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  1. 1. G.Sucharitha, A.Kumaraswamy / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 3, Issue 1, January -February 2013, pp.320-325 Experimental Analysis of Using Neem Oil as an Alternative Fuel G.Sucharitha*, A.Kumaraswamy** *(Department of Mechanical Engineering, Bharath University, Chennai, India) ** (Department of Mechatronics Engineering, Bharath University, Chennai, India)ABSTRACT Neem oil can be directly used in evaluated using preheated neem oil, neem oil estercompression ignition engine. However, the and neem oil-petrol dual fuel mode and the resultsperformance is inferior to diesel. This is due to its are compared with that of base diesel engine.high viscosity and carbon residue. Theperformance of the neem oil fuelled engine can II. PROBLEMS ASSOCIATED WITH USEbe improved by esterifying, preheating or using OF NEEM OIL IN DIESEL ENGINEdual fuel mode with petrol carburetion. In this Vegetable oils have generally moreexperimental work, performance and emission complex structure than normal hydrocarbons foundcharacteristics of a single cylinder, water cooled in diesel fuel. The diesel fuel molecule is a saturated,direct injection diesel engine operating on neem non-branched hydrocarbon with carbon numbersoil, its ester, preheated neem oil and neem oil- about 12 to 18. Vegetable oil molecules arepetrol dual fuel mode were evaluated and triglycerides, generally with non-branched chains ofcompared with diesel operation. The brake different degrees of saturation. The high viscosity ofthermal efficiency of the engine with neem oil is neem oil (as seen in Table 1) leads to poor24.9%,neem oil ester is 26.39%, preheated neem atomization during injection, resulting in inefficientoil at 160 deg Celsius (temperature at which mixing with air, which contributes to incompleteneem oil viscosity equals to diesel viscosity) is combustion. The poor volatility makes the neem oil29.1 % and that of diesel is 31.4% at full load. At difficult to evaporate and ignite. Hence, it is difficultknock limited point ( 60% full load,1500 rpm), to use neem oil without further processing as a fuelbrake thermal efficiency increases from 24% to in a direct injection diesel engine. Either the neem30.5% at 33.7% of energy share of petrol with oil has to be further processed or the engine has toneem oil, and from 26.8% to 32.3% at 30.3% of be modified to render the use of neem oilenergy share of petrol with neem oil ester, practicable. In the present work methods such asSmoke, HC/CO decrease with esterification and transesterification, preheating and petrol carburetionpreheating but increase with petrol carburetion. were investigated to improve the performance. Transesterification involves making the triglyceridesKeywords - vegetable oil, diesel engine, bio- of vegetable oil react with methyl alcohol in thediesel, neem oil. presence of a catalyst (NaOH) to produce glycerol and fatty acid ester. Which results in a vegetable oilI. INTRODUCTION ester. The byproduct is glycerol, which has its own Vegetable oils are promising alternative industrial application. Preheating of vegetable oilfuels for diesel engines, since they are easily reduces the viscosity considerably. The reduction inhandled liquid fuels with properties close to those of viscosity improves the formation of the air fueldiesel in many respects (1) They are renewable in mixture, resulting in good combustion .Engine cannature, can be produced in rural areas by well be operated on gasoline-neem oil (or its esters) dualknown agricultural practices Research findings (2) fuel mode. It is expected that the enginehave revealed that engine durability is adversely performance will improve because of many ignitionaffected by the use of vegetable oils as a fuel for centers, low viscosity and good mixinglong term. These problems can be attributed to the characteristics of petrol in the dual fuel mode.high viscosity, low volatility, and reactivity ofunsaturated hydrocarbon chains. Of these factors, the high viscosity ofvegetable oils is the predominant hurdle as it causesexcessive carbon deposit, ring sticking, plugging ofinjector orifices, improper injection and atomizationand hence incomplete combustion.Transesterification(3) and preheating(4) areeffective methods to reduce the viscosity of thevegetable oils. The performance of vegetable oilfuelled engine can be improved to some extent using Table.1.Properties Of Neem Oilpetrol induction. In this work, performance of asingle cylinder, water cooled, CI engine was 320 | P a g e
