EGR IN ETHANOL DRIVEN DIESEL ENGINE

The results of charting exhaust emissions show that emission of NOx can be reduced by varying exhaust gas recirculation (EGR) levels. Reduction as a mean during a test cycle was 60-70 per cent. This can be achieved while keeping hydro carbon (HC) and carbon oxide (CO) emissions at same level in combination with conventional oxidation catalyser. Engine power and fuel consumption are not appreciably affected at tested EGR levels. Automatic regulation of EGR can be reduced by hot EGR. Multivariate analysis of data from more than 400 test runs shows that 90 per cent of the variation in NOx level can be explained by EGR, torque and rpm. The analysis also shows that measurement of torque which has a great effect on formation of NOx can be replaced by measuring pressure of inlet gas to the engine. There is also a weak interaction effect between torque and EGR, A-weighted sound pressure level shows little variation for different types of EGR control. It is only at 1200 rpm and 25 per cent load, and 2000 rpm and 25-50 per cent load, that the difference is greater than 1dB(A). The new control system resulted in more effective regulation of EGR flow, back pressure and inlet temperature of gas to engine.