Search Results

Diesel-fueled HCCI combustion was achieved by multi-pulse injection before top dead center (TDC). However, the multi-pulse injections strategies have not been sufficiently studied previously due to the large number of parameters to be considered. In the present work, a series of multi-pulse injection modes with four or five pulses in each mode are designed, and their effects on diesel HCCI Combustion are experimentally studied. The results showed that the HCCI diesel combustion was extremely sensitive to injection mode. There were many modes to achieve very low NOx and smoke emissions, but the injection parameters of these modes must be optimized for higher thermal efficiency. A micro-genetic algorithm coupled with a modified 3D engine simulation code is utilized to optimize the injection parameters including the injection pressure, start-of-first-injection timing (SOI), fuel mass in each pulse injection and dwell time between consecutive pulse injections.

This paper presents a compound combustion technology of Premixed Combustion and “Lean Diffusion Combustion” for realizing the concept of HCCI combustion in a D I diesel engine. The premixed combustion is achieved by the technology of multi-pulse fuel injection. The start of pulse injection, injection-pulse number, injection period of each pulse and the dwell time between the injection pulses are controlled. The objective of controlling the pulse injection is to limit the spray penetration of the pulse injection so that the fuel will not impinge on the cylinder liner, and to enhance the mixing rate of each fuel parcel by promoting the disturbance to the fuel parcels. The last or main injection pulse is set around TDC. A flash mixing technology is developed from the development of a so-called BUMP combustion chamber, which is designed with some special bump rings.