Experimental Investigations on Diesel Engine Forced Induction and Exhaust Gas Recirculation (EGR) Using Exhaust Gas Assisted Jet Compressor

Even though the conventional method of supercharging and turbocharging of an internal combustion engine increases the engine specific power output, part of the shaft power developed by the engine is consumed by the superchargers. The control system that is present in both the chargers further complicates the system. This study proposes a novel method of forced induction in a diesel engine by using a jet compressor run by exhaust gas recirculation (EGR). This method apart from increasing the specific power output reduces the NOx formation by the engine due to forced induction. Performance analysis of the jet compressor using exhaust gas as the motive stream and atmospheric air as the propelled stream was carried out. Using the standard available code, the governing equations were solved numerically to get the optimum operating conditions such as exhaust gas pressure, temperature, and flow rate for a three cylinder diesel engine. The dimensions of the jet compressor were determined by solving the energy balance equations obtained from the constant rate momentum change method. Using the commercial software FLUENT, the performance optimization of jet compressor used for forced induction in a diesel engine was made for different percentage of EGR input and estimated the power output. From the results obtained, a performance map was drawn for the three cylinder diesel engine to get the optimum boost pressure and maximum entrainment ratio for a given percentage of exhaust gas recirculation and power output. Experiments were conducted on a three cylinder diesel engine fitted with a fabricated jet compressor with EGR used for forced induction application. Results obtained from the experiments were in good agreement with the numerical results obtained from fluent analysis.