Green Biofuel

Contents

List of Abbreviations

List of Figure

List of Table

1. INTRODUCTION
1.1 Introduction
1.2 Need of Biodiesel
1.3 History of Biodiesel
1.4 Source of Biodiesel
1.5 Fuel Properties
1.5.1 Density
1.5.2 Kinematic viscosity
1.5.3 FlashPointandFirePoint
1.5.4 Cloud point and pour point
1.5.5 Calorific value
1.5.6 Ash content
1.5.7 Carbon residue content
1.5.8 CetaneNumber
1.6 Specification of Biodiesel
1.7 Performance and Emission Characteristics
1.7.1 Performance Characteristics of C.I Engines
1.7.2 Engine performance and emission characteristics for biodiesel
1.8 Compression Ignition Engine
1.8.1 Classification of compression ignition combustion chamber
1.9 Nanoparticle As An Additive in Fuel
1.10 Nanoparticles With Biodiesel
1.11 Effect of Nanoparticle on CI Engine Parameters
1.11.1 Effect on Performance
1.11.2 Effect on Emissions
1.12 Types of Nanomaterial‘s Used in Fuel
1.13 Aim of The Research
1.14 Objectives of Research
1.15 Organization of Thesis

2 LITERATURE REVIEW
2.1 Review of Literature
2.2 Research Gap
2.3 Summary

3 METHODOLOGY AND EXPERIMENTAL SETUP
3.1 Methodology to Be Adopted
3.1.1 Collection of biodiesel
3.1.2 Preparation of biodiesel blend
3.1.3 Preparation of nanoparticle added biodiesel blend
3.1.4 Evaluation of fuel properties of biodiesel blends
3.1.5 Performance Emission parameters to be evaluate
3.1.6 Comparison of performance and emission characteristics of biodiesel with that of pure diesel
3.2 Experimental Setup
3.2.1 Equipment used for the evaluation of engine performance
3.2.2 Equipment used for the evaluation of engine emissions
3.3 Summary

4 EXPERIMENTAL RESULTS
4.1 Fuel Properties
4.1.1 Kinematic viscosity
4.1.2 Flash point
4.2 Performance Characteristics
4.2.1 Brake power
4.2.2 Brake thermal efficiency
4.2.3 Fuel consumption
4.2.4 Brake specific fuel consumption
4.2.5 Exhaust gas temperature
4.3 Emission Characteristics
4.3.1 NOx Emissions
4.3.2 CO Emissions
4.3.3 HC Emissions

5 RESULT VALIDATION
5.1 Introduction to Regression Analysis
5.2 The Regression Equations For Performance Characteristics
5.2.1 Brake power
5.2.2 Brake thermal efficiency
5.2.3 Fuel consumption (kg/hr.)
5.2.4 Brake specific fuel consumption (kg/kw hr.)
5.2.5 Exhaust gas temperature ( °C)
5.3 The Regression Equations For Emission Characteristics
5.3.1 NOx Emissions (PPM)
5.3.2 CO Emissions (PPM)
5.3.3 HC Emissions (PPM)

6 CONCLUSIONS
6.1 Conclusions
6.1.1 Fuel properties:
6.1.2 Optimum compression ratio:
6.1.3 Performance and emission characteristics comparison for optimum blend:
6.2 Future scope
6.3 Applications

REFERENCES

APPENDIX

INCLUSIONS

ACKNOWLEDGMENT

Abstract

The fossil fuel resources are limited along with the need to reduce emission which is major impulse to the development of alternative fuel; biodiesel has been developed as an alternative fuel for C.I. engine but it show slightly lower performance and reduction in SOx, CO, HC, CO2 emissions as compare with diesel. But due to higher oxygen contain in biodiesel the formation of NOx was observed higher. Nano-fuels have shown better improvement in combustion, performance and emission characteristics of CI engine. The blending of biodiesel increases the thermal efficiency near to that of diesel and also significantly large reduction in NOx is observed. In this present work, Nano fuels were prepared by adding the cerium oxide nanoparticles to the cottonseed biodiesel. Biodiesel was manufactured from cottonseed oil using trans-esterification process. Nano fuels were prepared with high speed ultra-sonication and agitation process to increase the stability.

In the present experimentation the experiments were conducted on variable compres­sion ratio single cylinder four strokes DI diesel engine running at constant 1500 RPM to find the effect of cerium oxide nanoparticles in diesel and blends of diesel-biodiesel. The load and compression ratio was varied from 0 to 6 kg and 14 to 18 on the engine. To increase the stability Nano fuels were prepared with high speed ultra-sonication and agitation process. Nanoparticles concentration was dispersed 50 ppm to the 10% and 20% cotton seed biodiesel in base diesel fuel. The properties of blends of biodiesel such as calorific value, flash point, and viscosity were also measured as per IS standards. Ex­periments were performed using neat diesel and different blends of cotton seed biodiesel such as 100D, 10CSB, 10CSBCeO250, 20CSB and 20CSBCeO250. The performance pa­rameters like BP, BSFC, BTE, EGT and emission parameters like CO, NOx and HC were compared to pure diesel. The test results revealed that cerium oxide blended cottonseed biodiesel blends improve the performance parameters and reduces harmful emissions es­pecially NOx.

