PERFORMANCE CHARACTERISTICS OF BIODIESEL MIXTURES IN A VARIABLE COMPRESSION RATIO ENGINE WITH CR 17

Transcription

1 International Journal of Mechanical Engineering and Technology (IJMET) Volume 6, Issue 8, Aug 215, pp , Article ID: IJMET_6_8_9 Available online at ISSN Print: and ISSN Online: IAEME Publication PERFORMANCE CHARACTERISTICS OF BIODIESEL MIXTURES IN A VARIABLE COMPRESSION RATIO ENGINE WITH CR 17 Biju Cherian Abraham Associate. Professor, Department of Mechanical Engineering, Mar Athanasius College of Engineering, Kothamangalam Ernakulum, India Chindhu Prasad M Tech Scholar, Department of Mechanical Engineering, Mar Athanasius College of Engineering, Kothamangalam Ernakulum, India ABSTRACT Petroleum based fuels are still the base of the automobile industry. The rapid depletion and fuel price points towards the need of alternative fuels. The biodiesel play a vital role as an alternative for diesel and the researchers are very much interested to investigate its performance from various sources. Performance and emission characteristics of biodiesel fuel from jatropha and rubber seed oil were studied experimentally. Bio-diesels are prepared from rubber seed oil and jatropha using transesterification process. A single cylinder, four stroke, constant speed, water cooled, direct injection variable compression ratio diesel engine is used for the experiment. The performance of the engine is measured using eddy current dynamometer and the emissions such as CO, CO 2, HC and NOx is measured using exhaust gas analyzer. The experimental data for various parameters such as brake thermal efficiency, volumetric efficiency, brake specific fuel consumptions (BSFC) and Mechanical efficiency were analyzed. The two biodiesels are blended with diesel by 2% and the characteristics are studied at compression ratios 16, 17, 18 and the mix shows better performance at CR 17. In this experiment 2% jatropha blend with diesel, 1% jatropha + 1% rubber seed blend with diesel and ordinary diesel are used as fuels. The experimental results proved that the use of biodiesel in compression ignition engine is a viable alternative to diesel. Key words: Biodiesel, Diesel engine, Variable compression Ratio, Biodiesel mixture 96 editor@iaeme.com

2 Performance Characteristics of Biodiesel Mixtures In A Variable Compression Ratio Engine with Cr 17 Cite this Article: Biju Cherian Abraham and Chindhu Prasad, Performance Characteristics of Biodiesel Mixtures In A Variable Compression Ratio Engine with Cr 17. International Journal of Mechanical Engineering and Technology, 6(8), 215, pp INTRODUCTION The large increase in industrialization and motorization in recent years has resulted in great demand for petroleum products. Energy demands increases as the combustion of fossil fuels increases and fossil fuels are limited, research is directed towards alternative fuels. The increase in crude oil import affects the country s economy and its development. The acid rain, global warming and health hazards are the results of ill effects of increased polluted gases like SOx, CO and particulate matter in atmosphere. The most modern scientific studies are researching on nature friendly inventions and to preserve nature for future life. Biodiesel is an alternative fuel similar to conventional or fossil diesel. Today s diesel engines require a clean burning with a stable fuel that performs well under the variety of operating conditions. Biodiesel is the only alternative fuel that can be used directly in any existing unmodified diesel engine. Because it has similar properties to diesel fuel, biodiesel can be blended at any ratio with diesel fuel. The present study focuses on the effect bio diesel blend s at various compression ratios in a compression ignition engine. A.Javidialesaadi and S. Raeissi investigates the pre-treatment step of biodiesel production from acid oils. In this work the effects of methanol-to-oil ratio, the amount of catalyst and time on the progress of the reaction are studied. Evangelos studied the exhaust emissions of diesel engines operating under transient conditions with biodiesel fuel blends. Irrespective of driving cycle type, the NOx emission penalty and the PM benefit with biodiesel seem to increase for more aggressive cycles/driving patterns. Moreover, biodiesels produced from unsaturated feedstocks tend to increase the NOx emission liability, such correlation has been established for the emitted PM, HC or CO. Hifjur Raheman studied Combustion characteristics and emissions of a compression ignition engine using emulsified jatropha biodiesel blend. With increasing percentage of water, ignition delay was longer at higher engine loads. Reductions in emission were observed for the emulsified fuel compared to JB1. Emulsified biodiesel can be recommended for use in place of biodiesel. Jincheng Huang studied the performances and emissions of a diesel engine is carried out using two different biodiesels derived from Chinese pistache oil and jatropha oil compared with pure diesel. The results shows brake thermal efficiencies of the engine run by the biodiesels are comparable to that run by pure diesel, with some increases of fuel consumptions. It is found that the emissions are reduced to some extent when using the biodiesels. Also the engine performance and emissions by Chinese pistache are similar to that run by jatropha biodiesel. 2. EXPERIMENT Biodiesel is produced from pure jatropha and rubber seed oil. These feedstock are purchased from local market. The biodiesel production is done by trasesterification method. Methanol and sodium hydroxide is used for this process. The experiment compare the characteristics of pure diesel (1%), ( 2% jatropha + 8% Diesel), 97 editor@iaeme.com

