Keywords: combustion chamber, diesel engine, HCCI combustion, multi-pulse fuel injection, premixed combustion, lean diffusion combustion, homogeneous charge compression ignition, injection strategy control
A diesel compound HCCI combustion engine based on injection strategy control
This paper presents a compound combustion technology of 'Premixed Combustion' and 'Lean Diffusion Combustion' for the purpose of realising the concept of homogeneous charge compression ignition (HCCI) combustion in a DI 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 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. The combustion of fuel in the main injection occurs at a much higher equivalence air/fuel ratio than does in a conventional diesel engine, which is called lean diffusion combustion.