Combustion Optimization of 62.5 kVA Genset Engine to Meet CPCB II Norms Using Taguchi Method

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. As an alternative, a statistical tool called design of experiments (DOE) of the Taguchi method can be used to reduce the number of experimental runs and still get the essence of large number of test runs. Hot (350 °C to 450 °C) and cold (200 °C to 250 °C) exhaust gas recirculation (EGR), EGR tube diameter, injection timing, nozzle tip protrusion and dimensions of high pressure fuel pipe (HPFP) are considered as important parameters for DOE in this work. Results of the study showed that a combination of cold EGR having 10 mm EGR tube diameter, 9 CAD bTDC injection timing, nozzle tip protrusion with 3 mm thick copper washer and 6 mm × 1.5 mm × 450 mm HPFP dimensions is an optimum operating condition for the engine. It has also been observed that EGR and injection timing played a major role to control emissions and brake specific fuel consumption as compared to the other two parameters. From the in-cylinder pressure analysis, it is noticed that EGR concentration altered the peak cylinder pressure whereas retard injection timing shifted the pressure curve towards expansion stroke and slow down the reactions.