Patent ID: 8177687

Claim:
A power transmission device provided with a transmission clutch interposed between an engine and a transmission, and control means for controlling connection and disconnection of the transmission clutch, the power transmission device comprising: first engine stall risk determination means for determining based on an engine operation state whether there is an engine stall risk when the transmission clutch is connected, wherein the control means disconnects the transmission clutch and controls the engine to a predetermined rotation speed for a predetermined time when the determination by the first engine stall risk determination means is affirmed, a fluid coupling provided with a lockup clutch interposed between the engine and the transmission clutch, and second engine stall risk determination means for determining based on an engine operation state whether there is an engine stall risk that is lower than the engine stall risk determined by the first engine stall risk determination means when the transmission clutch is connected and the lockup clutch is connected, wherein the control means disconnects the lockup clutch when the determination by the second engine stall risk determination means is affirmed.