Final thesis.pdf new

INTRODUCTION

The prices of petroleum products are generally on an increasing trend and consequently affecting the general cost of living. This continuous increase has resulted in the prices of some products tripling in the last decade. In some communities, in the developing nations these products are not only expensive but they are not readily available because of the poor road infrastructure necessary for their distribution. The consumption of petroleum products also has other inconveniencies such as environmental pollution and the emission of greenhouse gasses generally believed to be responsible for global warming. The general trend all over the world now is to reduce the over dependence on petroleum products so as to help reduce the effects of global warming. Other possible advantages of abandoning petroleum products is the fact that alternative sources can be produced from renewable resources that are available almost everywhere that there is life. This avoids the employment of heavy infrastructure for long distance transportation and distribution.

Background and Justification

Fuel additives are very important, since many of these additives can be added to fuel in order to improve its efficiency and its performance (Pandey and Gupta, 2016). Ethanol -gasoline blend with percentage volume of ethanol up to 15% can be used in SI engine without any modifications. The presence of oxygen and high octane number were significant features of using ethanol-gasoline blends.

The fuel consumption and specific fuel consumption showed a marginal decreasing with the use of ethanol-gasoline blends (Mostafa et al., 2017).Adding ethanol to gasoline will lead to a leaner better combustion. It was experimentally demonstrated that adding 5-15% ethanol to the blends led to an increase in the engine brake power, torque and brake thermal efficiency, volumetric efficiency and decreases the brake specific fuel consumption (Yusuf et al., 2010).

When engine was fueled with methanol gasoline blend, engine performance parameters such as brake torque, brake power, brake thermal efficiency, volumetric efficiency increases with increasing methanol amount in the blended fuel while bsfc and equivalence air-fuel ratio decreased (Shayan et al., 2011).

Statement of Problem

The reserves of petroleum-based fuels are directly correlated with the increasing demands of humankind for energy production. With growing world populations, industries, vehicles, and equipment, energy demand leads to the search for a substitute for petroleum fuels which can accommodate to the need of people today.

Considering the current global economic crisis, the curiosity in alternative fuels is extremely high.

Alternative fuels used as substitute petroleum-based fuels must be produced from renewable sources, and should be devised to use this fuel without bringing any modifications in the geometry of the engine. Alcohols have provided an answer to this problem. Ethanol is thought to be the most fitting fuel for spark ignition engines.

Researchers have generated a few alternative and cost-effectively viable fuels which are also environment friendly.

Ethiopia is also one of the country which totally import petroleum from other country and high demand of energy is observing from day to day. As a result the country's economy highly depend on the fuel price and vulnerable to it which shocked by its fluctuation.

According to the Ministry of Water and Energy, the country has a plan to top up an ethanol blended oil to the local market to reach E25 (a 25% ethanol content blended in Benzene and biodiesel) (Melas Teka.2007 The way followed by the previous researcher to know the performance of engine and emissions of greenhouse is time consuming and need professional on the area.

Despite a number of work is done on this area in other countries there is no common conclusion which is a basic route creating confusion to use the result of their experiment for practical operation and not easy to rely on it. But if the thermodynamic analysis of blend fuel is done and the computer program is developed for it, one can determine the engine performance and emissions rapidly and easily for every blend proportion.so this problem can be solved after completion of this thesis.

Objectives

General objective

The main aim of the work is to conduct performance analysis of spark ignition (SI) engine using various blends of gasoline and ethanol.

Specific objectives

The specific objectives of this work are listed as follow:

 To develop computer C++ program that can rapidly and easily determine engine performance and emissions for every amount of blend proportion.

 To validate the program using the practical data.

 To determine Engine performance such as, brake power, brake thermal efficiency, volumetric efficiency, brake torque, brake mean effective pressure and brake specific fuel consumption on different proportions of blend.

 To determine the amount of emission for all selected blend proportions by including combustion products like CO₂, H₂O, O₂, N₂, HC, CO, N2.

Significance of the Study

This project can benefit the natural environment on the first place by determining harmful emissions components and differentiate which blend proportion of ethanol and gasoline affect it highly. This means all living things are beneficiary .Not only this the future researcher can also get benefit while determining the performance of engine and emissions on the actual or real engine by using the computer c++ program developed in this research.

Generally the automobile companies, users and the country as a whole can be benefited from this thesis.

Scope

This project was studied the thermodynamic analysis of engine performance and emissions of different proportions of blend fuel (ethanol-gasoline) by mathematical model and develop the computer c++ program. The experimental investigation was done on real engine to validate or prove the result of computer c++ program. All the combustion products were not considered while the emission analysis was done.

This research work did not include the effect of different proportions of blend fuel on physical property of engine parts and accessories.

CHAPTER

Ethanol

Ethanol is manufactured from microbial conversion of biomass materials through fermentation. Ethanol contains 35 percent oxygen. The production process consists of conversion of biomass to fermentable sugars, fermentation of sugars to ethanol, and the separation and purification of the ethanol. Ethanol (ethyl alcohol, grain alcohol) is a clear, colorless liquid with a characteristic, agreeable odor. In dilute aqueous solution, it has a somewhat sweet flavor, but in more concentrated solutions it has a burning taste. Ethanol, CH3CH2OH, is an alcohol, a group of chemical compounds whose molecules contain a hydroxyl group, -OH, bonded to a carbon atom.

Fermentation initially produces ethanol, and separation and purification of ethanol.

Fermentation initial produces ethanol containing a substantial amount of water.

Distillation removes the majority of water to yield about 95 percent purity ethanol, the balance being water. This mixture is called hydrous ethanol. If the remaining water is removed in a further process, the ethanol is called anhydrous ethanol and suitable for blending into gasoline. Ethanol is "denatured" prior to leaving the plant to make it unfit for human consumption by addition of small amount of products such as gasoline. (https://en.wikipedia.org/wiki/Ethanol)

Gasoline

Gasoline or gas for short (American English), or petrol (British English), is a transparent, petroleum-derived liquid that is used primarily as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. On average, a 42-gallon barrel of crude oil (159 L) yields about 19 US gallons (72 L) of gasoline when processed in an oil refinery, though this varies based on the crude oil source's assay.

The characteristic of a particular gasoline blend to resist igniting too early (which causes knocking and reduces efficiency in reciprocating engines) is measured by its octane rating. Gasoline is produced in several grades of octane rating. Tetra ethyl lead and other lead compounds are no longer used in most areas to regulate and increase octane-rating, but many other additives are put into gasoline to improve its chemical stability, control corrosiveness and provide fuel system 'cleaning,' and determine performance characteristics under intended use. Sometimes, gasoline also contains ethanol as an alternative fuel, for economic, political or environmental reasons.

Gasoline used in internal combustion engines has a significant impact on the environment, both in local effects (e.g., smog) and in global effects (e.g., effect on the climate). Gasoline may also enter the environment un combusted, as liquid and as vapors, from leakage and handling during production, transport and delivery, from storage tanks, from spills, etc.( https://en.wikipedia.org/wiki/Gasoline)

Chemical and Physical Characteristics of Ethanol and Hydrocarbon Fuels

Characteristics of gasoline (A Hydrocarbon)

Hydrocarbon fuels (gasoline, diesel fuel, kerosene, jet fuel, etc.) generally have similar characteristics whether they are flammable liquids or combustible liquids.

Gasoline is a hydrocarbon produced from crude oil by fractional distillation. It is non-water miscible and has a flash point of approximately -45°F, varying with octane rating. Gasoline has a vapor density between 3 and 4. Therefore, as with all products with a vapor density greater than 1.0, gasoline vapors will seek low levels or remain close to ground level. Gasoline has a specific gravity of 0.72-0.76 which indicates it will float on top of water since it is non-water miscible or insoluble. Its auto-ignition temperature is between 536°F and 853°F, and it has a boiling point between 100°F and 400°F depending on fuel composition. Gasoline is not considered a poison but does have harmful effects after long-term and high-level exposure that can lead to respiratory failure. Smoke from burning gasoline is black and has toxic components. Gasoline's greatest hazard is its flammability even though it has a fairly narrow flammability range (LEL is 1.4 percent and UEL is 7.6 percent).

