LOW PRESSURE EGR SYSTEM HAVING FULL RANGE CAPABILITY

摘要

An exhaust treatment system (102) for an engine (100) is disclosed and may have an air induction circuit (112), an exhaust circuit (114), and an exhaust recirculation circuit (116). The air induction circuit may be configured to direct air into the engine. The exhaust circuit may be configured to direct exhaust from the engine and include a turbine (128) driven by the exhaust, a particulate filter (134) disposed in series with and downstream of the turbine, and a catalytic device (136) disposed in series with and downstream of the particulate filter. The exhaust recirculation circuit may be configured to selectively redirect at least some of the exhaust from between the particulate filter and the catalytic device to the air induction circuit. The catalytic device is selected to create backpressure within the exhaust circuit sufficient to ensure that, under normal engine operating conditions above low idle, exhaust can flow into the air induction circuit without throttling of the air.