Journal of Automobile Engineering and Application Volume 2, Issue 2 www.stmjournals.com

Experimental Investigation on 4-Stroke Diesel Engine Using Waste Cooking Oil Biodiesel Fuel Kondapalli Siva Prasad* Department of Mechanical Engineering, Anil Neerukonda Institute of Technology and Sciences, Visakhapatnam, India Abstract Due to using of fossil fuels, the world today is faced with serious environmental pollution. However, these fuels are limited and depleting day by day as the consumption is increasing very rapidly. Hence, it is necessary to find out a clean alternative fuel produced from renewable sources. Biodiesel production and applications are gaining popularity in recent times due to diminishing petroleum reserves and detrimental environmental impacts. Edible and non-edible oils are trans-esterified in the presence alcohol and a suitable catalyst to prepare the esters of the corresponding alcohol, commonly called as biodiesel. Biodiesel is an alternative fuel that can be used directly in diesel engine as pure or blended with diesel fuel. In this analysis, the effects of biodiesel produced from waste cooking oil (WCO) and its different blends with diesel fuel on the diesel engine torque and power, carbon monoxide(CO), hydrocarbons HC), oxides of nitrogen (NOx) and particulate matter (PM) emissions, brakespecific fuel consumption (BSFC) and brake thermal efficiency are analyzed and presented. Use of WCO biodiesel results in advanced start of injection, advanced combustion process, shorter ignition delay and increased heat release rate. Thus, higher cylinder peak pressure and temperature lead to increase NOx while PM is reduced. Although, the increase of the WCO percentage in the fuel blend reduces the engine torque and power, the results show some torque and power recovery for this reduction. The lower heating value of WCO results in increased BSFC but the engine brake thermal efficiency is not affected significantly. Keywords: Diesel engine, biodiesel, performance, waste cooking oil.

*Author for Correspondence E-mail: [email protected]

INTRODUCTION As the petroleum-based fuel resources are depleting day by day, it is necessary to replace alternative fuels for using in diesel engines. Vegetable oil esters are receiving increasing attention as non-toxic, biodegradable, and renewable alternative diesel fuel. These esters have become known as biodiesel. Biodiesel contains alkyl monoesters of fatty acids, which are environmental friendly and obtained through transesterification process of triglycerides. However, vegetable oil has high viscosity and low volatility, which leads to poor combustion in diesel engines [1–4]. Transesterification is the process of removing glycerides and mixing oil esters of vegetable oil with alcohol. It reduces the viscosity value, which is comparable with diesel, maintains high heating value and increases the cetane number, thereby improving performance characteristics within a diesel engine such as

injection timing, fuel vaporization, and ignition delay are altered with the use of biodiesel fuel relative to petroleum diesel fuel. The differences in chemical composition and structure between the fuels manifest such differences in engine processes, which ultimately lead to differences in engine parameters (i.e., combustion, performance and emissions).  Vegetable oil esters are known as biodiesel.  Transesterification process to reduce the viscosity of fuel.  Differences in chemical composition and structure lead to differences in engine parameters.  Combustion of biodiesel fuel in diesel engines results in lower PM, CO and HC emissions while the Brake thermal efficiency is either unaffected or is improved.

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Investigation on 4-Stroke Diesel Engine Using Biodiesel Fuel

Siva Prasad Kondapalli

Waste Cooking Oil  Biodiesel

Transesterification reaction for biodiesel production from waste cooking oil using calcium ethoxide as catalyst.

sulfates, polycyclic aromatic hydrocarbons, nitrated polycyclic aromatic hydrocarbons, and particulate matter.

Catalyst Preparation (Figure 1) Ca + 2(CH3CH2OH)  Ca(OCH2CH3)2 + H2

One of the most used renewable energy is biodiesel which is the most common biofuel in Europe. It is produced from oils or fats using transesterification and is a liquid similar in composition to mineral diesel. Its chemical name is fatty acid methyl ester (FAME). In this study, oils are mixed with potassium hydroxide KOH as catalyst and methanol and the chemical reaction produces biodiesel (FAME) and glycerol. One part glycerol is produced for every 10 parts of biodiesel.