Characteristics of ethanol (A Polar Solvent)

Ethanol is a renewable fuel source that is produced by fermentation and distillation process. The most common source of ethanol in the United States in 2008 is corn.

However, it can be produced from other products such as sugar cane, saw grass, and other natural products that will be conducive to the fermentation/distillation process.

Ethanol is a polar solvent that is water-soluble and has a 55°F flash point. Ethanol has a vapor density of 1.59, which indicates that it is heavier than air. Consequently, ethanol vapors do not rise, similar to vapors from gasoline which seek lower altitudes. Ethanol's specific gravity is 0.79, which indicates it is lighter than water but since it is water-soluble it will thoroughly mix with water. Ethanol has an auto- The most striking difference between these two fuels is that unlike gasoline, ethanol mixes easily with water. While it is possible to dilute ethanol to a condition where it no longer supports combustion, this is not practical in the field as it requires copious amounts of water. Even at 5 parts water to 1 part ethanol, it will still burn.

Comparison of gasoline and ethanol

Characteristics of Ethanol-Blended Fuels

Blending ethanol with gasoline has multiple effects. Ethanol increases the heat output of the unleaded gasoline, which produces more complete combustion resulting in slightly lower emissions from unburned hydrocarbons. The higher the concentrations of ethanol, the more the fuel has polar solvent-type characteristics with corresponding effects on conducting fire suppression operations. However, even at high concentrations of ethanol, minimal amounts of water will draw the ethanol out of the blend away from the gasoline. Ethanol and gasoline are very similar in specific gravity. The two differing fuels mix readily with minimal agitation, but the blend is more of a suspension than a true solution. Ethanol has a greater affinity for water than it does for gasoline. Over time, without agitation, gasoline will be found floating on a layer of an ethanol/water solution. The resulting ethanol/water solution is still flammable since the concentration of ethanol is still fairly rich. Phase separation can occur in fuel storage systems where water is known to be present. Blending these fuels together alters the physical and chemical characteristics of the original fuels. However, the resulting changes may be unnoticeable to emergency responders. One of the noticeable differences in the blended fuel versus unblended gasoline is the visual difference of the smoke and flame characteristics. The higher the content of ethanol, the less visible the black smoke content and orange flame production. These characteristics may be masked by other substrates that may also be burning such as vehicle tires. Another noticeable difference of ethanol-blended fuels under fire conditions is that when foam or water has been flowed on the burning product, the gasoline will tend to burn off first, eventually leaving the less volatile ethanol/water solution which may have no visible flame or smoke.

Ethanol is a polar solvent that is simultaneously water-soluble and flammable.

Creating a blend of gasoline and ethanol results in a chemical change that can easily go unnoticed by emergency responders. Knowing that the ethanol will be the last fuel to burn and that it may burn without visible smoke or flame is important in determining an approach to take in dealing with ethanol-involved incidents.

Summary of the Main Ethanol Blends Used Around the World

Several common ethanol fuel mixtures are in use around the world.

E10 or less

E10, a fuel mixture of 10% anhydrous ethanol and 90% gasoline sometimes called gasohol, can be used in the internal combustion engines of most modern automobiles and light-duty vehicles without need for any modification on the engine or fuel system. E10 blends are typically rated as being 2 to 3 octane numbers higher than regular gasoline and are approved for use in all new U.S. automobiles, and mandated in some areas for emissions and other reasons. The E10 blend and lower ethanol content mixtures have been used in several countries, and its use has been primarily driven by the several world energy shortages that have taken place since the 1973 oil crisis.

E15

Typical manufacturer's statement in the car owner's manual regarding the vehicle's capability of using up to E10.

E15 contains 15% ethanol and 85% gasoline. This is generally the highest ratio of ethanol to gasoline that is possible to use in vehicles recommended by some auto manufacturers to run on E10 in the US. This is due to ethanol's hydro philia and solvent power. According to the Brazilian ANP specification, hydrous ethanol contains up to 4.9

vol. % water. In hE15, this would be up to 0.74 vol. % water in the overall mixture.

Japanese and German scientific evidence revealed the water is an inhibitor for corrosion by ethanol.

E20, E25

E20 contains 20% ethanol and 80% gasoline, while E25 contains 25% ethanol. and since 2003, these limits were fixed at a maximum of 25% (E25) and a minimum of 20% (E20) by volume. Since then, the government has set the percentage on the ethanol blend according to the results of the sugarcane harvest and ethanol production from sugarcane, resulting in blend variations even within the same year.

Since July 1, 2007, the mandatory blend was set at 25% of anhydrous ethanol (E25) by executive decree, and this has been the standard gasoline blend sold throughout

Brazil most of the time as of 2011. However, as a result of a supply shortage and the resulting high ethanol fuel prices, in 2010, the government mandated a temporary 90-day blend reduction from E25 to E20 beginning February 1, 2010. As prices rose abruptly again due to supply shortages that took place again between the 2010 and 2011 harvest seasons, some ethanol had to be imported from the United States, and in April 2011, the government reduced the minimum mandatory blend to 18%, leaving the mandatory blend range between E18 and E25.

E70, E75

When the vapor pressure in the ethanol blend drops below 45 kPa, fuel ignition cannot be guaranteed on cold winter days, limiting the maximum ethanol blend percentage during the winter months to E75.

E70 contains 70% ethanol and 30% gasoline, while E75 contains 75% ethanol.

These winter blends are used in the United States and Sweden for E85 flexible-fuel vehicles during the cold weather, but still sold at the pump labeled as E85. The seasonal reduction of the ethanol content to an E85 winter blend is mandated to avoid cold starting problems at low temperatures.

In the US, this seasonal reduction of the ethanol content to E70 applies only in cold regions, where temperatures fall below 32 °F (0 °C) during the winter. In Wyoming for example, E70 is sold as E85 from October to May. In Sweden, all E85 flexiblefuel vehicles use an E75 winter blend. This blend was introduced since the winter 2006-07 and E75 is used from November until March.

For temperatures below −15 °C (5 °F), all E85 flex vehicles require an engine block heater to avoid cold starting problems. The use of this device is also recommended for gasoline vehicles when temperatures drop below −23 °C (−9 °F). Another option when extreme cold weather is expected is to add more pure gasoline in the tank, thus reducing the ethanol content below the E70 winter blend, or simply not to use E85 during extreme low temperature spells.

E85

E85, a mixture of 85% ethanol and 15% gasoline, is generally the highest ethanol fuel mixture found in the United States and several European countries, particularly in Sweden, as this blend is the standard fuel for flexible-fuel vehicles. This mixture has an octane rating of 94-97, which is significantly lower than pure ethanol, but still higher than normal gasoline (87-93 octane, depending on country). filling stations were available, with plans to expand to 15 stations by 2012.

ED95

ED95 designates a blend of 95% ethanol and 5% ignition improver; it is used in modified diesel engines where high compression is used to ignite the fuel, as opposed to the operation of gasoline engines, where spark plugs are used. This fuel was developed by Swedish ethanol producer SEKAB. Because of the high ignition temperatures of pure ethanol, the addition of ignition improver is necessary for successful diesel engine operation. A diesel engine running on ethanol also has a higher compression ratio and an adapted fuel system. This fuel has been used with success in many Swedish Scania buses since 1985, which has produced around 700 ethanol buses, more than 600 of them to Swedish cities, and more recently has also delivered ethanol buses for commercial service in Great Britain, Spain, Italy, Belgium, and Norway. As of June 2010 Stockholm has the largest ethanol ED95 bus fleet in the world.

As of 2010, the Swedish ED95 engine is in its third generation and already has complied with Euro 5 emission standards, without any kind of post-treatment of the exhaust gases. The ethanol-powered engine is also being certified as environmentally enhanced vehicle (EEV) in the Stockholm municipality. Standard.

