Characterization and Effect of Using Peanut Seed Oil Methyl Ester as

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Characterization and Effect of Using Peanut Seed Oil Methyl Ester as a Fuel in a Low Heat Rejection Diesel Engine Hanbey Hazar,* Ugur Oztürk, and Hakan Gül Department of Automotive Engineering, Technology Faculty, Firat University, Elazig 23119, Turkey ABSTRACT: To decrease hazardous emissions of internal combustion engines and to improve the combustion and thermal efficiency, thermal barrier coatings were applied. In this experimental study, cylinder, piston, exhaust, and inlet valves, which are combustion chamber components, were coated with a ceramic material and this enabled the engine to gain a low heat rejection feature. Cylinder, exhaust, and inlet valves of the diesel engine used in the tests were coated with ekabor-2 commercial powder, which is a ceramic material, to a thickness of 50 μm using the boronizing method. The piston of a diesel engine was coated in 300 μm thickness with bor-based powder using the plasma-coating method. Peanut seed oil methyl ester (PSME) was produced using the transesterification method. In addition, diethyl ether additive materials were used to improve the properties of diesel fuel, PSME, and its mixture. Diethyl ether was blended with test fuels, which were used as a pilot fuel, at the volumetric ratios of 4 and 8%. As a result of the thermal barrier coating, the brake-specific fuel consumption, carbon monoxide, hydrocarbon, and smoke density values of the diesel engine decreased, whereas nitrogen oxides, carbon dioxide, thermal efficiency, and exhaust gas temperature increased.

1. INTRODUCTION Today, in the energy types obtained from fossil fuels, wastes directly mix in the air.1 A major part of these wastes is converted into particularly carbon dioxide (CO2) and greenhouse gases. The rate of motor vehicles in large cities in total air pollution reaches up to 50%. Additionally, limited oil reserves signify2 that more fuel saving is required. Also, gases induced by vehicle emissions disperse in the atmosphere and threaten human health. One of the most important reasons for the increase in exhaust emissions is that the combustion in the engine does not take place completely. When an efficient combustion does not take place, both fuel consumption increases and harmful gases release more. Today, the basic fuel source of motor vehicles is petroleum. Because petroleum is an exhaustible resource, it becomes inevitable to investigate and find new fuels to be alternatives to petroleum.3−5 Vegetable oils come into prominence about this matter.6 Direct usage of pure vegetable oils as fuel in diesel engines brings along some harm. These are problems such as high viscosity of oil, acid composition, independent fatty acid content, adhesion induced by oxidation, etc.7 To eliminate these negative effects, numerous different methods are used in raw vegetable oil. Vegetable oils are esterified using various methods. However, they do not still reach the performance of petroleum fuels. If the burn-out temperature is increased, performance and emission values of vegetable-based fuels will improve. Coating combustion chamber elements with advanced technology materials in internal combustion engines will make combustion more efficient. In internal combustion engines, combustion chamber elements are coated with ceramic materials using various methods. Thermal barrier coatings are primary coatings among these methods. Thermal barrier coatings are used to increase the reliability and resistance of hot sections in metal components and to enhance performance and efficiency in engines. Thermal barrier coatings generally consist of a connection layer, which provides oxidation resistance, and a © XXXX American Chemical Society

resistant upper layer, which provides thermal insulation. Thermal barrier coating is generally applied to combustion chamber parts. Thermal-barrier-coated engines are called low heat rejection (LHR) engines. Insulating combustion chamber elements of a LHR engine reduces heat transfer between the cylinder jacket and gas in the cylinder. The concept of LHR is based on suppression of the heat transferring to the refrigerant and regaining the energy in a beneficial way.8 Some of recent studies have been conducted on additional fuel additives. There are numerous studies on developing the cetane number in diesel oil, and additives that prevent the formation of nitrogen oxides (NOx), decreasing smoke generation, are efficient on viscosity, prevent hydrocarbon (HC) branching, and reduce the freeze point. Alternative fuels and additives used in studies have given effective results on fuel as a result of their different properties. One of these additives is diethyl ether. Diethyl ether has properties such as high oxygen content and high cetane number (more than 125), suitable density during storing, low spontaneous combustion temperature, miscibility with diesel fuel, and high volatility compared to diesel fuel. This study involved three stages. In the first stage, combustion chamber elements were coated using the boronizing method. In the second stage, methyl ester was produced from raw peanut oil. In third stage, diethyl ether (its formula is CH3−CH2−O− CH2−CH3) was added to the produced peanut seed oil methyl ester (PSME) at certain rates and its performance and emission values were compared.