List of Abbreviations

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List of Figures

1.8.1.1 Direct injection volumetric combustion chamber

1.8.1.2 Indirect injection with swirl combustion chamber (Ricardo Cornet)

3.1.3.1 Sonication of nanoparticles added biodiesel

3.1.3.2OleicAcidsurfactant

3.1.3.3 Nanoparticle blended diesel-biodiesel blend 20CSBCeO2 50

3.1.4.1RedwoodViscometer

3.1.4.2 Bomb Calorimeter

3.1.4.3 Pensky Martin (closed cup) apparatus

3.2.1.1 Single cylinder four stroke, variable compression ignition engine

3.2.1.2 Schematic diagram of experimental system

3.2.2.1 Exhuast gas analyser

4.1.1.1 Variation of kinematic viscosity for different blends of biodiesel

4.1.2.1 Variation of flash point of different blends of biodiesel

4.2.1.1 Variation of BP with respect to load at compression ratio 14

4.2.1.2 Variation of BP with respect to load at compression ratio 16

4.2.1.3 Variation of BP with respect to load at compression ratio 18

4.2.1.4 Variation of BP with respect to load of 10CSBCeO250 at compression ratio 14, 16 and 18

4.2.2.1 Microexplosion and secondary atomization of nanoparticles [7]

4.2.2.2 Variation of Brake thermal efficiency with respect to load at compression ratio 14

4.2.2.3 Variation of Brake thermal efficiency with respect to load at compression ratio 16

4.2.2.4 Variation of Brake thermal efficiency with respect to load at compression ratio 18

4.2.2.5 Variation ofBrake thermal efficiency with respect to load of 10CSBCeO250 at Compression ratio 14, 16 and 18

4.2.3.1 Variation of Fuel consumption with respect to load at compression ratio 14

4.2.3.2 Variation of Fuel consumption with respect to load at compression ratio 16

4.2.3.3 Variation of Fuel consumption with respect to load at compression ratio 18

4.2.3.4 Variation of Fuel consumption with respect to load of 10CSBCeO250 at compression ratio 14, 16 and 18

4.2.4.1 Variation of BSFC with respect to load at compression ratio 14

4.2.4.2 Variation of BSFC with respect to load at compression ratio 16

4.2.4.3 Variation of BSFC with respect to load at compression ratio 18

4.2.4.4 Variation ofBSFC with respect to load of10CSBCeO250 at compression ratio 14, 16 and 18

4.2.5.1 Variation of Exhaust gas temperature with respect to load at compres- sionratio14

4.2.5.2 Variation of Exhaust gas temperature with respect to load at compres- sionratio16

4.2.5.3 Variation of Exhaust gas temperature with respect to load at compres- sionratio18

4.2.5.4 Variation ofExhaust gas temperature with respect to load of10CSBCeO250 at compression ratio 14, 16 and 18

4.3.1.1 Variation of NOx with respect to load at compression ratio 14

4.3.1.2 Variation of NOx with respect to load at compression ratio 16

4.3.1.3 Variation of NOx with respect to load at compression ratio 18

4.3.1.4 Results ofNOx for all fuels at different loads and compression ratios(PPM)

4.3.2.1 Variation of CO with respect to load at compression ratio 14

4.3.2.2 Variation of CO with respect to load at compression ratio 16

4.3.2.3 Variation of CO with respect to load at compression ratio 18

4.3.2.4 Variation of CO with respect to load of 20CSBCeO250 at compression ratio 14, 16 and 18

4.3.3.1 Variation of HC with respect to load at compression ratio 14

4.3.3.2 Variation of HC with respect to load at compression ratio 16

4.3.3.3 Variation of HC with respect to load at compression ratio 18

6.3.0.1 XRD image of cerium oxide nanoparticles

6.3.0.2 SEM image cerium oxide nanoparticles

List of Tables

1.2.0.1 Emission Standards for Gasoline Vehicles (GVW <3,500 kg) in India

1.4.0.2 Sources of Oil [11]

1.4.0.3 Production of non-edible oil seeds and Bio-residues in India [11]

1.6.0.1 Properties of biodiesel according to ASTM standards [9]

1.7.2.1 The performance and emissions of diesel and B100 [8]

3.2.1.1 Components of Single cylinder VCR Diesel Engine

3.2.1.2 Specification of VCR diesel engine

4.1.0.1 Properties of fuel

4.2.1.1 Results of BP for all fuel at different loads and compression ratio (KW)

4.2.2.1 Results of BTE for all fuels at different loads and compression ratios (%)

4.2.3.1 Results of FC for all fuels at different loads and compression ratios (kg/hr)

4.2.4.1 Results of BSFC for all fuels at different loads and compression ratios (Kg/KW-hr)

4.2.5.1 Results of EGT (°C) for all fuels at different loads and compression ratios

4.3.1.1 Results of NOx for all fuels at different loads and compression ratios (ppm)

4.3.2.1 Results of CO for all fuels at different loads and compression ratios(PPM)

4.3.3.1 Results of HC for all fuels at different loads and compression ratios(PPM)

1. INTRODUCTION

1.1 Introduction

Biodiesel refers to any diesel fuel alternative derived from renewable biological resource. More specifically, biodiesel is defined as oxygenated, sulfur-free, biodegradable, non-toxic and eco-friendly alternative diesel oil. Chemically, it can be defined as a fuel composed of mono-alkyl esters or methyl esters of long chain fatty acids derived from renewable sources, such as vegetable oil, animal fat and used cooking oil which is designated as B100 and also they meet the special requirements such as the ASTM and the European stan­dards. The conversion of vegetable oils into biodiesel is an effective way to overcome all the problems associated with the vegetable oils. Dilution, micro emulsification, pyrolysis and trans-esterification are the four techniques applied to solve the problems encountered with the high fuel viscosity. Trans esterification is the most common method and leads to mono alkyl esters of vegetable oils and called biodiesel when used for fuel purposes.

1.2 Need of Biodiesel

The large increase in number of vehicles in recent years has resulted in great demand for petroleum products. The depletion of fossil fuel reserves and rising oil prices would cause a major impact on the transportation sector. To meet ever increasing energy requirements, there has been increasing interest in alternative fuels to provide a suitable diesel oil substitute for internal combustion engines. As a result biodiesel seem a very promising alternative to diesel oil since they are renewable, directly used in diesel engine without any major modification in diesel engine and show almost similar properties like diesel. India is one of the biggest petroleum product consuming and importing countries.

India imports about 70% of its petroleum demands. Currently Indian annual re­quirement for petroleum products is about 120 million metric tons of which the diesel consumption is approximately 40 million tones [1]. The United States alone consumes about 21 million barrels of oil per day, of which, about 65% is used in transportation, while the world's oil consumption amounts to 90 million barrels per day [2].Diesel engines are usually employed in heavy duty vehicles which are used for transportation and agri­cultural purposes. It was reported that Turkey's demand for diesel fuel in 2006 is 12.07 million tones, which is higher than the unleaded gasoline demand of 3.88 million tones [3]. Forecasts are there which say that transport on a global scale will increase demand for conventional fuels with up to a maximum annual growth of 1.3 percent up to 2030. This would result in a daily demand of around 18.4 billion liters (up from around 13.4 billion liters per day in 2005) [The Royal Society, 2008].

Waste vegetable oil has been proposed by many researchers as the best source of alter­native oil to produce biodiesel. According to the United States Environmental Protection Agency (EPA), restaurants in the US produce about 300 million US gallons (1,000,000 cubic meter) of waste cooking oil annually.Further it is seen that exhaust of automobiles is one of the major contributors to the world's air pollution problem. Recent research and development in this area has made major reductions in engine emissions, but growing population and greater number of automobiles are clearly an indication that the problem will persist for many years to come. The use of biodiesel has shown substantial reduction in unburned HC, PM and CO emissions [8].

The air pollution in India has been recorded as one of the highest in the world. In 2005-06 there were 8.9 M vehicles sold and in five years this number has scaled to 15 M (in 2010-11) [5]. The city of Delhi, which is the capital of India, is one of the ten most polluted cities in the world, as pointed out by the World Health Organization. The number of vehicles currently running on the road in Delhi is around 5.6 million, as per the Economic Survey of Delhi [4]. It is of importance to quote here that various laws were passed in the United States and in other industrialized countries which limit the amount of exhaust emissions and give the guidelines for allowable limits. This has put a major restriction on automobile engine development during the 1980s and 1990s. For example, Euro 5 standard for passenger cars has reduced NOx and PM emission from 0.25 and 0.025 g/km to 0.10 and 0.005 g/km [6]. The exhaust gases from the automobiles affect human body and give rise to contagious diseases. Besides substantial CO2 emissions, significant quantities of CO, HC, NOx, PM and other air toxins are emitted from automobiles in the atmosphere, which cause serious health problems like cardio vascular disorder, nervous system disorder, vision and judgment impairment, nausea and vomiting.

Due to the problems and situation we have encountered now, we need to overcome challenges as well as an opportunity to look for substitutes of fossil fuels for both economic and environmental benefits for the society and the country itself.

Table 1.2.0.1: Emission Standards for Gasoline Vehicles (GVW <3,500 kg) in India

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1.3 History of Biodiesel

The depleting reserves of fossil fuel, increasing demands for diesels and uncertainty in their availability is considered to be the important trigger for many initiatives to search for the alternative source of energy, which can supplement or replace fossil fuels. One hundred years ago, Rudolf Diesel tested peanut oil as fuel for his engine for the first time on August 10, 1893. In the 1930s and 1940s vegetable oils were used as diesel fuels from time to time, usually only in emergency. The first International conference on plant and vegetable oils as fuels was held in Fargo, North Dakota in August 1982. The primary concern discussed were the cost of fuel, the effect of vegetable oil fuels on engine perfor­mance and durability and fuel preparation specification and additives. Oil production, oil seed processing and extraction also were considered in this meeting. Vegetable oils hold promise as alternative fuels for diesel engines. But their high viscosities, low volatilities and poor cold flow properties have led to the investigation of various derivatives. Fatty acid methyl esters, known as Biodiesel, derived from triglycerides by trans-esterification with methanol have received the most attention. The name Biodiesel was introduced in the United States during 1992 by the National Soy diesel Development Board (presently national bio diesel board) which has pioneered the commercialization of Biodiesel in the United States. Biodiesel can be used in any mixture with petroleum diesel as it has very similar characteristics but it has lower exhaust emissions.

