performance analysis of conventional engine using preheated jetropha...

Performance Analysis of Conventional Engine using Preheated Jetropha Oil

Rakesh Kumar Gangwar

Department of Mechanical EngineeringM.I.T., Moradabad, U.P. INDIA

Bhanu Pratap SinghAssociate Professor

Department of Mechanical Engineering M.I.T., Moradabad, U.P. INDIA

ABSTRACTThe rapidly depleting petroleum resources and its major contribution for pollutants have promoted research for alternative fuels for diesel engines. Bio-fuel is one of the best substitutes as an alternative fuel due to the limited sources of conventional fuels and environmental concern. Vegetable oil promises best alternative fuel. The Straight vegetable oil has main advantage of eliminating the energy; cost and time consumed in biodiesel production and vegetable oils are able to reduce net CO2 emissions to the atmosphere due to their agricultural origin. Oil derived from Jatropha curcas plant has been considered as a sustainable alternate fuel for diesel engine. The use of straight vegetable oil encounters problem due to its high viscosity. Hence neat vegetable oil does not give better performance. In this experimental work, performance of diesel engine operating on preheated Jatropha oil was evaluated and compared with diesel operation. The performance parameters considered for comparing are brake specific fuel consumption, thermal efficiency. This study targets on investigating the effects of the engine operating parameters viz. fuel injection pressure and injection timing on performance of diesel engine with preheated vegetable oil and diesel.Keywords: Jatropha oil, Diesel engine, preheating.

1. INTRODUCTION

In the world of modernization and industrialized there is regularly and very faster consumption of petroleum resources but petroleum resources are limited so that there is a necessity to invent an option for future to find an alternate of petroleum fuel which is most optimal, renewable and easily accessible in nature. As the petroleum fuel resource is non-renewable and limited, so the fuel price at faster pace is continuously increases for regularly fulfillment of demand and diminishing supply. The most important point is that the fuel prices have strongly goes on increasing that will create interest in the use of bio-oils. Different countries are looking for different vegetable oils for example in Thailand research on palm oil. U.S.A. research on soybean oil, Philippines research on coconut oil, Malaysia and Indonesia on palm oil and Europeans country research on sunflower oil etc., are being considered as an alternative of crude fuel (Srivasata et al., 2000). Using straight vegetable oils in diesel engines is not a new idea. Rudolf Diesel first used peanut oil as a fuel for demonstration of his newly developed compression ignition (CI) engine in year 1910. Certain edible oils such as palm, sunflower, rapeseed and cotton seed can be used in diesel engines. For longer life of the engines these oils cannot be used straightway. These oils are not cost effective to be used as an alternate fuel in diesel

engines at present. Some of the non-edible oils such as Karanja (Pongamia pinnata), mahua,castor, neem (Azadiracta indica), rice bran, linseed, jatropha (Jatropha curcas) etc. can be used in diesel engines after some chemical treatment. (Agarwal, 1998 Agarwa et al., 2009, Barnwal et al., 2005). Jatropha oil produced from the seeds of the Jatropha curcas. Jatropha oil can be used directly after extraction (i.e. without refining) in diesel engines. Jatropha has the potential to provide economic benefits at the local level since it has the potential to grow in dry marginal non-agricultural lands, thereby allowing villagers and farmers to leverage non farm land for income generation. As well, increased Jatropha oil production delivers economic benefits to India on the macro-economic or national level as it reduces the nation’s fossil fuel import bill for diesel production. Diesel fuel has higher calorific value than Petrol. Therefore for heavy-duty transportation, diesel engines are widely used in power generation and also in irrigation sectors. Hence, the consumption rate of diesel fuel is much higher than Petrol. During combustion of fossil fuel there is continuously emission of Green-House Gases (GHG) such as CO2 which is causing global warming and climate. Vegetable oils and their derivatives in diesel engine lead to substantial reductions in emissions of sulfur oxides, carbon monoxide (CO), poly aromatic hydrocarbons (PAH), smoke, particulate matter (PM) and noise (Murayama, 1994, Bona et al., 1999, Vicente et al.,

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MIT International Journal of Mechanical Engineering, Vol. 3, No. 2, August 2013, pp. 96–101ISSN No. 2230–7680 © MIT Publications

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1998, Sendzikiene et al., 2006) Jatropha oil is non-edible oil and thus, there is no such issue. The high viscosity of vegetable oils may cause engine problems .Heating the oil or blending with diesel fuel can help solve this problem. (Quick 1980) reported that over 30 different vegetable oils have been used to operate compression ignition (CI) engines since the 1900’s. Initial engine performance suggests that these oil- based fuels have great potential as fuel substitutes. During the 1980’s, there were many studies that tested the possibility of using vegetable oils as a replacement for diesel. (Goering et al., 1981) studied the characteristic properties of eleven vegetable oils to determine which oils would be best suited use as an alternative fuel source.