2. MATERIALS AND METHODS In the experimental study, a 4-cycle, four-cylinder, water-cooled diesel engine was used. Cylinder jacket, valves, and piston, which are the combustion chamber elements of the diesel engine, were coated. Received: June 15, 2016 Revised: August 14, 2016

A

DOI: 10.1021/acs.energyfuels.6b01462 Energy Fuels XXXX, XXX, XXX−XXX

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Energy & Fuels When the coating process was performed, two coating techniques were used. While a solid boronizing method was used in the coating of the cylinder jacket and valves, the piston upper surface was coated with ceramic material containing boron using the plasma spray method. In these coating processes, a surface that had a high wear and thermal conduction resistance and low friction coefficient was obtained. Adiabatic property was brought to the engine, and thus, the engine became a thermal-insulated engine. Figure 1 shows the schematic view

Table 1. Test Engine Specifications item

specification

type of engine stroke number of cylinders bore/stroke (mm) compression ratio maximum engine power (kW) fuel type lubricating type of injection type of coolant maximum engine speed (min−1) engine volume (mm3)

Aksa A4CRX18 4 4 80/90 18.0:1 16.50 (1500 min−1) diesel full pressure direct injection water coolant 3600 1.80

Table 2. Technical Properties of the Gas-Analyzing Device

Figure 1. Engine test mechanism schematic view.

component

measurement range

precision

CO CO2 HC O2 λ NO

0.00−10.00% vol 0.00−18.00% vol 0−9.999 ppm vol 0.00−22.00% vol 0.500−9.999 0−5000 ppm vol

0.001% vol 0.01% vol 1 ppm vol 0.01% vol 0.001 ≤1 ppm vol

As test fuel, PSME was produced from peanut oil by applying the alkali-catalyzed transesterification method. The obtained fuel was used by mixing it with normal diesel fuel at the rate of 20% biodiesel + 80% diesel fuel (B-20). Physicochemical properties of the obtained biodiesel fuel were determined at the analysis laboratory. In an uncoated engine, performance, exhaust emission, and exhaust gas temperature values were recorded by operating with normal diesel fuel (D-2) and B-20 fuels. Then, test fuels were tested again in a coated engine. Performance and exhaust emission values were recorded for the second time. Lastly, necessary evaluations were made by comparing all data, obtained from coated and uncoated engines, to each other. The engine speed is kept constant at 1500 rpm. The engine load is variable. 2.1. Biodiesel Production. Peanut oil, used as a source of biodiesel, was obtained from peanuts produced in Turkey. Belonging to the legume family (Fabaceae), peanut oil contains fat of 45−60%, protein of 20−30%, carbohydrate of 18%, vitamins, and metallic substances in its seeds. Free fatty acid determination was carried out before the production. Biodiesel production was carried out using the alkali-catalyzed transesterification method. Table 3 illustrates composition of fatty acids of peanut. 2.2. PSME and Experimental Procedure Applied for Its Production. In the production of PSME, 200 mL of methanol was used for 1000 mL of peanut oil. For base catalyst, methoxide solution

Figure 2. Image of the coated engine component. of the engine test setup. Figure 2 shows the coated engine component. Figure 3 shows the coating layer in the scanning electron microscopy (SEM) image taken from the cross-section of the cylinder surface. Table 1 shows test engine specifications. Table 2 shows technical properties of the gas-analyzing device.