Biodiesel has better properties than that of petroleum diesel such as renewable, biodegradable, non-toxic, and essentially free of sulphur and aromatics. Biodiesel fuel has the potential to reduce the level of pollutants and the level of potential or probable Carcinogens. Ma et al stated that Biodiesel has become more attractive recently because of its environmental benefits and fact that it is made from renewable resources. The raw materials being exploited commercially by the Biodiesel are the edible fatty oils derived from rapeseed, soybean, palm, sunflower, coconut, linseed, etc. In recent years, research has been directed to explore plant based fuels, have bright future. This chapter focused on the source of oils, problems associated with the use of oils, production of Biodiesel from non-edible oil, chemical properties of Physical and oils and esters; advantages, dis­advantages and challenges.

1.4 Source of Biodiesel

Alternative diesel fuels made from natural, renewable sources such as vegetable oil and fats. The most commonly used oils for the production of Biodiesel are soyabean, sun­flower, palm, rapeseed, canola, cotton seed and Jatropha. Since the prices of edible vegetable oils are higher than that of diesel fuel, therefore waste vegetable oils and non­edible crude vegetable oils are preferred as potential low priced Biodiesel sources. Use of such edible oil to produce Biodiesel in India is also not feasible in view of big gap in demand and supply of such oils. Under Indian condition only such plants can be consid­ered for Biodiesel, which produce non-edible oil in appreciable quantity and can be grown on large scale on non-cropped marginal lands and waste lands. Animal fats, although mentioned frequently, have not been studied to the same extent, as vegetable oils because of natural property differences. Animal fats contain higher level of saturated fatty acids therefore they are solid at room temperature. The source of Biodiesel in the form of vegetables oils, non-edible oils, animal fats and some other biomass are listed in Table 1.4.0.2 The source of Biodiesel usually depends on the crops amenable to the regional climate. In the United States, soyabean oil is the most commonly Biodiesel feedstock, whereas the rapeseed (canola) oil and palm oil are the most common source for Biodiesel, in Europe, and in tropical countries respectively. A suitable source to produce Biodiesel should not competent with other applications that rise prices, for example pharmaceu­tical raw materials. But the demand for pharmaceutical raw material is lower than for fuel sources. As much as possible the Biodiesel source should full fill two requirements: low production costs and large production scale. Refined oils have high production costs, but low production scale; on the other side, tm-edible seeds, algae and sewerage have low production costs and are more available than refined or recycled oils. The oil percent­age and the yield per hectare are important parameters to consider as Biodiesel source.

Productions of non-edible oil seeds percentage of oil content are given in Table 1.4.0.3

Table 1.4.0.2: Sources of Oil [11]

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Table 1.4.0.3: Production of non-edible oil seeds and Bio-residues in India [11]

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1.5 Fuel Properties

Some of the properties of the biodiesel are discussed below:-

1.5.1 Density

Density of biodiesel is larger than that of diesel (specific gravity 0.88 compared to 0.84 for diesel fuel) therefore biodiesel should be mixed at the top of diesel for proper mixing. If bio-diesel is first put at the bottom and then diesel fuel is added, it will not mix properly.

1.5.2 Kinematic viscosity

Viscosity is an important physical property of a diesel fuel and a measure of the resistance to flow. The performance of diesel fuel also greatly depends upon their viscosity. Too low a viscosity causes excessive leakage at the injection stage while too high viscosity produces coarse oil droplets which results in the formation of engine deposits owing to incomplete combustion. Diesel fuels with extremely low viscosities may not provide sufficient lubrication for the closely fit pumps and Injector plungers. Biodiesel have larger kinematic viscosity than diesel approximately 1.5 times higher. Due to this, biodiesel significantly suppresses the fuel spray evaporation and atomization process resulting in slower burning and longer combustion duration [7, 8].

1.5.3 Flash Point and Fire Point

Flash point of a fuel is defined as the minimum temperature at which the fuel generates just sufficient vapour to form inflammable mixture with air, as shown by the formation of momentary flame (flash) when an external source of fire is brought in contact with the vapour. The fire point is the minimum temperature at which the fuel vapour will continue to burn without external supply of flame. For the same product the fire point is higher than flash point. Fuel with flash point above 66°C is regarded as safe. The flash point and fire point of bio-diesel is higher than the petroleum based diesel fuel. Flash point and fire point of bio-diesel blends is dependent on the flash point of the base diesel fuel used and increase with percentage of bio-diesel in the blend. Thus when it comes to storage biodiesel is safer than conventional diesel [7].

1.5.4 Cloud point and pour point

Cloud point is defined as the temperature at which the oil becomes cloudy when it is cooled in specified manner. This temperature is higher than the pour point (usually 5 °C to 6°C). The cloud point becomes significant than pour point in diesel fuel where the formation of wax crystals can plug the filters in the diesel injection system and stop the flow even if the oil is above the pour point. The pour point is defined as the temperature 2.8 OC higher than that at which the oil ceases to flow when cooled and tested according to the prescribed conditions. The cessation of flow results from an increase in viscosity in diesel fuel. Pour point may also be reduced by increasing the proportions of lighter hydrocarbons in oil. Biodiesel generally has higher cloud point and pour point than diesel fuel which make it very sensitive to cold weather conditions and results in the difficulty of cold starting [7,8].

1.5.5 Calorific value

It is the total quantity of heat liberated by completely burning of one unit mass of fuel. The calorific value of a substance is the amount of energy released when the substance is burned completely to a final state and has released all of its energy. The calorific value of fuel is determined by Bomb calorimeter [7].

1.5.6 Ash content

It describes the amount of inorganic contaminants such as abrasive solids, catalyst residues and the concentration of soluble metal soaps contained in a fuel sample. These compounds are oxidized during the combustion process to form ash which is connected with engine deposits. The higher the ash content the higher is the risk of engine damage.

1.5.7 Carbon residue content

This property is important for oil used in diesel engine. The heavier complex compounds on decomposition form some carbonaceous deposits known as carbon residue [7].

1.5.8 Cetane Number

Higher the cetane number better are the ignition properties of the fuel. The ignition quality of diesel fuel is measured in a standard engine by matching against blends of two reference fuels n-paraffin and aromatic expressed in the term of cetane number. High speed engines above 1500 rpm need high cetane number 45-50. For low engine speeds 25-30 cetane numbers may suffice. The CN is a measure of the ignition quality of diesel fuels, and a high CN implies short ignition delay. The CN of biodiesel is generally higher than conventional diesel. Due to higher CN, combustion efficiency of biodiesel is higher.

1.6 Specification of Biodiesel

Standards play vital role for the manufacturers, suppliers and users of bio-fuels. Author­ities need approval standards for the evaluation of safety, risks and environmental protec­tion. Conventionally standards and codes for products have been developed, largely by examining existing standards and codes in different countries and then writing standards for own country. A worldwide survey of bio-diesel specification was done and an attempt was made to understand the objective behind them before proposing a norm for India. The main components, which represent the quality of biodiesel, are monoalkylesters, di­alkyl esters, residual vegetable oil, free glycerin, reactant alcohol, free fatty acids and the residual catalyst. In December 2001, American Society ofTesting and Materials (ASTM) issued a specification (D6751) for biodiesel (B100) which is written in tabular form as in Table 1.6.0.1

Table 1.6.0.1: Properties of biodiesel according to ASTM standards [9]

Abbildung in dieser Leseprobe nicht enthalten

1.7 Performance and Emission Characteristics

1.7.1 Performance Characteristics of C.I Engines

The performance of an engine is an indication of degree of success for with which it is doing its assigned job.