E100

E100 is pure fuel, straight hydrous ethanol as an automotive fuel has been widely used in Brazil since the late 1970s for neat ethanol vehicles and more recently for flexible-fuel vehicles. The ethanol fuel used in Brazil is distilled close to the azeotrope mixture of 95.63% ethanol and 4.37% water (by weight) which is approximately 3.5% water by volume. The azeotrope is the highest concentration of ethanol that can be achieved by simple fractional distillation. The maximum water concentration according to the ANP specification is 4.9 vol. % (approximately 6.1 weight %). The E nomenclature is not adopted in Brazil, but hydrated ethanol can be tagged as E100, meaning it does not have any gasoline, because the water content is not an additive, but rather a residue from the distillation process. However, straight hydrous ethanol is also called E95 by some authors.

(https://en.wikipedia.org/wiki/Common_ethanol_fuel_mixtures)

Summary of Related Works

Mostafa et al., (2017) this study led to some conclusions, which could be deduced as follow: 1 burning ethanol-gasoline blend in SI engine improves the engine-generator set performance characteristics.2. Ethanol -gasoline blend with percentage volume of ethanol up to 15% can be used in SI engine without any modifications.3. The presence of oxygen and high octane number were significant features of using ethanol-gasoline blends.4. The fuel consumption and specific fuel consumption showed a marginal decreasing with the use of ethanol-gasoline blends.5. Ethanol addition to gasoline resulted in an increase in overall efficiency of the enginegenerator set and exhaust gas temperature. For E15 blend, the overall efficiency and exhaust gas temperature at maximum load were increased by 14.88% and 3.85%

respectively as compared to base gasoline. Pikūnas et al., (2003) the engine performance and pollutant emission of a SI engine have been investigated by using ethanol-gasoline blended fuel E10 and pure gasoline. Experimental results indicated that when ethanol-gasoline blend is used, the engine power and fuel consumption of the engine slightly increase; CO emission decreases dramatically as a result of the leaning effect caused by the ethanol addition; HC emission decreases only in some engine working conditions; and CO2 emission increases because of the improved combustion. In this study, we found that using ethanol-gasoline blend, CO emission may be reduced by 10-30%, while CO2 emission increases by 5-10% depending on engine conditions. The engine power and specific fuel consumption increase approximately by 5% and 2-3%, respectively, in all working conditions. Gaurav Sharma* and Harvinder Lal. (2015) Ethanol's physical and chemical properties show that it can be used as an alternative fuel or additive in SI engine.

Ethanol-gasoline blends show very effective results. In this study, four different blends E5, E10, E15 and E20 were run on SI engine for analyzing performances and emissions. It was found that E5 and E10 blend was most effective blend they improved performance and reduced emissions. It was concluded that E5 and E10 blend improved brake thermal efficiency, brake torque reduced brake specific fuel consumption as compared to gasoline. Further both blends also reduced emissions like CO2, CO, HC and NOx as compared to gasoline.

Joshi et al. (2015) among the various blends tested, E20 blend was found to have least exhaust and greenhouse gases emissions, also not compromising on engine or vehicle performance.

E20 offers the following property:  Engine wear: There is no additional or unusual wear to that normally expected and there is no additional increase in wear metals or decrease in total base number (TBN) of the lubricating oil.

 Water tolerance: Quality of ethanol produced and stored should be extremely pure and the water content should be less than 1.25%. An ethanol compatible water detecting paste must be used to establish the water content of underground storage tanks (standard paste is not suitable) and the water content must be kept to a minimum and, older vehicles are more prone to suffer from phase separation when first fueled with ethanol-petrol blend;

however, subsequent continuous use of ethanol-petrol blend prevents water accumulation within the fuel tank. Kheiralla et al., (2014) the following conclusions could be drawn from this study:

Ethanol-gasoline blends can be used as an alternative fuel for variable speed spark ignition up to 35% blends without engine modification. − Fuel properties of the tested ethanol-gasoline blends such as density and viscosity increased continuously and linearly with increasing percentage of ethanol while API gravity and heat value decreased with decreasing percentage of ethanol increase. Furthermore, cloud point, flash and fire points were found to be higher than pure gasoline fuel, while distillation curves proved to be lower. − The tested blends Octane rating based

Research Octane Number (RON) increased continuously and linearly with the increasing percentage of ethanol.

Based on the results obtained during this study work it can be suggested that:

Comprehensive and extensive testing on fuel properties, engine performance, combustion, and emissions characteristics of ethanol-gasoline blends on SI engines should be conducted for long time. Research collaboration should be undertaken with sugarcane industry, and GIAD Automotive Group regarding using ethanol as bio-fuel for SI engines. Thakur et al., (2017) this study reveals a clear view of the progress made to improve the performance parameters of spark ignition engines using blends of gasolineethanol, gasoline with all other alcohol derivatives, and subsequent alternative fuels.

Some key findings of this study are as follows:

 Ethanol blends in lower proportions showed improvement in engine torque and brake power as observed during study. Using E5, E10, E20 an increment of 2.31, 2.77 and 4.16% in engine brake power and 0.29, 0.59 and 4.77% in torque was noted.

 Brake specific fuel consumption increased for higher volume of ethanol content as observed. Brake specific fuel consumption increased by 5.17, 10, 20, 37, and 56% using E20, E25, E30, E75, and E100 respectively.

 Varying the compression ratio and operating the engine at various speed also affected the performance parameters of the spark ignition engine.

Using E50 and E85 as fuel at compression ratio 10:1 and 11:1; increment of 20.3 and 45.6% and 16.15 and 36.4%, respectively, was observed for brake specific fuel consumption.

 Brake thermal efficiency was slightly on the high side when an ethanolgasoline blend was used. Maximum brake thermal efficiency of 3.5% for E20, 2.5% for E10, and 6% for E40 was concluded.

Raja et al., (2015) Gasoline-ethanol blends were experimented at part-throttle operation of motorcycle engine, without modifying compression ratio, intake system, fuel system and ignition timing, without and with catalytic converter. The following conclusions are derived from the results.

Blends up to E15 showed smooth and satisfactory engine operation and E20 blend resulted in choking and stalling at higher engine speeds.

Brake specific fuel consumption was higher for blends due to lower heating value of the blends compared to neat gasoline and correspondingly there was reduction in brake thermal efficiency. Among the blends, E5 and E10 were closer to neat gasoline. Volumetric efficiency and excess air factor increased with ethanol percentage in the blend due to higher heat of vaporization and oxygen in ethanol.

Exhaust temperature decreased with blends. This is because of lower engine temperature and higher excess air in the air-fuel mixture. The results indicated that effects of the ethanol/gasoline fuels on cars were not the same if the cars equipped with different fuel systems. For the carbureted car, using E10, E15 and E20 could increase power, reduce fuel consumption, and decrease significantly HC and CO emissions, whereas increase NOx emissions. For the fuel injected car, these blends nearly did not affect power and fuel consumption. HC and CO emissions were reduced for E10 but increased for E15 and E20, while NOx was higher for E10 and E15 but lower for E20 as compared to base gasoline RON92. In this study, it found that utilization of E10 possibly gave benefit for both of the cars.

Ozsezen et al., (2012) In this study, it was seen that the wheel power with the use of alcohol-gasoline blends slightly increased compared to pure gasoline. When the vehicle was fueled with alcohol-gasoline blends, more fuel was consumed to achieve the same wheel power with pure gasoline, and it caused an increase in the fuel consumption. Generally, the alcohol-gasoline blends at all vehicle speeds provided slightly higher combustion efficiency relative to pure gasoline. Bio-ethanol production is highest after three days of fermentation using natural methods. The highest bio-ethanol production came from maize although the values got were lower than those obtained in the United States. Addition of ethanol to gasoline reduces the energy density of the volume. Engine speed increases and engine torque decreases. However overall break power increases. There is loss of fuel economy and consequently mileage with blended rations of bio-ethanol gasoline because the alcohol has a lower energy value than gasoline. Blended fuel is not yet a good option for less developed countries that are not manufacturing resistant parts.