Table 3. Composition of Fatty Acids of Peanut

Figure 3. SEM photo of the cross-section of the coated cylinder. B

common name of the fatty acid

carbon number

molecular weight

lauric acid myristic acid palmitic acid palmitoleic acid stearic acid oleic acid linoleic acid linolenic acid arachidonic acid gadoleic acid behenic acid

C12:00 C14:00 C16:00 C16:01 C18:00 C18:01 C18:02 C18:03 C20:00 C20:01 C22:00

200.32 228.37 256.42 254.41 284.48 282.46 280.45 278.43 312.53 310.50 340.58

peanut oil (%)

11.28 3.18 52.46 31.29 1.2 1.9 0.95

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Figure 4. Reaction-end phase separation and biodiesel formation and glycerine. (methyl alcohol + NaOH) of 200 mL was used as the catalyst, with NaOH having a weight of 1.25% of oil (for 1000 mL), which was subject to reaction as mass. In other words, 11.5 g of NaOH was dissolved in 200 mL of methyl alcohol. Peanut oil of 1000 mL was transferred into a two-necked balloon and stirred in a magnetic stirrer at 55 °C and 400 revolutions per minute (rpm). Methoxide solution (methyl alcohol + NaOH) of 200 mL was slowly transferred to the oil within the two-necked balloon. The temperature was kept under control using a glass thermometer and constant at 55 °C. The reaction lasted for 75 min at 400 rpm. Figure 4 shows reaction-end phase separation of biodiesel and glycerine. As seen in Figure 4, at the end of the time, glycerine/biodiesel phase separation was observed clearly. At the end of the reaction, the mixture was taken into a separating funnel and kept for 5 h to complete the phase separation. At the end of the time, it was observed that the glycerine phase was on the bottom and the clear biodiesel phase was on the top. The glycerine phase was taken from the separating funnel using a controlled tap, and biodiesel was obtained. The amount of separated glycerine was collected to measure the efficiency of biodiesel. Biodiesel obtained by the irrigation process was shaken in the separating funnel by mixing with warm distilled water at the rate of 1/3 of its own volume. This process was repeated 3 times. Each time, the water phase at the bottom was taken out by being separated from the separating funnel. Purified biodiesel was subject to the evaporation process and purified completely from water and methanol, which were available in a trace amount. Finally, the filtering process was performed using a paper filter.

Figure 5. CO emission changes at a constant rpm under different loads.

decrease of approximately 14.22% was found as the average of all loads in PSME-20 fuel in the CE engine. If it is required to make a general assessment, CO emission of a diesel engine is based on physical and chemical properties of the fuel. When ester-based fuels were compared to D-2, the main difference between them is the calorific value, oxygen content, and cetane number of the fuel. Ester-based fuels contain oxygen on average of 12% or more. During combustion, these oxygen molecules enhance the combustion by increasing its efficiency.9 Thus, C molecules in fuel are included in the combustion process. Oxidized C elements release as CO2. Thus, they cause a decrease in CO emission. The reason for the decrease in CO emission for all test fuels in the CE engine compared to those in the SE engine was the thermal barrier. It was thought that increasing the burn-out temperature increased efficiency of the chemical reaction.10 Tests were performed by adding DEE additive into PSME fuel at the rate of 4 and 8% volumetrically. The oxygen rate of PSME fuel is actually higher than that of diesel fuel. The addition of the DEE additive with a high oxygen content into this fuel will show an improving effect on CO emission. As seen in Figure 5, as the DEE rate in PSME fuel increased for both engines, CO emission decreased. In the CE engine, while a decrease of 4.34% was observed for PSME20 + 4% D fuel, a decrease of 8.77% took place for PSME-20 + 8% D fuel. The fact that the DEE additive had more oxygen content in its chemical structure, lower carbon rate, lower

3. RESULTS AND DISCUSSION 3.1. Carbon Monoxide (CO) Emissions. Figure 5 shows CO emission changes of the diesel engine at a constant rpm under different loads. When Figure 5 was examined, it was observed that the highest CO emission took place in D-2 fuel, among all test fuels in both engines (SE and CE engines). When the SE engine was compared to the CE engine, a decrease in CO emission was observed for all test fuels in the CE engine because of the coating process. CO emission increased for both engines proportionally with the increase of the load amount in the engine. This was an expected situation. The increasing of the fuel amount taken into the combustion chamber as a result of the increase in the load and the decreasing of the time and oxygen amount necessary for combustion led to an increased CO emission. When fuels were compared for both engines, a decrease of approximately 10.11% was determined as the average of all loads in CE-D-2 fuel compared to those in SE-D2 fuel. In comparison to PSME-20 fuel in the SE engine, a C

