engaging the clutch without controlling said slippage level when the transmission is executing a power-on upshift from said at least one higher gear; wherein said partially engaging the clutch includes supplying pressurized fluid to the clutch at a predetermined pressure that is substantially less than a maximum available clutch pressure.