Anti-fuel properties of bio-ethanol blended fuels calls for serious engine modifications to avoid knock and unwanted emissions. These modifications include the advancing of engine timing, provision of airtight conduit lines, increasing the compression ratio and roughening of the piston head.

Yusuf et al., (2014) adding ethanol to gasoline will lead to a leaner better combustion. It was experimentally demonstrated that adding 5-15% ethanol to the blends led to an increase in the engine brake power, torque and brake thermal efficiency, volumetric efficiency and decreases the brake specific fuel consumption.

The lean combustion improves the completeness of combustion and therefore the CO emission is expected to be decreased. The oxygen enrichment generated from ethanol increased the oxygen ratio in the charge and lead to lean combustion.

The CO2 emission increased because of the improvement of the combustion and the chemical properties of Ethanol.

Unburned HC is a product of incomplete combustion which is related to A/F ratio. It can be concluded that that adding ethanol to the blends will reduces the HC emission because of oxygen enhancement.

When the combustion process is closer to stoichiometric, flame temperature increases, therefore, NOx formation is expected to be increased.

The results obtained with presented theoretical model are in acceptable agreement with those experimental ones. An agreement of 11% was determined between experimental and theoretical results. Kumar et al. (2016) in this study, the effect of unleaded gasoline and unleaded gasoline blended with 5%, 10 % and 15% of ethanol on the performance of a sparkignition engine were experimentally investigated. Performance tests were conducted for fuel consumption, engine torque, brake power, brake thermal efficiency and brake specific fuel consumption, using unleaded gasoline-ethanol blends with Shayan et al.,(2011) In this study, it was seen that when engine was fueled with methanol-gasoline blend, engine performance parameters such as brake torque, brake power, brake thermal efficiency, volumetric efficiency increases with increasing methanol amount in the blended fuel while bsfc and equivalence air-fuel ratio decreased. Since the latent heat of evaporation of ethanol is higher than that of gasoline, during compression process, the fuels containing methanol will absorb more heat from combustion chamber and eventually, the pressure of the combustion chamber will be decreased accordingly. Relying on above statements, during the compression process, the pressure of such combustion chamber will be decreased compared with when pure gasoline is used in combustion. On the other hand, due to presence of oxygen entered the combustion chamber during expansion process and after combustion of fuel and upon improvement of combustion, the pressure of the expansion process will be increased as well. Hence, the work of compression process, which is a negative work, will be decreased and that of the expansion process that is a positive work, will be increased for that reason.

Consequently, upon increase of enclosed area in the pressure-volume curve, the work done by the engine will be increased in case of use of the fuel containing methanol and finally, the indicated mean effective pressure will be increased as well. Therefore, brake power will be increased. E85 has greater effect on the emission reduction than E15.

 . Both combustion efficiency and thermodynamic efficiency are improved by the presence of ethanol because of the optimum combustion phasing and ower heat loss.E85

improved indicate fuel conversion efficiency by over 5% at 2000 rpm.

 The above results were obtained by keeping the relative air to fuel ratio to stoichiometric in the engine exhaust. In addition, future improvement in the fuel injector and combustion chamber design are expected to further reduce the HC and CO emissions and improve the thermal efficiency and indicated fuel conversion efficiency, making the 2-stroke poppet valve engine a viable low emission and high efficiency IC engine for automotive applications. Wang et al., (2015) the focus of this study was to evaluate the effects of hydrous ethanol gasoline on the combustion and emission characteristics on a port injection gasoline engine. Based on the experimental results, the conclusions are as follows:

 Compared with E0, E10W showed higher peak in-cylinder pressure at high load.

Increases in peak heat rise rates were observed for E10W fuel at all the operating conditions. Besides, the usage of E10W increased NOX emissions at a wide load range.

However, at low load conditions, E10W reduced HC, missions, while CO2 emissions were not significantly affected at higher operating points.

 Compared with E10, E10W showed higher peak in-cylinder pressures and peak heat release rates at the tested operating conditions. In addition, decreases in NOX emissions were observed for E10W from 5 Nm to 100 Nm, while HC, CO and CO2 emissions were slightly higher at low and medium load conditions.

 The practical consequence of burning E10W fuel showed a better combustion process, especially at higher loads. In addition, E10W fuel had lower NOX emissions than E10 at all operating conditions and lower HC, CO and CO2 emissions significantly and simultaneously than E0 at low load conditions. From the above, it can be concluded that E10W fuel can be regarded as a potential alternative fuel for gasoline engine applications.

CHAPTER THREE

MATERIALS AND METHODS

In this chapter the required data was collected, the theoretical thermodynamic analysis of real engine cycle was done, depending on the thermodynamic analysis and mathematical model computer c++ program was written and the written computer program is compiled and run. To validate the written computer c++ program experimental analysis conducted on the selected real engine.

Experimental Site

The experimental analysis was conducted at Dilla University. Dilla is a market town and separate woreda in southern Ethiopia. The administrative center of the Gedeo Zone in the Southern Nations, Nationalities, and Peoples Region (SNNPR), it is located on the main road from Addis Ababa to Nairobi. The town has a longitude and latitude of 6°24′30″N 38°18′30″ECoordinates: 6°24′30″N 38°18′30″E, with an elevation of 1570 meters above sea level. It was part of Wenagoworeda and is currently surrounded by DilaZuriaworeda.

Collection of Required Data

To validate the output of c++ computer program written in this work one engines was selected and its specification is summarized as follow.in addition to engine specifications the both fuel means gasoline and ethanol physical and chemical characteristics was collected and summarized in chapter 2(two) of this paper.

Not only each characteristic's the blend's characteristics also summarized in chapter 2(two) of this paper.

Engine specifications

Measuring Principle

The measuring principle of CO, CO2 and HC is based up on the interference correlation filter principle. Infrared light is radiated through the measuring chamber and is detected by sensor that operates an interference correlation filter. The Sensor signals are processed by microcontroller directly. Oxygen and optional nitrogen monoxide is measured using chemical sensors.

Technical Data

Mathematical Model for Actual Engine Cycle

State1

The intake stroke of the Otto cycle starts with the piston at TDC and is a constant pressure process at an inlet pressure of one atmosphere. The temperature of the air during the inlet stroke is increased as the air passes through the hot intake manifold.

The temperature at point TDC will generally be on the order of 25°to 35°Chotter than the surrounding air temperature. Mass of gas mixture in cylinder can be calculated at state 1.the mass with in the cylinder will then remain the same for the entire cycle.

In air-standard cycles, air is considered an ideal gas such that the following ideal gas relationships can be used:

Where Z= 0.99 for intake and 0.98 for exhaust. There is residual mass in cylinder (Mres) which is from 2% to 8% of mm.

Let take 5% residual mass which is the average.

Mres= 5/100* mm = 0.05*0.000483Kg = 0.000024kg

State 2

The compression stroke is isentropic. The following ideal gas relationships can be used to find pressure and temperature.

The compression stroke in the real engine is different from ideal one. This means the intake valve is not close at BDC rather after the BDC.so compression can be classified to two.

Polytropic compression

This is the stage from BDC to the point intake valve close after BDC.

Polytropic effective compression

This is the stage from intake valve close after BDC to the point at start of combustion. Where, k is compression index and Rc is compression ratio.

The type of fuel used in this work is blend of alcohol-gasoline (E15). The mass of gas mixture mm in the cylinder made up of air ma, fuel mf (mass of ethanol + mass of gasoline).

Mass of air ma = (AFR/ (AFR+1))* (1-XR)* (Mm1) ……………………………………3-7

Where, XR is percentage of residual Power stroke.

The following ideal gas relationships can be used to find pressure and temperature. Work of the intake stroke is canceled by work of the exhaust stroke.