DOI: 10.1021/acs.energyfuels.6b01462 Energy Fuels XXXX, XXX, XXX−XXX

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Energy & Fuels viscosity,11 high cetane number, and lower ignition temperature than diesel fuel12 had an effect on decreasing the CO emission. 3.2. NOx Emissions. Figure 6 shows NOx changes of the diesel engine at a constant rpm under different loads.

Figure 7. HC emission changes at a constant rpm under different loads.

decrease in HC emission was observed for all test fuels in the CE engine because of the coating process. It was observed that HC emission decreased for both engines proportionally with the increase of the load amount in the engine. The reason for the decrease in HC emission for all test fuels in the CE engine compared to those in the SE engine was the thermal barrier. It was thought that increasing the burn-out temperature increased efficiency of the chemical reaction. When fuels were compared in both engines, it was determined that there was a decrease of approximately 54.10% as the mean of all loads in D-2 fuel in the CE engine compared to those in D-2 fuel in the SE engine. A decrease of approximately 57.69% was determined as the average of all loads in PSME-20 fuel in the CE engine compared to those in PSME-20 fuel in the SE engine. As seen in Figure 7, the addition of DEE into test fuels caused an increase in HC emission. Because of the high evaporation value of DEE, a low air/fuel ratio and lower temperature period16 during combustion were effective. However, as a result of the coating, HC emissions of fuels with DEE additives decreased. While a decrease of 6.68% was observed for PSME-20 + 4% D fuel in the CE engine, a decrease of 9.32% was observed for PSME-20 + 8% D fuel. 3.4. CO2 Emissions. Carbon, which is in the structure of a petroleum-based fuel, is converted to CO2, during the combustion process. The resulting volume of CO2 is an indicator that shows how efficient the fuel is. Figure 8 illustrates CO2 emission changes of the diesel engine at a constant rpm under different loads. When fuels were compared in both of the engines, it was determined that there was a increase of approximately 10.18% as the mean of all loads in D-2 fuel in the CE engine compared to those in D-2 fuel in the SE engine. There was a increase of approximately 4.91% as the mean of all loads in PSME-20 fuel in the CE engine compared to those in PSME-20 fuel in the SE engine. While a increase of 12% was observed for PSME-20 + 4% D fuel in the CE engine, a increase of 3.02% was observed for PSME-20 + 8% D fuel. 3.5. Brake-Specific Fuel Consumption (BSFC). Figure 9 shows BSFC changes of the diesel engine at a constant rpm under different loads. When Figure 9 was examined, the highest BSFC was observed in D-2 fuel in all test fuels in both engines (SE and CE engines). When SE and CE engines were compared to each other, an improvement was observed in BSFC for all test fuels

Figure 6. NOx emission changes at a constant rpm under different loads.

