PERFORMANCE AND EMISSION CHARACTERISTICS OF A THERMAL BARRIER COATED FOUR STROKE CI ENGINE USING DIESEL, BIODIESEL AND ETHANOL BLENDs AS FUELs

ABSTRACT

India is producing a most of non-edible oils such as linseed, castor, mahua, rice bran, karanji (pongamia), neem, kusum (Schlechera trijuga),etc. Some of these oils produced are not being properly utilized. One hundred years ago, Rudolf diesel tested vegetable oil as a fuel for his engine. With the advent of cheap petroleum, appropriate crude oil fractions were refined to serve as a fuel and diesel fuels and diesel engines evolved together. In the 1930s and the 1940s vegetable oils were used as diesel engine fuels from time to time, but usually only in emergency conditions. Recently, because of increase of increase in crude oil prices, limited resources of fossil fuel and environmental concerns there has been renewed focus on vegetable oils and animal fats to make bio-diesel.

In the present work, Diesel-Biodiesel-Ethanol and Diesel-Biodiesel-Diethyl ether fuels were tested in normal diesel engine and thermal barrier coated (Al2O3) diesel engine. The various performance parameters are calculated and emission parameters were studied.

The results shows that the Brake thermal efficiency was found to be highest for TDBD .The Torque was found out to be constant irrespective of the fuel blends used .The Brake mean effective pressure was also out be constant irrespective of the fuel blends used.DBD was found to have lowest Specific energy consumption at initial loads. The Specific fuel consumption of all the fuels was found to be similar at higher loads .TDBE had lowest CO emissions among all fuels used. TDBE was also found have lowest CO2 at higher loads. DB had the lowest HC emissions at all loads .TDBE and TDBD had higher NOx emissions among all fuels used. TDBE and TDBD had higher smoke emissions at initial loads but eventually had lower smoke emissions at higher loads.

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TABLE OF CONTENTS

ABSTRACT 1

1. INTRODUCTION

1.1 NEED FOR ALTERNATIVE FUELS 7

2. LITERATURE SURVEY 9

3. AN OVERVIEW OF BIODIESEL, ETHANOL, DIETHYL

ETHER AND THERMAL BARRIER COATINGS

3.1 PRIMARY ALCOHOLS AS FUELS FOR ENGINES 16

3.2 PROPERTIES 18

3.3 VEGETABLE OILS AS ENGINE FUELS 19

3.4 BIODIESEL AS ENGINE FUELS 21

3.5 TRANSESTERIFICATION 21

3.6 THERMAL BARRIER COATINGS 23

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3.7 DEE 26

4. COMPARISON OF FUEL PROPERTIES 27

4.1 FUEL PROPERTIES 27

4.2 EVALUATION OF THE FUEL PROPERTIES 28

4.3 COMPARISON OF FUEL PROPERTIES OF DIESEL 29

5. EXPERIMENTAL SETUP DETAILS

5.1ENGINE SPECIFICATIONS 30

5.2 INSTRUMENTS USED

5.2.1 EDDY CURRENT DYNAMOMETERS 31

5.2.2 AVL 437 SMOKEMETER SPECIFICATION 31

5.2.3 FIVE GAS ANALYZER 32

5.2.4 AVL GAS ANALYZER SPECIFICATIONS 33

5.2.5 AVL SMOKEMETER 34

6. METHODOLOGY

6.1 FUELS USED 35

6.2 TEST PROCEDURE FOR ENGINE 36

6.3 EXPERIMENTAL SETUP 37

7. RESULTS AND DISCUSSIONS 38

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7.1 PERFORMANCE CHARACTERISTICS 39

7.1.1 BRAKE THERMAL EFFICENCY 39

7.1.2 TORQUE 40

7.1.3 BRAKE MEAN EFFECTIVE PRESSURE 40

7.1.4 SPECIFIC ENERGY CONSUMPTION 41

7.2 EMISSION CHARACTERISTICS 42

7.2.1 CO EMISSION 42

7.2.2 CO2 EMISSION 43

7.2.3 HC EMISSION 43

7.2.4 NOX EMISSION 44

7.2.5 SMOKE EMISSION 45

8. MATLAB PROGRAM AND SIMULINK MODEL 47

8.1 MATLAB AND SIMULINK 47

8.2 INPUT AND OUTPUT OF MATLAB PROGRAM 48

8.3 GRAPHS PLOTTED BY THE MATLAB PROGRAM 49

8.4 SIMULINK MODEL FOR FINDING

PERFORMANCE PARAMETERS 51

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CONCLUSION 53

APPENDIX 54

REFERENCES 55

TABLE OF FIGURES

1. MINIMUM THERMAL CONDUCTIVITIES OF SOME MATERIALS 24

2. THERMAL CONDUCTIVITY WITH TEMPERATURE

OF VARIOUS MATERIALS 24

3. COMPARISON OF FLASH AND FIRE POINTS OF DIESEL,

BIODIESEL AND ITS BLENDS 28

4. COMPARISON OF VISCOSITIES OF DIESEL, BIODIESEL

AND ITS BLENDS 28

5. COMPARISON OF CLOUD POINT AND POUR POINT OF

DIESEL, BIODIESEL AND ITS BLENDS 29

6. EXPERIMENTAL SETUP FOR THE PROJECT 36

7. PHOTOGRAPH OF THE EXPERIMENTAL SETUP 37

8. PISTON CROWN AND CYLINDER HEAD COATED WITH 5

Al2O3 37

9. VARIATION OF BRAKE THERMAL EFFICIENCY WITH

POWER 39

10.VARIATION OF TORQUE WITH RESPECT TO POWER 40

11.VARIATION OF BRAKE MEAN EFFECTIVE PRESSURE

WITH RESPECT TO POWER 41

12.VARIATION OF SPECIFIC ENERGY CONSUMPTION WITH RESPECT TO POWER 41

13.VARIATION OF CO WITH RESPECT TO POWER 42

14.VARIATION OF CO2 WITH RESPECT TO POWER 43

15. VARIATION OF HC WITH RESPECT TO POWER 44

16.VARIATION OF NOX WITH RESPECT TO POWER 45

17.VARIATION OF SMOKE WITH RESPECT TO POWER 45

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CHAPTER 1

INTRODUCTION

1.1 NEED FOR ALTERNATIVE FUELS

The world is presently confronted with the crises of fossil fuel depletion and environmental degradation. Indiscriminate extraction and excessive consumption of fossil fuels have led to reduction in underground carbon resources (fossil fuels) [11]. The search for alternative fuels, which promise a harmonious conservation, efficiency and environmental preservation, has become highly pronounced in the present context. The fuels of bio-origin can provide a feasible solution to this worldwide petroleum crisis. Gasoline and diesel-driven automobiles are the major sources of green-house emissions. Scientists around the world have the potential to quench the ever increasing energy thirst of today’s population. The other major problem the world is facing now is global warming [11].

Energy comes from renewable sources of energy such as wood, bio mass, wind, sunlight etc. It also comes from non-renewable sources of energy such as fossil fuels. The excessive use of these non-renewable fuels has caused pollution to air, water and land. Two centuries of unprecedented industrialization, driven mainly by fossil fuels, has changed the face of this planet. The present civilization cannot survive without motor cars and electricity. This pollution and accelerating energy consumption has affected the earths land mass, atmosphere and oceans [7]. Particularly, the more important is the loss of bio-diversity. Fortunately, the last 25 years has seen the growing awareness of some of these consequences.

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In this century it is believed that the crude oil and the petroleum products could become scarce and more costly. Day-to-day the fuel economy is becoming improved and it would continuously be improved. Another reason motivating the development of alternative fuels for IC engines is the concern over emission problems of gasoline and diesel engines. Combined with other air polluting systems, large number of automobiles is the major contributor of to the air quality problem of the world [4]. Quite a lot of improvements have been made in reducing the emissions from the automobile engines. Lots of effort has gone into reducing the exhaust. However more improvements are needed to bring down the ever-increasing air pollution due to automobile pollution. Another reason for the alternative fuel development is the fact that large percentage of crude oil is imported from other countries. This would reduce the economic revenue of the country [4]. Use indigenous alternative fuels would give a boost to the economic revenue of the country. The present energy scenario has also stimulated active research in interest in non-petroleum, renewable and non-polluting fuels. The world reserves of primary energy and raw materials are, obviously, limited. According to an estimate the reserves of primary energy will last for 218 for coal, 41 years for oil, and 63 years for natural gas, under a business –as-usual scenario [8]. The enormous growth of world population, increased technical development, and standard of living in industrial nations has led to this intricate situation in the field of energy supply and demand. The prices of crude-oil keep fluctuating and rising on a daily basis. This necessitates the developing and commercializing fossil fuel alternatives from bio-origin. This may well be the main reason behind the growing awareness and interest for unconventional bio energy sources and fuels in various developing countries, which are striving hard to offset the oil monopoly.

