The Impact upon Durability of Heavy-Duty Diesel Engine using 5 Percentage Biodiesel

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1 13PFL-0370 The Impact upon Durability of Heavy-Duty Diesel Engine using 5 Percentage Biodiesel Author, co-author (Do NOT enter this information. It will be pulled from participant tab in MyTechZone) Affiliation (Do NOT enter this information. It will be pulled from participant tab in MyTechZone) Copyright 2012 SAE International ABSTRACT Due to the increasing price of crude oil, biofuel as an alternative of fossil fuels is sought to be a global wide solution to reduce the emission of green house gas. In order to compare the influence on engine which meet euro IV emission standard by using pure fossil diesel, 2% and 5% biodiesel. A long-term operation with blended 2% and 5% biodiesel by standard engine test had been evaluated in this study. The results could be referred to the consideration of marketing promotion strategy as well as government policy in Taiwan. Both B2 B5 diesel fuel (2 and 5 vol% biodiesel) and diesel fuel were employed to the same engines for testing purpose to compare the influence. The engines were equipped with an electronically controlled common-rail fuel injection system. After 500 hours full load durability operation, the key components of the engines were analyzed and characterized by a series of inspections to identify the degree of decay and wear behavior. In addition, the engine performance which by the test procedure for SAE J1995 and emission measured which by the test procedure for FTP transient cycle were also determined at each maintenance stage. In this study, oil characteristics after durability test had also been evaluated. The results indicated that the engine components including piston rings, cylinder liners and needle valves of injector were less difference in dimensions comparison before and after durability tests. The fuel supply system of the diesel engine consists of a fuel tank, fuel pipes, fuel filters, and a low pressure pump had also been evaluated. According to microscopic characterization and engine oil analyses, the wear loss of the key components was insignificant and tribological performance of the B5 biodiesel was slightly better than that of diesel fuel. It was found that the performance and emissions were varied under ±3% when diesel engine was fueled with B5 biodiesel. Page 1 of 10 INTRODUCTION The biofuel used in diesel engines is mostly produced from animal fats or vegetable oils via transesterification process. The last decade has seen growing importance placed on research in application of biodiesel field. The advantages of biodiesel have been widely discused,compared with fossil diesel, biodiesel produces lower engine emissions of carbon monoxide (CO), hydrocarbons (HC), particular matter (PM), polycyclic aromatic hydrocarbons (PAHs), and carbon dioxide (CO2), which significantly reduce the impact of greenhouse effect on the earth [1~3]. Biodiesel is composed of methyl esters and has higher oxygen content, about 11% of total composition, lower emission of the particles and CO during the burning process. Besides, pure biodiesel contains almost no sulfur and it is renewable energy to be one of solutions in oil market and reducing impact on economy [4]. Most researches found that the fretting wear performance of biodiesel was better than that of diesel fuel. The engine oil, used in a compression ignition engine fueled with linseed oil methyl ester (LOME) for durability test, has been analyzed by atomic absorption spectroscopy (AAS). The results showed that the wear debris of metal in the engine oils was significant decreased than that with the traditional diesel fuel. Moreover, according to the dimensions difference of the engine component before and after durability test, the difference in dimensions of engine component test with biodiesel is smaller than that with traditional diesel. These results imply that biodiesel can reduce the wear of engine components [5~7]. However, some researches indicated that biodiesel could cause more wear on some engine components and affect engine operation. S. Kaul et al. presented the study of using nonedible oils for corrosion tests. It soaked the diesel engine components in four kinds of oils chronically. Only salvadora oil caused dramatically corrosion on engine components. It is attributed to the high content of sulfur while the others had the same results as that of petro-diesel [8]. Japanese Automobile Manufacturers Association (JAMA) also pointed out that using biodiesel over a long period of time possibly caused negative influence on vehicles. For instance, the components

