Driver circuit for fuel vapor leak detection system

摘要

An on-board evaporative emission leak detection system has a module (22) for detecting leakage from an evaporative emission space of a fuel system of an automotive vehicle. Interior space (103) of the module's enclosure (102) is communicated to atmosphere. A pump (50) is disposed within space (103) and has an inlet (56) communicated to the interior space and a flow passage (70, 72) at its outlet (58) to allow the pump to create pressure in the evaporative emission space suitable for performance of a leak test. A vent valve (52) is disposed within space (103) and is selectively operable to vent and not vent the flow passage to space (103). An electromagnet actuator (104) has a single electric coil (116) that operates both the pump and the vent valve. A driver circuit (1000) to the coil provides a first current component for operating the pump and a second current component for operating the vent valve.