Patent ID: 6227037
Filing Date: 2001-05-08
Classification: F02M

Abstract:
A diagnostic apparatus for an evaporative emission control system, the diagnostic apparatus comprising:a first passage conveying evaporative fuel vapor from a fuel tank to a canister;a second passage extending between the canister and an intake passage section downstream of a throttle valve;a purge control valve opening and closing the second passage;a drain cut valve opening and closing an atmospheric port of the canister;a pressure sensor sensing a pressure in a fluid passage from the fuel tank to the purge control valve; anda controller holding the fluid passage from the fuel tank to the purge control valve in a state of a closed space by closing the purge control valve and the drain cut valve when an engine is out of operation, and performing a leak diagnosis by checking a pressure decrease due to condensation of the fuel vapor in the fluid passage held in the state of a closed space when the engine is started.