3 Biju Cherian Abraham and Chindhu Prasad (1% jatropha + 1% rubber seed + 8% Diesel). The characteristics include both the performance and emission. The test is conducted at a compression ratio of 17 in a VCR engine. Properties Jatropha oil Table 1 Properties of Fuel Jatropha biodiesel Rubber seed oil biodiesel Rubber seed oil Diesel Density, g/ml C, cst Calorific Value, MJ/kg Flash point, C Cloud point, C Experiments were initially carried out on the engine using diesel as fuel in order to provide base line data. Initially the engine was started using diesel fuel and allowed to run for few minutes until to reach steady state; the base line data were taken. Load was varied from zero loads to full load condition using an eddy current dynamometer and Emissions and fuel consumption reading were recorded. The engine was started with biodiesel blends as fuels e the supply either by using a two way valve or a premixing tank. Once the engine reaches steady state, the emission and fuel consumption were taken. The same procedure is carried from zero to full load condition. Similarly same procedures were carried for other fuels to be tested. Figure 1 Experimental set up The experimental test set up as shown in Fig 1 consists of four stroke, constant speed and single cylinder diesel engine. The engine is water cooled. The test was conducted in a computerized variable compression ratio multi fuel engine test rig developed by Legion Brothers. Extensive range of experiment can be done this test rig. The compression variable from 5:1 to 1:1 for petrol and 14:1 to 2:1 for diesel. It consists of spark plug, ignition coil, diesel injector, diesel pump and carburetor. It has facility to export the data to Microsoft excel. A standard air tank is fitted with a Differential pressure sensor for measuring the Actual volume of air drawn into the cylinder. The thermocouple and necessary signal conditioner for the measurement of temperature at various points are suitably provided. The loading of the engine is 98 editor@iaeme.com

