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An experimental investigation is carried out to evaluate the effects of biodiesel-dimethylcarbonate (BC) blends and biodiesel-diglyme (BG) blends on the combustion, performance and emission characteristics of a diesel engine at different loads and constant engine speed. The results show that for a specific engine load, compared with biodiesel, the ignition delay increases with the increase of dimethyl carbonate fraction in the blends while it decreases with the increase of diglyme (dimethylene glycol dimethyl ether) fraction in the blends. Compared with biodiesel, for a specific engine load, the total combustion duration decreases with the increase of both dimethyl carbonate and diglyme fraction in the blends. Compared with biodiesel, for a specific engine load, the BC blends have lower peak cylinder pressure at full load, while the BG blends show a slight variation in the peak cylinder pressure.

An experimental investigation is carried out to evaluate the effects of biodiesel-dimethylcarbonate (DMC) blends on the combustion, performance and emission characteristics of a diesel engine at different loads and constant engine speed. The results show that for a specific engine load, the ignition delay increases and the total combustion duration decreases with the increase of DMC fraction in the blends. Compared with biodiesel, for a specific engine load, the BC blends have lower peak cylinder pressure and cylinder temperature at almost all engine loads. The heat release rate is higher at higher engine loads during premixed combustion phase for BC blends than for biodiesel. In comparison with biodiesel, the BC blends have slightly higher brake thermal efficiency. Drastic reduction in smoke is observed with BC blends at higher engine loads. The NOx emissions are found slightly lower for BC blends at all loads.

Fuel crisis and environmental concerns have led to look for alternative fuels of bio-origin sources such as vegetable oils, which can be produced from forests, vegetable oil crops and oil bearing biomass materials. Vegetable oils have energy content comparable to diesel fuel. Straight vegetable oils posed several operational problems and durability problems when subjected to long-term usage in CI engine. These problems are attributed to higher viscosity and lower volatility. The viscosity can be brought in acceptable range by (i) converting the vegetable oil into methyl ester, (ii) blending of oil with diesel fuel, (iii) blending of oil with alcohols or (iv) increasing the fuel temperature to over 200°C using exhaust gas waste heat. Reduction of viscosity by blending or exhaust gas heating saves the chemical processing cost of transesterification.