| 摘要 |
A module for an on-board evaporative emission leak detection system that detects leakage from an evaporative emission space of a fuel system of an automotive vehicle. The module has a housing that includes a first port for communicating the housing to the evaporative emission space and a second port for communicating the housing to atmosphere. The housing contains a particulate filter through which the second port communicates with two parallel flow branches that extend within the housing to the first port. One branch contains a vacuum regulator valve, and the other, a solenoid-operated vent valve. During a leak detection test, the vent valve is operated closed, and a purge valve, that selectively communicates the evaporative emission space with the engine intake manifold, is operated open to cause vacuum to be drawn in the evaporative emission space. The vacuum regulator valve regulates evaporative emission space vacuum to a defined vacuum. Subsequently, the purge valve is operated closed. Leakage is evidenced by loss of vacuum, and a pressure sensor signals vacuum loss.
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