Various bio-fuel energy resources include biomass, biogas, primary alcohols, vegetable oils, biodiesel etc. These alternative energy resources are largely environmental friendly but they have to be evaluated for on case-to-case basis for their advantages, disadvantages and specific applications [2]. Some of these fuels can be used directly while the others need to be formulated to bring the relevant properties closer to conventional fuels.

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CHAPTER 2

LITERATURE SURVEY

K. Suresh Kumar , R.Velraj , R.Ganesan [1] was tested using diesel, pure biodiesel and four different blends of diesel and biodiesel (B20, B40, B60, B80). For the blends B20 and B40 the BSFC is lower than or equal to the diesel. As the concentration of PPME increases in the blends the BSFC increases at all loads and the percentage difference is higher at low loads. The CO emission is almost absent for B40 and B60 at all operating conditions. The HC emission increases for diesel for increase in load and is almost nil for all PPME blends except for B20. The NOX

emission follows an increasing trend with respect to load. From the experimental investigations it can be seen that PPME with diesel up to 40% by volume (B40) could replace diesel for diesel engine operations by giving better performance and lesser emissions.

H.Raheman , A.G. Phadatare [2] The karanja methyl ester (biodiesel, B100) and its blends (B20, B40, B60, B80) were used to test a single cylinder, four stroke, water cooled diesel engine. The torque increased with increase in load. The torques produced in case of B20 and B40 were 0.1-13% higher than diesel. In case of B60 to B100, it reduced by 4-23% from that of diesel. The BSFC decreased with increase in load. B20 and B40 showed 0.8-7.4% lower than that of diesel. In case of B60-B100, the BSFC consumption was 11-48% higher than that of diesel. The BTE was found to increase with the increase in load. The maximum brake thermal

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efficiencies 26.79% and 26.19% for B20 and B40, which were higher than that of diesel (24.62%).

Sanjib Kumar Karmee , Anju Chadha [3] Transesterification of the crude oil of pongamia pinnata was done using KOH at two different temperatures (45°C and 60°C) with two different molar ratios of oil to methanol (1:3 and 1:10). Transesterification of crude pongamia oil was also done using solid acids catalyst (Hβ-Zeolite, Montmorillonite K-10 or ZnO) with oil to molar ratio of 1:10.At 45°C, the maximum conversion of 80% was observed for molar ratio of 1:3 whereas the conversion of 83% was observed with molar ratio of 1:10 with an initial lag time. At a molar ratio of 1:10 increasing the reaction temperature from 45°C to 60°C resulted increase of conversion from 83% to 92%. When the transesterification reaction was catalyzed by solid catalyst (Hβ-Zeolite, Montmorillonite K-10, or ZnO) at 120°C the conversion ratios were 83%, 59% and 47% for ZnO, Hβ-Zeolite and Montmorillonite K-10 respectively. The transesterification of pongamia oil increased to 95% at 60°C at a molar ratio of 1:10 with addition of THF (Tetrahydrofuran).

Nagarhalli M.V, Nandedkar V.M, Mohite K.C [4] The test was carried on a single cylinder, four stroke, constant speed engine using base diesel and diesel-biodiesel blends (B20 and B40). At an injection pressure of 200 bar HC emissions decreased by 12.8% for B20 and 3% for B40 at full load. NOX decreased by 39% for B20 and 28% for B40 at full load. BSEC increased by 7% for B20 and 1.9% for B40 at full load. There was no significant change in efficiency in all the 3 cases.

R.K.Singh , Saraswath Rath [5] Karanja methyl ester was blended with diesel in proportions of 5%, 10%, 15%, 20%, 30%, 40%, 50% and 100%. The test was carried out in a four stroke, single cylinder DI diesel engine. The brake thermal efficiency at all load conditions was higher for B100. Almost all blends show slightly better BTE than diesel at higher-load conditions. The brake specific energy consumption (BSEC) was found to be lower for B30 than diesel. The exhaust gas temperature was found to be lowest for diesel fuel. The mechanical efficiency for B30 is better than diesel fuel for no lower load conditions.

S.Sivalakshmi , Dr.T.Balusamy [6] The blends of di-ethyl ether in JOME was tested, namely 5%(B-D5), 10%(B-D10), 15%(B-D15) and 20%(B-D20) by volume

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in addition to base diesel and 100% JOME. The experiments were conducted on single cylinder, four stroke, naturally aspirated direct injection diesel engine. The brake thermal efficiency was found to be lowest for JOME at all loads when compared to diesel fuel. The brake thermal efficiency increases with addition of DEE. However addition of DEE above 15% causes decrease in thermal efficiency. The brake specific fuel consumption was found to reduce with the increase in load for all blend of fuels. It was found that the brake specific fuel consumption is improved about 9% with 15% DEE blend at maximum load. Addition of DEE made the lowest level of smoke at no load and part load conditions and the highest level of smoke at higher and full load conditions. At high loads, the exhaust CO emissions increases with increase in DEE fraction in the blends. The hydrocarbon emission was found to be higher with the increase of DEE fraction in the blends. Addition up to 15% DEE made the lowest level of carbon di oxide at low and part loads whereas the highest level was at high and full load.

K.Sureshkumar , R.Velra [7] The biodiesel was mixed with diesel in varying proportions from 20% to 100% (B20, B40, B60, B80 and B100. The test was carried on a single cylinder, four stroke, water-cooled and constant speed compression ignition engine. The BSFC and BSEC for all fuel blends and diesel tested decrease with the increase in load. For B20 blend the BSFC is lower than diesel for all loads. For B40, the BSFC was almost the same as that of diesel. For blends with biodiesel concentration above 40%, the BSFC was observed to be greater than diesel. The BSEC also increases than the diesel as the concentration of biodiesel in the blend increases. The CO emission for diesel is more than all the biodiesel blends under all the loading conditions. The CO concentration is totally absent for the blends of B40 and B60 and as the biodiesel concentration in the blend increases above 60% the presence of CO observed. The CO2 emission increased with the increase in load for all the blends. The blends B40 and B60 emit low CO2 emissions. The HC emission decreases with the decrease in load except for B20 where some traces are seen at no load and full load. The NOx emissions for all the fuel tested followed an increasing trend with respect to load. The reduction was remarkable forB20 and B60.

Avinash Kumar Agarwal [8] Ethanol is one of the possible alternative fuels for the partial replacement of mineral diesel in CI engines. The results indicate no power

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reduction in the engine operation on diesel-ethanol blends (up to 20%) at a 5% level of significance. BSFC increased by up to 9% (with ethanol up to 20%) in the blends. The exhaust temperatures and exhaust emissions (CO and NOx) were lower on operations on ethanol-diesel blends. The thermal efficiency of an engine operating on biodiesel is generally better than operating on diesel. The brake specific energy consumption (BSEC) is a more reliable criterion compared to brake specific fuel consumption (BSFC) for comparing fuels with different calorific values and densities. The specific fuel consumption values of methyl esters were generally less than those of raw vegetable oils. Higher thermal efficiency, lower BSFC and exhaust temperature are reported for all blends of biodiesel compared to mineral diesel. The carbon deposits for biodiesel-fueled engine were found to be substantially lower than the diesel fueled engine.

