Swirl combustion system for low smoke and particle emissions

In large diesel engines, mixing of fuel and air in the combustion chamber is usually generated by turbulence caused by the fuel jet. At low loads, with conventional fuel injection systems, the injection pressure is, however, low resulting in weak turbulence and large droplet sizes. This is considered a main reason for high smoke and particle emissions at low load in large diesel engines. A concept with increased horizontal swirl in the combustion chamber of a medium- speed diesel engine by modification of the intake air channel shape has been developed for solving problems mentioned above. Subsequently, proper modifications in combustion chamber shape and fuel injection spray pattern, for avoiding fuel jet - cylinder liner wall contact, has been performed utilising a CFD tool to optimise whole engine performance. A so called squish effect has been achieved with the new deep-bowl piston