Net indicated work for one cylinder during one cycle is:

Mathematical Model for Engine Performance

The following 'Empirical Relations' are obtained from experimental data of 'engine performance test' using a 'curve fitting method'.

 for SI (Carburetion) Engines:

Note: Using a computer Programming Language (C++,) in appendix 1 and Application

Software's (MS-Excel,), the expected 'Engine Performance Curves' can be plotted.

Mathematical Model For Incomplete Combustion Emission of Blend Fuel.

The chemical reaction of blend fuel for not stoichiometric reaction is as follows.in this reaction there is additional oxygen and carbon monoxide. But since it is rich fuel type mixture there is no oxygen in product part. If there is dissociation reaction in the combustion chamber the product part element is not limited to five rather ten (10) products.

To calculate the molar fraction of all combustion product the very complex numerical mathematical model is needed.

For this reason this work is limited to only five combustion products.

MFA (CnHmOHm) +MFG (CaHb) +atha (O2+3.76N2) =n1CO2+n2H20+n3N2+n4O2+n5CO

Where, MFA is molar fraction of alcohol MFG is molar fraction of gasoline atha is molar fraction of air for stoichiometric air fuel ratio.

Where, ath is molar fraction of air for not stoichiometric reaction. λ is equivalence ratio of air fuel

The equilibrium of reactants and product parts are done as follow.

Experimental Analysis for E0 and E15

To Plot a power curve and the torque curve at full load the following procedures are under taken.

Setting up

CHAPTER FOUR

RESULT AND DISCUSSION

Output of computer c++ program for E0

Temperature

The maximum temperature is created at 390 o of crank angle which can be adjusted initially on the engine. This temperature can be affected by ambient temperature of environment.so it depends initially on the environmental temperature. The angle at which combustion started before TDC and the duration of combustion determine the crank angle at which maximum temperature occurred. This temperature (Tmax) can affect the work net from the engine which has direct relation with brake power and other engine performance parameter. The computer c++ program written for actual engine cycle virtually consider all factors like in real engine.

For this specific engine and environment the maximum temperature created in engine was 3180k .

The maximum temperature created by E15 (15% ethanol and 85% of gasoline) was 3220k at 390 o crank angle. This show that the angle at which maximum temperature created is not depends on the type fuel rather ignition timing. 100 140 180 220 260 300 340 380 420 460 500 540 580 620 660 700 Temperature(k)

Because of the high equivalence air-fuel ratio (λ value) of alcohol, the thermal efficiency of blend fuel is greater than pure gasoline. As shown on the figure 4.19 the maximum temperature created by E0, E5, E10 and E15 is 3180k, 3200k, 3110k and 3220k respectively.

Pressure vs volume diagram

The pressure vs volume diagram is very important for the design of every engine. The peak pressure is one of the determinant factor for brake power and other engine performance parameter. This peak pressure depends on compression ratio, environmental pressure and the nature of fuel used. The value of this peak pressure is the same with maximum pressure (55.67 bar) developed in engine. This peak pressure mostly depends on the type of fuel used and ignition timing.

The pressure volume diagram which depends on the value of peak pressure for E0,

Brake power

Brake power is the function of brake mean effective pressure, engine capacity, and engine revolution per minute and mechanical efficiency. There is two possible ways of calculating brake power.

The first one is analytical method which can be used to calculate the maximum power for thermodynamic analysis of actual engine cycle and by using only this method one cannot draw the following diagram.

The brake power produced by E15 is higher than E0.this increment is also for E5 and E10 and as a result the power produced by E15>E10>E5>E0. This is due to high thermal efficiency of oxygenated fuel. This thermal efficiency is dependent on equivalence ratio of air-fuel (λ value).

There is no oxygen in hydrocarbon fuel but in alcohol. Due to this ethanol has higher equivalence ratio of air fuel than pure gasoline. For this reason the brake power produced by E15 is greater than E0.

So the maximum brake power produced by E15 in this specific engine is 7.24kw at 3000rpm.This graph is drawn by using empirical method which is the result of experimental result.

According to computer c++ program developed, as the amount of ethanol proportion increase in gasoline the brake power increase. As a result the brake power produced by E0, E5, E10 and E15 are 7.13kw, 7.18kw, 7.22kw and 7.24kw at 3000rpm respectively. One of the factor affecting brake power is the thermal efficiency of the fuel, due to this the increment of the brake power follow the path of it.

The maximum brake power recorded by using pure gasoline is 7.1kw.This value was the result of experimental investigation and directly taken from the engine test stand.

This maximum brake power was obtained at the 2950rpm.staterting from 2200rpm the brake power increase up to 2950rpm which is the speed at maximum brake power recorded and then decreases up to maximum speed of the engine.

When the ethanol content in the blend fuel is increased, the engine brake power is somewhat increased for all engine speeds (Fig.4.35). The improvement of the engine power was due to the rise of the indicated mean effective pressure and the in cylinder pressure due to the higher ethanol content in the blends. The heat of evaporation of ethanol is higher than that of gasoline, this provides fuel air charge cooling and increases the density of the charge, and thus higher power output is obtained. The maximum brake power for both blend fuel and pure petrol occurred at the same engine rpm.

Volume(cc)

The second one is empirical method which can be used to calculate the maximum brake power by observing engine specification. This method is used for drawing the following diagram which is almost the same with the output of computer simulator of dynamometer.

As a result the maximum brake power for selected engine by using pure gasoline was 7.13kW at 3000rpm.

Brake torque

Brake torque is the function of brake power, engine capacity, and engine rpm. The factor which affect the brake power has significant role on brake torque. Both of them has directly proportional to each other.

The two possible way used to calculate brake power is also functional for brake torque. The maximum brake torque created was 27.75NM at 2000rpm. But this maximum brake torque is greater than the engine maximum brake torque. For this reason running the engine at lower speed is impossible and can damage engine.so computer c++ program can indicate at which speed engine can run safely. As shown on the following diagram running the engine above broken line area can possibly damage it.

The brake torque is directly proportional to brake power.as a result the increment of brake power increase the brake torque. This increment is due to the increase of thermal efficiency and break mean effective pressure.

The basic cause for this change is equivalence ratio of air-fuel (λ value) and this means the λ value of blend fuel is greater than pure gasoline because of oxygen content of alcohol.

On this specific study the maximum brake torque as the result of computer c++ program is 28.18 NM at 2000rpm.But this maximum brake torque is greater than the engine maximum brake torque. For this reason running the engine at lower speed is impossible that can damage engine.so computer c++ program can indicate at which speed engine can run safely. As shown on the following diagram running the engine above dash line area can possibly damage it.

The following diagram computer gram is drawn by using empirical method which is the result of experimental analysis.

The brake torque and brake power are directly proportional to each other and they are interdependent. As a result the brake torque produced by E0, E5, E10 and E15 are 27.75NM, 27.95NM, 28.1NMand 28.18NM at 2000rpm respectively which are above the engine maximum brake toque.so this indicate that the selected engine for test cannot run to lower engine speed.

The brake torque is one of the engine performance parameter that can directly measure from engine dynamometer. Experimental analysis was conducted on the selected engine by using pure gasoline fuel type. As a result the maximum brake torque recorded is 25.32NM at 2420rpm.This value is somewhat greater than the engine rated brake torque, and happens since engine run at lower engine revolution per minute which is not recommended by manufacturer. Like that of pure gasoline the brake torque for blend fuel was experimentally investigated. The maximum brake torque created on this selected engine by using E15 (15% ethanol and 85% gasoline) was 25.51NM at 2560rpm.Due to higher thermal efficiency for blend fuel the brake power of E15 is higher than E0.This brake torque is directly recorded from engine test stand and investigated at all engine speed tested for E0. The fig 4.33 shows the relation between brake torque and engine speed experimentally investigated for E15.

