Patent ID: 6935162

Claim:
An apparatus for determining leakage in an evaporated fuel processing system, the evaporated fuel processing system extending from a fuel tank to a purge passage through which evaporated fuel from the fuel tank is purged to an intake manifold of an engine, the apparatus comprising: a system pressure sensor for detecting a pressure of the evaporated fuel processing system; an atmospheric pressure sensor for detecting an atmospheric pressure; a control unit connected to the system pressure sensor and the atmospheric pressure sensor, the control unit configured to; detect a stop of the engine; correct a determination value according to the atmospheric pressure; close the evaporated fuel processing system after the stop of the engine is detected; and determine whether the evaporated fuel processing system has leakage after the evaporated fuel processing system is closed based on the pressure detected by the system pressure sensor and the corrected determination value, wherein the correction for the determination value is made so that the determination value is made larger as the atmospheric pressure decreases.