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Air motion in a cylinder in a compression ignition engine affects on mixing of air-fuel, quality of combustion and emission produced. With upcoming stringent norms for diesel engines, it is necessary to enhance air-fuel mixing for proper combustion. Swirl and tumble are forms of air motion. Swirl is a rotational motion of a bulk mass within cylinder. Swirl is generated by shaping and countering intake manifold and valve ports. Swirl enhances air-fuel mixing and helps to spread flame-front during combustion. The objective of this paper is to analyze the impact of different swirl ratios on NOx and soot emission characteristics inside the cylinder of a DI Diesel engine. The effects of different geometrical parameters of helical port were studied and the swirl ratios are optimized by optimizing the geometrical parameter of helical port. This can be done by different manufacturing, polishing and grinding processes.

Diesel exhaust is a complex mixture of combustion products of diesel fuel, and the exact composition of the mixture depends on the nature of the engine, operating conditions, lubricating oil, additives, emission control system, combustion parameters and fuel composition. In a diesel engine, NOx (NO & NO2) and PM (Particulate Matter) are the most critical constituents for the emission legislation. In order to control the PM emission of diesel engine and comply with increasingly stringent exhaust legislation, more information is required on the components and genesis of PM. In general, PM from diesel engines is classified into two fractions: Insoluble Organic Fraction (ISOF) and Soluble Organic Fraction (SOF). In this experimental study, a series of 13 mode ESC cycle were run on a light duty diesel engine after optimization of combustion parameters (Injection Pressure, Injection Timing, Multiple Injections, EGR rate, etc) in successive tests and PM component was analyzed.

Future emissions regulations like BSIV and above in India, Diesel engine manufacturers are forced to find complex ways to reduce exhaust gas pollutant emissions, in particular NOx and particulate matter (PM). Exhaust gas recirculation (EGR) into the engine intake is an established technology to reduce NOx emissions. The distribution of EGR in each cylinder plays vital role in combustion process and hence it will affect exhaust emissions. The influence of EGR mixture design and its effect on distribution across the cylinder has significant impact on the NOx-PM trade-off which is studied on light duty direct injection diesel engine. A simulation and experimental study of EGR mixer design is conducted to explain this effect and the distribution of EGR across the cylinder at different EGR flow rate.

Exhaust gas recirculation (EGR) is one of the most effective methods for reducing the emissions of nitrogen oxides (NOx) of diesel engines. EGR system has already been used to mass-produce diesel engines, in which EGR is used at the low and medium load of engine operating condition, resulting in NOx reduction. In order to meet future emission standards, EGR must be done over wider range of engine operation, and heavier EGR rate will be needed. It is especially important for EGR to be done in a high engine load range since the amount of NOx is larger than the other engine operation conditions. EGR systems adapted to the diesel engines of trucks usually recirculate exhaust gas utilizing the pressure difference between upstream part of the turbocharger turbine and downstream part of the compressor. The venturi throat diameter plays the vital role for the flow of EGR across the exhaust and intake.