The raise of ethanol content will increase the torque of the engine. Added ethanol will produce lean mixture that increases the relative air-fuel ratio (λ) to a higher value and makes the burning more efficient. The improved anti-knock behavior (due to the addition ethanol, which raised the octane number) allowed a more advanced timing that result in higher combustion pressure and thus higher torques .As shown on fig 4.36 the maximum brake torque of E15 blend fuel is higher than pure gasoline at all engine speed.

Engine speed(rpm)

Like that of the graph of brake power the following diagram is drawn by using empirical relation of maximum power, speed at maximum power and speed which is the result of experimental analysis. This parameter has also related to the pressure and temperature of the environment.

The type of engine and fuel can affect the amount of brake specific fuel consumption.

Brake specific fuel consumption is high at lower speed and decreasing as speed increase and become optimum at the medium and increase as speed increase.

As that of brake power and torque brake specific fuel consumption diagram is drawn by using empirical method.as result the minimum fuel consumption is 0.39kg/kWh at speed between 2000rpm.

Brake mean effective pressure

Brake mean effective pressure is the function of brake power, engine capacity and engine revelation per minute. Brake mean effective pressure is directly proportional to brake power and brake torque. So all factors which affect brake power can directly affect brake mean effective pressure. This pressure is crucial point for designer of engine and as other performance engine parameter graph brake mean effective pressure is also drawn by using empirical method.

So as shown on the graph the maximum brake mean effective pressure is 8.89bar at 1000rpm.

Break mean effective parameter is one of the important parameter used to determine the brake power and other parameter which is used for perform evaluation.

As break mean effective increase brake power and torque increase. This means they are directly proportional to each other. As shown on the following diagram the maximum brake mean effective is 9.03 bar at 1000rpm.Due to higher thermal efficiency and λ value of blend fuel than pure gasoline the break mean effective pressure of blend fuel is higher than pure gasoline.

The break mean effective pressure increase as the amount of ethanol increase in blend proportion. Brake mean effective pressure also follow path of the thermal efficiency.

As a result the brake mean effective pressure produced by E0, E5, E10 and E15 are 8.89bar, 8.95bar, 9bar, 9.03bar and at 2000rpm respectively.

Output of computer c++ program for E15

Crank angle(degree)

All factors which listed in pure gasoline can affect the value of maximum temperature in E15.Due to higher air-fuel equivalence ration or λ (LAMBDA) value in ethanol, the thermal efficiency of blend fuel is higher than pure gasoline, as result the combustion efficiency of blend fuel is higher than pure gasoline. Due to this the maximum temperature created in engine by blend fuel is higher than pure gasoline.

Pressure

The maximum pressure created by this blend fuel means E15 is 56.32 bar. This pressure is

As the amount of ethanol in gasoline increase the maximum pressure created also increase. As shown on the figure 4.20 the maximum pressure created by E0, E5, E10

and E15 are 55.67bar, 55.99bar, 56bar and 56.32bar respectively.

Volume

In this specific study only one compression ratio is taken as input from the engine specification.one of the determinant factor for the value of swept and clearance volume is compression ratio. Theoretically the compression of oxygenated fuel is higher than hydrocarbon fuel but for this work the compression ratio for both blend and pure gasoline is the same. Due to this there is no the variation of swept volume and clearance volume created in both blend and pure gasoline. Despite this variation can highly affect engine performance practically, the compression ratio for both blend and pure gasoline is not the same. The pressure vs volume diagram is very important for the design of every engine. The peak pressure is one of the determinant factor for brake power and other engine performance parameter. This peak pressure depends on compression ratio, environmental pressure and the nature of fuel used. Due to this the maximum pressure created by blend fuel is higher than pure gasoline. The value of this peak pressure is the same with maximum pressure in E15 (56.32 bar).for this reason the type of fuel used in producing power has significant role in affecting the brake power of engine.

Brake specific fuel consumption

Brake specific fuel consumption is the function of mass of fuel delivered to engine and brake power produced by the engine.

According to the output of this computer c++ program the brake specific fuel consumption decrease if ethanol is blended to gasoline. But this continuous only up to E40 and then increase after it. The minimum brake specific fuel consumption of E0 is 0.39kg/kWh and E5, E10 and E15 are 0.37kg/kWh.

Engine rpm

The brake specific fuel consumption is inversely proportional to brake power. According to computer c++ program that written depending on the empirical relation between fuel consumption and speed, the following diagram is drawn.

As shown on the graph the minimum fuel consumption is 0.37kg/kWh which less if compared with pure gasoline.

The shape diagram for both blend fuel and pure gasoline is the same but brake specific fuel consumption is less for E15 at all speed if compared with E0 (pure gasoline).

Summary of Computer C++ Program Output for E0 -E15

Combustion and thermal efficiency

As shown on the graph below combustion and thermal efficiency increase as the amount of ethanol increase in blend proportion. But according to this computer c++ program it continuously increase only up to E85 and then commence to decrease.

Emissions

In this work five incomplete combustion product was considered even though there is ten product which emitted from internal combustion engine. Considering all combustion product is good, but it needs very complex numerical method. So by using simple simultaneous equation one cannot find the amount of all combustion products. Due to this in this paper only five combustion products are like CO2, CO, H2O, N2 and O2 are considered. Due to this the mathematical model and the computer c++ is developed for the only five combustion products listed above.As the amount of ethanol increase in blend proportion, the molar fraction emission of CO2 decrease. This emission depends on the λ value of fuel used.As shown on the figure 4.26

CO2 emission deceased because of the improvement of the chemical properties of blend fuel.

One of the most dangerous emission from internal combustion engine is carbon monoxide (CO) which is very harmful gas for living things.

This gas is not only harmful but also plays great role in global warming. According to this computer c++ program the emission of carbon monoxide decrease as the amount of ethanol in blend proportion increase.

This is due to the change of λ value as blend proportion increases. Carbon monoxide is a product of incomplete combustion due to insufficient amount of air in the air-fuel mixture.

Result from experimental analysis for E0 and E15

Result from experimental analysis for E0

Result from experimental analysis for E15

Fuel consumption

As shown on the figure 4.34 the fuel consumption for E15 was experimentally investigated and recorded for all speed. The minimum fuel consumption recorded was 0.64kg/h at 2308 rpm.

The effects of ethanol-gasoline blends on fuel consumption vs. engine speed are shown in Figure 4.37.As shown in this figure, the fuel consumption decreases as the ethanol content increase from E0 to E15. This is due to the increase in brake thermal efficiency and decreases in equivalence air fuel ratio (φ). Further, increase in engine speed results in increasing FC (fuel consumption), since the brake thermal efficiency decreases and air fuel ratio (φ)

increases. It is clear from figure 4.37 that in case of E0 and E15, the lower FC was observed on E15

Summary from experimental analysis for E0 and E15

Emission result from experimental investigation of E0 and E15

The experimental investigation on emission was conducted on both E0 and E15 and the result is tabulated in table 4.6 and 4.7 as follows. Blending ethanol to gasoline is the best way to minimize the amount of green house and harmful gases emission to the environment.

According to experimental investigation and shown on the figure 4.38 and 4.39, emission of CO and CO2 increase with speed. But emission of HC is higher at lower and higher speed while lower at the medium speed.

CO:

The most important parameter that affects CO emission is the air fuel equivalence ratios. With air fuel equivalence ratio approaching unity, CO emission diminishes, and even becomes zero in lean condition.CO emissions are likely to be reduced for various blends due to the oxygen enrichment coming from ethanol.

CO2:

O2:

The emission of O2 decreases with increasing engine speed. This imply that as the engine speed increase the equivalence air fuel ratio decrease due to this the emission of O2 also decrease.

generally according to experimental investigation the emission of CO, CO2, HC and O2 is lower for E15 than E0.

CHAPTER FIVE

CONCLUSION AND RECOMMENDATION

Under this chapter summary of the all work in this paper, conclusion of the result and discussion and the recommendation for the future researcher are explained.

