A single cylinder diesel engine upgraded to operate Common Rail Direct Injection (CRDI) system and employed in this investigation. Tests were conducted on this engine using High-Speed diesel (HSD) and Simarouba biodiesel (SOME) blends to determine the influence of Injection Pressure (IP) and Injection Timing (IT) on the performance and emissions. Four unique IP of 400 bar to 1000 bar, in steps of 200 bar and four differing ITs of 10°, 13°, 15° and 18° before Top Dead Center (bTDC) combinations were attempted for the 25% to full load. Compression Ratio (CR) of 16.5 and Engine speed of 1500 RPM was kept constant during all trails. Critical performance parameter like Brake Thermal Efficiency (BTE) and Brake Specific Fuel Consumption (BSFC) were analyzed, primary emission parameters of the diesel engine The NOx and Smoke opacity were recorded. Finally, the outcomes of each combination were discussed.

Petroleum products with the current consumption rate will be depleting in upcoming decades. Ethanol usage in the transport sector can fulfill the requirement and contribute to mitigate the greenhouse gas emissions of the vehicles. Hence it is better to develop the engine which can work on pure ethanol or add ethanol in the petrol and use the blends of that. This paper aim was to study the effect of ethanol/and blends on Spark Ignition (SI) engine behavior. The experiments were carried out on the 4-stroke spark ignition engine with pure petrol, pure ethanol and 10%, 20%, 40%, 60%, 80% ethanol-gasoline blend. The experiments were carried out at a constant speed of 3000 rpm for various loads of 25%, 50%, 75% and full load and emissions were analyzed. This study concludes that ethanol blending is lowering exhaust emissions with considerable improvement in the performance of the SI engine under part load and full load operations and also promising as a future fuel which can successfully replace petrol and its depletion problem.

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Diesel engines are the primary source of power for heavy duty vehicles; diesel engines have better fuel economy than equivalent gasoline engines and produce less green house gas emission. On the other hand, formation of smoke due to diffusion combustion and emission of oxides of nitrogen released due to high combustion temperatures are the major limitations of the existing diesel engine designs. Diesel engine manufacturers have to address these most critical situations to meet the future emissions regulations whilst improving performance and fuel economy at a minimal cost. The fuel economy, increased dynamic response and strict exhaust emission regulations resulted in invention of new technology development required improving the diesel engine performance along with exhaust emissions reduction. These improvements are made possible with new fueling technologies by improvements in combustion process through increased injection pressure. High pressure fuel injection results in better fuel atomisation and improves the fuel/air mixing to promote complete combustion, thereby increasing the fuel efficiency with emission control. The objective of this paper is to investigate the effect of fuel injection pressure on performance, fuel consumption and emission of a diesel engine. A study was done on a single cylinder 4 stroke direct injection diesel engine and the performance and emission characteristics were presented graphically. Based on experimental results, the best performance was found at 220 bar fuel injection pressure.