Abstract: A diesel engine (E) has a combustion chamber (C), a piston (T) movable in the chamber, air intake and exhaust valves (IV, EV), and a nozzle (N) injecting fuel into the combustion chamber. By controlling characteristics of an air-fuel mixture, emissions produced by combustion of the air-fuel mixture in the chamber are reduced to levels which satisfy the Tier 2 requirements established by the Environmental Protection Agency (EPA) for the engine. This may include controlling hydraulic flow characteristics through the nozzle, increasing the compression ratio within the combustion chamber, lowering the manifold air temperature (MAT), and retarding the start of fuel injection (SOI) within the chamber.

Abstract: A diesel engine (E) has a combustion chamber (C), a piston (T) movable in the 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 which 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 air and 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 ignition injection (SOI) within the chamber.