4 Performance Characteristics of Biodiesel Mixtures In A Variable Compression Ratio Engine with Cr 17 controlled by the computer, hence precise loading is achieved. The test rig is provided with Eddy Current Dynamometer. Figure 2 Test Engine, DAQ and Dynamometer Experiments System has a lot of capabilities such as calculate Actual volume of air, Calculate Volumetric Efficiency, Calculate specific fuel consumption (SFC), Calculate brake Thermal Efficiency, Calculate Brake power, Heat Balance chart, Brake power, Calculate mechanical efficiency, Calculate Frictional Power, Calculate indicated Power, mechanical efficiency, PV and P-θ diagrams, Estimated End of Combustion Angle, Gross IMEP, Maximum Heat Release Rate, Maximum Heat Release rate crank angle, Maximum pressure rise rate, Maximum pressure rise rate crank angle, Maximum pressure, Maximum pressure crank angle, Calculate Start of Combustion, Ignition delay, ignition duration can be studied. Measurement of temperature at different points are Inlet water temperature in calorimeter (range - 3 C), Outlet water temperature in calorimeter (range -3 C), Inlet exhaust gas temperature in calorimeter (range -15 C), Outlet exhaust gas temperature in calorimeter (range -15 C), Inlet water temperature to engine (range -3 C) and Outlet water temperature from the engine cylinder (range -3 C). K type temperature sensor is used for the purpose. Windows based powerful software for real time data measurement, auto zoom graphs, analog and digital display of data in the computer, store indefinite no of graphs for analysis. Facilities to export data to Microsoft excel. The data acquisition software is developed by legion brothers. The following table shows the specifications of various components editor@iaeme.com

5 PRESSURE PRESSURE Biju Cherian Abraham and Chindhu Prasad Table 2 Specification Engine Make Legion Brothers Compression Ratio 5: 1 to 2:1 No of cylinders Single Type: Make (Selectable by the client) Dynamometer PowerMag Cooling Water Cooling Air Fuel Diesel Load Speed RPM Measurement Strain Gauge method HP 3 to 5HP Max Speed 3 rev/m Starting Manual Crank start HP 5 HP Lubrication Forced Coupling Type Direct 3. RESULTS AND DESCUSSION 3.1. Engine performance The combustion analysis tests are presented at various loads with a speed of 15 rpm. The cetane number (CN) of biodiesel derived from the jatropha is 54 and Rubber seed is 51 which is slightly higher than diesel which has the value of 49. PRESSURE VS CRANK ANGLE AT Kg CRANK ANGLE PRESSURE VS CRANK ANGLE AT 9Kg CRANK ANGLE Figure 3 Pressure vs Crank Angle Ignition delay is an important combustion parameter in diesel engine as it affects start of combustion, rate of heat release and peak pressure which depends on its cetane number. The maximum cylinder gas pressure was found to be Bar, 43.4 Bar, 45.3 Bar at Kg and Bar, Bar, Bar at 9 Kg for, and respectively. At all engine loads, combustion starts earlier for biodiesel than for diesel. This is due to a short ignition delay and advanced injection timing for biodiesel (because of a higher bulk modulus and higher density of biodiesel). In spite of the slightly higher viscosity and lower volatility of biodiesel, the ignition delay seems to be lower for biodiesel than for diesel. The reason may be that a complex and rapid pre-flame chemical reaction takes place at high temperatures. As a result of the high cylinder temperature existing during fuel injection, biodiesel may undergo thermal cracking and lighter compounds are produced, which might have ignited earlier to 1 editor@iaeme.com

6 VOL. EFF. MECH. EFF. BR. TH. EFF. S. F. C. Performance Characteristics of Biodiesel Mixtures In A Variable Compression Ratio Engine with Cr 17 result in a shorter ignition delay. At lower engine speed the variation is low as compared to higher loads. As the engine load decreases, the residual gas temperature and wall temperature decreases, which result in lower charge temperature at injection time and lengthening the ignition delay B. P. VS BR. TH. EFFICIENCY B. P B. P. VS S. F. C. Figure 4 BR TH Efficiency Figure 5 SFC The variation of brake thermal efficiency of the engine for and biodiesel is shown in Fig 4 and compared with the brake thermal efficiency obtained with diesel. At lower brake powers the BTE of biodiesel blend and biodiesel mixtures are same as that of diesel fuel. The reasons for this improvement of Brake thermal efficiency is better combustion and better lubricating property of biodiesel. Fig 6 compares the specific fuel consumption of diesel and various bio blends. It was observed that the specific fuel consumptions of the diesel as well as the blends were decreased with increasing load up to 8% load and then increases. Due to lower calorific value of biodiesel, for the same power output B2 needed more fuel flow than diesel as shown, which is also reported by many researchers. At maximum power, the fuel flow rate of was about 2% higher than diesel. From the figure it is clear that for jatropha biodiesel blend the volumetric efficiency is very low. The volumetric efficiency of the diesel engine mainly depends upon the combustion chamber temperature. The increase in the chamber temperature increases the intake air temperature and consequently reduces the mass of air drawn in each cycle thereby decreasing the volumetric efficiency. Biodiesel mixture has higher volumetric efficiency when compared to biodiesel. B. P. VS VOL. EFFICIENCY B. P. BP VS MECH. EFFICIENCY B. P. j2 Figure 6 Vol. Efficiency Figure 7 Mech. Efficiency 11 editor@iaeme.com

