International Journal of Applied Engineering Research ISSN 0973-4562 Volume 3, Number 2 (2008), pp. 229–240 © Research India Publications http://www.ripublication.com/ijaer.htm Study of Fuel Injection Pressure Effect on Performance and Fuel Consumption of Diesel Engine Based on Load and Engine Speed Semin 1 and Rosli Abu Bakar 2 1 Marine Engineering Department, Institute of Technology, Sepuluh Nopember Surabaya, Indonesia 2 Faculty of Mechanical Engineering, University Malaysia, Pahang, 25000 Kuantan, Malaysia Abstract Diesel engines fuel injection pressure is most important aspect. The diesel engine selected in this study such as fuel direct injection is generated from the unit pump system. Effect of fuel injection pressure on engine performance is investigated and analyzed in the study. Experiments are performed on a four- cylinder two-stroke, direct injection diesel engine. The diesel engine power performance values such as indicated pressure, indicated horse power, shaft horse power, brake horse power, break mean effective pressure and fuel consumption investigated both of variation engine speeds - fixed load and fixed engine speed – variation loads by the fuel injection pressure variation. Based on the experiment results, the best performance of the pressure injection is obtained. The experiment results shown, that the increasing injection pressures have been given increased of engine power and fuel consumption of the diesel engine. Keywords: Diesel engine, engine performance, fuel consumption, fuel injection pressure Introduction There are several factors that the engine designer varies to provide high performance and fuel consumption economically. Some of these factors is researched based on the shape of the combustion chamber, the location and angle of the fuel nozzle, the injection rate and nozzle spray pattern, injection timing, and camshaft timing [15]. This has also had a positive effect on economy and performance. Fuel injection systems are designed to obtain lower and higher injection pressure than current used.