Summary

After the title was identified depending on the existing gap or problem the objective of research means general and specific objective of research was identified. The benefit and scope of this work was also recognized. Different literature which has relation with selected title was reviewed and summarized.to accomplish the objective of research, different methods such as preparing mathematical model, developing computer c++ program and executing experimental investigation are used. Depending on the result from both computer c++ program and experimental investigation enough discussion was done on each topic. Finally the result was concluded and the recommendation was listed for the future researcher.

Conclusion

In this work the thermodynamic analysis of actual engine cycle with ethanol gasoline blend fuel (E15) is done. Depending on the thermodynamic analysis which can be the mathematical model, the computer c++ program was developed and performance parameter such as brake power, brake torque, thermal efficiency, break mean effective pressure, combustion efficiency, brake specific fuel consumption and emission was analyzed by using developed computer c++ program. This program is versatile that can be functional for every type of engine and any type of blend proportions. As a result the brake power, brake torque, combustion efficiency, thermal efficiency and break mean effective pressure are higher for E15 than E0 and the brake specific fuel consumption is lower for E15 than E0.

The molar fraction emission of CO2, CO and water vapor is less for E15 than E0 but molar fraction of N2 is higher for E15 than E0.

To validate and prove the result of computer c++ program the experimental investigation was done on selected engine.

The motivation of performance parameter gained by computer c++ program is also proper for experimental investigation. According to the experimental investigation the brake power and brake torque for E15 is higher than that of E0, but the fuel consumption of E15 is less than E0.

The emission value which gained by computer c++ program and experimental investigation was almost similar.

According to experimental investigation the emission of CO, CO2, HC and O2 is lower for E15 than E0.the emission of CO, CO2, HC increase with increase of engine speed and O2 emission decreases.

The deviation between result of developed computer c++ program and experimental investigation was less than 5% for all analyzed engine parameter.

Recommendation

After conclusion of this work the following listed points are very important that can enhance the trustworthiness of the outcome of research.

 For the future work I recommend the researcher to investigate further on this topic because there is no common conclusion between researchers executed work concerning the topic.

 Computer c++ program developed in this work can easily identify the performance parameter, calculate the value of material charged to combustion and identify the amount of emission so before testing on real engine using computer c++ program is cost efficient and highly support the exponential investigation process. float theta_2,theta_ec,theta_3 = theta_ec,theta_evo,theta_4,theta_5; float theta_6,theta_0,Ec_liter,Ec, Vs,Vcl,Vt,Vs_cc,Vcl_cc,Vt_cc,d,d_mm; float powd,s,s_mm,r,r_mm,lcon,lcon_mm, Ap,g,Ru,mA,mF,mres,Tim,theta_c;float a1O2r,a2O2r,a3O2r,a4O2r,cpO2,cvO2,a1N2r,a2N2r,a3N2r,a4N2r,cpN2;float cvN2,cpA6b,cvA6b,MmA,cp6b,cv6b,R6b,n6b,RHO6b,v6b,Z6b,Z1,V1,R1;float mm,MmO,MmN,MmC,MmH,yO2,yN2,MmO2,MmN2,xAl,xG,xF,MmG,MmAl,QLHV_G;float nAl,nG,nAlG,yAl,yG,yF,yAl_per,MmF,n1th,n2th,atha,ath,n3th;float n10,n3,n1r,n1,n2,nt,y1,y2,y3,y10,MmAth,MmFth,nO2,nN2,nA,AFth,AF,QLHV _F;float RHO_Fkgplit,RHO_F,ETA_cmax,ETA_c,ETA_cper,T6bi,RHO_Gkgplit; float Rm,Zm,Vm,n4,n5,y4,y5,yAL,Mm1,Mm2,Mm3,Mm4,Mm5,nF,Tb_NM; const float PI = 3.1416; g = 9.81; Ru = 8.314; // process 0-b (constant pressure intake process).

float V0bi,p0bi,T0bi,m0bi,R0bi,rad,Z0b,xp0b,Vs0b,V0b,p0b,T0b,R0b,m0b; float Vb,pb,Tb,mb,thetab,deltheta,theta,mb1i; // process b-1 (polytropic compression):