2 of common-rail system may tend to wear, which caused poor atomizing during injection period and unexpectedly engine burning. Biodiesel may also corrode fuel tank and pipes for long-term operation [9]. In June 2007, Taiwan government has legislated as national biodiesel standard and 1471 which allowed blends up to 5% of fatty acid methyl ester (FAME) in diesel fuel. B1 biodiesel has been widely used in Taiwan from July Furthermore, the biodiesel percentage has been increased to B2 in market from 2010 to achieve the goal of at least one hundred million liters of biodiesel used for each year. In Taiwan, the next step of biodiesl policy will upgrate to B5 in In order to confirm the influence of nationally-made biodiesel on vehicle, the effects on engine components, including cylinders, piston rings, needle valves, pistons and fuel injection nozzles had been examined in this paper to explore the differences of wear with microscopic analysis. The compositions of carbon deposits in engines had been observed and the exhaust emissions, performance and fuel consumption of test engines had also been evaluated during durability tests. EXPERIMENTAL METHODS Three new diesel engines of the same type were used for durability tests. The engine equipped with common rail fuel injection system was a 2977 c.c. MITSUBISHI 4M42-4AT2 diesel engine which widely used as a commercial truck engine, complied with the environmental protection regulations in Taiwan. The basic specifications of the test engine are shown in Table 1. The test fuels complied with 1471 (Chinese National Standards, )were 100% diesel (D100), B2 biodiesel which was blended with 2 vol% biodiesel and 98 vol% diesel and B5 bidiesel which was blend with 5 vol% bidiesel and 95% vol% diesel. The biodiesel (B100) was made from waste cooking oils by local manufacturers in Taiwan and complied with the biodiesel standard which worked out based on EN Table 1. Test engine specifications Item Specification Engine Type MITSUBISHI 4M42-4AT2 Displacement 2977 c.c. Rated Power 92.0 kw/3200rpm Rated Torque 294 Nm/1700rpm Cylinders In-line 4 Cylinder/4 Stroke Compression Ratio 17:1 Fuel System Common Rail (Direct Injection) Injection Pressure 1600 bar Nozzle Hole Air Intake System Turbocharged with intercooler Emission Control System DOC, PCV, EGR The properties of biodiesel are different from fossil diesel fuel, such as cetane index and viscosity are higher, lower content of sulfur so it would not increase the sulfur content after blending, as well as aromatic hydrocarbon. The lubricity of engine can be improved with adequate amount of biodiesel. Table 2 shows the properties of the test fuels and it indicated that except the lubricity, the difference between B5, B2 and D100 can be neglected. Test item Table 2. Fuel properties Engine Engine Engine 1-D100 2-B2 3-B5 Unit Cetane index Density, 15 Copper strip corrosion (3hr at 50 ) Test method g/ml a 1a 1a rating 1219 Flash point Kinematic viscosity, cst Carbon residue (on 10% distillation <0.1 <0.1 <0.1 residue) Distillation, IBP Distillation, T Distillation, FBP Ash % (m/m) < % (m/m) Sulfur content ppm Polyaromatics % content (m/m) Lubricity, corrected wear scar diameter μm (1.4 wsd, 60 ) Fatty acid methyl % ester content (v/v) Water and sediment 0-0 % (v/v) Water content ppm Total contaminant ppm Pour point* Cold filtration plug point (CFPP)* Oxidation stability, 110 Heating value g/m kcal/kg D min. report No.1 52 min * Diesel fuel blended with fatty acid methyl ester must conform to at least one of the above requirements. - Page 2 of 10

3 The equipment of engine exhaust emission laboratory and the sampling system of engine exhaust of this study is shown in Figure 1, including AC Motor Engine Dynamometer, Exhaust Analysis, Full Flow Dilution Sampling System, Direct Sampling System, Particle Matter Sampling System, etc, to conduct the durability tests and the examination of the amount of exhaust emission. The examination equipment and sampling systems of engine exhaust are described as the followings. This experiment used the SCHENCK MP-DYNAS 335 AC motor engine dynamometer and specifications are 800N.m maximum within 8000rpm. The engine dynamometer reaction rate of positive torque and negative torque is less than one second; it can effectively conduct EU ETC and EU ESC test cycle. The durability test with full-load operation was performed in the present of study. At each maintenance stage (125hr or 250hr), the engine performance was determined using SAE J1995 test method and the measurement of emission was conducted by engine dynamometer under US FTP transient cycle. Table 3 shows the test methods in this study. Figure 2 is the running mode of full-load operation for durability test, where each cycle takes 2 hours and is repeated for 500 hours [10]. HORIBA CVS 9400T was the sampling equipment and HORIBA MEXA 7500D was exhaust emission analysis instrument has been used in this study. Engine performance Wear of Engine Components Carbon Deposits Engine Oils Fuel Supply System Engine speed (rpm) SAE J1995 Dimension, microscopic observation (Cylinder liner, piston ring, needle valve) Weight, composition, microscopic observation(piston, nozzle) Replaced oil during maintenance period ( test method) Fuel tank, fuel pipe, filter, rubber hose ( test method) Time (hr) Figure 2. Full-load operating procedure for engine durability test As for the wear of engine components in detailed inspection, the 3D coordinate measuring machine (CMM), profile meter and other measuring rigs were used to measure the dimension of specific parts and calculate the dimension variation for each component before and after durability tests. After the tests, the engine components were cut into appropriate dimensions and characterized by Field-Emission Scanning Electron Microscope (FESEM) to identify the wear characteristics of each part of the components. In