When Figure 6 was examined, it was observed that the highest NOx emission occurred in the CE engine in PSME-20 fuel, among all test fuels in both engines. A high oxygen content of biodiesel13,14 fuel leads to an increase for NOx emission. The evaporation characteristic of the biodiesel fuel is poorer than that of diesel. Thus, it affects the NOx emission.15 When the SE engine was compared to the CE engine, an increase was observed in NOx emission for all test fuels in the CE engine because of the coating process. It was observed that NOx emission increased for both engines proportionally with the increase of the load amount in the engine. The reason for the increase in NOx emission for all test fuels in the CE engine compared to those in the SE engine was the thermal barrier. It was thought that increasing the burn-out temperature increased efficiency of the chemical reaction because the temperature had an important effect on the formation of NOx. When fuels were compared in both engines, an increase of approximately 40.89% was determined as the average of all loads in D-2 fuel in the CE engine compared to those in D-2 fuel in the SE engine. There was an increase of approximately 32.73% as the average of all loads in PSME-20 fuel in the CE engine compared to those in PSME-20 fuel in the SE engine. Here, an increase of 32.73% in PSME-20 fuel used in the coated engine compared to PSME-20 fuel used in the uncoated engine was an expected situation. The addition of DEE into test fuels caused NOx emission to decrease. As the rate of DEE in test fuels increased, NOx emission decreased. This is because the decrease of the controlled combustion diffusion phase, the low-temperature period in combustion time, and the high evaporation value of DEE16 were effective on NOx emission. As seen in Figure 6, as the rate of DEE in PSME fuel increased for both engines, NOx emission decreased. While a decrease of 0.94% was observed for PSME-20 + 4% D fuel in the CE engine, a decrease of 1.65% occurred for PSME-20 + 8% D fuel. 3.3. HC Emissions. Figure 7 shows HC emission changes of the diesel engine at a constant rpm under different loads. When Figure 7 was examined, the highest HC emission was observed in D-2 fuel, among the all test fuels in both engines. When the SE engine was compared to the CE engine, a D

DOI: 10.1021/acs.energyfuels.6b01462 Energy Fuels XXXX, XXX, XXX−XXX

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the fuel. Ester-based fuels contain oxygen on average of 12% or more. During combustion, these oxygen molecules increase the efficiency of combustion.17 The reason for the decrease in BSFC for all test fuels in the CE engine compared to those in the SE engine was the thermal barrier. Heat transfer is reduced as a result of coating. It was thought that increasing the burnout temperature increased efficiency of the chemical reaction. In the CE engine, a decrease of 6.30% was observed for PSME20 + 4% D fuel and a decrease of 4.49% was determined for PSME-20 + 8% D fuel. It was thought that a higher oxygen content in the chemical structure of the DEE additive, a low carbon rate, a low viscosity,7,18 a high cetane number, and a low ignition temperature8 compared to diesel fuel had a positive effect on decreasing BSFC. 3.6. Exhaust Gas Temperature (EGT). The EGT measurement is an important parameter that enables us to comment on the heat releasing as a result of combustion and temperature values occurring depending upon this heat. Owing to these measurements, we can have information about calorific values of consumed fuels and fuel composition. Figure 10 shows EGT changes of the diesel engine at a constant rpm under different loads.

Figure 8. CO2 emission changes at a constant rpm under different loads.

Figure 9. BSFC emission changes at a constant rpm under different loads. Figure 10. EGT changes at a constant rpm under different loads.

in the CE engine because of the coating process. BSFC increased for both engines proportionally with the increase of the load amount in the engine. This was an expected situation. This is because the increase of the fuel amount taken into the combustion chamber with the increase in the load and the decrease of the time and oxygen amount necessary for combustion caused an increase of the BSFC. The rate of BSFC, which was the closest to D-2 fuel in the SE engine, was detected in PSME-20 + 8% D fuel. The reason for the decrease in BSFC for all test fuels in the CE engine compared to those in the SE engine was the thermal barrier. It was thought that increasing the burn-out temperature increased efficiency of the chemical reaction. When fuels were compared in both engines, a decrease of approximately 5.81% was determined as the mean of all loads in D-2 fuel in the CE engine compared to those in D-2 fuel in the SE engine. There was a decrease of approximately 4.57% as the average of all loads in PSME-20 fuel in the CE engine compared to those in PSME-20 fuel in the SE engine. The rate of BSFC, which was the closest to D-2 fuel in the CE engine, was detected in PSME-20 + 8% D fuel. If a general assessment is required, BSFC of a diesel engine is based on physical and chemical properties of the fuel. When ester-based fuels were compared to D-2, the main difference was the calorific value, oxygen content, and cetane number of

