| 摘要 |
A diesel engine (E) has a combustion chamber (C), a piston (T) movable in th e chamber, air intake and exhaust valves (IV, EV), and a nozzle (N) injecting fuel into the combustion chamber. By controlling hydraulic flow characteristics of an air-fuel mixture particulate matter (PM) produced by combustion of the air-fuel mixture in the chamber is reduced to a level whic h meets the Tier 2 requirements established by the Environmental Protection Agency (EPA) for the engine. This is further accomplished by increasing the injection pressure of the fuel injected into the chamber, changing the size and/or shape of the injector nozzle to increase a ratio of the air to fuel while fuel is injected into the chamber through the nozzle, increasing the compression ratio within the combustion chamber, lowering the manifold air temperature (MAT), and retarding the start of injection (SOI) within the chamber. Besides reducing particulate matter to within the Tier 2 limits, th e NOx produced by the engine is also maintained within the Tier 2 requirements , and the engine's fuel consumption is reduced.
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