The research work started from the fundamental aspects of fuel spray combustion which were approached both theoretically and experimentally. An extended survey of existing automotive fuel injection technologies was also conducted and the results were organised using a specifically developed evaluation scheme. Based on the results of this ranking procedure, the three most promising fuel injection concepts were selected for further evaluation on research and production DI Diesel engines.
The results clearly showed the advantages of the high pressure common rail fuel injection systems which, thanks to their flexibility in controlling the individual injection pressure, timing and schedule, resulted in a very good control of engine-out emissions with simultaneous reduction of combustion noise and improvements in engine performance. The attributes of the variable geometry nozzle concept were also evaluated positively during this study and a proposal for combining this feature with common rail injection systems emerged.
The main objective of this research is to improve the Direct Injection Diesel combustion characteristics by developing novel Fuel Injection Systems (F.I.S.) which will allow NOx and particulate emissions to be significantly reduced at their source. The research will :
a. Define the optimal specifications of the F.I.S. in the whole range of engine operating conditions.
b. Develop design methodologies for high pressure electronically-controlled F.I.S.s suitable for achieving the required injection specifications.
c. Make available F.I.S. prototypes for validation of the developed methodologies.
These objectives will be achieved through the following main research phases :
- Selection of a number of F.I.S.s, based on various technologies, assisted by matematical modelling and experimental analysis
- Installation and refinement of three systems on engines and experimental study of the effect of the injection characteristics on the combustion process, engine performance, fuel consumption, noise and emissions.
- Analysis, on transparent engine, of the selected systems in order to improve understanding of the interrelation between spray and combustion.
- Assessment of the maximum benefits actually with the developed systems.
The immediate outcome of this programme will be the basic technology of future F.I.S.s which will enable the DI Diesel engine to comply with future emission standards, keeping their typical high fuel efficiency, leading to a reduction of fuel consumption in passenger cars in the Community and improved environmental protection.
Funding SchemeCSC - Cost-sharing contracts