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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.

There is currently interest in finding means to improve motor vehicle fuel economy while complying with emissions regulations. Fuel additives have been widely reported to improve engine cleanliness and performance with diesel engines. Diethyl Ether (DEE ) has high octane number and compatible with current vehicle technology and fuel infrastructure. Although DEE has long been known as a cold start aid for engines, knowledge about using DEE for other operations, such as significant component of a blend or additive is limited. In this present work, experiments were conducted to study the influence of DEE on the performance and emissions of a 4-S direct injection diesel engine. From the experimental results, it is observed that the addition of DEE to diesel fuel improves the performance of the diesel engine. A slight improvement in the thermal efficiency and reduction in smoke, carbon monoxide and hydro carbon emissions were observed with B5 Blend (5 % DEE + 95 % Diesel).

There is an increasing interest in India, to search for suitable alternative fuels that are environment friendly. This led to the choice of non edible mahua oil as one of the main alternative fuels to diesel oil. Hence in the present work, Methyl Ester of Mahua Oil (MEMO) was used as pilot fuel and Liquefied Petroleum Gas (LPG) was used as primary fuel. A single cylinder, direct injection, four stroke, diesel engine was modified to work in dual fuel mode and the effect of injection time on the performance and emission of the dual fuel engine was studied. During tests, the engine was running smoothly with the MEMO. From the test results, it is observed that, at part loads, the advanced injection timing of 30° bTDC results in slight increase in brake thermal efficiency and lower exhaust emissions as compared to rated injection timing of 27° bTDC and retarded injection timing of 25° bTDC.

There is an increasing interest in India to search for suitable alternative fuels that are environment friendly. This led to the choice of karanja oil as one of the main alternative fuel to diesel oil. Karanja Oil Methyl Ester (KOME) was prepared by transesterfication method. In the present work, blend of diesel and karanja oil methyl ester (B20) were used as fuel and the effect of injection pressure on the performance and emissions of a direct injected, four stroke, single cylinder diesel engine was studied. Results showed that for the B20 blend, the injection pressure of 200 bar results in better performance and lower emissions than other injection pressures. The brake thermal efficiency of karanja methyl ester at 200 bar was comparable with diesel. The engine emissions such as carbon monoxide, hydrocarbons, oxides of nitrogen and smoke emission were lower than 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.