초록 ▼

The present invention is a dual-stage fuel injection strategy for compression ignition engines in which 15-40% of the fuel is injected into the combustion chamber no later than about −20 to −30 CA ATDC and as early as IVC. The remaining fuel is then injected in one or more fuel pulses, none of which

The present invention is a dual-stage fuel injection strategy for compression ignition engines in which 15-40% of the fuel is injected into the combustion chamber no later than about −20 to −30 CA ATDC and as early as IVC. The remaining fuel is then injected in one or more fuel pulses, none of which start before about −20 to −30 CA ATDC. The fuel injected early in the compression stroke forms a lean mixture that burns with low soot and low NOx emissions. The combustion of that fuel serves to increase in-cylinder temperature such that the ignition delay of subsequent fuel injection pulses is short. This mode is utilized when it is predicted that a NOx spike is imminent. Various other alternative methods for reducing NOx spikes are also disclosed such as specialized EGR systems that can provide EGR with low manifold vacuum.

대표청구항 ▼

We claim: 1. A system for an engine having an intake manifold coupled to an intake conduit and an exhaust manifold coupled to an exhaust conduit, the system comprising:, the engine having a compression device coupled with a first portion to the engine, and comprising a compressor coupled to into to

We claim: 1. A system for an engine having an intake manifold coupled to an intake conduit and an exhaust manifold coupled to an exhaust conduit, the system comprising:, the engine having a compression device coupled with a first portion to the engine, and comprising a compressor coupled to into to the intake conduit and a second portion turbine coupled to the exhaust manifold of the engine, the system comprising: into the exhaust conduit and configured to drive the compressor;a combustion chamber communicating with the intake manifold and with the exhaust manifold;a soot filter coupled into the exhaust conduit downstream of the turbine;a fuel injector configured to inject a first pulse of fuel into the combustion chamber during a compression stroke and a second pulse of fuel during an expansion stroke, the compression stroke and the expansion stroke occurring during a first operating condition and in one engine cycle;a first exhaust gas exhaust-gas recirculation system having a first end coupled to the exhaust manifold upstream of the second portion of the compression device turbine and a second end coupled to the intake manifold downstream of the first portion compression device compressor, said first the first exhaust-gas recirculation system also having a first valve that, which adjusts a first flow amount from the exhaust manifold to the intake manifold; anda second exhaust gas exhaust-gas recirculation system having a first end coupled downstream of the second portion of the compression device turbine and the soot filter and a second end coupled to the intake manifold, said first the second exhaust-gas recirculation system also having a second valve that, which adjusts a second flow amount from the exhaust conduit to the intake manifold.