addition, the test methods of standard were also employed to probe into the change of the composition in the engine oils and fuel hoses to interpret the difference on the wear of components. RESULTS AND DISCUSSION Wear on Engine Components Figure 1. Schematic of Equipments of Engine Test Lab. Table 3. Test methods of engine operation and components Item Engine1-D100 Engine2-B2 Engine3-B5 Durability operation Full loading 500hour Emission test cycle FTP Transient Cycle Page 3 of 10 The wear analysis of the diesel engine components, including cylinders, piston rings, and needle valves were accomplished as shown in following sections. The dimension variation for the specific positions and detailed cut view on worn components were examined. Cylinder For engine operation, the friction mainly loss was between the piston ring and cylinder. The cylinders are made of cast iron with acceptable damping ability which is one of the best

4 materials used to make cylinder walls. Table 4 is the change of average measurement values for the diameter (Dy) in the impinging direction, side diameter (Dx), and overall change of average diameter (D0) of the cylinder in all test conditions. In general, after the engines run for a long-term operation, the surface of the cylinder will be worn and the material will be lost. However, the durability test results (see Table 4) depicted a significant reduction in Dy of the engine due to burning substances and reactants in the oil adhered to the impact surface or the contrast surface. Meanwhile, the distance variation of Dx bore diameter is insignificant, which means the biodiesel makes no difference on the wear of cylinder. SEM analysis was performed in order to evaluate the wear behavior on the cylinder. Table 5 shows three samples for SEM analysis were cut from the cylinder which was located in top dead center (1 st row), middle point of the stoke (2 nd row), and bottom dead center (3 rd row), separately. On the cylinder wall, there are many dents which are the marks left after the graphite peel off. The artificial oil-containing line is evident, meaning that after the durability test, there was no critical wear on the cylinder wall for detailed measurement. For the three engines examined, the dents in the D100 cylinder is significant, showing that B5 has better performance on wearing tests for other two engines. In addition, the smoothness of the cylinder using B5 for 500 hours is better than that of B2 as well as D100 as the surface wear is promotional to the running period. Table 4. The Dimension difference of cylinder liner before and after durability test (mm) (0hr vs. 500hr) Engine1-D100 Engine2-B2 Engine3-B5 Dx Dy D D0 (Roundness) Remark Bottom dead center (3 rd row) Piston Ring Piston rings, consists of compression ring and oil ring, prevent the air leakage from the clearance between piston and cylinder wall. The experimental results indicate that piston rings of all tested engines have slight decrease of the dimension due to the wear during durability test process. The decrease dimension is mainly due to the polishing effect on the surface of the piston ring under normal operation. However, the dimension of piston ring is probably increased when the carbon deposits are not easily washed. Table 6 shows the present of carbon deposits obviously between the contact surface of piston and the first compression ring. The wear of the first ring is due to the abrasive wear and surface fatigue. Depending on the operation duration, the surfaces conditions are different. It can be concluded that there is no serious wear found on the surface regardless of using D100, B2 as well as B5. For second piston ring in D100 engine, the accumulation of carbon deposits is evidence and the surface of the carbon deposits show the considerable protuberance and cracks. In contrast, the carbon deposits exist in B5 engine as well, but the surface is more uneven and has peeled off. Comparing the contact surface between the piston ring and cylinder, it was observed fretting wear behavior on the surface in D100 engine and B2 engine which are more than that in the B5 engine. Finally, both the contact surfaces of the third piston ring on the D100, B2 and B5 engine are very smooth and there are no clear wear reviewed as the surfaces are protected by oil between the surfaces of the piston ring. Table 6. The microscopic surfaces of the piston rings after durability tests Table 5. The microscopic surfaces of cylinder wall Engine1-D100 Engine2-B2 Engine3-B5 Ring NO.1 (outside) Engine1-D100 Engine2-B2 Engine3-B5 Top dead center (1 st row) Ring NO.2 (inside) Middle (2 nd row) Page 4 of 10

