EVAPORATIVE EMISSION SYSTEM FOR LOW ENGINE INTAKE SYSTEM VACUUMS

摘要

An evaporative emission control system (10) for a fuel system of an internal combustion engine (12) of an automotive vehicle has a purge flow path through which an evaporative emission containment space of the fuel system for containing volatile fuel vapors is purged to an intake system (12i) of the engine. A purge valve (18) controls purge flow through the purge flow path. When the intensity of intake system vacuum falls below a threshold, an electric-motor-driven blower (24) operates to create a pressure rise in the purge flow path upstream of the purge valve (18) and downstream of the containment space. A differential pressure sensor (26) senses pressure differential across the purge valve (18), and the purge valve (18) includes an integral valve position sensor (18s), both sensors providing feedback signals to a controller (32) that controls operation of both the purge valve (18) and the blower (24).