Ecology, Environment and Conservation Paper

EFFECT OF INJECTION PRESSURE ON EXHAUST EMISSIONS OFDIESEL ENGINE FUELLED WITH LPG

K. Laxmi and M.V.S. Murali Krishna

Abstract

In the context of exhaustion of fossil fuels day by day due to heavy demand with the use of agriculturesector and transport sector, escalation of fuel prices in International Oil Market causing huge economicburden on developing countries like India and rise of pollution levels with fossil fuel, the conservation offossil fuels has become pertinent. Gaseous fuels have many merits over liquid fuels, as the pollutants emittedby gaseous fuels are low due to clean combustion, high calorific value in comparison with liquid fuels.Vegetable oils are good substitutes for diesel, as they are renewable, comparable calorific value and cetane(meausre of combustion quality) number when compared with neat diesel operation. However, thedisadvantages associated with vegetable oils such as high viscosity and low volatility cause combustionproblems in diesel engines. They can be rectified to some extent by converting them into biodiesel. They aremany methods to induct gaseous fuels such as port injection, carburetion technique, injection of gaseousfuel at the near end of compression stroke etc,. Investigations were carried out with LPG as primary fuelinducted by port injection and diesel was injected into the engine in conventional manner. Particulatematter (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. Theyalso cause environmental effects like Green-house effect and Global Warming. Hence control of theseemissions is an immediate effect and an urgent step. The pollutants of PM, NOx,CO and UBHC weredetermined at full load operation of the engine with varied injection pressure and compared with dieseloperation on conventional engine. The maximum induction of LPG was 35% of total mass of diesel as fullload operation. Particulate emissions were determined by AVL Smoke meter, while other emissions weremeasured by Netel Chromatograph multi-gas analyzer at full load operation. These pollutants weredrastically reduced with induction of LPG and further reduced with an increase of injection pressure.