2. EXPERIMENTAL SETUPIt is very important to characterize the properties of fuels such as kinetic viscosity, density, surface tension and calorific value, to study the performance of the engine with diesel and Jatropha oil. The engine is integrated with engine load system, fuel consumption measurement unit. The heat exchanger is designed, fabricated and installed on engine. The study was conducted on a computerized single cylinder four-stroke, naturally aspirated, open chamber (Direct Injection) and water-cooled diesel engine test rig commonly used in agriculture sector for minor irrigation needs as shown in Fig. 1. The specifications of diesel engine used for experiments are given in Table 1.

Fig. 1: Schematic diagram of experimental Set up.T1- Inlet engine water temperature; PT - Pressure transducer, N - RPM Decoder; Ta, Tb - In and out temperature of Exhaust; Tf—Fuel temperature at outlet of H.E; F1—Fuel Flow (Differential Pressure unit)

Table 1: Specifications of Diesel Engine

Product VCR Engine test setup 1 cylinder, 4 stroke, Diesel (Computerized)

Manufacturer KirloskarType 1 cylinder, 4 stroke Diesel, water cooledPower 3.5 kW at 1500 rpm,Stroke 110 mm, Bore 87.5 mm, 661 cc

The main components of the experimental setup are two fuel tanks (Diesel and Jatropha oil), fuel conditioning system, heat exchanger, exhaust gas line, by-pass line, and performance measurement equipment. Two fuel filters are provided next to the Jatropha oil tank so that when one filter gets clogged, supply of fuel can be switched over to another filter while the clogged filter can be clean/replace without stopping the engine operation. The engine is started with diesel and once the engine warms up, it is switched over to Jatropha oil. After concluding the tests with Jatropha oil, the engine is again switched back to diesel before stopping the engine until the Jatropha oil is purged from the fuel line, injection pump and injector in order to prevent deposits and cold starting problems. This purging typically takes about 15 min at idling. A shell and tube type heat exchanger is designed to preheat the vegetable oil using waste heat of the exhaust gases.

Table 2: Evaluated properties of Jatropha oil and Diesel

Property Diesel Jatropha OilDensity(kg/m3) 817 910Kinetic Viscosity (cSt) 3.4 48.5Calorific Value (MJ/kg) 43.04 37.08Surface Tension (N/m) 0.028 0.042

3. RESULT AND DISCUSSION Higher viscosity is a major problem in using vegetable oil as fuel for diesel engines. In the present investigations, viscosity was reduced by heating the oil with the help of diesel engine. Viscosity of Jatropha oil was measured at different temperatures in the range of 30–100°C.The result is shown in Fig. 2. Viscosity of Jatropha oil decreases remarkably with increasing temperature and it becomes close to diesel at temperature above 90°C. Viscosity of diesel was 3.4cSt at 30°C. For Jatropha oil, viscosity was 3.6 cSt at 100°C. Therefore, Jatropha oil should be heated up to 100°C before injecting it into the engine in order to bring its physical properties close to mineral diesel (at 30°C).

Fig. 2: Kinetic Viscosity vs Temperature


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Effect of Varying Fuel Injection Pressure and Fuel Injection Point on Brake specific fuel consumption of Engine

Brake specific fuel consumption of the engine was measured at different fuel injection pressures and fuel injection points for diesel and preheated jatropha oil. It was observed that the BSFC of the engine with diesel fuel at 200 BTDC and 175 kgf/cm2 was optimum as shown in Fig. 3. The BSFC of the engine fueled with PHJO was higher than the BSFC of diesel engine at 200 BTDC and 175 kgf/cm2 as shown in Fig. 5. The BSFC of the engine fueled with PHJO was optimum at 240 BTDC and 195 kgf/cm2 as shown in Fig.4. The BSFC of the engine fueled with PHJO was lower than the BSFC of the engine fueled with diesel at 240 BTDC and 195 kgf/cm2 as shown in Fig. 5. This is due to low calorific value, high viscosity, higher surface tension i.e. low combustion characteristics. The BSFC was plotted against the varying load, varying fuel injection pressure and fuel injection point. The variation of BSFC with all operating points with increasing load is as shown in Fig. 3 and Fig. 4. It is found from graphs that BSFC decreased as the engine load was increasing from no load to 80% load and further increase as load BSFC increases.

Fig. 3: Effect of fuel injection pressure and fuel injection points on BSFC of diesel fueled engine.