The degree of success is compared on the basis of the following.

a. Brake power developed or BMEP.
b. Specific fuel consumption (kg/ kW-hr).
c. Specific power output (kW/ kg of engine weight).
d. Specific weight

The application of the engine decides the relative importance of these parameters. The specific power output is more important for marine engines whereas specific fuel consumption is more important for industrial engines. The basic parameters which are considered for evaluating the engine performance are:

a. Indicated power.
b. Mechanical efficiency.
c. Thermal efficiency.
d. Specific fuel consumption.
e. Volumetric efficiency.
f. Exhaust emission
g. Fuel-air ratio

1.7.2 Engine performance and emission characteristics for biodiesel

Biodiesel has low calorific value, on weight basis because of presence of substantial amount of oxygen in the fuel but at the same time biodiesel has a higher specific gravity (0.88) as compared to diesel (0.85) so overall effect is approximately lower energy content per unit volume. Thermal efficiency of an engine operating on biodiesel is generally better than diesel. Brake-specific fuel energy consumption (BSEC) is a more suitable parameter compared to brake-specific fuel consumption (BSFC) for comparing fuels having different calorific values and densities. The hydrocarbon emissions are much lower in case of biodiesel as compared to diesel. This is also due to oxygenated nature of biodiesel where more oxygen is available for Burning and reducing hydrocarbon emissions in the exhaust. CO is a toxic combustion product resulting from incomplete combustion of hydrocarbons. Since biodiesel is free from sulfur hence less sulfate emissions and particulate drop is found in the exhaust. Because of the absence of sulfur biodiesel reduces the problem of acid rain due to transportation fuels. Many researchers have evaluated the engine performance of different biodiesel blends. Yage Di et al. investigated the waste cooking oil methyl esters in the diesel engine. They observed that the engine performance, especially the brake power output and exhaust emission characteristics improved significantly. The brake thermal efficiency of biodiesel was found to be slightly higher as compared to diesel at medium and higher loading conditions. For combustion and emission characteristic slightly shorter ignition delay and slightly reduction was found in major emission like HC and CO while NOx and NO2 increases, as shown in the Table 1.7.2.1

1.8 Compression Ignition Engine

The compression ignition engines draw only fresh air into the cylinder during induction stroke and then on their return stroke compress this charge into 1/15 to 1/22 of the un-swept volume until the temperature is raised well in excess of 550^C. Just before the piston reaches the end of the compression stroke an accurately metered quantity of fuel

Table 1.7.2.1: The performance and emissions of diesel and B100 [8]

Abbildung in dieser Leseprobe nicht enthalten

is injected into the cylinder at 350 bar pressure or more. The finely atomizing and well charged fuel spray mixes with the hot air causing it to ignite and burn rapidly. The time for injecting the fuel over a 40° crank angle movement at 5000 RPM is 0.000133 min. Air combustion in a CI engine is an unsteady process occurring simultaneously into the engine when it is un-throttled, with engine torque and power output controlled by the amount of fuel injected per cycle.

1.8.1 Classification of compression ignition combustion chamber

The compression ignition combustion chambers can be subdivided into two categories as given below:

(a) Direct injection combustion chamber: In these types of chambers fuel is directly in­jected into the chambers. These chambers are normally used for large (10 to 16 liter) low to medium speed (up to 2500 rpm) commercial vehicle diesel engine where fuel consump­tion is low and torque output is high. Direct injection volumetric combustion chamber is shown in Fig. 1.8.1.1

Figure 1.8.1.1: Direct injection volumetric combustion chamber

(b) Indirect combustion chamber: In this chamber combustion takes place into the divided chambers. These chambers are normally used on small (1.5 to 3.5 liter) diesel car engines which can run with a clear exhaust up to 5000 rpm and where a smooth low speed low noise level engine is required. Indirect combustion with swirl combustion chamber is shown in Fig 1.8.1.2

Figure 1.8.1.2: Indirect injection with swirl combustion chamber (Ricardo Cornet)

1.9 Nanoparticle As An Additive in Fuel

Application of nanoscale energetic metal particle additives in liquid fuel is an interest­ing concept yet unexplored to its full potential. Depending on the physical, chemical, and electrical properties of the added nanomaterials, nanofluid fuels can achieve better performance emission characteristics for diesel engine. Such formulated nanofuels offer: shortened ignition delay, decreased burn times and rapid oxidation, enhanced catalytic ef­fect, microexplosion behavior which leads to complete combustion. Overall calorific value of the liquid fuel increases due to higher energy density of metal particles, eventually im­proving the performance of engine by boosting power output. The study of evaporation rate and ignition probability plays an important role in determining two critical prop­erties: ignition delay and ignition temperature which characterizes the performance of a diesel engine and are also instrumental in limiting emissions. Certain drawbacks such as strong particle aggregation, and stability and metal oxide particles may limit applica­tions of Nano fluid fuels. To overcome this problem one more chemical called surfactant is used to bind the molecules of the constituent liquids. Then a mechanical agitator and ultrasonicator are used to mix the liquids thoroughly.

1.10 Nanoparticles With Biodiesel

Biodiesel is a renewable and eco- friendly alternative diesel fuel for diesel engine. Biodiesel has higher viscosity, density, pour point, flash point and cetane number than diesel fuel. Biodiesel is an oxygenated fuel which contains 10-15 percent oxygen by weight. This fact lead biodiesel to total combustion and reduces the exhaust emissions particulate matter (PM), carbon monoxide (CO), sulfur oxides (Sox), and unburned hydrocarbons (HC) as compare to diesel fuel. But due to the lesser energy content and complete combustion, it gives poor performance and shown drastic incensement in NOx. So to improve the performance and emission especially NOx and particulate matter of diesel and diesel blended with biodiesel nanofuels have become an essential part of today's fuels. With use of fuel additives in the blend of biodiesel and diesel fuelled in CI Engine which furthers more improve performance, combustion, and diminish emission characteristics and also improved fuel properties which enhance the combustion characteristics.

1.11 Effect of Nanoparticle on CI Engine Parameters

1.11.1 Effect on Performance

Addition of nanoparticles in diesel and diesel-biodiesel blends not only enhances the calorific values but also promotes complete combustion due to higher evaporation rates, reduced ignition delay, higher flame temperatures and prolonged flame sustenance. All these factors support the full release of thermal energy thereby leading to higher brake thermal efficiency and lower BSFC. This phenomenon could have led to catalytic com­bustion, and in turn enhanced the thermal efficiency of the diesel engine. Nanoparticle addition to the fuel decreased ignition delay and consequences of ignition delay lowered the peak cylinder pressure.

1.11.2 Effect on Emissions

Air pollution nowadays serious problem in many countries some researchers are working in the same way to reduce engine emissions. The increasingly use of CI engine vehicles has led to deterioration of the quality of air to a level. One prospective method to solve this issue is to use the fuel additives. Emissions of Particulate Matter and Oxides of Nitrogen are the focus of today's diesel emission control technologies. Nanometal oxide additives are reported to be effective in lowering diesel emissions. The principle of this additive action consists of a catalytic effect on the combustion of hydrocarbons. Use of transition (or) noble metals in the form of fuel additives lowers the soot ignition temperature. The metal additive in the diesel fuel changes the cetane number (by about 1-1.2 percent) and affects combustion and emissions. Fuels with a high cetane number have smaller premixed fuel portions and lower NOx emissions for the same BMEP compared to lower cetane number. Some metal-based additives are reported to be effective in lowering diesel emissions. They may reduce diesel emissions by two ways. First, the metals either react with water to produce hydroxyl radicals, which enhance soot oxidation, or react directly with carbon atoms in the soot, thereby lowering the oxidation temperature.

1.12 Types of Nanomaterial‘s Used in Fuel

Later, many experimental studies have been carried out on performance and emission of CI engine using a variety of nanomaterials like:

- Oxide ceramics: alumina (Al2O3), copper oxide, (Cuo), magnetite (Fe3O4, zinc oxide (Zno), manganese oxide (Mno) and ceria (CeO2)
- Metals: copper (Cu), iron (Fe), Cobalt (Co), Magnesium (Mn), Boron (Br) and aluminum (Al)
- Single and multi-walled carbon nanotubes (SWCNTs, MWCNTs)

1.13 Aim of The Research

To analyze effect of cerium oxide nanoparticle on performance & emission characteristics of single cylinder variable compression ratio D.I. diesel engine with different blends of cotton seed biodiesel and its blend.