Huseyin Aydin , Cumali Ilkilhc [9] Commercial diesel fuel, 20% biodiesel and 80% diesel fuel, called here as B20 and 80% biodiesel and 20% ethanol, called here as BE20, were used in a single cylinder, four stroke direct injection engine. Maximum torque was obtained at 2000 rpm for both B20 and BE20 fuels but at 2500 rpm for DF. The engine torque that obtained for BE20 was higher than both those obtained for diesel and B20 fuels. Average increase of torque values for BE20 was 1.2% and 1.3% when compared to diesel fuel and B20, respectively. The obtained power for DF and BE20 was almost similar. However the power that obtained from B20 was lower than that of other fuels. BE20 fuel operation showed lower BSFC, than expected, as especially at lower engine speeds. Higher BSFC was observed when running the engine with B20 fuel. Average brake-specific fuel consumption for usage of B20 was 22.32% higher than that of diesel fuel and 20.13% higher than that of BE20. It can be observed that brake thermal efficiency was 31.71% at 2500 rpm for BE20 and those of DF and B20 were 28.15% and 25.95% respectively. The brake thermal efficiency of B20 blend was lower compared to DF and BE20. The exhaust gas temperature with BE20 was higher when compared to those of diesel and B20 fuels. The CO emitted by B20 and BE20 biodiesel blends, is lower than the ones for the corresponding diesel fuel case. The NOx emissions were found to be high, 102 and 129 ppm at 1000 rpm and 1500 engine speeds for the BE20 operated engine. However, at 2000 rpm and higher speed engine operations, the NOx emission was lower when compared with

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both diesel and B20 fuels. At 3000 rpm engine speed, for BE20 operation NOx was found to be lower, 131 ppm compared to diesel of 245 ppm. CO2 emissions were found to be higher for diesel and BE20 fuels.

D.H.Qi , H.Chen , L.M. Geng , Y.Z.Bian [10] An experimental investigation is conducted to evaluate the effects of using diethyl ether and ethanol as additives to biodiesel/diesel blends on the performance, emissions and combustion characteristics of a direct injection diesel engine. The test fuels are denoted as B30 (30% biodiesel and 70% diesel in vol.), BE-1 (5% diethyl ether, 25% biodiesel and 70% diesel in vol.) and BE-2 (5% ethanol, 25% biodiesel and 70% diesel in vol.) respectively. The results indicate that, compared with B30, there is slightly lower brake specific fuel consumption (BSFC) for BE-1. Drastic reduction in smoke is observed with BE-1 and BE-2 at higher engine loads. Nitrogen oxide (NOx) emissions are found slightly higher for BE-2. Hydrocarbon

(HC) emissions are slightly higher for BE-1 and BE-2, but carbon monoxide (CO) are slightly lower. The peak pressure, peak pressure rise rate and peak heat release rate of BE-1 are almost similar to those of B30, and higher than those of BE-2 at lower engine loads. At higher engine loads the peak pressure, peak pressure rise rate and peak heat release rate of BE-1 are the highest and those of B30 are the lowest. BE-1 reflects better engine performance and combustion characteristics than BE-2 and B30.

Gvidonas Labeckas ,Stasys Slavinskas , Marius Mazeika , Kastytis Laurinaitis[11] The tests were conducted on a four stroke, four cylinder, direct injection, unmodified, naturally aspirated diesel engine operating on baseline (DF) arctic class 2 diesel fuel (80 vol %), rapeseed methyl ester (5 vol %) and anhydrous (200 proof) ethanol (15 vol %) blend (B5E15). The BSFC of a fully loaded engine operating on ethanol-diesel-biodiesel blend B5E15 under BMEP 0.75, 0.76 and 0.68 MPa is higher by 10.30 %, 10.71 % and 9.65 % because of both net heating value of biofuel lower by 6.18 % comparing with diesel fuel and brake thermal efficiency lower by 5.56 %, 2.86 % and 2.86 % relative to that of neat diesel fuel at corresponding 1400, 1800 and 2200 rpm speeds. The maximum NOx emissions emanating from blend B5E15 are lower by 13.4 %, 18.0 % and 12.5 % and smoke opacity is diminished by 13.2 %, 1.5 % and 2.7 % throughout a whole speed range relative to their values measured from neat diesel fuel. As a reasonable payoff for NOx related advantages, CO amounts from oxygenated blend BE15 are lower by

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6.0 % for low 1400 rpm speed and they are bigger by 20.1 % and 28.2 % for a higher 1800 and 2200 rpm speeds and emissions of HC are higher by 35.1 %, 25.5 % and 34.9 % relative to that measured from neat diesel fuel at corresponding 1400, 1800 and 2200 rpm speeds. In the case of operating on blend B5E15 residual oxygen O2 content in the exhaust manifold is lower by 5.0 %, 7.4 % and 4.3 % and carbon dioxide CO2 emissions are higher by 2.8 %, 3.4 % and 2.4 % relative to that obtained from diesel fuel at speeds of 1400, 1800 and 2200 rpm.

M.Mohamedmusthafa, S.Sivapirakasam,M.Udayakumar,K.Balasubramanian [12] The compression ignition engine used for the study was Kirloskar TV-I, single cylinder, four stroke, constant speed, vertical, water cooled and direct injection diesel engine. In the first phase, engine combustion chamber elements (cylinder head, cylinder liner, valves, and piston crown face) were coated with 200 µm thickness nano-ceramic material of Al2O3 by using plasma spray-coating method. In second phase, experiments were carried out on Al2O3- coated engine by using pongamia methyl ester (PME), PME blends of 20 and 40% by volume with diesel and pure diesel. The test run was repeated on uncoated engine and the results were compared. The increase in thermal efficiency was 1.6% for pure diesel, 0.8% for PME40 and 7.8% for PME20 in the coated engine when compared to the uncoated engine. It was observed that the specific fuel consumption (SFC) of the test fuel decreased with the increase in load. The decrease in SFC was observed to be 2% for pure diesel, 4% for PME 100, 5.8% for PME40 and 7.8% for PME20 in the coated engine when compared to the uncoated engine. The decrease in smoke density for 100% power output in the coated engine when compared with the uncoated engine are 24.4% for diesel, 27.2% for PME100, 32.2% for PME40 and 20% for PME20. NOx emission increases with the increase in engine load. Increase in NOx emission in the coated engine, compared with the uncoated engine are 44.2% for diesel, 12.8% for PME100, 30.9% for PME40 and 32.6% for PME20. There was an increase in the temperature of exhaust gas in the case of the coated engine for all test fuels than that of the uncoated engine.

Murat Ciniviz [13] The test was carried out on a Mercedes benz OM 364A direct injection turbo diesel four cylinder engine. The cylinder heads, valves and pistons with yttria stabilized zirconia layer with a thickness of 0.35 mm nickel-chromium-aluminium bond coat, as well as the atmospheric plasma spray coating method with a thickness of 0.15 mm. The pure diesel fuel was tested on both the coated (LHR) and the uncoated engine (SDE). A sole blend of diesel and ethanol (10% ethanol and 90% diesel) was tested in the coated engine (LHReth) alone. All

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comparisons are made according to the SDE diesel conditions. The engine power increases by 2% at all speeds in LHR diesel engine condition. In LHReth condition, the engine power decreases by 22.5% at all speeds. The engine torque increases by 2.5% at all engine speeds in the LHR diesel engine condition. In the LHReth condition, the engine torque decreases by 23% at all engine speeds. The brake power increased with the increase in speed in the LHReth condition. The specific fule consumption was lower than by 1% during all operating range of the SDE in the case of the use of LHR. Similarly, the specific fuel consumption increases approximately to 54% during all operating range of the SDE engine in case of the use of LHReth. According to the SDE, LHR shows an increment of average 1% depending on the engine speed at full load in effective efficiency. LHReth shows a decrement of average 35% depending on engine speed at full load in effective efficiency.

Danepudi Jagadish, Puli Ravi Kumar, K. Madhu Murthy [14] The effect of supercharging on performance of a DI diesel engine using ethanol and diesel blends as fuel and using palm-stearin methyl ester as additive is studied. The performance of the engine is evaluated in terms of BSFC, thermal efficiency, exhaust gas temperature, unburnt hydrocarbons, carbon monoxide, nitrogen oxide emissions and smoke opacity. The investigation results showed that the output and torque performance of the engine with supercharging was improved in comparison of a naturally aspirated engine. It is observed that the thermal efficiency of diesel ethanol blends were higher than that of diesel. With supercharging brake thermal efficiency is further increased. BSFC of ethanol, ester and diesel blends are lower compared to diesel at full loads. Further reduction in BSFC was noted by supercharging. NOx emission seems to decrease and HC, CO emissions are more with diesel-ethanol-ester mixtures. K.Muralidharan, P.Govindarajan [15] In this paper, effect of fuel injection timing on engine performance and emission characteristics of a single cylinder DI engine has been experimentally investigated using pongamia pinnata methyl ester and its blends with diesel from 0% to 30% with an increment of 50% at varying loads(20%,40%,60%,80%). The tests were conducted at three different injection timings (19, 23 and 27 CA). The experimental work reveals that increasing the concentration of methyl ester in diesel increases DSFC and emissions of NOx and CO2 while BTE and emissions of CO and HC showed a decreasing trend. Better

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performance, HC and CO was observed during advanced injection timing for blend B10. Retarted injection timing showed improvements over NOx and CO for blend of B10.