Fig. 4: Effect of fuel injection pressure and fuel injection points on BSFC of PHJO fueled engine.


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Fig. 5:.Effect of fuel injection pressure and fuel injection points on BSFC of Diesel and PHJO fueled engine.

It was observed that BSFC for the PHJO fueled engine is lower at 195 kgf/cm2 injection pressure and 240 BTDC advanced angle of fuel injection.

Effect of Varying Fuel Injection Pressure and Fuel Injection Point on Brake Thermal Efficiency of Engine.

It was found that the BTE of the engine with diesel fuel increased as the load was increased up to 80% after this BTE was decreased. The results obtained from experimentally shown that BTE at constant fuel injection pressure decreased from 200 BTDC, 260 BTDC in case of diesel fuel. Same experiments was carried out at injection pressures 175 kgf/cm2, 185 kgf/cm2, 195 kgf/cm2, 205 kgf/cm2.The BTE decreased continuously at all injection pressures in case of diesel engine.It was also observed that the angle of fuel injection and injection pressure which give optimum output with diesel fuel were 200 BTDC and 175 kgf/cm2 as shown in Fig. 6. The same experiments was performed with PHJO the BTE of engine at 200 BTDC fuel injection point and 175 kgf/cm2 fuel injection pressure was observed 30% which was much less than the efficiency with diesel 32.6% at same operating conditions. It was observed that the BTE with PHJO gradually increased as fuel injection was advanced to 220 BTDC& 240 BTDC and BTE started decreasing as fuel injection point was advanced to 260 BTDC. The above results shows that desirable fuel injection advance angle at a constant fuel injection pressure to give better efficiency for PHJO was 240 BTDC. The BTE of engine with PHJO fuel at 240 BTDC and 195 kgf/cm2 was 33.8% in comparison 30% when diesel fuel was used at 200 BTDC fuel injection point and 175 kgf/cm2 fuel injection pressures as shown in Fig. 7.It can be concluded that the BTE of engine with PHJO fuel

give optimum output at 240 BTDC fuel injection point and 195 kgf/cm2 injection pressure.

Fig. 6: Effect of fuel injection pressure and fuel injection points on BTE of diesel fueled engine.


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Fig. 7: Effect of fuel injection pressure and fuel injection points on BTE of PHJO fueled engine.

Fig. 8: Effect of fuel injection pressure and fuel injection points on BTE of Diesel and PHJO fueled engine

4. CONCLUSIONThe main objective of the present investigation was to reduce the viscosity of Jatropha oil close to that of conventional diesel in order to make it suitable for use in a C.I. engine and to evaluate the performance of the engine with new alternate fuels. In the present study, viscosity was reduced by preheating the Jatropha oil. It was found that heating the Jatropha oil between at 100°C is reducing the viscosity of jatropha oil close to diesel. It can be concluded from the experimental data that the BTE and BSFC of engine with PHJO fuel give optimum output at 240 BTDC fuel injection point and 195 kgf/cm2 injection pressure.Optimum fuel injection pressure and fuel injection point were evaluated for PHJO which was found to be 195 kgf/cm2 and 240 BTDC for preheated jatropha oil.

REFERENCES

[1] Srivasata and R. Prasad, “Triglyceride based diesel fuel “Renewable and Sustainable Energy Reviews, Vol. 4, No. 2, 2000, pp. 111-133.

[2] Agarwal, A.K., “Vegetable oils versus diesel fuel: development and use of biodiesel in a compression ignition engine,” TERI Inf Digest on energy, 1998, pp. 191-204.

[3] Agarwal, A.K. and K. Rajamanoharan, “Experimental investigations of performance and emissions of Karanja oil and its blends in a single cylinder agricultural diesel engine” Applied Energy 86, 2009, pp. 106 112.


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[4] B.K. Barnwal, M.P. Sharma, “Prospects of Bio-diesel Production from Vegetable Oils in India,” Renewable and Sustainable Energy Reviews 9, 2005, pp. 363-378.

[5] E. Sendzikiene, V. Makareviciene, P. Janulis, Influence of fuel oxygen content on diesel engine exhaust emissions, Renewable Energy, 31 29–35. (2006) 2505–2512.

[6] Goering, C.E., Schwab, A.W., Daugherty, M.J., Pryde EH, Heakin AJ (1981). Fuel properties of eleven vegetable oils. ASAE Paper, No. 81-3579.

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[8] Quick, G.R. (1980). Developments in use of vegetable oils as fuel for diesel engines. ASAE Paper, No. 80-1525.

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[10] T. Murayama, Evaluating Vegetable Oils as a Diesel Fuel, Inform (1994) 1138–1145.

performance analysis of conventional engine using preheated jetropha...

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