1.14 Objectives of Research

The literature surveyed has been carefully analyzed to find out the objective of the present study. The literature survey has studied on the basis of the performance and emission characteristics of diesel biodiesel blends on CI engine. The main objective of present investigation will be to do a comparative study on effect of cerium oxide nanoparticle dose level of 50 PPM in diesel-biodiesel fuel based on their performance and emission characteristics on variable compression ratio diesel engine. Two kind of biodiesel blend (10CSB and 20CSB) will be prepared using dose level of 50 PPM and it will be tested and examined at different engine load and repeated with 14, 16 and 18 compression ratios.

1. To develop different blends of cottonseed biodiesel.
2. Blending of nanoparticles with diesel and biodiesel blend.
3. Determination of biodiesel properties.
4. To develop/maintenance of experimental setup.
5. Evaluation of performance parameters.
6. Evaluation emission parameters.
7. Comparison of performance and emission characteristics of diesel-biodiesel blends with nanoparticle added blends and base fuel diesel.

1.15 Organization of Thesis

This thesis is organized into six parts as follows;

Chapter 1 is aboout general introduction to biodiesel,it‘s history,need of biodiesel as an alternative source of fuel for future is discuss. properties of fuel, specifications according to ASME standerds are mention. performane and emission characteristics of C.I. engine with it‘s classification are explain. Types of nanparticles and it‘s effect on engine perfor­mance and emission were discussed. Aims and objectives of reasearch are also stated.

Chapter 2 presents the literature review of effect of different nanoparticle‘s on different biodiesel blends. The variation in blends of nanoparticle as a fuel additives are reported. It also includes the gap in reasearch which explains the new idea of research.

Chapter 3 describes the step by step methodology follow during the complition of project and the experimental setup use to measure the performance & emission charactaristics of fuel blends.

Chapter 4 describes the experimental results carried out on VCR diesel engine which incluids the performance & emission parameters for cottonseed biodiesel blends with and without nanoaprticles and compaire all the results with neat diesel for variable compres­sion ratio & variable load.

Chapter 5 presents the extension of actual results obtain on VCR diesel engine by using regression analysis of all blends for all performance & emission parameters for varible compression ratio & variable load. this incluedes the regression equation from which one can find the values of performance & emission parameters at any load & at any compres­sion ratio for all blends.

Chapter 6 concludes the thesis in which conclusions, future scope and applications of the research carried out are stated.

2 LITERATURE REVIEW

In this chapter many research papers were studied to find out the research gap. Research topic is related to the Nano fuels. The Nano fuels were prepared by adding nanoparticles to the diesel-biodiesel blends. The experiments were performed at variable compression engine. In this chapter lot of research papers were studied which are related to synthesis of nanoparticles, addition of nanoparticles to the biodiesel blends, effect of nanoparticles on fuel properties , effect on combustion performance and emission characteristics. Some papers were reviewed related to the biodiesel manufacturing, performance and emission characteristics.

2.1 Review of Literature

Selvaganapthy et al. [1] evaluated the performance and emission characteristic of single cylinder four stroke vertical water cooled diesel engine using diesel fuel and the zinc oxide nano particles which were mixed with the diesel fuel at the rate of 250 ppm and 500 ppm. The obtained particle size range was from 24-71 nm. A magnetic stirrer was used to disperse the nano particles into the diesel and laser spectrometer was used to measure the dispersion. The addition of zinc oxide further increased the heat release rate by 12.8 % for 250 ppm concentration of zinc oxide and 20 % for 500ppm of Zinc Oxide. The NOx emission was lower for the neat diesel compared to all the fuel blends. The brake thermal efficiency was found to improve by 2.71% with 250ppm ZnO and 4.53% for 500ppm ZnO.

Ajin C. Sanjeevan et al. [2] had conducted an experiment on a naturally aspirated four stroke single cylinder water-cooled compression ignition engine operating at rated speed of 1500 RPM to investigate the catalytic activity of cerium oxide. The performance and emission were compared with diesel and diesel having cerium oxide nano particle with 5, 15, 25 and 35PPM concentration. It was seen that the viscosity, flash and fire point increases with addition of nano particle. The load tests were conducted by varying the dosing levels of cerium oxide nano particle in diesel, the brake thermal efficiency was found to be increase at the dosing level of 35 ppm of cerium oxide with 2 % DDSA. The hydrocarbon emission decreased on addition of catalytic nano particle by about 40 to 45%, especially at higher load. The NOx emission was found to decrease by a maximum of 30% on the addition of cerium oxide nano particle in diesel especially at higher loads and further reduction up to 50% with the addition of 5% volume fraction of surfactant treated nano particle.

V. Arul Mozhi Selvan et al. [3] investigated the performance and emission char­acteristics of neat diesel and diesel-biodiesel-ethanol blends with 25 PPM and 32 nm size cerium oxide as fuel borne additive on a single cylinder four stroke variable compression water cooled engine at the compression ratio of 19. The phase separation between diesel and ethanol was prevented by adding biodiesel. The turbidity procedure was used to assess the stability of the resulting suspension. All the results were plotted against brake mean effective pressure (BMEP). The lower BSFC was observed for Cerium oxide blend of neat diesel. The higher brake thermal efficiency was observed for neat diesel. The addition of cerium oxide further decreased the CO, HC emission when compared to neat diesel. The NOx emission was lower for the neat diesel as compared to all the fuel blends.

V. Sa jith et al. [4] had studied the influence of dosing level ranging from 20 to 80 PPM of cerium oxide nano particles in biodiesel derived from jatropha, on a single cylinder water-cooled direct injection diesel engine operating at 1500 RPM. The physiochemical properties, performance and emission characteristics were measured. The size of nano particle was 10 to 20 nm and density was 7.13 g/ml. The results so obtained were plotted against the load on test engine. Increasing trend was seen in the physiochemical properties of fuel like flash point, viscosity and volatility with addition of nano particle. The results concluded that an average reduction of 25% to 40% in the hydrocarbon emission was obtained for the additive dosing level ranging from 40 to 80 PPM of the additive. The NOx emission was found to be generally reduced by 30% on the addition of cerium oxide nano particle to biodiesel with dosing level of 80 PPM. The reduction influence of the fuel additive on carbon monoxide emission was not so prominent.

Rakhi N. Mehta et al. [5] Investigated the burning characteristics, engine perfor­mance and emission parameters of a single-cylinder Compression Ignition engine using nano fuels which were formulated by sonicating nano particles of aluminum (Al) having 30-60nm, iron (Fe) 5-150 nm and boron (Bo) 80-100 nm in size in base diesel with 0.5 wt% and 0.1wt% Span80 as a surfactant for stable suspension. The nano fuels reduced ignition delay, longer flame sustenance and agglomerate ignition by droplet combustion mechanism testSpecific fuel consumption was reduced by 7% with A1 in comparison to diesel. Exhaust gas temperatures of A1, Fe, and Bo rose by 9%, 7% and 5% respectively, resulting into increase in brake thermal efficiencies by 9%, 4%, and 2% as compared to diesel at higher loads. At higher loads, the emission study showed a decline of 25-40% in CO (vol. %), along with a drop of 8% and 4% in hydrocarbon emissions for A1 and Fe nano fuels respectively. Due to elevated temperatures a hike of 5% and 3% was observed in NOx emission with A1 and Fe.

M. A. Lenin et al. [6] investigated the effect of metal additives MnO (200 mg/l) and CuO (200 mg/l) doped in diesel on performance and emission characteristics of single cylinder diesel engine. The ranges of nano particle between 50-210 nm was observed with SEM. All the results were revealed against the load. The improvement in fuel properties (viscosity, flash point and fire point) was noted due to the addition of nano metal oxide. Brake thermal efficiency was raised marginally by 4% from the diesel fuel. The HC emissions were highest at lower load. At full load it was seen that 1% decrease in the HC emission, it was observed that manganese has the stronger effect in reducing the diesel exhaust emissions. The exhaust emission measurements for the fuel with manganese additive showed that CO was decreased by 37%, and NOx was reduced by 4 %.