7 NOx CO2% CO% HC ppm Biju Cherian Abraham and Chindhu Prasad The variations of mechanical efficiency with compression ratio for various blends are shown in Figure 7. It has been observed that the mechanical efficiency of the blends is less which may be due to difference in fuel properties such as viscosity and density. The mechanical efficiency of the fuel blends is in general very close to that of diesel Emission By using this analyzer Carbon monoxide (CO), Hydrocarbon (HC), Nitrogen oxides (NOx), Carbon dioxide (CO2) and Oxygen (O2) were measured for different blends biodiesel with standard diesel and analyzed for different loads. Fig 8 shows the variation of carbon monoxide with changing the load conditions. Generally CO emissions are affected by start of injection timing, injection pressure, physical and chemical properties of the fuel used, engine load, speed and improper air fuel mixing. and produced lower CO than diesel. Biodiesel contains 1 11% oxygen content which promotes more complete combustion resulting lower CO emissions. However, effects of biodiesel on CO emissions vary significantly among vehicles, engine technology, test cycle, and the feed stocks used to produce the biodiesel. B. P. Vs CO% B. P. VS HC ppm Figure 8 CO% Figure 9 HC The variation of hydrocarbon emission with different loads for different blends is given in Fig.9. The fuel viscosity, fuel spray quality and characteristics also the incomplete combustion affects the HC emission. At higher loads curve became too steeper due to the rich fuel air mixture. It is seen that unburnt hydrocarbon emission increases with that of load for all prepared test fuels. From figure it is understood that biodiesel produces less HC emission in comparison to that of diesel because of better combustion of the test fuel and its blend due to presence of oxygen. B. P. Vs NOx B. P. Vs CO2% Figure 1 NO X Figure 11 CO 2 % 12 editor@iaeme.com

8 Performance Characteristics of Biodiesel Mixtures In A Variable Compression Ratio Engine with Cr 17 The production of NO X is significantly influenced by the in-cylinder gas temperature, availability of oxygen and residence time. The variation of nitrogen oxide with respect to load for both fuels and their blends are as shown in the graph. The present test results show that NO X emission increases almost linearly with increase in engine load which is because of higher cylinder pressure and temperature at higher loads. Due to higher oxygen content the has highest rate of NOx production. Proper oxygen content and appropriate temperature is necessary for complete combustion. The variation of carbon dioxide emission with different compression ratios are shown in Fig 11. Due to lower calorific value of biodiesel more fuel was needed to produce the same power and also due to fuel-borne oxygen in biodiesel, more carbon was oxidized to CO2 than partial oxidation of carbon to CO. has the highest level of CO2 emission as shown above. Table shows the values of CO 2 emission for all the fuels at the corresponding brake power. 4. CONCLUSION The pressure developed in the engine is higher for the diesel as compared to the biodiesel blends in all loads. The cetane number of the biodiesel is higher than the diesel, which leads to a higher ignition delay for diesel. Ignition delay for all fuels decreases as the engine load increases because the gas temperature inside the cylinder is higher at high engine loads, which reduces the physical ignition delay. BTE curve shows similar characteristics in lower loads and in higher loads the biodiesel shows better performance. This may be due to better combustion of biodiesels and lubricating property. For biodiesel mixture it can be see that SFC is much higher than that of diesel at lower BP and closer to diesel at higher brake power due to increased fuel efficiency. Volumetric efficiency is low for the biodiesel as compared to the diesel. The biodiesels are oxygen rich fuels, so the requirement of air reduces even under low volumetric efficiency. The mechanical efficiency is higher for the Biodiesel fuel. As compared to diesel, fuel blends have improved quality of spray, high reaction activity in the fuel rich zone and heat loss due to lower flame temperature may be the reason for increase in efficiency. CO and HC emission are lower for both and biodiesel mixtures when compared to diesel due to complete combustion of fuel. The curves are steeper in higher loads due to rich mixture combustion. The trend can be attributed to the higher oxygen content of Jatropha biodiesel and biodiesel mixtures due to which complete combustion takes place inside the cylinder. It is observed that the CO 2 emission of biodiesel is much higher value due to the complete combustion of fuel. NOx emission is more for than diesel due to increase in oxygen content because biodiesel contain many mono-unsaturated and poly-unsaturated fatty acids. The exhaust temperature is higher for the jatropha biodiesel, which results higher NOx values editor@iaeme.com