Fig. 1: CETCAT. 

Transesterification reaction using calcium ethoxide catalyst with methanol at 60 °C for two hours produced high yield of biodiesel (95%).

FUEL PREPARATION Biodiesel is prepared from natural, renewable sources, such as new and used vegetable oils and animal fats, for use in a diesel engine. Its physical properties are very similar to petroleum-derived diesel fuel, whereas its emission properties are superior to that of diesel. It substantially reduces emissions of unburned hydrocarbons, carbon monoxide,

Biodiesel can be used in all types of diesel engines when mixed with mineral diesel. In some countries, manufacturers cover their diesel engines under warranty for 100% biodiesel use. Most of the manufactures recommend 15% biodiesel blended with mineral diesel. Blends Preparation In the waste cooking oil bio-diesel and methanol in a molar proportion of 1:6 were reacted to produce biodiesel. Then 1% weight of KOH of the waste cooking oil was added as a catalyst in the transesterification reaction. Potassium methoxide and water was first mixed and KOH was added as a catalyst with methanol. The mixture of potassium methoxide and water was then poured into a reacting tank to mix with the waste cooking oil and stirred by a homogenizer to obtain a transesterification reaction. Because of high

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Journal of Automobile Engineering and Application Volume 2, Issue 2

solubility in oil, fast reaction rate, good physical and chemical properties, and low cost, methanol is commonly used. The reacting temperature of the transesterification process was set at 55 C, which is below the boiling temperature of methanol at 64 C to prevent methanol from vaporizing from the reacting mixture during transesterification process. The transesterification process takes 60 min to complete. After the completion of the transesterification process, the mixture was separated into coarse biodiesel and glycerin by settling for 2 h. A water washing method was then used to remove the un-reacted methanol and other impurities contained in the coarse biodiesel. The biodiesel obtained after this process was pure biodiesel (B100) in this study [5–9]. This pure bio-diesel is mixed with pure diesel in proportion and required blends are obtained. Initially 25% of bio-diesel (i.e., half liter) and 75% of diesel (i.e., one and a half liter) are taken in a tumbler and then placed on the magnetic stirrer with stirring paddle in the tumbler as shown in Figure 2. Then the mixture of fuels is allowed to stir for 30 min using electric power to magnetic stirrer. The blend obtained after complete stirring is B25 (i.e., 25% bio-diesel and 75% diesel fuels mixture)

Fig. 2: Magnetic Stirring Process. Similarly the blends of B 50 (i.e., 50% biodiesel and 50% diesel) and blend B75 (i.e., 75% bio-diesel and 25% diesel) as prepared in the lab using magnetic stirrers with paddles. Experiments Held on Blends After preparation of bio-diesel blends B25, B50, B75 few experiments are made in mechanical lab for extracting the few properties of the blends like Pensky Martens which gave the value of Flash point, Red Wood Viscometer Experiment for calculating the viscosity of fuel (Figures 3 and 4). The obtained values of the blends, pure bio-diesel and diesel are tabulated in Table 1.

Table 1: Properties of Fuels. S. No.

Property

Bio-diesel

B 75

B 50

B 25

Diesel

1

Density; 15 °C

Kg/m3

Units

860

853.25

846.5

839.75

833

2

Viscosity; 40 °C

mm2/S

4.9

4.375

3.85

3.325

2.8

3

Flash point

°C

101

91.5

82.5

73

64

4

Cetane number

---

51

53

54

56

57

Fig. 3: Redwood Viscometer-I.

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Investigation on 4-Stroke Diesel Engine Using Biodiesel Fuel

Siva Prasad Kondapalli

Fig. 4: Pensky Martens Apparatus.

