Patent ID: 7578128

Claim:
An air bypass valve failure detection device in a supercharging device of an engine, the supercharging device comprising: a first intake passage, a supercharger, a second intake passage, a throttle valve, and a third intake passage which are sequentially arranged from an upstream side to a downstream side in a flowing direction of an intake air flowing to a cylinder of the engine; a bypass passage bypassing the supercharger and connecting the first and second intake passages to each other; an air bypass valve provided in the bypass passage; the supercharging device outputting an opening command to the air bypass valve when a rate of change in a throttle valve opening degree is equal to or larger than a predetermined value in a throttle valve closing direction; the air bypass valve failure detection device comprising: failure detection permitting means for permitting failure detection for the air bypass valve when a command to the air bypass valve is an opening command and an intake air quantity of the engine immediately before the command is changed from a closing command to the opening command is equal to or larger than a predetermined value; surging determining means for determining whether surging has occurred in the second intake passage when the failure detection permitting means permits the failure detection for the air bypass valve; and failure determining means for determining that valve closing failure of the air bypass valve has occurred when the surging determining means determines that surging has occurred, and determining that the air bypass valve is normal when the surging determining means determines that surging has not occurred.