CHAPTER 3

AN OVERVIEW OF BIODIESEL, ETHANOL, DI ETHYL ETHER AND THERMAL BARRIER COATINGS

3.1 PRIMARY ALCOHOLS AS FUELS FOR ENGINES

Avinash Kumar [8] explained that ethanol has been known as fuel for many decades. Indeed, when henry Ford designed the Model T, it was his expectation that ethanol, made from renewable biological materials would be a major automobile fuel. However, gasoline emerged as the dominant transportation fuel in the early twentieth century because of the ease of operation of gasoline engines with the materials then available for engine construction, and a growing supply of cheaper petroleum from oil field discoveries. But gasoline had many disadvantages as an automotive fuel. The ‘new’ fuel had a lower octane rating than ethanol, was much more toxic, was generally more dangerous, and emitted harmful air pollutants. Gasoline was more likely to explode and burn accidently, gum would form on storage surfaces, and carbon deposits would form in the combustion chamber. Pipelines were needed for distribution from ‘area found’ to ‘area needed’. Petroleum was much more physically and chemically diverse than ethanol, necessitating complex refining procedures to ensure the manufacture of consistent ‘gasoline’ product. Because of its lower octane rating relative to ethanol, the use of gasoline meant the use of lower compression engines and larger cooling systems. Diesel engine technology, which developed soon after the emergence of gasoline as the dominant transportation fuel, also resulted in the generation of large quantities of pollutants. However, despite these environmental flaws, fuels made

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from petroleum have dominated automobile transportation for the past three quarters of the century. There are two reasons: cost per kilometer has been virtually the sole selection criteria. Second, the large investments made by the oil and auto industries in physical capital, human skills and technology make the entry of a new cost competitive industry difficult. Until very recently, environmental concerns have been largely ignored.

Ethanol is one of the possible fuels for diesel replacement in compression ignition (CI) engines also. The application of ethanol as a supplementary CI engine fuel may reduce environmental pollution, strengthen the agricultural economy, create job opportunities, reduce diesel fuel requirements, and thus contribute in conserving a major commercial energy source. Ethanol was first suggested as an automotive fuel in USA in the 1930s, but was widely used only after 1970. Nowadays, ethanol is used as fuel, mainly in Brazil, and as a gasoline additive for octane number enhancement and improved combustion in USA, Canada and India. As gasoline prices increase and emission regulations become more stringent, ethanol could be given more attention as a renewable fuel or gasoline additive.

Alcohol is made from renewable resources like biomass from locally grown crops and even waste products such as waste paper, grass and tree trimmings etc. Alcohol is an alternative transportation fuel since it has properties, which would allow its use in existing engines with minor hardware modifications. Alcohols have higher octane number than gasoline. A fuel with higher octane number can endure higher compression ratios before engine starts knocking, thus giving engine an ability to deliver more power efficiently and economically, produce less CO, HC and oxides of nitrogen. Alcohol has higher heat of vaporization, therefore, it reduces the peak temperature inside the combustion chamber leading to lower NOx

emissions and increased engine power. However, the aldehyde emissions go up significantly. Aldehydes play an important role in the formation of photochemical smog.

Methanol is a simple compound. It does not contain sulfur or complex organic compounds. The organic emissions from methanol combustion will have lower reactivity than gasoline than gasoline fuels hence lower ozone forming potential. If pure methanol is used then the emission of benzene, Methanol, gives higher

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efficiency and is less flammable than gasoline but the range of methanol fueled vehicle is as much as half less because of lower density and calorific value, so larger fuel tank is required. M100 has invisible flames and it is explosive in enclosed tanks. The cost of methanol is higher than gasoline. Methanol is toxic, and has corrosive characteristics, emits ozone creative formaldehyde. Methanol poses an environmental hazard in case of spill, as it is totally miscible with water. Ethanol is similar to methanol, but it is considerably cleaner, less toxic and less corrosive. It gives greater engine efficiency. Ethanol is grain alcohol and can be produced from agricultural crops e.g. sugarcane, corn etc. Ethanol is more expensive to produce, has lower range, poses cold starting problems and large harvest of these crops. Higher energy input is required in ethanol production compared to other energy crops and it leads to environmental degradation problems such as soil degradation [8].

3.2 PROPERTIES

Ethanol is isomeric with di-methyl ether (DME). The oxygen atom in the ethanol possibly induces three hydrogen bonds. Although, they may have the same physical formula, the thermodynamic behavior of ethanol differs significantly from that of DME on account of stronger molecular association via hydrogen bonds in ethanol. Alcohol fuels, methanol and ethanol have similar physical properties and emission characteristics as that of petroleum fuels. Alcohol’s production is cheaper, simple and eco -friendly. This way, alcohol would be a lot cheaper than gasoline fuel. Alcohol can be produced locally, cutting down the transportation costs. Alcohol fuels can be successfully used as IC engine fuels wither directly or preparing biodiesel. Transesterification process utilizes methanol or ethanol and vegetable oils as the process inputs. This route if utilizing alcohol as a diesel engine fuel is definitely a superior route as the toxic emissions are drastically reduced. The problem of corrosion of various engine parts utilizing alcohol as fuel is also solved by way of transesterification. Alcohols have been attracting worldwide. Consumer wants a cleaner fuel that can risk of harm to environment and health. Governments aim to reduce reliance on imported energy and promote domestic renewable energy programs, which could utilize domestic resources and create new economic activities. Though biofuels remain relatively small in use compared to more traditional forms, the scenario is changing rapidly. When factors

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are coupled with vast agricultural resources, new technologies that reduce abatement and a strong will from government and private entrepreneurs, the markets for biofuels are slowly but surely gaining momentum. The fuel ‘ethanolisation’ of the world alcohol industry is set to continue [8].

3.3 VEGETABLE OILS AS ENGINE FUELS

Dr. Rudolf Diesel invented the diesel engine to run on a host of fuels including coal dust suspended in water, heavy mineral oil, vegetable oils. Dr. Diesel’s first engine experiments were catastrophic failures, but by the time he showed his engine at the world exhibition in Paris in 1900, his engine was running on 100% peanut oil. Dr. Diesel was a visionary. In 1911 he stated “The diesel engine can be fed with vegetable oils and would help considerably in the development of agriculture in countries, which use it”. In 1912, Diesel said, “The use of vegetable oils for engine fuels may seem insignificant today. But such oils may become as important as petroleum and the coal tars of the present time” [8]. Since Dr. Diesel’s untimely death in 1913, his engine has been modified to run on the polluting petroleum fuel, now known as “diesel”. Nevertheless, his ideas on agriculture and his invention provided the foundation for a society fueled with clean, renewable, locally grown fuel.

In the 1930s and 1940s, vegetable oils were used as diesel substitutes from time to time, but usually in emergency situations. Recently, because of increase in crude oil prices, limited resources of fossil fuel and environmental concerns, there has been a renewed focus on vegetable oils and animal fats to make biodiesel. Continued and increasing use of petroleum will intensify local air pollution and magnify the global warming problems caused by carbon di oxide. In a particular case, such as the emission of pollutants in the closed environment of underground mines, biodiesel has the potential to reduce the level of pollutants and the level of potential for probable carcinogens.

The advantages of using vegetable oils as fuels are:

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1. Vegetable oils are liquid fuels from renewable sources.

2. They do not over-burden the environment with emissions.

3. Vegetable oils have potential for making marginal land productive by the property of nitrogen fixation in the soil.

4. Vegetable oil’s production requires lesser energy input in production.

5. Vegetable oils have higher energy content than other energy crops like alcohols. Vegetable oils have 90% of the heat content of diesel and they have a favorable output/input ratio of about 2-4:1 for un-irrigated crop production.

6. The current process of the vegetable oils in world are nearly competitive with petroleum fuel price.

7. Simpler processing technology

8. These are not economically feasible yet.

9. Need further R&D work for development of on farm processing technology.

Due to the rapid decline in crude oil reserves, the use of vegetable oils as diesel fuels is again promoted in many countries. Depending upon climate and soil conditions, different nations are looking into different vegetable oils for diesel fuels. An acceptable alternative fuel for engine has to fulfill the environmental and energy security needs without sacrificing the operating performance. Vegetable oils can be successfully used in CI engines through engine modifications and fuel modifications. Engine modifications include dual fuelling, injection system modifications, heated fuel lines etc. fuel modifications include blending of vegetable oils with diesel, transesterification, cracking/pyrolysis, micro-emulsions, and hydrogenation to reduce polymerization and viscosity [8].

