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Environmental pollution as a result of improper disposal of agricultural and food industry waste has been a concern lately. In the present study, an attempt has been made to produce energy from these wastes. Biodiesel produced from residual cooking oil (RCOB) and hexanol produced from agricultural waste have been investigated as alternatives to petroleum-based fossil fuels in a dual-fuel low-temperature combustion engine. Hexanol was injected in the inlet port at 3 bar injection pressure whereas RCOB was injected directly inside the combustion chamber using a common rail direct injection system. The proportion of Hexanol to RCOB was varied from 40% to 60% at rated load. The operating parameters such as intake air temperature, exhaust gas recirculation (EGR) quantity along with multiple injection timing, duration, quantity, and pressure were optimized for lower oxides of nitrogen (NOx) and smoke emissions.

Reactivity controlled compression ignition has been a proven combustion strategy for better reduction of NOx and PM emissions without compromising the fuel economy. However, the combustion strategy still need more investigation to overcome its operational stability. In this study, the influence of hot/cooled exhaust gas recirculation and premixed mass percentage and there cyclic variation of Methanol/Diesel dual fuel reactivity controlled compression ignition (RCCI) combustion was investigated in a modified 3 cylinder light duty, turbocharged, CRDI diesel engine. Methanol/Diesel RCCI combustion was achieved by premixing methanol with intake air in the intake port and injecting diesel directly into the cylinder by flexible common rail direct injection system. The intake manifold was altered to adopt port fuel injection of methanol and EGR. Experiments were conducted at 3.4 bar and 5.1 bar BMEP at 1500 rpm by varying EGR and premixed mass percentage.

Biofuels are bio-origin renewable fuels which are capable of replacing mineral-based non-renewable fossil fuels. The use of biofuels which have oxygen molecules in its structure makes major variation in exhaust emissions in Compression Ignition Engines. Research works in the field of biofuels as alternative fuels for Internal Combustion Engines show a reduction in Unburned Hydrocarbons (HC), Carbon monoxide (CO), smoke and Particulate Matter (PM). However the emission level of Oxides of Nitrogen (NOx) increased in certain cases. The explanation for both reduction and increase in the emissions shows that the presence of oxygen molecules in the fuel is critical. The present work forms on the investigation of the performance and the exhaust emissions from a diesel engine with respect to the oxygen content in the alternative diesel fuels.

The present work deals with statistical optimization of a direct-injection diesel engine. Due to the NOX and particulate tradeoff relation in diesel engines it is difficult to reduce these two pollutants simultaneously. Previous studies have indicated the effects of inlet air components and injection nozzle opening pressure on NOX and particulate emissions. The objective of this study was to find the optimized operating parameters point for a single-cylinder DI diesel engine at 1500 rpm and 75% load to reach a desired NOX, smoke and fuel efficiency levels, using a Response Surface Method (RSM). The operating parameters used in the optimization process are inlet air CO₂% (simulation of EGR) and injection nozzle opening pressure. A mathematical statement of goal was defined in the form of an objective function. It was shown that RSM is an effective method to obtain the optimum operating parameters point.

During the last decade the use of alternative fuels for diesel engine has received renewed attention. The interdependence and uncertainty of petroleum based fuel availability and environmental issues, most notably air pollution are among the principal forces behind the movement towards alternative sources of energy. The main pollutants from the conventional hydrocarbon fuels are unburned / partially burned hydrocarbon (UHC), carbon monoxide (CO), oxides of Nitrogen (NOx), smoke and particulate matter. These emissions are harmful to human, animal and plant life. Emissions from automobiles are currently a dominant source of air pollution representing 70 % of carbon monoxide, 41 % of oxides of Nitrogen (NOx), 38 % of hydrocarbon emissions globally. In addition 25 % of the man made CO2 emissions globally adds to the green house effect, which results in global warming. In the present investigation hydrogen is used in a diesel engine in the dual fuel mode using diesel as an ignition source.

The world is confronted with the two major crisis namely, fossil fuel shortage and environmental degradation. The non edible vegetable oil and its methyl ester have been considered a promising option. In the present investigation, tests were carried out to analyze the combustion process of Rubber Seed Oil Methyl Ester (RSOME), Rubber Seed Oil (RSO) and compared with diesel. The engine performance and exhaust emissions were also studied for better understanding of the combustion process. It was observed that the premixed combustion phase of RSOME combustion was more intense than that of RSO due to its lower ignition delay. It was also noted that the ignition delay and combustion duration decreased with RSOME, which indicated higher heat release resulting in higher thermal efficiency than RSO. The brake thermal efficiency is 26.53% with RSO, 27.89% with RSOME and 29.93% with diesel at full load. The peak pressure increased by 2.3 bar for RSOME compared to that of RSO.

Hydrogen is expected to be one of the most important fuel in the near future to solve greenhouse problem and to save conventional fuels. In this study, a Direct Injection (DI) diesel engine was tested for its performance and emissions in dual-fuel (Hydrogen-Diesel) mode operation. Hydrogen was injected into the intake port along with air, while diesel was injected directly inside the cylinder. Hydrogen injection timing and injection duration were varied for a wider range with constant injection timing of 23° Before Injection Top Dead Centre (BITDC) for diesel fuel. When hydrogen is used as a fuel along with diesel, emissions of Hydro Carbon (HC), Carbon monoxide (CO) and Oxides of Nitrogen (NOX) decrease without exhausting more amount of smoke. The maximum brake thermal efficiency obtained is about 30 % at full load for the optimized injection timing of 5° After Gas Exchange Top Dead Centre (AGTDC) and for an injection duration of 90° crank angle.

In the efforts for developing relatively clean and efficient burning fuels, attention is being focused on various gaseous fuels. Gaseous fuels in diesel are possible in dual fuel operation. It is well known that the operation of LPG-Diesel dual fuel engine at lower loads suffers from lower thermal efficiency and higher unburned percentages of fuel. To overcome this drawback, a new methodology has been adopted in the present work, namely, isomerisation of gaseous fuels. Experiments have been conducted by using Al2O3/Pt as an isomerisation catalyst. It is concluded that thermal efficiency at light loads can be improved significantly and emission levels reduced at all loads.