  2. 2. G.Sucharitha, A.Kumaraswamy / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 3, Issue 1, January -February 2013, pp.320-325III EXPERIMENTAL SETUP A single cylinder 4-stroke water-cooleddiesel engine developing 3.7kW at 1500rpm wasused. The schematic diagram of the experimental setup is shown in Fig.1. A swinging field electricaldynamometer was used for loading the engine. Acarburetor was fitted in the intake port of the enginefor supplying petrol. The petrol supply could bevaried. A turbine type meter connected to a largetank was attached to the engine to make air flowmeasurements. The fuel flow rate was measured onthe volumetric basis. An infrared exhaust gasanalyzer was used for the measurement of HC/COin the exhaust. Smoke levels were obtained using astandard Bosch Smoke Meter. In order to reduce the viscosity of neem oil,an electrical oil heater incorporating a relay circuitwith electronic controller was designed. Fig.2 showsthe details of the fuel heating system in the tank.Neem oil is preheated over a period of time in thepreheating tank prior to injection and reduction inviscosity is accomplished. The electric heater (2kW,230V) submerged in the fuel tank was connected toa.c. power supply. The relay controller with an autoreset function, on - off action; operating range of 0-600 C, k type thermocouple and digital displaywere employed to regulate fuel temperature. Initially, the tests were conducted at aconstant speed of 1500 rpm with variable load fordiesel, neem oil and its esters as fuels. Then the tests were conducted with neemoil, at different fuel temperatures. The temperaturewas increased till the viscosity of neem oil becomesequal to diesel viscosity. Engine was operated on dual fuel modenamely gasoline-diesel oil, gasoline-neem oil andgasoline-neem oil ethyl ester. Petrol has lowviscosity and high self ignition temperature. So atfull load condition the engine knocks even for alittle amount of petrol carburetion. So experimentwas conducted at 60% of full load. At constant IV. RESULTS AND DISCUSSIONspeed of 1500 rpm the amount of petrol carbureted Tests with Neem Oil, Neem Oil Methyl Ester andwas varied from 0% to 40% of the total input Dieselenergy. Brake Thermal EfficiencyFigure captions appear below the figure, are flush As seen in Fig 3, at maximum load, brakeleft, and are in lower case letters. When referring to thermal efficiency with neem oil is 24.9%, whicha figure in the body of the text, the abbreviation increases to 26.39% in neem oil methyl ester"Fig." is used. Figures should be numbered in the operation. However these values are low comparedorder they appear in the text. to diesel operation (31.4%).The lower brake thermal efficiency with neem oil is due to poor mixture formation as a result of low volatility, higher viscosity and density. But slight improvement in brake thermal efficiency with neem oil ester is due to improved combustion as a result of reduced viscosity. 321 | P a g e
  3. 3. G.Sucharitha, A.Kumaraswamy / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 3, Issue 1, January -February 2013, pp.320-325 HC EmissionSmoke Emission Fig.5 shows the variation of HC emission Fig.3 compares the smoke emission of with brake power. The HC emissions of neem oilneem oil, neem oil ester with that of diesel and its ester are higher than diesel operation. Theoperation. At maximum load smoke emission of higher density and viscosity of the neem oil causeneem oil is 4.1 BSU, which decreases to 3.6 BSU in poor mixture formation, which results in partiallyneem oil methyl ester operation. The smoke burned hydrocarbons during combustion process. Soemission with diesel operation is 2.8 BSU. The high the hydrocarbon emission is higher for the neem oil.viscosity and low volatility of neem oil leads to After converting neem oil to neem oil methyl ester,larger droplet sizes with consequent sluggish the HC emission decreases, indicating improvedcombustion, which results in increased smoke combustion with esters.levels. But