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The Indian automotive industry has taken a big leap towards stringent Bharat Stage VI (BS VI) emission standards by year 2020. A digital driven design and development focusing on innovative and commercially viable technologies for combustion and exhaust after-treatment system is the need of the time. One-dimensional (1D) simulation serves as a best alternative to its counterparts in terms of obtaining faster and accurate results, which makes it an ideal tool for carrying out optimization studies at system level. In this work, 1D chemical kinetics modelling and analysis of exhaust after-treatment system (EAT) for a heavy-duty diesel has been performed using GT-Power. Initially, a single site 1D model for a diesel oxidation catalyst (DOC) has been developed and then, a two-site, 1D model for a selective catalytic reduction (SCR) catalyst was also developed based on reactor data.

Diesel engines are one of the primary mode of power generation in India due to its higher thermal efficiency and greater torque. In one hand, the demand for higher brake horse power genset is growing in India and the other hand, the stringent engine emission norms are going to be imposed to control the air pollution. In present scenario, the major challenges countered by the automobile industries are to design the engines which meet the norms along with high load capacity with least modifications in existing design. Optimization of various parameters is considered as a viable solution. Full factorial experimental study (large numbers of experiments) is required to be carried out to evaluate the effects of all the parameters on performance and emissions of the engine which is time consuming as well as expensive.

The mixture generation in Diesel engines is mainly driven by the combustion chamber geometry and the fuel spray characteristics. Thus, combustion chamber geometry is considered as an important parameter for Diesel engine in-cylinder emission control strategy. In this work, effect of nozzle tilt angle and various combustion chamber geometries such as mexican-hat combustion chamber (MHCC), double-lip combustion chamber (DLCC), bow combustion chamber (BCC) and toroidal combustion chamber (TCC) on in-cylinder processes and emissions has been studied numerically using a CFD-tool called Converge. Converge code has been validated against the experimental results of a Diesel engine. Results showed that a significant reduction in soot, HC and CO has been achieved with the optimum (156°) nozzle tilt angle; but NOx was increased.

In this work, optimization of various parameters, such as injection timing, compression ratio (CR) and amount of ultra-cooled exhaust gas recirculation (EGR) has been done for a variable compression ratio engine. The CR can be adjusted dynamically by changing the clearance volume through a tilting cylinder block arrangement. An EGR system, suitable for achieving ultra-cooled as well as treated EGR and large range of flow rates, has been implemented. Taguchi analysis was employed to carry out minimum number of experimental runs and still get the essence of large number of test cases. Effect of these parameters on engine performance and exhaust emissions has also been studied with the help of signal to noise (SN) ratio analysis. Flatter and wider HRR traces were observed in previous work of Brijesh et al., indicating a low temperature combustion (LTC) mode for the runs having optimized input parameters.