1. Micro-emulsions:

To solve the problem of high viscosity of vegetable oils, micro-emulsions with solvents such as methanol, ethanol, 1-butanol have been investigated. A micro-

20

emulsion is defined as a colloidal equilibrium dispersion of optically isotropic fluid microstructures with dimension generally in the 1-150 nm range, formed spontaneously form two normally immiscible liquids. They can improve the spray characteristics by explosive vaporization of the low boiling constituents in the micelles. Short term performance of micro-emulsions of aqueous ethanol in soybean oil was nearly as good as that of no.2 diesel, inspite of the lower cetane number and energy content.

2. Pyrolysis (Thermal cracking):

Pyrolysis is the conversion of one substance into another by mean sof heat or by heat in presence of a catalyst. The paralyzed material can be vegetable oils, animal fats, natural fatty acids or methyl esters of fatty acids. The pyrolysis of fats has been investigated for more than 100 years, especially in those areas of the world that lack deposits of petroleum. Many investigators have studied the pyrolysis of triglyceride to obtain products suitable for diesel engines. Thermal decomposition of triglycerides produces alkanes, alkenes, alkadines, aromatics and carboxylic acids.

3. Transesterification:

In organic chemistry, transesterification is the process of exchanging the alkoxy group of an ester compound by another alcohol. The reactions are often catalyzed by an acid or a base. Transesterification is crucial for producing biodiesel from bilipids. The transesterification process is the reaction of a triglyceride (fat/oil) with a bio-alcohol to form esters and glycerol.

3.4 BIODIESEL AS ENGINE FUEL

The best way to use vegetable oil as a fuel is to convert it in to biodiesel. Biodiesel is the name of a clean burning mono-alkyl ester-based oxygenated fuel made from natural, renewable sources such as new/used vegetable oils and animal fats. The resulting biodiesel is quite similar to conventional diesel in its main characteristics. Biodiesel contains no petroleum products, but it is compatible with conventional diesel and can blended in any proportion with mineral diesel to create stable biodiesel blend. The level of blending with petroleum diesel is referred to as Bxx, where xx indicates the amount of

21

biodiesel in the blend (i.e. B10 blend is 10% biodiesel and 90% diesel. It can be used in CI engine with no major modification in the engine hardware) [8].

3.5 TRANSESTERIFICATION

Vegetable oils have to undergo the process of transesterification to be usable in internal combustion engines. Biodiesel is the product of the process of transesterification. Biodiesel is biodegradable, non-toxic and essentially free from sulfur, it is renewable and can be produced from agricultural and plant resources. Biodiesel is an alternative fuel, which has correlation with sustainable development, energy conservation, management, efficiency and environmental preservation [8].

Transesterification is the reaction of a fat or oil with alcohol to form esters and glycerol. Alcohol combines with the triglyerides to form glycerol and esters. A catalyst is usually used to improve the reaction rate and yield. Since the reaction is reversible, excess alcohol is required to shift the equilibrium to the product side. Among the alcohols that can be usd in transesterification process are ethanol, methanol, propanol, butanol and amyl alcohol. Alkali-catalyzed transesterification is much faster than acid-catalyzed transesterification and is most often used commercially. The process if transesterification brings a drastic change in the viscosity of the vegetable oils. The biodiesel thus produced by this process is totally miscible with mineral diesel in any proportion. Biodiesel viscosity comes very close to that of handling system. Flash point of the biodiesel gets lowered after esterification and the cetane number gets improved. Even lower concentrations of biodiesel act as cetane improver for biodiesel blend. Calorific value of biodiesel is also found to be very close to mineral diesel. Some typical observations from the engine tests suggested that the thermal efficiency of the engine generally improves, cooling losses and exhaust gas temperature increases, smoke opacity generally gets lower for biodiesel blends. Possible reason may be additional lubricity properties of the biodiesel; hence reduced frictional losses (FHP). The energy thus saved increases thermal efficiency, cooling losses and exhaust losses from the engine. The thermal efficiency starts reducing after a concentration of biodiesel. Flash point, density, pour point, cetane number,

22

calorific value of biodiesel come in very close to that of the mineral diesel range [8].

Diesel engine can perform satisfactory for long run on biodiesel without any hardware modifications. 20% of biodiesel is the optimum concentration for biodiesel blend for improved performance. Increase in exhaust temperature however leads to increased NOx emissions from the engine. While short term tests are almost positive, longterm use of neat vegetable oils or their blends with diesel leads to various engine problems such as, injector coking, ring sticking, injector deposits etc. High viscosity, low volatility and a tendency for polymerization in cylinder are root causes of many problems associated with direct use of these oils as fuels. The process of transesterification yields vegetable oil ester, which has shown promises as alternative diesel fuel as a result of improved viscosity and volatility. Several researchers investigate the different vegetable oil esters and find esters comparable with that of diesel. The yield of biodiesel in the process of transesterification is affected by several parameters [3]. The most important variables affecting are:

1. Reaction temperature

2. Molar ratio of alcohol and oil

3. Catalyst

4. Reaction time

5. Presence of moisture and free fatty acids

3.5 THERMAL BARRIER COATINGS

Clarke and phillphot [16] said that somewhat surprisingly, the experimental investigation of thermal conductivity at very high temperatures has been a largely neglected field since the work of Kingery and colleagues in the 1950s. They measured the thermal conductivity of many oxides as a function of temperature and studied the effects of porosity and of mixing two different oxides. They also demonstrated that, after correction for the temperature dependence of thermal expansion, the thermal conductivity of almost all oxides decreases as 1/T, in accord with thermal conductivity being controlled by the Umklapp inelastic phonon-phonon scattering process. The majority of their measurements (Fig 2) do

23

not extend to the temperatures of interest for future TBCs, but they did find that three fluorite oxides, YSZ, UO2-x, and Th0.7U0.3O2+x, exhibit temperature-independent thermal conductivity at high temperatures, quite different from other crystalline oxides but very similar to that of fused silica. The absence of the characteristic 1/T dependence was ascribed to the fact that both YSZ and UO2-x

contain very high concentrations of point defects that scatter phonons.

Fig 1. Minimum thermal conductivities of some materials [16]

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Fig 2. Variation of Thermal conductivity with Temperature for various materials [16]

The thermal conductivity of a material is a measure of heat flow in a temperature gradient. In the first successful model for thermal conductivity, Debye used an analogy with the kinetic theory of gases to derive an expression of the thermal conductivity:

κ = CVνmΛ/3where, Cv is the specific heat, νm is the speed of sound, and Λ is the phonon mean free path. Both Kittel in 1949 and Kingery in 1955 suggested that the minimum value of the thermal conductivity at high temperatures was that given by the above equation with the phonon mean free path equal to the interatomic spacing. This simple approach works quite well because, at temperatures in excess of the Debye temperature T > ΘD, the specific heat is close to its asymptotic, temperature-independent value of Cv → 3kB per atom, as predicted by the Dulong-Petit equation. Other, more sophisticated approaches also assume that the major contribution to thermal conductivity in the high-temperature regime is caused by phonons whose mean free path is the interatomic spacing. In a similar way, the low

25

temperature-independent thermal conductivity of fused silica and other glasses has been attributed to their random structure precluding any long-wavelength phonon modes, with the dominant phonon contributions being limited by the size of the tetrahedral unit of the glass. The minimum thermal conductivity for more complex, multicomponent materials also has a similar form and can be expressed as:

κmin = kBνmΛmin → 0.87kBΩa-2/3(E/ρ)1/2

where, Λmin is the minimum phonon mean free path, Ωa = M/(mρNA) is the average volume per atom, E is the elastic modulus, and ρ is the density. The data for a variety of materials is plotted in Fig. 1, illustrating that materials with low thermal conductivity tend to have large volumes per atom and low specific elastic modulus E/ρ. A particularly important feature of the minimum thermal conductivity is that, in contrast to conductivity at lower temperatures, it is independent of the presence of defects such as dislocations, individual vacancies, and long-range strain fields associated with inclusions and dislocations. This is largely because these defects affect phonon transport over length scales much larger than the interatomic spacing. This also means that measurements at low and intermediate temperatures can be a poor guide to the thermal conductivity at high temperatures

3.6 DI ETHYL ETHER

As a compression ignition fuel, DEE has several favorable properties, including an outstanding cetane number and reasonable energy density for onboard storage. Based on measurement of ignition delay in combustion bomb compared to known reference fuels, cetane number of DEE is higher than 125 [17]. DEE is liquid at ambient conditions, which makes it attractive for fuel handling and infrastructure requirements. Storage stability of DEE and blends of DEE are of concern because of tendency to oxidize, forming peroxides in storage. Flammability limits of DEE are broader than most of the fuels[17]. DEE is widely known as an anesthetic, which may be of concern for direct human health impacts. DEE’s lubrication properties are unknown, but these probably pose less problem than expected for dimethyl ether.

