| 摘要 |
<p>A system and method for exhaust gas recirculation (EGR) in a heavy-duty diesel engine (10) is disclosed. The disclosed EGR system (12) comprises an EGR conduit (50), an EGR valve (52a, 52b), an EGR cooler (54), and an EGR driver (56) such as an auxiliary compressor (56) driven by the exhaust gas driven turbine (46) of the engine (10) to forcibly drive the recirculated exhaust gas from the exhaust manifold (42a, 42b) via an EGR conduit (50) to the intake manifold (22) when the EGR valve (52a, 52b) is open. The disclosed EGR system (12) also includes a bypass conduit (60), the flow through which is governed by an electronically controlled bypass valve (62). The EGR system (12) also includes an ECM that controls the bypass valve (62) such that a flow of exhaust gas is directed through the EGR conduit (50) and EGR driver (56) during selected engine operating conditions where the primary EGR valve (52a, 52b) is open (i.e. EGR is on) and directs a flow of intake air from the intake system (24) through the bypass conduit (60) and EGR driver (56) when EGR valve (52a, 52b) is closed (i.e. EGR is off).</p> |
