Turbocharged engine canister system and diagnostic method

摘要

An evaporative emission control system for a turbocharged engine. The system includes a fuel vapor canister in fluid communication with an intake manifold of the engine, a purge valve positioned between the intake manifold and the canister, a bypass valve positioned between the purge valve and the canister and connected to the atmosphere, and an evaporative system integrity monitor operable to seal the canister from the atmosphere when the engine is off. In operation, the monitor is closed so as to seal the canister from the atmosphere, the purge valve is closed so as to isolate the intake manifold from the canister, and the bypass valve is opened so as to connect the canister to the atmosphere. Proper operation of the monitor is determined if the monitor toggles from closed to open when a vacuum in the fuel vapor canister reaches a predetermined level.

主权项

1. An evaporative emission control system for a turbocharged engine comprising:
a fuel vapor canister in fluid communication with an intake manifold of the turbocharged engine; a purge valve positioned between the intake manifold and the fuel vapor canister; a bypass valve positioned between the purge valve and the fuel vapor canister and connected to the atmosphere; an evaporative system integrity monitor operable to seal the canister from the atmosphere; and a vacuum ejector tee fluidly coupled between the intake manifold and the purge valve, the vacuum ejector tee having:
a first port in fluid communication with the fuel vapor canister;a second port in fluid communication with an output of a turbocharger between the turbocharger and the intake manifold; anda third port in fluid communication with an input to the turbocharger.