DEE is fit to use for diesel engines mixed with vegetable oils and/or diesel fuel and presents a case for Brazil using alcohol in diesel engine instead of Otto cycle

26

engines. The main advantages of DEE are; for example; it is the simplest way to transform alcohol to any other derivative. This transformation could be achieved by dehydration with solid fixed bed catalysts instead of standard process using sulfuric acid. DEE’s advantages over ethanol includes its non corrosive nature and its greater heating value [17].

CHAPTER 4

COMPARISON OF FUEL PROPERTIES

4.1 FUEL PROPERTIES:

The comparison of the different properties of the Diesel, Pongamia Biodiesel, Ethanol and Diethyl ether are shown in the following table

PROPERTY DIESEL PONGAMIA BIODIESEL

ETHANOL DIETHYL ETHER

Calorific value (KJ/Kg)

42500 36050 25500 31875

Flash point 52 147 16.6 -4527

(°C)

Fire point (°C) 61 153 25 -48

Cloud point (°C)

7 19 -25 >5

Pour point (°C)

-3 14 -113 >5

Specific gravity

0.840 0.886 0.750 0.714

Cetane number

40-48 54 8 >125

Stoichiometric A/F ratio

15:1 13.8:1 9:1 11.1:1

Self ignition temperature

(°C)

240-250 368 422 175

4.2 EVALUATION OF THE FUEL PROPERTIES OF DIESEL, BIODIESEL AND BLENDS

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D B DB DBE DBD0

20

40

60

80

100

120

140

160

180

FLASH POINT(°C)FIRE POINT(°C)

Fig (4.1). Comparison of Flash and Fire points of Diesel, Biodiesel and its Blends

D B DB DBE DBD6.5

7

7.5

8

8.5

9

VISCOSITY (Cst)

VISCOSITY (Cst)

Fig (4.2) Comparison of viscosities of Diesel, Biodiesel and its Blends

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D B DB DBE DBD

-5

0

5

10

15

20

25

CLOUD POINT(°C)POUR POINT(°C)

Fig (4.3) Comparison of Cloud and Pour points of Diesel, Biodiesel and its Blends

The viscosities of the various fuels are tested using the Redwood viscometer shown in (Fig 4.2). It was found that Pongamia biodiesel (B) had the highest viscosity of 8.8 Cst. The least viscosity was found to be for DBD fuel. The value is 7.54 Cst. This reduction in viscosity as due to the addition of Diethyl ether to the fuel. The viscosity if this blend is similar to that of the diesel fuel. The viscosities of DB and DBE are also found to be similar. The viscosities of all fuels were of permissible range and are suited for use in diesel engines.

The Flash and Fire points of the various fuels were found out using the Flash and Fire point apparatus shown in (Fig 4.1). The Flash and Fire points of DBD and DBE are found to be lower than diesel fuel but within the safer range. The highest values were out be for Pongamia biodiesel (B). The Flash and Fire point of DB was also higher but less than B. The values indicate the fact that all these fuels are safer to handle.

The Cloud and Pour points of the various fuels were found out using the Cloud and Pour point apparatus shown in (Fig 4.3). The Cloud and Pour point was out to be least for diesel fuel (D). It is interesting to note that the Cloud point for B, DB, DBE and DBD were similar with a variation of 1°C. The Pour point of DBD was found to be lower among the blends (-3°C). It was due to the addition of Diethyl ether. Diethyl ether gives the fuel better cold weather starting conditions.

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CHAPTER 5

EXPERIMENTAL SETUP DETAILS

5.1 ENGINE SPECIFICATION (KIRLOSKAR ENGINE):

ENGINE: The engine is a stationary four stroke single cylinder CI water cooled as shown in fig (5.1) the brief technical specification of the engine is given in table.

Fig (5.1)

DESCRIPTION SINGLE CYLINDER,FOUR STROKE COMPRESSION IGNITION,WATER COOLED

POWER 5.9KW/8 BHP

SPEED 1800 rpm

BORE DIAMETER 87.5 mm

STROKE LENGTH 110 mm

CUBIC CAPACITY 661 cc

FUEL INJECTION PRESSURE 210 bar

INJECTION TIMING 23 deg BTDC

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5.2 INSTUMENTS USED:

The list of various equipments used in the study are

1. Eddy current dynamometer

2. AVL smokemeter

3. AVL-Five gas analyzer

5.2.1 EDDY CURRENT DYNAMOMETER

The engine is coupled with a BENZ make eddy current dynamometer is used, An eddy current dynamometer used in the experimental setup is controlled by a monitor which has knob adjustments on the control panel. It consists of a stator on which are fitted on a number of electromagnets and rotor disc made of copper or steel are coupled to the output shaft of the engine. When the rotor rotates eddy current are produced in the stator due to the magnetic flux set up by the passage of field current in the Electromagnets. The eddy currents oppose the rotor motion, thus loading the engine. The eddy currents are dissipated in producing heat so that this type of dynamometer also requires some cooling arrangements. The torque is measured exactly as in other types of absorption dynamometers i.e. with the help of momentum. The load is controlled by regulating the current in the electromagnets

5.2.2 AVL 437 SMOKEMETER SPECIFICATIONS

Continuous flow smoke meter for measuring smoke level of diesel engines, based on the Hartridge principle with the following features,

1. Capable of measuring opacity level during steady speed and free acceleration

2. Self inbuilt calibration for linearity check and calibration when the equipment is switched ON

3. Measurement range:a. Absorption: 0-99.9 per meterb. Opacity:0-100%

4. Resolution:0.01 per meter

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5. Accuracy:0.1 per meter6. Measurement length: 430 mm7. Operating temperature range:5.50°C8. Oil temperature range:0-120°C and resolution 1°C9. Should work on both AC and DC (both 12V and 24V battery)10. Standard RS 232 serial port for data logging with computer11. Certified by: ARAI, Pune12. The temperature of the exhaust gas in the chamber should lie between the

minimum temperature of 70°C13. The exhaust gas pressure should not be more than atmospheric pressure in

the measurement chamber.

5.2.3 FIVE GAS ANALYZER

AVL Five gas analyzer and smoke meter

33

The five gases HC, CO,CO2, NOx, O2 are measured by using this five gas analyzer. HC, CO, C O2 are measured by the principle of NDIR and O2, NOx by the chemiluminescent analyzer (CLA).

a.) NDIR PRINCIPLE

In the Non-Dispersive Infra-Red Analyzer the exhaust gas species being measured is used to detect itself. This is done by selective absorption. The infrared energy of a particular wavelength is peculiar to a certain species will absorb the infrared energy of this wavelength and transmit the infrared energy of other wavelengths.

b.) CHEMILUMINESCENT ANALYZER PRINCIPLE

The method of chemiluminescent utilizes the reaction of NO with the ozone to produce NO2 at an excited state. The excited molecule spontaneously relaxes the unexcited state with the release of a discrete quantity of photo energy. Measurements of this energy provide a measure of the NO2 and the NO involved in the reaction.

5.2.4 AVL GAS ANALYZER SPECIFICATIONS

Continuous five gas analyzer for diesel engine exhaust capable of measuring HC, CO,CO2, NOx, O2 with the following features. The measurement ranges of AVL gas analyzer for these five emissions are given

a. Measuring range and resolutionb. Basic analyzer principle

HC, CO,CO2 - InfraredNOx , O2 - Electrochemical cell

c. Type of measurement -continuousd. Operating temperature range - 5-45°Ce. Provision for E calculation

34

f. In built prnter with interface for external PC printerg. Period of calibration: 1 yearh. Should work on both AC and DC (12 V)i. The pressure of the exhaust gas should be maintained 0.4 to 0.6 bar in the

instrument. If the pressure is too high, it will cause damage to te analyzing instrument.

