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Exhaust gas recirculation (EGR) is an effective means to reduce NOx emissions in Diesel engines. An innovative concept of EGR admission was developed for diesel engine of heavy-duty application. A 4-cylinder, naturally aspirated, water-cooled engine was selected for experimental investigation. One-dimensional simulation software was used to predict emission and performance parameters. The engine model was initially validated with experimental data and then used for parametric study for EGR. The best EGR flow rates were determined for experimental study, to study the effect of EGR on engine emissions. A significant reduction in emissions of NOx with minimal increase in CO and HC emission was achieved. Based on number of experiments and simulations an innovative EGR system was developed to control flow of hot exhaust back into the intake manifold for NOx reduction.

The fuel crises of the 1970's and early 1980's focused attention on the desirability of developing alternative fuels and decreasing the dependency on petroleum-based fuels. Vegetable oils and derivatives are among the materials that were extensively investigated as alternative diesel fuels. Vegetable oils are a potential alternative to the partial or total substitution of diesel fuels. It was known that short-term engine tests have been successful with vegetable oils; however, long-term tests have revealed the fuel limitations regarding lubricating oil contamination, deposits on engine surfaces and performance problems. This study shows how the added advantages of air-cooled engine over the water-cooled engine become the preferred choice for the SVO run diesel engine. Based on the 100 hrs SVO run diesel engine, the modification has been carried out for the long run. Different emission measurements were carried out and studied in comparison with conventional diesel.

The research work focus on the occurrence of incylinder peak pressure variation and fuel spray characteristics on piston seizure. The study has been carried out for direct injection diesel engine of heavy duty off-highway application. The well optimized and normal combustion results into the peak cylinder pressure variation within 3.5 bar to 4 bar, whereas the abnormal combustion signposts the peak cylinder pressure almost double of normal combustion. The research work has been carried out to study the effect of different peak cylinder pressure variation and its effect on the start of piston seizure. The three different range of peak cylinder pressure variation have been selected for the study. The selected range of peak cylinder pressure depicts normal to abnormal combustion characteristics. The effect on piston motion dynamics and start of piston seizure has been carried out successfully.

A major task faced by engine manufacturers all over the world is to upgrade running engine designs with least possible modifications to meet next level of emission norms. This saves the precious lead-time and investments. In addition simplicity of design has to be maintained as far as possible while improving emissions. This is possible only by optimal combinations of FIE and engine. This paper describes such a cost effective up-gradation of an engine from US Tier 1 to US Tier 2 in very short time with minimal design changes. This difficult task was achieved by using latest techniques of simulations, measurements and concurrent engineering. For variable speed application it is desirable to retard injection timing as speed decreases, to compensate gain in absolute time. For constant speed application, retardation at part load is required as more weightage is given at part loads for the emission test cycle.