Journal for Research| Volume 02| Issue 1 | March 2016 ISSN: 2395-7549
Optimization of Static Injection Timing of Diesel Engine Fuelled with Mahua biodiesel using EGR P. Vetrivel Assistant Professor Department of Mechanical Engineering Jayam College of Engineering and Tech., Dharmapuri 636 813, Tamil Nadu, India
Dr. K. Sundaramurthy Professor & Head Department of Mechanical Engineering Jayam College of Engineering and Tech., Dharmapuri 636 813, Tamil Nadu, India
Abstract The engine performance and emission characteristics of mahua (madhuca indica) biodiesel and its blends with diesel is presented. The thermo-physical properties of all the fuel blends have been measured and presented. The engine tests are conducted on a 4 Stroke Tangentially Vertical (TV) single cylinder kirloskar 1500 rpm water cooled direct injection diesel engine with eddy current dynamometer at different injection timings of 20°, 21°, 22° and 23° bTDC with standard nozzle opening pressure of 220 bar maintained as constant throughout the experiment. From the test results, it is observed that the lower injection timing of 20° bTDC and modified nozzle opening pressure of 220 bars gives better performance and significant reduction in emissions. Keywords: Diesel; Emissions; Mahua biodiesel; Performance; Static Injection Timing _______________________________________________________________________________________________________ I.
INTRODUCTION
In recent years, a growing interest is evinced concerning renewable and alternative fuels. These fuels are bio-degradable and oxygenated and the examples include vegetable oils, their derivatives and their mixtures with diesel. Research on vegetable oils in diesel engine is in progress at least for over 100 years. A brief literature review of research work carried out by various researchers is presented below. Sukumar Puhan et al. 1 investigated significant improvement in engine performance and emission of DI engine with mahua oil methyl ester, mahua oil ethyl ester, mahua oil butyl ester and diesel fuel. Subramanian et al. 2 operated the diesel engine for calibrating the performance and emission characteristics fuelled with diesel-ethanol-pungamia oil methyl ester. They concluded that 10% diesel, 80% of pungamia oil methyl ester and 10% ethanol proportion gives better performance of the diesel engine without any modification in it. Sukumar Puhan et al.3 operated engine tests with mahua oil methyl ester and mahua oil ethyl ester in a direct injection diesel engine. They concluded that mahua oil methyl ester gives better results as compared with ethyl ester of mahua oil. Sukumar Puhan and Nagarajan 4 carry out the direct injection diesel engine tests using methyl ester of mahua oil. They concluded that the mahua oil biodiesel gives lowest NOx as compared with diesel fuel. Puhan et al. 5 tested the diesel engine with mahua biodiesel in naturally aspirated diesel engines. They used neat diesel and neat bio diesel. Emissions are measured and reported that the impact of bio diesel (B100) is lower than that of diesel (B0). Kapilan and Reddy 6 investigated the diesel engine with mahua oil and LPG by changing the injection pressure for the entire operations. They concluded that methyl ester of mahua oil can be used as an alternative fuel in dual fuel engine with pilot fuel of 5 mg per cycle and injection pressure of 200 bar. Raheman and Ghadge 7 used madhuca indica biodiesel blended with fossil diesel and discussed extensively the engine performance obtained by blend with different volumetric ratios. They concluded that B20 gives better performance and lower emissions. Vetrivel and Sundaramurthy8 operaetd the diesel engine with hot EGR fuelled with mahua biodeisel. They concluded that B20 gives better performance and lower emissions. From the previous studies, it is observed that most of the studies were mainly related to the performance emission characteristics of diesel engine using bio diesel as fuel. In this paper an analysis of four stoke Tangentially Vertical single cylinder (TV1) direct injection (DI) with injection timings of 20°, 21°, 22° and 23°bTDC and nozzle opening pressure of 220 bar at full load condition of the diesel engine with eddy current dynamometer using B0, B25, B50, B75 and B100 as fuel is presented. II. EXPERIMENTAL SETUP AND PROCEDURE Experiments have been conducted on a 4 stroke, kirloskar, TV 1 direct injection diesel engine developing power output of 5.2 kW at 1500 rpm connected with water cooled eddy current dynamometer. The schematic of the engine setup is shown in Figure 1. Specifications of the engine are presented in Table 1.
