Particulate filter regeneration during engine shutdown

摘要

Various systems and method are described for controlling an engine having an exhaust system which includes a particulate filter. One example method comprises, after shutting down the engine and spinning down the engine to rest, operating a vacuum pump to draw fresh air through the exhaust system to an intake system, and regenerating at least a portion of the particulate filter during the engine rest.

主权项

1. A method for controlling a vehicle engine having an exhaust system which includes a particulate filter, comprising:
during vehicle motion:
shutting down the engine and spinning down the engine to rest; andduring engine rest after the engine is spun down,
if vehicle speed is greater than a threshold speed, closing an EGR valve arranged in an EGR passage coupled to the exhaust system upstream of a catalyst, opening a ram air valve arranged in a scoop inlet coupled in the exhaust system downstream of the catalyst and upstream of a particulate filter, the scoop inlet opening toward a vehicle front end, and drawing a ram air flow, via the scoop inlet, into the exhaust system and through the particulate filter to assist in regeneration of the particulate filter; andif vehicle speed is not greater than the threshold speed, opening the EGR valve.