EXPERIMENTAL SETUP Initially the test rig of diesel engine is inspected for the working specification of engine, and the temporary fixing of muffler is

made as shown in Figure 5 and 6. Then the fuel tank is made empty and filled with the pure diesel initially.

Fig. 5: Diesel Engine Test Rig and Muffler Arrangement. emission values are tabulated at each load with muffler and without muffler regularly. After complete cycle, the experiment is repeated with varying of pressure (i.e. 180 to 200 bar, to 225 bar, to 250 bar).

Fig. 6: Test Rig Specifications. Then load test is held with varying loads and parallel the emissions from exhaust pipe are measured by smoke analysis meter. The

After complete experiment, the fuel tank is made empty and the new fuel blend B25 is filled into tank and then the procedure is repeated and corresponding readings are tabulated. After B25 blend fuel, with B50 and B75 also procedure is made repeat and corresponding values are tabulated (Figure 7). After Experiment using the reading fuel consumption, mechanical efficiency, brake thermal efficiency, specific fuel consumption, etc., are calculated by using relevant formulae.

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Journal of Automobile Engineering and Application Volume 2, Issue 2

Fig. 7: Loading and Unloading of Fuel in the Engine.

PERFORMANCE CALCULATIONS As a part of performance calculations, initially the load is applied on the engine and spring balance reading is noted and the fuel consumption for 10 cc for each loading condition is noted. The important performance characteristics are calculated using the following equations. Maximum load = Rated BP × 60,000/2π NR × 9.81 kg 2πN(W−S) × 9.81 × R kW Brake power “BP” = 60,000 Fuel consumption “FC” = 10 × SP gravity × 3600 kg/h t × 1000 Indicated power “IP” = BP + FP Mechanical efficiency “ηmech” = BP/I.P Brake thermal efficiency “ηbth” = BP × 3600 FC × CV Indicated thermal efficiency “η1th” = IP × 3600 FC × CV

Brake mean effective pressure “BMEP” = BP × 60,000 N/m2 L × (π/4D2) × (N/2) Indicated mean effective pressure “IMEP = I.P × 60,000 N/m2 L × (π/4 D2) × (N/2) Specific fuel consumption “SFC” = FC/BP kg/kWh

RESULTS AND DISCUSSION After calculating the performance characteristics analysis had been done, comparison of mechanical efficiency, brake thermal efficiency and specific fuel consumption at various injection pressures for different samples of fuel are presented. Comparison of Mechanical Efficiency Performance graphs for brake power versus mechanical efficiency are plotted at various injection pressures and presented in Figures 8–11.

Fig. 8: Mechanical Efficiency for Pure Diesel.

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Investigation on 4-Stroke Diesel Engine Using Biodiesel Fuel

Siva Prasad Kondapalli

Fig. 9: Mechanical Efficiency for 25-75 Bio-Diesel (B25).

Fig. 10: Mechanical Efficiency for 50-50 Bio-Diesel (B50).

Fig. 11: Mechanical Efficiency for 75-25 Bio-Diesel (B75).

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Journal of Automobile Engineering and Application Volume 2, Issue 2

Comparison of Brake Thermal Efficiency Performance graphs for brake thermal efficiency and fuel injection pressure are plotted for various compositions of fuels and are presented in Figures 12–15.

Fig. 15: Brake Thermal Efficiency for 25-75 Biodiesel (B75).

Fig. 12: Brake Thermal Efficiency for Pure Diesel.

Fig. 13: Brake Thermal Efficiency for 75-25 Biodiesel (B25).

Fig. 14: Brake Thermal Efficiency for 50-50 Biodiesel (B50).

Comparison of Specific Fuel Consumption Performance graphs for specific fuel consumption and fuel injection pressure are plotted for various compositions of fuels and are presented in Figures 16–19.

Fig. 16: Specific Fuel Consumption for Pure Diesel.