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Optimization of Static Injection Timing of Diesel Engine Fuelled with Mahua biodiesel using EGR (J4R/ Volume 02 / Issue 1 / 002)
Fig. 1: Schematic of the engine setup with EGR Table - 1 Specification details of the engine Make Kirloskar TV – I Type Vertical single cylinder, DI diesel engine (87.5 x110) mm Bore Stroke Compression Ratio 17.5:1 Rated brake power 5.2 kW Rated Speed 1500 rpm Static Injection Timing 20, 21, 22 and 23 bTDC (modified) Nozzle Opening Pressure 220 bar (modified) at full load EGR Orifice Diameter 4 mm EGR Manometer Length of water column 30 mm Table - 2 Properties of Mahua biodiesel and its diesel blends S. No. Name of the Properties B0 B25 B50 B75 B100 1 Gross calorific value in MJ/kg 45.59 43.98 43.27 42.52 41.82 2 Kinematic viscosity at 40ºC in cSt 2.6 3.49 4.17 4.98 6.04 3 Flash Point in ºC 65 71 78 112 170 4 Fire Point in ºC 70 79 88 123 183 5 Cloud Point in ºC -15 4 8 11 13 6 Specific gravity 0.82 0.83 0.85 0.87 0.88 7 Cetane number 46 51.6 51.7 51.8 52.4 8 Acidity 0.065 0.067 0.070 0.083 0.26
From table 2, it is clear that specific gravity, acidity, kinematic viscosity, flash point, fire point and cloud point increases with increase in the bio diesel content. Especially, the significant increase in the fire point shows that the volatility of the mixture with increased biodiesel content will decrease. The gross calorific value decreases as the bio diesel content in the mixture increases. This is due to the oxygen concentration in the fuel and it requires more fuel to be burnt for a given heat release. The cetane number also increases along with different blends of bio diesel with fossil diesel fuel.
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Optimization of Static Injection Timing of Diesel Engine Fuelled with Mahua biodiesel using EGR (J4R/ Volume 02 / Issue 1 / 002)
III. RESULTS AND DISCUSSIONS Brake Thermal Efficiency:
Fig. 2: Brake Thermal Efficiency Vs Blend Ratio
Figure 2 shows variation of brake thermal efficiency with respect to blend ratio of the injection timings of 20°, 21° 22° and 23° (standard) at full load condition. For B0 and B25 fuel, 20° bTDC of injection timing give highest brake thermal efficiency (%) as compared to all other static injection timings. Among all blends, the B0 and B25 give almost same and higher brake thermal efficiency at full load condition as compared to all blends of fuel. The Brake thermal efficiency depends on heating value and specific gravity. The combination of heating value and mass flow rate indicate energy input to the engine. This energy input to the engine in case of B50, B75 and B100 are more compared to neat diesel. Smoke Density:
Fig. 3: Smoke Density Vs Blend Ratio
Figure 3 shows variation of Smoke density with respect to blend ratio of the static injection timings of 20°, 21° 22° and 23° (standard). From the test results, it is observed that the 20° bTDC of injection timing gives lowest smoke density (HSU) as compared to all other static injection timings. It is noted that as blends of fuel ratio increases, the smoke density also increases. This is to be expected because; more fuel is injected into the engine to take care of the load of blends of fuel. As the engine is running at constant speed there is less time for complete combustion to take place which can cause an increase in smoke density.
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Optimization of Static Injection Timing of Diesel Engine Fuelled with Mahua biodiesel using EGR (J4R/ Volume 02 / Issue 1 / 002)
Hydrocarbon:
Fig. 4: Hydrocarbon Vs Blend Ratio
The variation of hydrocarbon with respect to blend ratio of the injection timings of 20°, 21° 22° and 23° (standard) is shown in figure 4. From the test results, it is observed that the 20° bTDC of static injection timing gives lowest hydrocarbon as compared to all other static injection timings for all blends of fuel. Among all blends, the B25 gives highest percentage reduction of hydrocarbon at full load condition. This may be due to the viscosity and surface tension affects the penetration rate, maximum penetration and droplet size of the fuel, which in turn affects the mixing of fuel and air. Cetane number of the fuel also plays a vital role in ignition process. Oxides of Nitrogen
Fig. 5. Oxides of Nitrogen Vs Blend Ratio
Figure 5 shows variation of oxides of nitrogen (NOx) with respect to blend ratio for the static injection timings of 20°, 21° 22° and 23° (standard) DC. From the test results, it is seen that the 20° bTDC of static injection timing gives lowest NO x as compared to all other static injection timings for all blends of fuel. Among all blends, the B25 gives highest percentage reduction in NOx at full load condition. This is due to decrease in exhaust gas temperature. It is wee known that vegetable based fuel contains a small amount of nitrogen. This contributes towards NOx production. IV. CONCLUSIONS From these readings, it is concluded that the B25 could be effectively used as an alternative fuel for operating four stroke tangentially vertical single cylinder kirloskar direct injection water cooled constant speed diesel engine with static injection timing of 20° bTDC and nozzle opening pressure of 220 bar. Generally, all diesel trains are operated at full load conditions. From these findings, it can be concluded that B25 gives better results in terms of performance and lower emissions.
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Optimization of Static Injection Timing of Diesel Engine Fuelled with Mahua biodiesel using EGR (J4R/ Volume 02 / Issue 1 / 002)
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