| Summary: | Blending diesel with biofuels such as ethanol and PME leads to better fuel properties in producing a better engine performance and lower emission. However, the presence of ethanol that contains low cetane number and low heating value reduces the fuel combustibility. Injection system, compression ratio and air intake modification delivering good results of improving blends combustibility. The objective of this paper is to study the effect of injection parameter, compression ratio (CR) and air intake temperature (Ti) modification on blends combustibility from the combustion characteristics. Diesel-ethanol-PME blends in a diesel engine with the least engine modification also are identified. Simulation work was conducted using Converge CFD software based on single cylinder direct injection compression ignition Yanmar TF90 engine parameter. Diesel-ethanol-PME blends of 10% ethanol with 40% PME (E25B25), E25B25 and E40B10 were used and conducted on different injection parameter, compression ratio and intake temperature, T-i. This study was carried out by running the simulation at high engine speeds. Results show that advancing time, shortened the injection duration has a very small effect on ignition. For the blends with ignition problem such as E40B10, increasing compression ratio and ambient temperature helps the fuel to ignite due to high temperature and pressure in the cylinder. This modification allowed the blends to ignite at high engine speed with minimum CR of 20 and T-i of 350 K. In conclusion, blending high ethanol contents in diesel engine can be applied by advancing the injection, increasing the compression ratio and increasing the ambient temperature. The most suitable blends that can be operated in the engine without modification is E25B25.
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