S No. Gas Capable of measuring in the

range of

Resolution

1 CO 0-10% Vol 0.01% Vol2 CO2 0-20% Vol 0.1%Vol3 HC 0-20000 ppm Vol 1 ppm4 NOx 0-5000 ppm Vol 1 ppm5 O2 0-23% Vol 0.01% Vol

5.2.5 AVL SMOKEMETER

The principle of the smoke meter is that it work on the light extinction principle. It essentially consists of two optically identical tubes, one containing clean air and the other moving sample of smoke. The clean air tube is used as the reference. A light source and a photoelectric cell are mounted, facing each other from one tube to another. Connected to the photoelectric cell is the LED display with a scale calibrated 0-100% which is equal to the Hartridge unit, indicating the light absorbed by the smoke in %.

35

CHAPTER 6

METHODOLOGY

6.1 FUELS USED

The engine was tested under two different conditions. The following are the testing conditions and blends:

1. Normal engine:

a. Base diesel

b. Diesel (50%) and pongamia biodiesel (50%) blend

c. Diesel (50%), pongamia biodiesel (40%) and Diethyl ether (10%)

d. Diesel (50%), pongamia biodiesel (40%) and ethanol

2. Thermal barrier coated engine:

a. Diesel (50%), pongamia biodiesel (40%) and diethyl ether (10%)

b. Diesel (50%), pongamia biodiesel (40%) and ethanol (10%)

The different fuel blends were tested in the CI engine under these two different conditions and the results were calculated. The coating was done on the piston crown and cylinder head for a thickness of about 0.3 mm. The coating was done by a process called Plasma spray coating. Plasma spray coating has the advantage to produce value added to products, and also deposit ceramics, metals and coatings with a desired microstructure of the substrate. The nano ceramic material of Al2O3

was deposited using this method. The substrates of piston crown are made ready for coating deposition by sand blasting to produce a surface roughness of 4 -6 µm. Plasma sprayed coatings are deposited with a non-transferred arc plasma torch operating at various power levels ranging from 10 to 20 KW DC. Al2O3 powder is fed at the rate of about 10L/min. The torch to base distance is kept at 100 mm. The grit blast substrates were ultrasonically cleaned using anhydrous ethylene alcohol and dried in cold air prior to coating deposition. In this way the coating of 0.3 mm was done on the piston crown and cylinder head.

36

6.2 TEST PROCEDURE FOR ENGINE

1. Before starting the engine various blends that are to be used for testing are readily mixed and emulsified.

2. The coolant water circulation for the dynamometer and engine are checked.3. The fuel connection and the level of fuel are checked.4. The engine is started and made to run at no load condition for 15 minutes as

warm-up phase.5. The engine is made to run with diesel fuel.6. The readings are taken with various loads.7. The time taken for 50cc fuel consumption using gravity flow burette and

temperature at various positions is noted down.8. The emissions such as HC, CO,CO2, NOx are measured using the five gas

analyzer; the smoke is measured using AVL smoke meter.9. All the emulsions that are prepared should be in appropriate volume.10. The engine is then made to run with different emulsions.11. All the results are tabulated and the discussions are made upon the result

obtained.

6.3 EXPERIMENTAL SETUPFig(5.1)

37

Fig (5.2). Experimental set up for the project

The Kirloskar engine was connected to the eddy current dynamometer. The load is to be given with the help of eddy current dynamometer. A fuel tank is connected to a burette to measure the time taken for 50 cc of fuel to be consumed. The exhaust gas pipe is connected to the AVL five gas analyzer and AVL smokemeter for the purpose of measuring the five gases (HC, CO,CO2, NOx, O2) and the smoke opacity. The engine is cranked and the load is given and the readings are noted down.

Fig (5.3) Piston crown and cylinder head coated with Al2O3.

38

CHAPTER 7

RESULTS AND DISCUSSIONS

CONFIGURATION OF ENGINE

The different fuel blends are denoted as follows:

FUEL COMPOSITION NAME

1. BASE DIESEL D

2. PONGAMIA BIODIESEL B

3. DIESEL(50% by Vol) and PONGAMIA BIODIESEL(50% by Vol)

DB

4. DIESEL(50% by Vol), PONGAMIA BIODIESEL(40% by Vol) and ETHANOL(10% by Vol)

DBE

5. DIESEL(50% by Vol), PONGAMIA BIODIESEL(40% by Vol) and DIETHYL ETHER(10% by Vol)

DBD

6. DIESEL(50% by Vol), PONGAMIA BIODIESEL(40% by Vol) and ETHANOL(10% by Vol) in Thermal barrier coated engine

TDBE

7. DIESEL(50% Vol), PONGAMIA BIODIESEL(40% by Vol) and DIETHYL ETHER(10% by Vol)

TDBD

7.1 PERFORMANCE CHARACTERISTICS39

The different values like load, time and speed of the engine were taken down during the testing of the engine. The various constants were incorporated in to the formulae and the different performance parameters corresponding to the load were calculated. The smoke was measured using the AVL smokemeter. The smoke os measured in terms of Hartridge Units (HU). The CO, CO2,, NOx and HC were measured using the AVL five gas analyzer and tabulated.

7.1.1 BRAKE THERMAL EFFICIENCY

Fig (7.1) Variation of Brake Thermal Efficiency with Power

The variation of Brake Thermal Efficiency with respect to Power is shown in Fig 7.1 The maximum thermal efficiency is obtained to be for TDBD (34.15%) and the least efficiency is obtained for D (29.24%) at higher load. Addition of Biodiesel increases the thermal efficiency since it has better lubricity compared to diesel. This results in the lessening of frictional losses and thereby thermal efficiency is increased [8]. Addition of Diethyl ether and Ethanol to blends will decrease the viscosity of blends and leads to fine spray pattern and atomization and thus leading to complete combustion[14]. Also presence of oxygen in Biodiesel, Ethanol and Diethyl ether leads to complete combustion leading to higher efficiency [1]. Thermal barrier coated engine shows higher efficiency as the coating reduces the heat loss to the surrounding leading to increase in the

40

efficiency [12]. The maximum efficiency of DBD, DBE, DB and TDBE are 32.35%, 30.62%, 31.95% and 32.18% respectively.

7.1.2 TORQUE

The variation of Torque with respect to Power is shown in Fig. 7.2 The variation of torque is constant for all blends of fuel. This is due to the reason that torque is a function of engine speed and power. Since the test engine is a constant speed engine and the power produced also being constant irrespective of the fuel at the corresponding loads, the torque is also constant.

Fig 7.2 Variation of Torque with respect to Power

7.1.3 BRAKE MEAN EFFECTIVE PREESURE

The variation of Brake mean effective pressure with respect to Power is shown in Fig. 7.3 The Brake mean effective pressure is also same irrespective of the fuel used. This is due to the reason that the BMEP is a function of Torque and thereby follows a similar trend as Torque.

41

0 1 2 3 4 5 60

10

20

30

40

50

60

BMEP vs POWER

DBDBDDBETDBDTDBED

POWER(KW)

BMEP

(.KN

/m2)

Fig 7.3 Variation of BMEP with Power

7.1.4 SPECIFIC ENERGY CONSUMPTION (SEC):

Fig.7.4 Variation of Specific energy conversion with Power

The variation of Specific energy consumption with respect to Power is shown in Fig 7.4 The variation of SEC is more significant at lower loads but at higher loads the SEC is similar to that of D. The SEC of DB, DBE and DBD are lower or equal

42

to D. This is due to the presence of higher amounts of oxygen that leads to better combustion and hence lower SEC [5]. The SEC of TDBD and TDBE are higher initially and they are almost equal to D at higher loads. This may due to higher amount of energy required to raise the cylinder temperature initially and then the heat transfer is maintained by the thermal barrier so there is decrease in SEC substantially [12].

7.2 EMISSION CHARACTERISTICS

7.2.1 CO EMISSION

Fig 7.5 Variation of CO with Power

The emission of CO with respect to Power is shown in Fig.7.5 The variation of CO follows an irregular trend. At high loads DBE and TDBD show highest CO emissions. The CO emission is higher for D up to part loads when compared to other blends. CO emission for DBE, DBD and also TDBD, TDBE are lower initially and at part loads. This may be due to the reason that addition of Ethanol and Diethyl ether causes lowering of viscosity thereby better combustion [14]. Moreover, thermal barriers lead to lesser heat loss and thereby complete combustion is possible [12]. DB causes high CO initially due to its high viscosity [1].