When Figure 10 was examined, it was determined that the highest EGT took place in D-2 fuel, among all test fuels in both engines. When the SE engine was compared to the CE engine, EGT increased for all test fuels in the CE engine because of the coating process.19 It is considered that it reduced heat conduction as a result of coating. EGT increased for both engines with the increase of the load amount in the engine. The reason for the increase in EGT for all test fuels in the CE engine compared to those in the SE engine was the thermal barrier. It was thought that increasing the burn-out temperature increased efficiency of the chemical reaction. When fuels were compared in both engines, an increase of approximately 6.43% was determined as the average of all loads in D-2 fuel in the CE engine compared to those in D-2 fuel in the SE engine. An increase of approximately 11.07% was determined as the average of all loads in PSME-20 fuel in the CE engine compared to those in PSME-20 fuel in the SE engine. The addition of DEE into test fuels caused EGT to increase. As the rate of DEE in test fuels increased, EGT also increased. As seen in Figure 10, as the rate of DEE in PSME fuel increased for both engines, EGT increased. In the CE engine, an increase of 8.51% was observed for PSME-20 + 4% D fuel and an increase E

DOI: 10.1021/acs.energyfuels.6b01462 Energy Fuels XXXX, XXX, XXX−XXX

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ignition temperature12 within its chemical structure compared to diesel fuel had effects on the decrease in CO emission. Additionally, it is thought that the DEE additive forming a poor mixture in the combustion chamber was effective on low smoke emission. The addition of the DEE additive with a high oxygen content into test fuels will show an improving effect on smoke emission. As seen in Figure 11, as the rate of DEE in PSME fuel increased for both engines, smoke emission decreased. In the CE engine, a decrease of 11.16% was observed for PSME-20 + 4% D fuel and a decrease of 14.87% was observed for PSME-20 + 8% D fuel. 3.8. Brake Thermal Efficiency (BTE). Figure 12 shows thermal efficiency changes of the diesel engine at a constant rpm under different loads.

of 3.43% was determined for PSME-20 + 8% D fuel. It was thought that a slightly higher EGT was associated with a late diffusion combustion, a higher oxygen amount compared to diesel fuel, a high evaporation value,9 a low air/fuel ratio, and a low viscosity. 3.7. Smoke (Smoke Density). Figure 11 shows smoke density changes of the diesel engine at a constant rpm under different loads.

Figure 11. Smoke changes at a constant rpm under different loads.

When Figure 11 was examined, the highest smoke emission was found in D-2 fuel, among all test fuels in both engines. When the SE engine was compared to the CE engine, a decrease was observed in smoke emission for all test fuels in the CE engine because of the coating process. Smoke emission increased for both engines with the increase of the load amount in the engine. This was an expected situation. This is because the increase of the fuel amount taken into the combustion chamber with the increase in the load and the decrease of the time and oxygen amount necessary for combustion caused an increase in smoke emission. The reason for the decrease in smoke emission for all test fuels in the CE engine compared to the SE engine was the thermal barrier.20,21 It is considered that it reduced heat conduction as a result of coating. It was thought that increasing the burn-out temperature increased efficiency of the chemical reaction. Thus, it was thought that more carbon atoms entered in the chemical reaction. When fuels were compared in both engines, a decrease of approximately 13.40% was determined as the average of all loads in D-2 fuel in the CE engine compared to those in D-2 fuel in the SE engine. A decrease of approximately 14.22% was determined as the average of all loads in PSME-20 fuel in the CE engine compared to those in PSME-20 fuel in the SE engine. When ester-based fuels were compared to D-2, the main difference was the calorific value, the oxygen content, and the cetane number of the fuel. The fact that ester fuels contain more oxygen compared to diesel fuel has a positive effect on combustion efficiency.22 Thus, C molecules in the fuel are included in the combustion reaction. Oxidized C elements release as CO2. Thus, they cause a decrease in smoke emission. The reason for the decrease in smoke emission for all test fuels in the CE engine compared to those in the SE engine was the thermal barrier. It was thought that increasing the burn-out temperature increased efficiency of the chemical reaction. The fact that the DEE additive has more oxygen content, a low carbon rate, a low viscosity,11 a high cetane number, and a low

Figure 12. Thermal efficiency changes at a constant rpm under different loads.