N. R. Banapurmath et al. [7] had conducted the test to determine the combustion, performance and emission characteristics of single cylinder four stoke direct injection diesel engine using Hinge oil methyl ester (HOME) biodiesel fuel blended with multi walled carbon nano tube (MWCNT) with 25 and 50 PPM concentration. Neat diesel was used for base line data generation for experimentation purpose also the compression ratio, injection opening pressure, injection timing was kept at 17.5, 205 bar and 23BTDC for diesel operation and 17.5, 230 bar and 17.5 BTDC for blend of HOME-MWCNT respectively. The entire test was conducted at a constant speed of 1500 RPM and by varying the load. The maximum brake thermal efficiency for HOME50MWCNT was 25.0% whereas it was 24% for HOME25MWCNT as compared to 23 percent for HOME and 28% for neat diesel at 80% load respectively. Additive blended fuel reduced the smoke opacity as compared to HOME. The observed smoke opacity for HOME25MWCNT and HOME50MWCNT was 63 and 59 HSU as compared to 78HSU for HOME and 52 HSU for neat diesel respectively at 80% load. The NOx emission for HOME25MWCNT was 600 PPM where it was 750 PPM for HOME50MWCNT, compared to 580 PPM for HOME and 800 PPM for neat diesel at the 80% load respectively.

G. R. kannan et al. [8] examined the use of ferric chloride (FeCl3 ) as a fuel borne catalyst (FBC) for waste cooking palm oil based biodiesel. The metal based additive was added to biodiesel at a dosage of 20 mol/L. Experiments were conducted to study the effect of ferric chloride added to biodiesel on performance, emission and combustion characteristics of a direct injection diesel engine operated at a constant speed of 1500 rpm at different operating conditions. The results revealed that the FBC added biodiesel resulted in a decreased brake specific fuel consumption (BSFC) of 8.6% whiles the brake thermal efficiency increased by 6.3%. FBC added biodiesel showed lower nitric oxide (NO) emission and slightly higher carbon dioxide (CO2 ) emission as compared to diesel. Carbon monoxide (CO), total hydrocarbon (THC) and smoke emission of FBC added biodiesel decreased by 52.6%, 26.6% and 6.9% respectively compared to bio diesel.

Ali Keskin et al. [9] had investigated the influences of tall oil biodiesel with Mg and Mo based fuel additives on single cylinder DI diesel engine at variable speed up to 3600rpm under full load conditions for performance and emission. Tall oil resinic acids were reacted with MgO and MoO2 stoichiometrically for the production of metal-based fuel additives. The additives were added into tall oil biodiesel B60 (60% biodiesel + 40% diesel fuel) at a dosage of 4 mol/l, 8 mol/l and 12 mol/l for preparing test fuels. The significant effect was that both the additives shown improvement in the fuel properties. All the results were shown against the speed. The performance of engine did not change considerably with biodiesel fuels, but exhaust emission shown drastic change. Maximum increase of fuel consumption was 5.51% with B60 at 2800 rpm, and minimum increase was 3.08% with B60-8Mo at 1800 rpm. CO emissions and smoke opacity decreased by 56.42% and by 30.43%, respectively. In general, low NOx and CO2 emissions were measured with the biodiesel fuels. The Maximum reduction in CO2 observed 8.82% with B60-12Mg at 1800 rpm. In addition, in comparison with Mo-based additives, lower CO2 concentration was measured with Mg-based additive. NOx emissions were reduced with all biodiesel fuels at high engine speed. According to diesel fuel, the ratio of maximum increase is 12.78% with B60-12Mo at 2200 rpm and the maximum reduction was 23.19% with B60-8Mo at 2800 rpm, respectively.

A. Keskin et al. [10] had performed the experiment on single cylinder diesel at full load conditions with variable speed from 1,800 to 3,200 rpm with an interval of 200 rpm to determine the effect of tall oil biodiesel with cobalt (Co)-based additive for engine performance and exhaust emissions. The tall oil sample consists of 53.6% resin acids, 36.3% fattyacids, 4.5% unsaponifiables matter, and 5.6% water. Co-based additive at the rate of 4, 8, and 12mol/l was added to mixtures of 60% tall oil methyl ester and 40% diesel fuel (T60). On the addition of additives the fuel properties like pour point and viscosity significantly decreased. Biodiesel fuels had insignificant influence on engine torque and the power output values The lowest value of specific fuel consumption were observed at 2400 rpm for the all test fuels. Specific fuel consumption values declined slightly with the addition of Co-based additive. Additive added biodiesel shown decreasing trend in CO emission which was ranged from 19.52 to 53.37%. CO2 emission values of biodiesel fuels were reduced by 7.6% than diesel. The Co-based additive did not affect CO2 concentration Higher NOx emissions were measured at low engine speed whereas lower NOx emissions were obtained at higher speed with all biodiesel fuels. The maximum reduction in smoke level was 29.47% with T60-12 at 1,800 rpm.

Ranaware A. A. et al. [11] had investigated the performance and emission char­acteristics of a compression ignition engine by correlating the cerium oxide nanoparticles and water-based ferrofluid as additive to diesel fuel. The cerium oxide acts as an oxygen donating catalyst and provides oxygen for the oxidation of CO or soak up the oxygen for the reduction of NOx. The activation energy of cerium oxide burn off carbon deposits within the engine cylinder wall and reduces the HC emissions. The ferrofluid was prepared on reacting iron II (FeCl2) and iron III (FeCl3) ions in an aqueous ammonia solution. All the results had represented against the break mean effective pressure. The experiments shown that highest brake thermal efficiency was obtained 25.66% for neat diesel whereas it was seen 23.63% for the D+CERIA25 blend under the same BMEP of 0.44 MPa. On the other hand, 0.4% ferrofluid to diesel fuel improved the BTE by 3.33-6.89% relatively and adding 0.8% ferrofluid to diesel fuel increased the BTE by 5.33-12.17% relatively. The lowest BSFC was examined as 0.3586kg/kW-hr for the D+CERIA25 blend whereas it was 0.3931kg/kW-hr for neat diesel at the brake mean effective pressure (BMEP) of 0.44Mpa. It was found out that 0.4% ferrofluid added to diesel fuel decreased the BSFC relatively by 3.23-6.45%, and0.8% ferrofluid added todiesel fuel decreased the BSFCrel- atively by 5.06-10.85%. Also, from the analysis of engine exhaust emissions, it was seen that NOx emissions were lower than that of diesel fuel of D+4F and D+8F at all loads. Adding 0.4% ferrofluid to diesel fuel reduced NOx emissions by 9 to 15 ppm, and adding 0.8% ferrofluid to diesel fuel cut NOx emissions by 14 to 24ppm. But the CO emissions were increased when used ferrofluid and in opposite case cerium oxide nanoparticle added fuel shown the decreasing trend for the CO. The results of this paper had shown that If both cerium oxide nanoparticles & ferrofluid are added to the neat diesel then we can improve performance & emission characteristics of CI engines.

Samarjeet Bagri et al. [12] experimental work had done on single cylinder, water cooled, two stroke, direct injection, Textool Diesel Engine under the full load and varying speed at 300,500,700rpm using SC5D additive in different -different proportions. The blends were prepared D0 (pure diesel), D1 (1000:1) ml , D2 (1500:2)ml, D3 (2000:3)ml, D4 (2500:5)ml, D5 (3000:7)ml. The emissions and performance results were compared with base fuel diesel. By adding of this additive, it was found out that cetane index number was increased from 46.22 as of base fuel to 47.63, 49.40, 51.91, 54.91 and 60.66 respectively. The results revealed that HC, CO & NOx emissions were reduced by 35%, 30% & 4% respectively. Brake power was boosted 6% whereas brake specific fuel consumption and smoke density were reduced by 23% and 35%. It was seen that, when cetane index number was increased from 54.91 to 60.66 the engine performance and emission characteristics were not effective. The results revealed that the cetane index no. was increased from 46.22 to 54.91, brake power increased and brake specific fuel consumption reduced linearly in all speeds, 300, 500 and 700 rpm.