with its ester, it is reduced, due to itsreduction in viscosity and density. Tests with Preheated Neem Oil at Various Temperatures In these tests the diesel engine wasCO Emission operated with preheated neemoil at various fuel It is evident from Fig.4 that the COemissions of neem oil and its ester are higher than temperatures like 50C, 90C, 120C and 160Cdiesel operation. A possible explanation for higherCO emission is the presence of local mixture at core Brake Thermal Efficiencyof injection spray, with insufficient air during the It is evident from Fig.6 that the maximumcombustion process. The reduction in CO emission brake thermal efficiency at full load increases bywith neem oil methyl ester is due to improved air preheating the fuel because of lower viscosity.fuel mixture as a result of reduction in viscosity. When operating with neem oil at 160C (temperature at which neem oil viscosity is equal to diesel viscosity at ambient temperature) the maximum brake thermal efficiency at full load 322 | P a g e
  4. 4. G.Sucharitha, A.Kumaraswamy / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 3, Issue 1, January -February 2013, pp.320-325increases from 24.5% to 29.1%, which is close to decreases. The fall in CO emission is an outcome ofdiesel operation 31.4%. Higher fuel temperature improved oxidization of carbon monoxide to carbonhelps to reduce the viscosity of neem oil, which dioxide. The increase in fuel temperature ofimproves the fuel spray characteristics; atomization preheated neem oil helps to increase the combustionproves the fuel spray characteristics, atomization, temperature, thus reduction in CO emission isresulting in better combustion. obtained. HC EmissionSmoke Emission Fig.9 shows the comparison of HC Fig.7 shows the comparison of smoke emission of neem oil at different fuel temperatures.emission at various fuel temperatures. The smoke The HC emission of neem oil decreases withemission with neem oil is higher than diesel. When increase in fuel temperature. The HC emission offuel temperature increases the smoke tends to neem oil without heating is 120 ppm, which reducesreduce. While neem oil is operating at 160C smoke to 60 ppm at 160C. The HC emission of diesel isreduces from 4.1 to 3.1 BSU, which is near to diesel 40 ppm at maximum load. When fuel temperatureoperation with a smoke intensity of 2.8 BSU at increases, there will be some thermal dissociation ofmaximum load. The reduction in smoke emission is fuel particles, which increases concentration ofdue to more complete combustion of preheated chemically active fuel radicals. The pre-activatedneem oil. fuel radicals will ignite and combust much more rapidly upon injection in to the cylinder than fuel at conventional temperature. So the unburned hydrocarbon decreases with increase in fuel temperature.CO Emission Fig.8 shows the comparison of carbonmonoxide emission of neem oil at different fueltemperatures. The CO emission of neem oil without Neem Oil- Gasoline Dual Fuel Mode- Brakeheating is 0.34% at maximum load, which decreases Thermal Efficiencyto 0.22% at fuel temperature 160C. The CO The variation of the break thermalemission of diesel is 0.19% at maximum load. When efficiency is shown in Fig.10. With zero percentagethe fuel temperature increases, the CO emission of energy share of petrol, the values of brake 323 | P a g e
  5. 5. G.Sucharitha, A.Kumaraswamy / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 3, Issue 1, January -February 2013, pp.320-325thermal efficiency are 28.4% for diesel, 24% forneem oil and 26.8% for neem oil ester. The brakethermal efficiency increases with the increasingamount of petrol carbureted at constant loads. Thishappens because of the better combustion of thepetrol-air mixture. At 60% of full load, the breakthermal efficiency increases up to 35.2% from28.4% at 24.4% energy share of petrol in petrol-diesel fuel mode. For the same load, brake thermalefficiency increases up to30.5% from 24% at 33.7%energy share of petrol in petrol-neem oil fuel modeand brake thermal efficiency increases up to 32.7%from 26.8% at 30.3% energy share of petrol inpetrol-neem oil ester fuel mode. When petrol isinducted into combustion chamber, a homogeneousmixture is formed, resulting in better combustion,thus causing an increase in