If it is necessary to make a general assessment, as seen in Figure 12, it was observed that thermal efficiency increased with the increase of the load for all fuel types. Additionally, it was observed that thermal efficiency increased for all test fuels used in the CE engine compared to those in the SE engine. An increase in the rate of thermal efficiency in test fuels in the CE engine was determined as 8.7% for D-2 fuel, 6.49% for PSME20 fuel, 7.57% for PSME-20 + 4% D fuel, and 12.31% for PSME-20 + 8% D fuel. It was thought that the increase in the combustion chamber temperature and burn-out temperature as a result of the thermal barrier23 is the cause of the thermal efficiency increase in test fuels used in the CE engine. The reason for the increase in thermal efficiency of DEE fuel mixtures was thought that they had lower viscosity compared to D-2 and PSME. It was thought that a better atomization may occur because of the lower viscosity, and this situation would increase the efficiency of the combustion.3

4. CONCLUSION This study consisted of three stages. In the first stage, combustion chamber elements were coated using the boronizing method. In the second stage, methyl ester was produced from raw peanut oil. In third stage, diethyl ether was added to the produced PSME at certain rates and performance and emission values were compared. (1) CO, smoke, HC, and BSFC rates of all fuels used in the CE engine decreased compared to those in the SE engine. (2) NOx and CO2 emission, EGT, and thermal efficiency of all fuels used in the CE engine increased compared to those in the SE engine. (3) F

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(15) Kim, H.; Kim, Y.; Lee, K. An Experimental Study on the Spray, Combustion, and Emission Characteristics of Two Types of Biodiesel Fuel. Energy Fuels 2013, 27, 5182−5191. (16) Rakopoulos, D. C.; Rakopoulos, C. D.; Giakoumis, E. G.; Dimaratos, A. M. Characteristics of performance and emissions in high-speed direct injection diesel engine fueled with diethyl ether/ diesel fuel blends. Energy 2012, 43, 214−224. (17) Sivalakshmi, S.; Balusamy, T. Effect of biodiesel and its blends with diethyl ether on the combustion, performance and emissions from a diesel engine. Fuel 2013, 106, 106−110. (18) Rakopoulos, D. C. Combustion and emissions of cottonseed oil and its bio-diesel in blends with either n-butanol or diethyl ether in HSDI diesel engine. Fuel 2013, 105, 603−613. (19) Hazar, H.; Gul, H. New Modeling and Experimental Study Regarding Tungsten-Carbide-Coated Parts of the Combustion Chamber of a Compression-Ignition Engine. Energy Fuels 2016, 30, 5148−5157. (20) Gosai, D. C.; Nagarsheth, H. J. Performance and Exhaust Emission Studies of an Adiabatic Engine with Optimum Cooling. Procedia Technology 2014, 14, 413−421. (21) Das, D.; Majumdar, G.; Sen, R. S.; Ghosh, B. B. The Effects of Thermal Barrier Coatings on Diesel Engine Performance and Emission. J. Inst. Eng. India Ser. C 2014, 95, 63−68. (22) Soloiu, V.; Weaver, J.; Ochieng, H.; Vlcek, B.; Butts, C.; Jansons, M. Evaluation of Peanut Fatty Acid Methyl Ester Sprays, Combustion, and Emissions, for Use in an Indirect Injection Diesel Engine. Energy Fuels 2013, 27, 2608−2618. (23) Hazar, H.; Oner, C.; Nursoy, M. Effects of CrN coating of cylinders on engine performance. Energy Educ. Sci. Technol., Part A 2009, 23, 71−85.

As a result of adding DEE into PSME fuel, CO, smoke, NOx, and BSFC rates decreased but only HC emission increased. However, HC emission of fuels with the addition of DEE in the coated engine decreased. By means of this study, it has been concluded that coating of the combustion chamber elements of a diesel engine by boronizing generally improves the performance and harmful emissions of the engine and the fuels with DEE and PSME additives can be used in these engines.

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AUTHOR INFORMATION

Corresponding Author

*Telephone: +90-424-2370000, ext. 4363. E-mail: [email protected]. Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS The authors thank Firat University for the financial support of investigations. This study is sponsored by the Firat University Research Fund under Project TEKF.13.03.

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REFERENCES

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DOI: 10.1021/acs.energyfuels.6b01462 Energy Fuels XXXX, XXX, XXX−XXX