Lu Xing cai et al. [13] had determined the influence of cetane number improver on performance ,combustion characteristic, heat release rate and emissions of a high­speed DI ,water cooled four cylinder diesel engine fueled with diesel ,ethanol-diesel and different percentage of cetane number enhancer (0,0.2,0.4%) blend fuel . The analysis­grade anhydrous ethanol (99.7% purity) were mixed with solublizer 1.5%v/v and then blended with diesel. The results revealed that from the combustion analysis the ignition delay extended and the total combustion duration decreased for ethanol- diesel blend fuels when compared to diesel fuel. The combustion characteristics of ethanol-diesel blend at higher load may be nearest to diesel fuel by CN improver, but a large difference exists at lower load. From the heat release rate at specific BMEP at 3400 r/min, it was found that the premixed combustion for all ethanol-diesel blends was increased when compared to neat diesel fuel, but the premixed combustion gradually decreased with the increase of CN improver volume in blend fuels. It was seen that the BSFC and thermal efficiency improved remarkably when engine operated with CN improver. From the emission results it was found that CO increased at lower and medium load, while the increasing trend decreased at higher load with CN improver. The HC was very lower at all loads. The NOx and smoke emissions decreased at all loads simultaneously for all blends as compared to diesel.

V. Arul Mozhi Selvan et al. [14] evaluated the combustion, performance and emis­sion characteristic of variable compression ratio engine using Cerium Oxide Nanoparticles and Carbon Nanotubes which were mixed with the Diesterol each at the rate of 25 ppm, 50 ppm and 100 ppm. Castor oil biodiesel act as a bridging agent for Diesel and Ethanol those were immiscible in each other. Combustion, performance and emission results were taken at optimum compression of 19:1 but at different loading conditions. Results showed that, the Carbon Nanotubes decreases ignition delay and advances the peak heat release rate where as Cerium Oxide Nanoparticles donates oxygen which helps in the oxidation and reduction of carbon monoxide and nitrogen oxides respectively. Cerium Oxide also provides extra energy to burn off carbon deposits within the engine cylinder. Decrease in harmful exhaust gas emission and cleaner combustion was the significant effect of both.

T. Shaafi et al. [15] investigated the performance and emission characteristics of two blends diesel- soybean biodiesel blend(D80B20) and diesel-soybean biodiesel-ethanol blends with alumina additive 100 mg/l and 1% isopropanol (D80B15E4S1+alumina(100mg/l)) on naturally aspirated, air cooled , single cylinder constant speed compression ignition engine. Alumina nanoparticles were added to blends with the help of ultrasonicator. Re­sults showed that higher cylinder pressure and heat release rate was observed for alumina added blends as compared to neat diesel. In case of alumina added blend brake thermal efficiency was obtained 17.9% increasement than neat diesel. It was seen that BSFC 11.46% declined and minimum BSEC for alumina added fuel as compared to diesel. Ex­haust gas temperature also decreased in the case of alumina blend. Further, the soybean biodiesel provided extra oxygen and alumina nanoparticles accomplished complete com­bustion and resulted in decreased CO, CO2 and UBHC. But NOx emission was observed 9.9% higher than diesel.

K. Muralidharan et al. [16] studied the performance, combustion and emission characteristics of waste cooking oil methyl ester and its blends (20%, 40%, 60% and 80% by volume biodiesel) with diesel. Transesterification process was used for the production of biodiesel. All the experiments were performed on single cylinder four-stroke variable compression ratio engine at a constant speed of 1500 rpm and 50% load. Compression ratio was varied from 18:1 to 22:1. All the graphs were plotted against the different com­pression ratio. Maximum brake power of 2.07 KW was obtained for B40 at compression ratio of 21:1 on the other hand for diesel fuel it was 2.12 KW. Whereas brake thermal efficiency was slightly higher and specific fuel consumption was lower in case of B40 as compared to diesel. Exhaust gas temperature was higher than diesel for all blended fuels at lower compression ratios whereas it was lower than diesel in case of higher compres­sion ratios. The hydrocarbon emission for B40 shown increasing trend with increase in compression ratio. NOx emission was observed for B40 higher than other blends and diesel. It was seen 6400 ppm and 621 ppm for B40 and diesel. The CO emissions were found nearest to diesel but at higher compression ratio observed higher. At lower com­pression ratio lesser CO2 was seen but at higher compression ratio vice versa. At higher compression ratio biodiesel blends released higher combustion pressure.

Mohammed E.k. et al. [17] Examined the effect of compression ratio on engine fuelled with biodiesel. Biodiesel was produced from the waste cooking oil collected from the restaurants with the help of transesterification process and the mixed with pure diesel to produce blends with the concentration of 10%, 20%, 30% and 50% by volume. In the experiment compression ratio was varied from 16 to 18 with the step of two. Emission and combustion data obtained from the experiment shown that, with the increases of compression ratio engine torque was increased for all the blended fuels as compared to pure diesel. Brake thermal efficiency was increased by 18.39%, 27.48%, 18.5% and 19.82% for B10, B20, B30 and B50 respectively. From the emission point of view blends shown nearly 52% and 37.5% reduction in HC emission and CO emission when compression ratio varied from 14 to 18. CO2 and NOx emission was increased by 14.28% and 36.84% respectively when compression ratio changed from 14 to 18. It was concluded that delay period was decreased 13.95% during the variation of compression ratio from 14 to 18.

J. Sadhik Basha et al. [18] conducted an experiment on single cylinder constant speed diesel engine to study the effects of Carbon Nanotubes (CNT) which were added 25,50 and 100 ppm concentration to Jatropha Methyl Esters (JME) emulsion fuel. Trans­esterification process was used to produce Jatropha Methyl Esters from the Jatropha oil and then 5% water with 2% surfactant by volume was added to produce JME emulsion fuel. The HLB (hydrophilic-lipophilic) value was 10. The stability of CNT added emul­sion fuel was more than five days due to high speed agitation at 3000 rpm. Experimental results revealed that, 100CNT blended JME emulsion fuel shown 28.45%, JME emulsion fuel shown 26.34% and neat JME shown 24.80% increase in brake thermal efficiency at full load. The reduction in peak cylinder pressure was observed when added 100 ppm con­centration of CNT to the JME emulsion. Further, the harmful emission gasses like CO, NOx and smoke reduced due micro-explosion and secondary atomization phenomena's. There was nearly 31% reduction in NOx emission with neat JME and 51% reduction for CNT blended JME emulsion fuel.

Mohamed F. Al-Dawody et al. [19] performed the experiment on single cylin­der, direct injection variable compression diesel engine fuelled with soybean methyl ester (SME) blend with diesel to study the effect of compression ratio on performance combus­tion and emissions. The experiment was conducted at compression ratios of 15, 16, 17.5 and 19 while speed remained constant 1500 rpm. Three blends was prepared by adding soybean biodiesel to diesel with a concentration of 20%, 40% and 100% on volume basis and named as B20, B40, and B100. As Increased the concentration of biodiesel decreased the heat release rate. Hydrocarbon, carbon monoxide and smoke from engine decreased when increased the compression ratio from 15 to 19. The NOx emission was increased when compression ratio varied from 15 to 19. From all the above three, B20 was given best results as compared to B40, B100.

C. Syed Aalam et al. [20] studied the effect of 25% zizipus jujube methyl ester blended with diesel fuel on performance, combustion and exhaust emissions characteristics in single cylinder, common rail direct injection (CRDI) system supported diesel engine. Aluminum oxide nanoparticles were also added with a concentration of 25 ppm and 50 ppm on mass basis, to blends with the help of a mechanical Homogenizer and an ultrasonicator. All the graphs were drawn against brake power. Blends with aluminum oxide nanoparticles shown a significant reduction in BSFC and exhaust emission. The HC and smoke emissions reduced from 13.459 g/kWh and 79 HSU to 8.599 g/kWh and 49 HSU with the addition of aluminum oxide nanoparticles. Nanoparticles also had shown a dominant effect on brake thermal efficiency and heat release rate.

