EXPERIMENTAL INVESTIGATIONS ON EXHAUST EMISSIONS OF DIESEL ENGINE FUELED WITH BIOGAS

In the scenario of depletion of fossil fuels, increase of fuel prices in International Market causing economic burden on developing countries like India and increase of pollution levels with fossil fuel, the search for alternative fuels has become pertinent. Gaseous fuels have many advantages than liquid fuels, as the pollutants emitted by gaseous fuels are low and less dangerous when compared with liquid fuels. The drawbacks associated with vegetable oils such as high viscosity and low volatility can be rectified to some extend by converting them into biodiesel. How they (biodiesel) cause combustion problems in diesel engine and hence call for low heat rejection (LHR) engine, which can burn low calorific value fuel, give high heat release rate and faster rate of combustion. They are many methods to induct gaseous fuels such as port injection, carburetion technique, injection of gaseous fuel at the near end of compression stroke etc,. Investigations were carried out with biogas gas as primary fuel inducted by port injection and cottonseed biodiesel was injected into the engine in conventional manner. Particulate matter (PM), oxides of nitrogen (NOx), carbon mono oxide (CO) levels and un-burnt hydro carbons (UBHC) are the exhaust emissions from a diesel engine. They cause health hazards, once they are inhaled in. They also cause environmental effects like Green-house effect and Global Warming. Hence control of these emissions is an immediate effect and an urgent step. The pollutants of PM, NOx, CO and UBHC were determined at full load operation of the engine with varied injection pressure and compared with diesel operation on conventional engine. The maximum induction of biogas was 35% of total mass of biodiesel as full load operation. Particulate emissions were determined by AVL Smoke meter, while other emissions were measured by Netel Chromatograph multi-gas analyzer at full load operation. These pollutants were drastically reduced with induction of biogas and further reduced with an increase of injection pressure