9 Biju Cherian Abraham and Chindhu Prasad REFERENCES [1] Hanny Johanes Berchmans, Shizuko Hirata, Biodiesel production from crude Jatropha curcas seed oil with a high content of free fatty acids, Science Direct 99 PP , March - 28 [2] Jetsada Posom, Panmanas Sirisomboon Evaluation of the moisture content of Jatropha curcas kernels and the heating value of the oilextracted residue using near-infrared spectroscopy, Biosystem Engineering 2(13), June [3] Javidialesaadi, S. Raeissi, Biodiesel Production from High Free Fatty Acid- Content Oils: Experimental Investigation of the Pretreatment Step5, Science Direct 15(474), Nov 213 [4] Jincheng Huang, Jincheng Huang, Yaodong Wang, Jian-bin Qin, Anthony P. Roskilly, Comparative study of performance and emissions of a diesel engine using Chinese pistache and jatropha biodiesel, International Journal of Research and Development 1(1), June 212 [5] Supriyono, Hary Sulistyo, Manuel F. Almeida, Joana M. Dias, Influence of synthetic antioxidants on the oxidation stability of biodiesel produced from acid raw Jatropha curcas oil, Eurasian Journal of Soil Science 4(11), March 215 [6] Keiya Nishida Xiangang Wang, Zuohua Huang, Olawole Abiola Kuti, Wu Zhang, Keiya Nishida, Experimental and analytical study on biodiesel and diesel spray characteristics under ultra-high injection pressure IOSR Journal of Mechanical Engineering 23, Nov 212, pp [7] Saptarshi Basu, Ranganathan Kumar, Xin Gu, Dispersion and vaporization of biofuels and conventional fuels in a crossflow pre-mixer, International journal of Heat And Mass Transfer 55(336), Nov 212 [8] Eugenio Sánchez-Arreola, Gerardo Martin-Torres, José D. Lozada-Ramírez, Luis R. Hernández, Erick R. Bandala-González, Horacio Bach, Biodiesel production and de-oiled seed cake nutritional values of a Mexican edible Jatropha curcas, Science Direct 76(143), Nov 214 [9] Md. Mofijur, H. Masjuki, M. A. Kalam, M. Shahabuddin, Assessing idling effects on a compression ignition engine fueled with Jatropha and Palm biodiesel blends, Renewable Sustainable Energy Reviews, 3, Nov 214, pp [1] Biju Cherian Abraham, Georgekutty S M, Dr. Shajan Kuriakose, Biodiesel Production From Rubber Seed Oil and Testing In A Twin Cylinder Direct Injection Diesel Engine, International Journal of Engineering Research & Technology 2(6) June editor@iaeme.com