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7.2.2 CO2 EMISSION

The variation of Carbon-di-oxide with respect to power is shown in Fig 7.6 The percentage of Carbon-di-oxide increases with increase in load for all the fuels. The variation is not that significant initially and at part loads but it is somewhat significant at higher loads. DB causes higher Carbon-di-oxide due to its complete combustion due to presence higher amount of oxygen as explained in [15]. At part loads, the higher viscosity leads to lower Carbon-di-oxide emissions for DB. Similar is the case of DBD and DBE at higher loads [6]. Thermal barrier coated engine causes better combustion and hence lesser Carbon-di-oxides at higher loads [13].

Fig 7.6 Variation of CO2 with Power

7.2.3 HC EMISSION

The variation of HC emission with respect to Power is shown in Fig. 7.7The HC emission increases with the increase in load for all the fuel blends. The HC emission is least for DB as it exhibits a shorter delay period and results in better combustion leading to low HC emissions [1]. The cetane number of ester based fuel DB is also higher than D. The HC emission of DBE and DBD are almost similar. The higher latent heat of vaporization of both Ethanol and Diethyl ether

44

leads to incomplete combustion and hence the HC emission is higher for them at full loads [14]. TDBD and TDBE show emission at an intermediate range due better combustion compared to DBE and DBD.

Fig 7.7 Variation of HC with Power

7.2.4 NOX EMISSION

The variation NOx of with respect to Power is shown in Fig 7.8 The variation of NOx follows an increasing trend with respect to load. TDBD and TDBE show higher oxides of nitrogen due to the increae in combustion temperature as the heat loss is minimized in the engine [12].DBE shows higher oxide of nitrogen as ethanol leads to longer ignition delay and thereby increasing the cylinder temperature [9]. DBD due to presence of Diethyl ether has shorter ignition delay and thereby lower oxide of nitrogen [6]. The trend of DBD is similar to D. The reduction of oxides of nitrogen for DB could be due complete combustion when compared to D. The prime factors for the formation of NOx are higher cylinder tempertures and residence time. Both these contribute to higher NOx emissions. Obviously thermal barrier coated engines would emit higher NOx due to the less amount of heat loss and thereby increasing the cylinder temperature.

45

Fig 7.8 Variation of NOx with Power

7.2.5 SMOKE

Fig 7.9 Variation of Smoke with respect to Power

The variation of smoke with respect to power is shown in Fig 7.9 The smoke emission is less in initial and lower loads but it increases at higher loads. The smoke emission of TDBD and TDBE are higher at lower loads but it is lesser at

46

higher loads. This may be due to complete combustion due to oxygen molecules and higher cylinder temperature due to thermal barrier coating [12]. The smoke emissions of DBD, DBE and DB are also less as the blend is overall “leaner” due to presence of oxygenated fuel compared to D [10].

47

CHAPTER 8

MATLAB PROGRAM AND SIMULINK MODEL

8.1 MATLAB AND SIMULINK

A MATLAB is a software for solving almost all types of mathematical models and calculations. It has several in built sub-softwares that can serve for numerous engineering and scientific applications. SIMULINK is a simulation window of the MATLAB. Mathematical formulae and equations can be modeled in there and the outputs can be got [18].

A MATLAB program and SIMULINK model are created based upon the performance calculation equations. The MATLAB programs would the inputs like load, engine capacity, time, calorific value, speed etc. and give the output like TFC, SFC, thermal efficiency, BMEP, Torque, SEC etc. It would also plot graphs of the various performance curves with respect to load. The SIMULINK model is also created for calculating the performance parameters alone. A look-up table is used to give input to the model.

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8.2 INPUT AND OUTPUT OF THE MATLAB PROGRAM

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8.3 GRAPHS PLOTTED BY THE MATLAB PROGRAM

0 1 2 3 4 5 6 7 80

1

2

3

4

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6figure1

Load,Kg

Bra

ke H

orse

Pow

er,K

W

0 1 2 3 4 5 6 7 80

0.5

1

1.5

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3figure2

Load,Kg

Torq

ue,N

m

50

0 1 2 3 4 5 6 7 80

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20

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60figure3

Load,Kg

Bra

ke m

ean

effe

ctiv

e pr

essu

re,B

ar

0 1 2 3 4 5 6 7 80.4

0.6

0.8

1

1.2

1.4

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1.8figure4

Load,Kg

Tota

l fue

l con

sum

ptio

n,K

g/hr

0 1 2 3 4 5 6 7 80

5

10

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20

25

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35figure5

Load,Kg

Effi

cien

cy,%

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8.4 SIMULINK MODEL FOR FINDING PERFORMANCE PARAMETERS

1. MATLAB PROGRAM1. %Developed by SIDDHARTH and TEAM2. %PROGRAM FOR FINDING AND PLOTTING THE PERFORMANCE PARAMETERS3. %FINAL YEAR PROJECT4. %Prompt for input5. CV=input('Enter the value of calorific value(kJ/kg):');6. K=input('Enter the value Density(Kg/m^3):');

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7. CC=input('Enter the value of engine capacity(liters):');8. L=input('Enter the values of load(kg):');9. N=input('Enter the values of speed(rpm):');10. T=input('Enter the values of time(s):');11. %Compute values12. BHP=((L.*N)*(0.746/2000));13. To=((BHP./N)*955.41);14. TFC=(0.18./T)*K;15. SFC=(TFC./BHP);16. SEC=(SFC*CV);17. E=((360000./SFC)*(1/CV));18. BMEP=((To./CC)*12.58);19. %Display values20. disp('values of BHP(KW):'),disp(BHP);21. disp('values of torque(Nm):'),disp(To);22. disp('values of BMEP(KN/cm^2):'),disp(BMEP);23. disp('values of TFC(Kg/hr):'),disp(TFC);24. disp('values of Efficiency(%):'),disp(E);25. disp('values of SFC(Kg/hr/KW):'),disp(SFC);26. disp('values of SEC(KJ/hr):'),disp(SEC);27. %Plotting the values28. plot(L,BHP);29. title('figure1')30. xlabel('Load,Kg')31. ylabel('Brake Horse Power,KW')32. figure33. plot(L,To);34. title('figure2')35. xlabel('Load,Kg')36. ylabel('Torque,Nm')37. figure38. plot(L,BMEP);39. title('figure3')40. xlabel('Load,Kg')41. ylabel('Brake mean effective pressure,Bar')42. figure43. plot(L,TFC);44. title('figure4')45. xlabel('Load,Kg')46. ylabel('Total fuel consumption,Kg/hr')47. figure48. plot(L,E);49. title('figure5')50. xlabel('Load,Kg')51. ylabel('Efficiency,%')

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CONCLUSION

The following conclusions are obtained based upon the experimental results

1. The Brake thermal efficiency is 5% increased for TDBD compared to the base diesel at higher load.

2. The Torque was found out to be constant irrespective of the fuel blends used.

3. The Brake mean effective pressure was also out be constant irrespective of the fuel blends used.

4. DBD was found to have lowest Specific energy consumption at initial loads. The Specific fuel consumption of all the fuels were found to be similar at higher loads.

5. TDBE had lowest CO emissions among all fuels used.

6. TDBE was also found have lower CO2 at higher loads.

7. DB had the lowest HC emissions at all loads.

8. TDBE and TDBD had higher NOx almost (100 ppm ) more than the diesel engine, because peak temperature of the combustion is increased.

9. TDBE and TDBD had higher smoke emissions at initial loads but eventually had 30 % reduced smoke emissions at higher loads due to higher combustion temperature.

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APPENDIX

FORMULAE USED:

1. BRAKE POWER: B.P=(W*N*0.746)/2000 KW

2. TORQUE: T=(B.P*6000)/(2*3.14*N) Nm

3. TOTAL FUEL CONSUMPTION: TFC=(50*3600*ρ*10-6)/(t) Kg/KW

4. SPECIFIC FUEL CONSUMPTION: SFC=(TFC/B.P) Kg/KW-hr

5. SPECIFIC ENERGY CONSUMPTION: SEC = (SFC*Cv) KJ/KW-hr

6. THERMAL EFFICIENCY: η=(3600*100)/(SEC) %

7. BRAKE MEAN EFFECTIVE PRESSURE: BMEP=(T/D)*12.58 KN/m2

Where,

W – Load in Kg

N – Speed in rpm

t - Time in seconds

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