Experimental Investigations On Exhaust Emissions Of High Grade Low Heat Rejection Diesel Engine with Pongamia Biodiesel

In the scenario of depletion of fossil fuels, the search for alternative fuels has become pertinent. Vegetable oils are promising substitutes for diesel fuels. Biodiesels derived from vegetable oils present a very promising alternative to diesel fuel since biodiesels have numerous advantages compared to fossil fuels as they are renewable, biodegradable, provide energy security and foreign exchange savings besides addressing environmental concerns and socio-economic issues. Experiments were conducted to determine exhaust emissions of a low heat rejection (LHR) diesel engine with different operating conditions [normal temperature and pre-heated temperature] of pongamia biodiesel with varied injection timing and injector opening pressure. LHR engine consisted of air gap insulated piston, air gap insulated liner and ceramic coated cylinder head. Exhaust emissions of particulate emissions and nitrogen oxide levels were determined at various values of brake mean effective pressure of the engine fuelled with biodiesel. Comparative studies on exhaust emissions were made with diesel working on similar conditions. Particulate emissions decreased while nitrogen oxide levels increased with biodiesel operation on LHR engine over conventional engine. They further improved with increase of injector opening pressure, advanced injection timing and preheating of biodiesel.