| abstract |
An engine system comprises an engine 110, a turbocharger 320, 330, a fluid control valve 270, and an aftertreatment component 130 such as a lean NOx catalyst. The engine has a first set of dedicated cylinders 210 fluidly coupled to an intake manifold to form an exhaust gas recirculation system (EGR) and a second set of cylinders 300, 310, 315 which are fluidly isolated from the intake manifold of the engine. The fluid control valve is disposed between the first exhaust outlet and the exhaust conduit and is structured to selectively fluidly couple the first exhaust outlet to the exhaust conduit. Also, the lean NOx catalyst has an inlet structured to receive exhaust gases from the exhaust conduit at a position downstream of the turbine outlet and the fluid control valve. The systems and methods disclosed enable complete and stable combustion at higher air-fuel ratios, which can improve the efficiency of engines by enabling lean operation. |