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Selective Catalytic Reduction (SCR) is a most promising technique for reduction of nitrogen oxides (NOx) emitted from the exhaust of diesel engines. Urea Water Solution (UWS) is injected to hot exhaust gas stream to generate reducing agent ammonia. The droplet evaporation of Urea Water Solution (UWS) is investigated for single droplet in heated environment ranging temperatures 373K-873K theoretically. The theoretical methods which are implemented into CFD code Fire 8.3 from AVL Corp. involve Rapid Mixing model and Diffusion Limit model which consider stationary droplet and variable properties of the UWS. The UWS droplet revealed different evaporation characteristics depending on its ambient temperatures which are numerically predicted by simulated results. The simulated results are validated with experimental values of Wang et al. [9] which are helpful in predicting the evaporation and UWS dosing strategy at different exhaust gas temperatures in real SCR system.

In recent years, there has been a considerable effort to develop and introduce alternative renewable fuel, to replace conventional petroleum based fuels. This led to the choice of non-edible mahua oil (MO) as one of the main alternative fuels to diesel oil in India. When MO was used as fuel in the compression ignition (CI), it results in lower thermal efficiency and higher smoke emission due to its higher viscosity and lower volatility. Hence in the present work, biodiesel was derived from MO using transesterification process and the effect of injector nozzle opening pressure (IOP) on the performance of the direct injection (Dl), CI engine was studied. The engine tests were conducted on a single cylinder, naturally aspirated, water cooled, diesel engine, which is used in the agricultural machinery, at different IOPs and loads. The engine performance with MO biodiesel was compared with neat diesel operation.

Producing and using renewable fuels for transportation is one approach for a sustainable energy for India, as well as the rest of the world. In the transportation sector, alcohols produced from biomass shows promise as an alternative fuel for spark ignited (SI) engines because of its high octane number. In the present work, methanol was used as an alternative fuel. In two stroke engines, In-cylinder injection of fuel results in excellent fuel economy potentional with lesser emissions. The objective of this work was to study the effect of injection timing and compression ratio on the performance and emissions of the engine. An air cooled, constant speed, single cylinder, two stroke, spark ignition scooter engine was modified to work in fuel injection mode. The performance of the modified engine was compared with the base engine.

Dimethyl Ether (DME), the methanol analog to Diethyl Ether (DEE), was recently reported as a low emission, high quality diesel fuel replacement. Literature review indicates that significant work is not carried out with respect to its performance analysis and in regard to pollution levels. In the present work, the effect of DEE on the performance and emissions of a four-stroke direct injection diesel engine have been studied. Tests were conducted on the diesel engine with different blends of DEE and diesel as fuel. Test results show that 5 % DEE blend gives better performance and low emissions compared to other blends of DEE and diesel fuel. Hence, 5 % DEE can be blended with diesel fuel to improve the performance and to reduce emissions of the diesel engine.