EFFECT OF INJECTION PRESSURE ON PERFORMANCE AND EMISSION OF DIESEL HYDROGEN OPERATED C.I ENGINE

Abstract

The use of alternative fuels for diesel engine has received renewed attention during the last decade. In recent years many countries are used diesel engine as a power source for different purpose like generating electricity, agriculture and transportation. These engines consumes heavy quantity of fuel, where these engines produce bulk power as well as there also produces the different types of toxic emissions that harmful to the living beings and environment. The best method of tackling these problems are by using gaseous hydrogen fuel inducted in the intake manifold along with air.In this experimental investigation,the hydrogen was inducted into the intake manifold along with air, while diesel was injected directly inside the cylinder. The fuel injection pressure is one of the most important factors controlling the combustion process, engine performance and engine emission. In this study, a Direct Injection (DI) diesel engine was tested with dual-fuel (hydrogen-diesel) mode operation with various injection pressures (180bar, 200bar, 220bar). The performance and emission characteristics was evaluated and compared with neat diesel operations. Experiments are carried out on a diesel engine with hydrogen inducted into the intake manifold along with air and diesel was injected directly inside the cylinder. The hydrogen flow rate was kept constant at 20 LPM and engine was run for different load conditions with constant speed of 1500 rpm. The fuel injection pressure was set for 180bar, 200bar, 220bar and the engine performance, emission and combustion parameters are evaluated. The supply pressure of hydrogen gas to the engine was reduced to 2 bar from 120 bar by using pressure regulator. Performance parameters such as brake specific fuel consumption and brake thermal efficiency are calculated based on experimental results of the engine. Emissions such as carbon monoxide (CO), oxides of nitrogen (NOx) and Unburned Hydrocarbons (UHC) are measured. It is found that maximum brake thermal efficiency obtained with 20LPM hydrogen enrichment of injection pressure 180bar, 200bar, 220bar are 30.15%, 27.62%, 26.59%. The BSFC decreased for injection pressure of 180bar compared to diesel and other injection pressures. In this experiment it was observed that the HC, CO and NOx emissions are decreased for 180bar injection pressure compared to diesel and other injection pressure namely 200bar and 220bar. But the cylinder pressure and heat release rate are lower for diesel, compared to other injection pressures.