Patent ID: 7346442

Claim:
A lockup control device of a lockup clutch of a torque converter for a vehicle, the torque converter comprising a pump impeller connected to an engine and a turbine runner connected to an automatic transmission, and transmitting a torque therebetween via a fluid and via the lockup clutch according to an engaging force of the lockup clutch, the device comprising: a mechanism which adjusts the engaging force; and a programmable controller programmed to: perform feedforward control of the mechanism; calculate a target engine rotation speed based on a running state of the engine; compute a reference value related to a rotation speed of the engine based on a capacity characteristics of the torque converter; perform, when the rotation speed of the engine falls to less than the reference value during feedforward control, a change-over from feedforward control of the mechanism to feedback control of the mechanism in which a deviation of the rotation speed of the engine from the target engine rotation speed is reduced; and perform, when a predetermined condition is satisfied, even if the rotation speed of the engine has not fallen to less than the reference value, perform a change-over from feedforward control of the mechanism to feedback control of the mechanism.