Fig. 17: Specific Fuel Consumption for 25-75 Biodiesel (B25).

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Investigation on 4-Stroke Diesel Engine Using Biodiesel Fuel

Fig. 18: Specific Fuel Consumption for 50-50 Biodiesel (B50).

Siva Prasad Kondapalli

Fig. 21: K-value at Injection Pressure of 200 bar.

Fig. 19: Specific Fuel Consumption for 75-25 Bio-Diesel (B75).

Fig. 22: K-value at Injection Pressure of 225 bar.

Combustion Analysis Combustion analysis is carried out using an exhaust gas smoke analyzer. Comparison of Smoke Density Smoke density is represented with K-value. Graphs are drawn for K-value and brake power for different compositions of fuel (Figures 20–23).

Fig. 23: K-value at Injection Pressure of 180 bar.

Fig. 20: K-value at Injection Pressure of 180 bar.

Fig. 24: Opacity at Injection Pressure of 180 bar.

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Journal of Automobile Engineering and Application Volume 2, Issue 2

Comparison of Opacity of Smoke Graphs are drawn between opacity and brake power for different compositions of fuel (Figures 24–27).

Fig. 25: Opacity at injection pressure of 200 bar.

Fig. 26: Opacity at injection pressure of 225 bar.

Fig. 27: Opacity at injection pressure of 250 bar.

CONCLUSIONS The following conclusions are drawn from the analyses carried out on 4-stroke diesel engine. a) Higher Mechanical efficiencies are obtained at fuel injection pressure 225 bar for all compositions of fuels. b) Specific fuel consumption is low at fuel injection pressure 225 bar for all compositions of fuels. c) Smoke density (K-value) is low for B25 bio-diesel. d) Opacity is low for B25 bio-diesel. e) The optimum results on a 4-stroke diesel engine are achieved at an injection pressure of 225 bar and using B25 biodiesel.

REFERENCES 1. Energy Story. http://www.energyquest.ca. gov, Chapter 8. Fossil fuels: Coal, Oil and Natural gas. 2. Coady D, El-Said M, Gillingham R, et al. The magnitude and distribution of fuel subsidies: Evidence from Bolivia, Ghana, Jordan, Mali and Sri Lanka. IMF Working Paper. 2006. 3. The effects of fossil-fuel subsidy reform: A review of modelling and empirical studies. The Global Subsidies Initiative. 31p. 4. Canakci M, Van Gerpen JH. Comparison of engine performance and emissions for petroleum diesel fuel, yellow grease biodiesel, and soybean oil biodiesel. Transactions of the ASAE. 2003; 46(4): 937–44p. 5. Tat ME, Van Gerpen JH, Wang PS. Fuel property effects on injection timing, ignition timing, and oxides of nitrogen emissions from biodiesel-fueled engines. Transactions of the ASAE. 2007; 50(4): 1123–28p. 6. Monyem A, Van Gerpen JH, Canakci M. The effect of timing and oxidation on emissions from biodiesel-fueled engines. Transactions of the ASAE. 2001; 44(1): 35–42p. 7. Graboski MS, Ross JD, McCormick RL. Transient emissions from No. 2 diesel and biodiesel blends in a DDC series 60 engine. SAE paper no. 961166. 1996.

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8. Peterson CL, Reece DL. Emissions testing with blends of esters of rapeseed oil fuel with and without a catalytic converter. SAE paper no. 961114. 1996. 9. Jiafeng S, Jerald AC, Timothy JJ. Oxides of nitrogen emissions from biodieselfuelled diesel engines. Progress in Energy and Combustion Science. 2010; 36: 677– 95p.

Siva Prasad Kondapalli

Cite this Article Siva Prasad Kondapalli. Experimental investigation on 4-stroke diesel engine using waste cooking oil biodiesel fuel. Journal of Automobile Engineering and Application. 2015; 2(2): 19–28p.

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