G. Vairamuthu et al. [21] explored the effect of Calophyllum Inophyllum biodiesel on performance, combustion and emission characteristics in single cylinder, vertical, nat­urally aspirated four stroke, water cooled, Direct injection, constant speed, Kirloskar diesel engine. Cerium oxide nanoparticles were added to diesel blends using ultrasonic agitator. Precipitation method was used for synthesis of cerium oxide nanoparticles. The concentration of cerium oxide nanoparticles was kept 20 ppm to the biodiesel blend. Brake thermal efficiency was seen as 25.09% for B100+200 ppm, whereas it was observed 21.61% for the B100 fuel. Cerium oxide nanoparticles were provided additional oxygen for the oxidation of carbon monoxide and reduction of nitrogen oxides. The NOx reduced up to 25.08% at full load while using nanoparticles.

GVNSR Ratnakara et al. [22] performed the experiments on variable compression ratio single cylinder four stroke diesel engine. In this research experiments were conducted using diesel fuel to determine the optimum compression ratio. The compression ratio was varied on engine 13.2, 13.9, 14.8, 15.7, 16.9, 18.1 and 20.2. All the graphs were plotted against the brake power. Results showed that compression ratio 14.8 was shown less fuel consumption, less smoke emission and moderate temperature of exhaust.

Mehardad Mirza janzadeh et al. [23] investigated the performance and emission characteristics of novel -soluble additives biodiesel OM355 EU2 engine at IDEM Com­pany. All the experiments were performed at 1000, 1200, 1400, 1500, 1600, 1800, 2000 and 2200 rpm at full load. At 1500 rpm lends produced maximum torque. Novel -soluble additives were hybridized of cerium oxide and multiwall carbon nano tubes using solvent -aided method. After the hybridization size of the nanoparticles 40-50 nm was confirmed by SEM. Two biodiesel blends B5 and B20 was prepared with diesel and 30, 60, and 90 ppm concentrations were added to the blends. All the result was graphed against the different fuel blends at 1500 rpm and full load. Results showed that power and torque was improved by 7.81% and 4.91% respectively for the B20 with 90 ppm concentration when compared to B20. The fuel consumption was decreased up to 4.50% for the B20 with 90 ppm blend compared to B20. CO, NOx,soot and HC were reduced by up to 38.8%, 18.9%, 71.4% and 26.3% in B20 with 90 ppm as compared to pure B20.

K. Shrinivasa Rao et al. [24] analyzed the performance and emission charac­teristics of diesel and diesel-biodiesel blends on single cylinder four stroke compression ignition diesel engine using cerium oxide nanoparticles. The cerium oxide nanoparticles were added to the pure diesel and B20 (20% biodiesel by volume). The nanoparticles were mixed in the proportion of 20, 40 and 60 ppm to the B20. The biodiesel was prepared by transesterification process from eucalyptus oil. Using high speed ultrasonication stability was improved. Results were plotted against the load. It was observed that BTE was shown improving trend with all the nanofuels from B20. The least BSFC was reported 0.268 kg/kW-hr for B20 with 60 ppm addition of nanoparticles at full load. Results showed that cerium oxide was acted as oxygen buffer and results reduced the both CO and NOx. Results revealed that the activation energy of cerium oxide nanoparticles helped to reduce the HC emissions.

Ganesh et al. [25] had performed the experiments on single cylinder four stroke diesel engine at 1500 rpm to study the performance and emission characteristics. The nanofuels additive Cobalt Oxide (Co3 O4 ) and Magnalium (Al-Mg) were added 100 mg/l to the B100 jatropha biodiesel. Synthesis of Cobalt Oxide was done with Sol-Gel method and Magnalium with Ball Mill method. The range of particle size was characterized with SEM and size varied between 38-70 nm. The cationic surfactant Cetyl Trimethyl Ammonium was used to stabilize the nanofluid. Surfactant was added 100% wt. of the nanoparticles to the nanofluid. All the results were plotted against the BMEP. Nearly 1% enhancement was seen in BTE for magnalium added biodiesel as compare to pure biodiesel. At 75% load on the engine cobalt oxide added biodiesel shown 83% decline in HC compare to pure biodiesel. A same trend was seen with magnalium additive and at 50% load 70% decline observed of HC. On the addition of magnalium the CO reduction was observed about 66% at 50% load conditions. The similar trend was followed by cobalt oxide and shown 50% reduction at 75% load. The drastic results were seen with NOx when added cobalt oxide. About 47% reduction was seen with these nanofuels. Cobalt oxide showed better decrease in NOx at all load compare to magnalium.

Ajay Kumar et al. [26] had reported in this publication that water /diesel emul­sion decrease the emissions without compromising with performance characteristics. The commercial diesel had reported rise in emissions. Nanofluid had shown the potential to reduction in emissions and improvement in performance characteristics. The combustion efficiency, fuel properties and ignition delay were improved using nanoparticles. A surfac­tant was reported that it was enhanced the stability of nanofluid. Authors had reported that cerium oxide nanoparticles can used with water /diesel emulsion to improve the performance and emission characteristic on four cylinder four stroke diesel engine.

Gurinder Singh et al. [27] reviewed the literature to study the performance and emission characteristics of CI engine using biodiesel with additives as alternative fuel. Biodiesel had not shown significantly improvement in performance, but shown decreasing trend in emission parameters, especially in Sox, CO and CO2 except to NOx. Nanoparticle added fuel improves the emissions and performance of CI engine due to the positive effect of nanofuels on the fuel properties and ignition delay. To improve the performance and emission especially NOx and particulate matter of diesel and diesel blended with biodiesel nanofuels had become an essential part of today's fuels. From the literature concluded that addition of nanoparticles in diesel and diesel-biodiesel blends not only enhanced the calorific values but also promotes complete combustion due to higher evaporation rates, reduced ignition delay, higher flame temperatures and prolonged flame sustenance. Nanometal oxide additives were reported to be effective in lowering diesel emissions.

Yu Ma et al. [28] had accounted the results of experiments perform on single cylin­der four stroke diesel engine. The Fe-based combustion promoter homogenous catalyst contained ferrous picrate was mixed in the pure diesel in the ratio of 1:3200 (FTC-D) and investigations 1:10000 (FPC-D). Test was performed at 2800 rpm and 3200 rpm engine speed respectively. The results were plotted against the BMEP. After the addition of very low dosage of FTC and FPC fuel properties were not changed. Results concluded that maximum 3.7% BSFC decreased at 3200 rpm and 0.14 MPa BMEP for FTC-D than reference diesel. On the other hand FPC-D shown 3.1% BSFC reduction at 2800 rpm and 0.14 MPa BMEP compared to reference diesel. In the case of emissions of CO, Particulate matter and UHC using picrate solution maximum reduction were observed 21.1%, 39.5 and 13.1%. But in opposite for NOx emissions had not shown any positive effective. Due to the improved fuel combustion efficiency a little higher NOx observed.

S. Krthikeyan et al. [29] performed the experiment on single cylinder four stroke vertical diesel engines at 1500 rpm constant speed. The compression ratio and injection timing was set 17:1 and 23.4 BTDC for all the tests. The grape seed oil methyl ester biodiesel prepared by transesterification method and blends were prepared by emulsifica­tion technique. The zinc oxide nanoparticles were dispersed to the B20 (20% biodiesel and 80% diesel) in the concentration of 50 ppm and 100 ppm. The stability of nanoparticle s added blends were extended using mechanical agitator and ultrasonicator. The average particle size was obtained 100 nm. All the graphs were made against the brake mean effective pressure. The fuel properties especially improved and it were effected the BTE and BSFC. The results revealed that performance characteristics Brake power, Brake thermal efficiency and BSFC were improved due to the addition of zinc oxide nanopar­ticles to the blends compared to the biodiesel blend without addition of nanoparticles. The exhaust gas temperature was seen slightly higher the biodiesel blend B20. This was happened due to the complete combustion. The similar trend was observed with ed due to higher surface area to volume ratio and better A/F ratio. But higher NOx and CO2 was observed for nanoparticles added fuel compared to B20.CO, smoke and HC. More the concentration more the reduction in emissions was observed.

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