float Vb1i,pb1i,Tb1i,Rb1i,xpb1,Vsb1,Vb1,delmb1,VbVb1,nb1,nb1T,Rb1; float Zb1,pb1,Tb1,mb1,theta1; // process 1-2 (polytropic effective compression): float m12i,V12i,p12i,T12i,xp12,Vs12,V12,V1V12,n12,n12T,R12,Z12; float p12,T12,m12,V2,p2,T2,theta2; // process 2-3 (polytropic combustion): float V23i,p23i,T23i,T23,W23i,xp23,Vs23,V23,m23,theta2dc,rad2dc; float xb, Qin,Q1,Q23,cpO2o2,R23;float cpN2o2,cpFo2,cpr2,cvr2,Mmr2,cp2,cv2,R2,m2,RHO2;float v2,hfoF,hfoO2,hfoN2,delhFo2,delhO2o2,delhN2o2,UrFo2,UrO2o2,UrN2o2;float Ur2,Ur,a1CO2p,a2CO2p,a3CO2p,a4CO2p,cpCO2,cvCO2,cp123,a1H2Op,a2H2Op;float a3H2Op,a4H2Op,cpH2O,cvH2O,cp223,a1N2p,a2N2p,a3N2p,a4N2p;float cp323,a1O2p,a2O2p,a3O2p,a4O2p,cp423,a1COp,a2COp,a3COp;float a4COp,cpCO,cvCO,cp523,cp23_kmol,cv23_kmol,Mm23,n23,cp23,cv23;float delh1o23,delh2o23,delh3o23,delh5o23,hfo1,hfo2,hfo3,hfo4,hfo5,U123; float U223,U323,U423,U523,U23,Up,Qin23,mF23,nF23,delUpr,error23,T3; float p23,delV23,delW23,W23,V3,p3,m3,theta3,To,Qin1,QW23; // process 3-4 (polytropic expansion): float V34i,p34i,T34i,m34i,xp34,Vs34,V34,V3V34,n34,n34T,R34,Z34,p34,T34; float delm34,m34,V4,p4,T4,theta4; // process 4-5 (polytropic exhaust blowdown): float V45i,p45i,T45i,m45i,xp45,Vs45,V45,V4V45,n45,n45T,R45,Z45,p45,T45; float delm45,m45,V5,p5,T5,theta5; // process 5-6 (polytropic exhaust): float xp56,Vs56,V56,V5V6,m56,V6,theta6,p6,T6; // engine parameters float Wnet,ETA_ith,ETA_ithper,imep_bar,W12,W2,W3,Q3,W4,W34,W45,W5; float Wi,n_cps,Pi,Pb_kW,mF_kgps,mF_kgph,bsfc,LAMBDAMAX,LAMBDAMIN; float na,ng,nag,na1,n5r,na2; clrscr (); ofstream outfile ("EAEC-SI3.dat"); cout << "\n\n\t\t Adama Science and Technology University (ASTU) "; outfile << "\n\n\t\t Adama Science and Technology University (ASTU) "; cout << " \n\t Department of Mechanical and Vehicle Engineering "; outfile << " \n\t Department of Mechanical and Vehicle Engineering "; cout << " \n\t\t Tamiru Tesfaye (Asst. lecturer) "; outfile << " \n\t\t Tamiru Tesfaye (Asst. lecturer) "; cout << "\n. ; if (theta >= theta_0 && theta <= theta_b) { // process a-7 (constant pressure intake process). rad = theta*(PI/180.0); Z0b = 0.99; xp0b = r*((1.0-cos(rad))+((Rrl*sin(rad)*sin(rad))/2.0)); Vs0b = Ap*xp0b; V0b = Vcl+Vs0b; p0b = p0bi; T0b = T0bi; R0b = 0.287; m0b = m0bi+((pim*1.0e5*V0b)/(Z0b*R0b*1.0e3*T0b)); Vb = V0b*1.0e6; pb = p0b; Tb = T0b; mb = m0b; thetab = theta; cout << setprecision(2)<<"\n\t"<<thetab; outfile << setprecision(2)<<"\n " <<thetab; cout << setprecision(2)<<"\t "<<Vb; outfile << setprecision(2)<<"\t"<< Vb; cout <<setprecision(2)<<"\t "<<pb; outfile <<setprecision(2)<<"\t " << pb; cout <<setprecision(2)<<"\t"<<Tb; outfile <<setprecision(2)<<"\t " << Tb; getch(); } Vb1i = Vb*1.0e-6; pb1i = pb; Tb1i = Tb; mb1i = mb; if (theta > theta_b && theta <= theta_1) { // process b-1 (polytropic compression): rad = theta*(PI/180.0); xpb1 = r*((1.0-cos(rad))+((Rrl*sin(rad)*sin(rad))/2.0)); Vsb1 = Ap*xpb1; Vb1 = Vcl+Vsb1; VbVb1 = Vb1i/Vb1; nb1 = 1.35; nb1T = nb1-1.0; Rb1 = 0.287; Zb1 = 0.99; pb1 = pb1i*pow(VbVb1,nb1); Tb1 = Tb1i*pow(VbVb1,nb1T); delmb1 = mb1i-((pb1*1.0e5*Vb1)/(Zb1*Tb1*Rb1*1.0e3)); mb1 = mb1i-delmb1; V1 = Vb1*1.0e6; p1 = pb1; T1 = Tb1; theta1 = theta; cout << setprecision(2)<<"\n\t"<<theta1; outfile << setprecision(2)<<"\n " <<theta1; cout << setprecision(2)<<"\t "<<V1; outfile << setprecision(2)<<"\t"<< V1; cout <<setprecision(2)<<"\t "<<p1; outfile <<setprecision(2)<<"\t " << p1; cout <<setprecision(2)<<"\t"<<T1; outfile <<setprecision(2)<<"\t " << T1; getch(); } m12i = mb1; V12i = V1*1.0e-6; p12i = p1; T12i = T1; m12i = mb1; if (theta > theta_1 && theta <= theta_2) { // process 1-2 (polytropic effective compression): rad = theta*(PI/180.0); xp12 = r*((1.0-cos(rad))+((Rrl*sin(rad)*sin(rad))/2.0)); Vs12 = Ap*xp12; V12 = Vcl+Vs12; V1V12 = V12i/V12; n12 = 1.35; n12T = n12-1.0; R12 = 0.287; Z12 = 0.99; m12 = m12i; p12 = p12i*pow(V1V12,n12); T12 = T12i*pow(V1V12,n12T); W12 = (m12*R12*(T12-T12i))/(1.0-n12); W2 = W12; V2 = V12*1.0e6; p2 = p12; T2 = T12; theta2 = theta; cout << setprecision (2)<<"\n\t"<<theta2; outfile << setprecision (2)<<"\n " <<theta2; cout << setprecision (2)<<"\t "<<V2; outfile << setprecision(2)<<"\t"<< V2; cout <<setprecision(2)<<"\t "<<p2; outfile <<setprecision(2)<<"\t " << p2; cout <<setprecision(2)<<"\t"<<T2; outfile <<setprecision(2)<<"\t " << T2; cout<<setprecision(2)<<"\t " << W12; getch(); } W12 = W2; V23i = V2*1.0e-6; p23i = p2; T23i = T2; T23 = T2+5.0; if (theta > theta_2 && theta <= theta_3) { rad = theta*(PI/180.0); p23 = p3; xp23 = r*((1.0-cos(rad))+((Rrl*sin(rad)*sin(rad))/2.0)); Vs23 = Ap*xp23; V23 = Vcl+Vs23; m23 = m12i; theta2dc = ((theta-theta_2)/theta_dc)*PI; rad2dc = theta2dc; cv23 = 0.821; R23 = 0.287; n23 = 1.3; // Z23 = 0.98; xF = 1.0/(AF+1.0); mF = (xF*(1.0-xR))*m23; xb = 0.5*(1.0cos(rad2dc)); Qin = (mF*QLHV_F*1.0e6)*ETA_c; Q1 = Qin*xb; Q23 = Q1; W23 = (p23*1.0e5)*(V23-V23i); QW23 = (Q23-W23)/(m23*cv23*1.0e3); T23 = QW23+T23i; p23 = ((T23/T23i)*(V23i/V23))*p23i; W3 = W23/1000.0; Q3 = Q23/1000.0; V3 = V23*1.0e6; p3 = p23; T3 = T23; T23 = T3; m3 = m23; theta3 = theta; cout << setprecision(2)<<"\n\t"<<theta3; outfile << setprecision(2)<<"\n " <<theta3; cout << setprecision(2)<<"\t "<<V3; outfile << setprecision(2)<<"\t"<< V3; cout <<setprecision(2)<<"\t "<<p3; outfile <<setprecision(2)<<"\t " << p3; cout <<setprecision(2)<<"\t"<<T3; outfile <<setprecision(2)<<"\t " << T3; getch(); } W23 = W3; Q23 = Q3; V34i = V3*1.0e-6; p34i = p3; T34i = T3; m34i = m3; if (theta > theta_3 && theta <= theta_4) { // process 3-4 (polytropic expansion): rad = theta*(PI/180.0); xp34 = r*((1.0-cos(rad))+((Rrl*sin(rad)*sin(rad))/2.0)); Vs34 = Ap*xp34; V34 = Vcl+Vs34; V3V34 = V34i/V34; m34 = m12i; n34 = 1.35; n34T = n34-1.0; R34 = 0.287; Z34 = 0.99; p34 = p34i*pow(V3V34,n34); T34 = T34i*pow(V3V34,n34T); delm34 = m34i-((p34*1.0e5*V34)/(Z34*T34*R34*1.0e3)); m34 = m34i-delm34; W34 = (m34*R34*(T34-T34i))/(1.0-n34); W4 = W34; V4 = V34*1.0e6; p4 = p34; T4 = T34; theta4 = theta; cout << setprecision (2)<<"\n\t"<<theta4; outfile << setprecision (2)<<"\n " <<theta4; cout << setprecision(2)<<"\t "<<V4; outfile << setprecision(2)<<"\t"<< V4; cout <<setprecision(2)<<"\t "<<p4; outfile <<setprecision(2)<<"\t " << p4; cout <<setprecision(2)<<"\t"<<T4; outfile <<setprecision(2)<<"\t " << T4; cout<<setprecision(2)<<"\t " << W34; getch(); } W34 = W4; V45i = V4*1.0e-6; p45i = p4; T45i = T4; m45i = m12i; if (theta > theta_4 && theta <= theta_5) { // process 4-5 (polytropic exhaust blowdown): rad = theta*(PI/180.0); xp45 = r*((1.0-cos(rad))+((Rrl*sin(rad)*sin(rad))/2.0)); Vs45 = Ap*xp45; V45 = Vcl+Vs45; V4V45 = V45i/V45; m45 = m12i; n45 = 1.35; n45T = n45-1.0; R45 = 0.287; Z45 = 0.99; p45 = p45i*pow(V4V45,n45); T45 = T45i*pow(V4V45,n45T); delm45 = m45i-((p45*1.0e5*V45)/(Z45*T45*R45*1.0e3)); m45 = m45i-delm45; W45 = (m45*R45*1.0e3*(T45-T45i))/(1.0-n45); W5 = W45/100.0; V5 = V45*1.0e6; p5 = p45; T5 = T45; theta5 = theta; cout << setprecision(2)<<"\n\t"<<theta5; outfile << setprecision(2)<<"\n " <<theta5; cout << setprecision(2)<<"\t "<<V5; outfile << setprecision(2)<<"\t"<< V5; cout <<setprecision(2)<<"\t "<<p5; outfile <<setprecision(2)<<"\t " << p5; cout <<setprecision(2)<<"\t"<<T5;

Table 3 .