the brake thermalefficiency. HC and CO Emissions The variation of HC and CO emissions are shown in the Figs.13 and 14 for constant load. The HC emissions increase with the increase in the carbureted amount of petrol. The diesel quantity decreases as a result of which some quantity of the carbureted fuel does not burn completely due to flame quenching. The CO emissions also increase with the increase in the petrol carburetion. This is again due to fuel flame quenching in a duel fuel engine.. At 60% of full load the HC emission increases up to 90 ppm from 70 ppm and CO emission increases up to 0.38% from 0.3% at 24.4% energy share of petrol in petrol-diesel fuel mode. For same load condition, HC emission increases up to 140 ppm from 90 ppm and CO emission increases up to 0.7% from0.6% at 33.7% energy share of petrol in petrol-neem oil fuel mode and HCWhen the petrol flow rate is higher, the flame emission increases up to 120 ppm from 80 ppm, COpropagation is enhanced so the combustion becomes emission increases up to 0.57% from 0.39% atvery rapid and engine starts knocking after a 30.3% energy share of petrol in petrol-neem oil esterparticular amount of petrol admission for all fuels fuel modemode at constant load. Engine starts knocking justafter the point, where the maximum brake thermalefficiency is obtained.Smoke Emissions The variation of smoke emissions is shownin the Fig.12 for all three fuel modes. The smokeemission decreases considerably, with the increasein carburetion of petrol, for constant load condition.The petrol air mixture is more homogeneous andpilot fuel quantity is reduced so the combustionprocess is accelerated resulting in less smokeemission. Smoke intensity reduces, from 3.1 BSU to2.3 BSU for (neem oil + petrol) at 33.7% energyshare of petrol; from 2.4 BSU to 1.5 BSU for (neemoil ethyl ester + petrol) at 30.3% energy share ofpetrol and 2.1 BSU to 1.3 BSU for (diesel+ petrol)at 24.4% energy share of petrol. 324 | P a g e
  6. 6. G.Sucharitha, A.Kumaraswamy / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 3, Issue 1, January -February 2013, pp.320-325 REFERENCES [1]. Gerhard Vellguth, “Performance of vegetable oil and their monoesters as fuel for diesel engine”, SAE Paper No: 831358, 1983. [2]. Barsic, N.J. and Humke, A.L, “Performance and emission characteristics of naturally aspirated diesel engine with vegetable oil fuels”, SAE Paper No: 810262, 1981 [3]. M.Senthil Kumar, A.Ramesh and B.Nagalingam, “Investigations on the use of Jatropha oil and its methyl ester as a fuel in a compression ignition engine”, Journal of Institute of Energy,V. CONCLUSION March 2001, 74, pp24-28The following conclusions are given based on the [4]. A.Ramesh, “Study of Enginepresent work Performance and Emission characteristics The break thermal efficiency of neem oil is of a diesel engine using preheated24.9%, neem oil ester is 26.39% and that of diesel is vegetable oil as a fuel,” M.Tech31.4% at full load. The reduced break thermal Thesis, Jan 2003, Dept of Mechefficiency of neem oil is due to poor combustion as Engg., IIT Madras.a result of high viscosity and density. The smoke number of neem oil is 4.1 BSU,neem oil ester is 3.6 BSU and diesel is 2.8 BSU.The high viscosity and low volatility of neem oilleads to larger droplet sizes, poor mixture formation,sluggish combustion and increased smoke levels. When neem oil operating with fueltemperature at 160C (fuel temperature at which itsviscosity is equal to diesel viscosity), the maximumbrake thermal efficiency obtained is closer to thebrake thermal efficiency of diesel. There is a drasticreduction in smoke emission also. The increase in brake thermal efficiencyand reduction in smoke emission with increase infuel temperature of neem oil are due to bettercombustion of fuel air mixture as a result ofimproved atomization during injection. At 60% offull load and 1500 rpm with petrol carburetion,brake thermal efficiency increases from 24% to30.5% at 33.7% of energy share of petrol for neemoil and from26.8% to 32.3% at 30.3% of energyshare of petrol for neem oil ester. Smoke intensitydecreases from 3.1 BSU to 2.2 BSU for neem oil,from 2.4BSU to 1.5BSU for neem oil ester at thesame operating condition. HC/CO emissionsincrease with increase in petrol energy share. 325 | P a g e