Performance and Emission Characteristics of Single Cylinder Diesel Engine Fuelled with Biodiesel Blends

Abstract

The scarcity of conventional fuels and continuous trend of hike in the prices leads a serious concern to reach for alternative fuels .On other hand there is possibility to reduce pollutants formations taking place significantly in transportation & industrial sector. Several researches have prover proven that the fuels like bio-diesel, bio-mass, alcoholic fuels, hydrogen, non-fossil methane and non-fossil gases(like LPG,CNG) can be used an substitute fuels in place of petro diesel fuel. Generally bio-diesel is the renewable fuel which is derived by chemically reacting with the source of bio diesel like vegetable oils, animal oils, plastics, and waste automobile tyres etc. The chemical reaction requires a catalyst usually a strong acid or base such as sulfuric acid, sodium or potassium hydroxide, and produces a new chemical compounds called methyl or ethyl esters of the vegetable crude oil which is called as bio-diesel. Therefore in the present investigation an attempt is to be made with rice bran oil as substitute fuel. In the initial stage the tests are to be conducted on the 4-stroke single cylinder air cooled direct injection diesel engine. In the second stage experimental investigations are to be carried out on the same engine with same operating parameters by using the rice bran oil blending with diesel in different proportions such as RB35, RB45, RBE35 and RBE45 to determine the performance parameters and emissions. Further investigation carried on base engine with Ethanol and Ethyl Hexyl Nitrate(EHN) as additives to the diesel-biodiesel blends. favourable fatty acid composition and unique combination of naturally occurring biologically active and antioxidant compounds (1). RBO has been difficult to refine because of the its high content of free fatty acid (FFA), unsaponifiable matter and dark colour (2) . The results obtained show a 49% reduction in smoke, 35% reduction in HC and 37% reduction in CO emissions for the blends whereas the brake power and BTE are reduced by 2.4% and 3.2% respectively with 4.3% increase in the SFC . Therefore it is concluded from the present experimental study that the blends of RBO and Diesel fuel can successfully be used in Diesel engines as an alternative fuel without any modification in the engine and it is also environment friendly by the emission standards. The present research is aimed to investigate experimentally the performance and exhaust emission characteristics of a direct injection (DI) diesel engine when fuelled with conventional diesel fuel, rice bran oil biodiesel, a blend of diesel and rice bran oil biodiesel and three blends of diesel-biodiesel-ethanol over the entire range of load on the engine. The experimental results showed that the highest brake thermal efficiency was observed with 15% ethanol in diesel-biodiesel-ethanol blends. The exhaust gas temperature and the sound intensity from the engine reduced with the increase of ethanol percentage in diesel-biodiesel-ethanol blends. The Carbon monoxide and smoke emissions reduced significantly with higher percentage of ethanol in diesel-biodiesel-ethanol blends. The unused oxygen with 5% ethanol in diesel-biodiesel-ethanol blend was lower than that of diesel fuel (3). .From the literature it is concluded that alternate fuels can be used as substitute for diesel by evaluating its properties and blending them with diesel in small proportions can improved performance parameters and reduce emissions without modifying the engine design.