5 Ring NO.2 (outside) Ring NO.3 (outside) * Right side (outside) of the piston ring is contacted with cylinder wall. Needle Valve The function of the nozzle is to nebulize and inject the fuel into the combustion chamber for the diesel engine. The solenoid valve and spring control the movement of needle valve. According to the experimental results, the outer diameters of needle valves decrease insignificant without excess the tolerance range for three engines. Table 7 shows the inspected surfaces at X1, X2 and X3 position after the 500 hours test of Engine3-B5. Due to the surfaces of X1 and X2 do not contact with the inner wall of nozzle directly, the surface wear is not evident. The single contacted area for the nozzle, as shown by X3, the surface has little abrasive wear with ignorable depth. Examined with detailed measurement for the outer diameter, there is no serious wear on the surface of X3. Table 7. The microscopic surfaces of the Engine3-B5 needle valves 500 hr (After durability test) Remark X1 X2 X3 Machining direction Machining direction Slide direction carbon particles extracted from the tested pistons. The weight of carbon deposit from the piston of B2 and B5 engine, both at the full-load 500 hours test, are larger than the D100 engine by 21% to 7% approximately. The result implies that the amount of carbon deposits adhered to the piston of B2 engine is more than that of D100 engine and B5 engine. The reason that there is lower deposit buildup is due to the higher solubility of the biodiesel. This carbon buildup is being dissolved by the added biodiesel and washed away. The amount of carbon deposits is different according to the fuel quality. Table 8. Weight of carbon deposit on piston surfaces Engine1-D100 Engine2-B2 Engine3-B5 Weight (g) Surface of piston The composition of the carbon deposit particles is analyzed by Energy Dispersive Spectrometer (EDS), qualitative and semiquantitative method. Figure 3 shows the results of composition analysis of the carbon deposit particles of Engine3-B5 after 500 hours test. Five areas of carbon deposit, extracted from the piston, are randomly picked for analysis. It is shown that the edges of the particles are mostly blunt. The comparison of the composition of the carbon deposits from the three engines is shown in Figure 4. The piston carbon deposits are mostly composed of carbon, and oxygen, while there is more oxygen in the carbon deposits from the B2 engine. This is because the methyl ester in the biodiesel contains more oxygen elements. As a result, the oxygen elements in the deposits are more than those in the D100 engine after the burning process. Besides, due to the additives used in diesel fuel and engine oil, EDS also inspects some zinc, phosphorous, sulfur, and calcium. For B5 engine, the fewer above elements has been found in the carbon deposits. As a result, sulfur and phosphorous decreased when biodiesel blend percentage increased. We could only find 0.39% of Sulfur and could not find out the phosphorous of carbon deposits of Engine3-B5. Carbon Deposits on Engine Components The subsections below show the weight and microscopic observation of the accumulated carbon deposits around piston and the analysis of the surface composition of the components. Piston The carbon deposits accumulated on the piston is extracted for weight measurement. The piston is immersed in acetone and washed by the ultrasonic cleaner. The carbon particle is then filtered from the acetone solution. Table 8 shows the weight of Page 5 of 10 Figure 3. Appearance of carbon deposits on piston head (Engine3-B5)

6 content(%) Page 6 of 10 D hr B2-500hr B5-500hr C O P S Zn Ca Al Elements Figure 4. Comparison between test engines for the composition of carbon deposits on piston head Fuel Injection Nozzle The fuel injections of this engine have seven spray orifices and all of them are at the same level. The nozzle appearance by the SEM is shown in Table 9, the nozzle of the engine for B5 biodiesel is not blocked by the carbon deposits after the 500 hours test as the carbon deposits around the spray orifices are loose and unstacked. In contrast, more carbon deposit is found around the nozzle orifices in D100 engine. Table 9. The microscopic observation of fuel injection nozzle orifices (after durability tests) Nozzle tip Spray orifice Engine1-D100 Engine2-B2 Engine3-B5 The Influence on Engine Oil At each engine maintenance stage during the process of durability tests, the engine oils were changed and assayed the composition to interpret the wear on the B5 engine. The replacement cycle of Engine3-B5, Engine1-D100 and Engine2-B2 is 125 hours. The test results are shown in Table 10 and the description is as follows: (a) Viscosity Fuel dilution or deterioration of the engine oil can be obtained through examining viscosity. Comparing the viscosity before and after the durability tests, the deterioration of Engine3-B5 was more evident. The viscosity indexes showed less difference indicating there was no obvious deterioration in the engine oils. (b) Total Base Number and Total Acid Number These two items reflect the concentration of the cleanness of the fuel, anti-oxidation, and part of the anti-wear additive to determine if the alkalinity was decreased and the lubricant should be replaced. The test result showed that B2 biodiesel influenced less on the total base number, but B5 had the slightly higher than both of D100 and B2.The higher TBN indicate the more stability and durability of lube oil. Furthermore the total acid number is lower than that of diesel whether under stable durability tests. The reason is that biodiesel contains anti-oxidant additives. (c) Additives In general, engine oil containing 10% to 25% additives increases the performance of lubrication. The results showed that the difference content of P, Zn, Ca, Ba between new and used oils was within the reasonable range, indicating that the engine ran smoothly. (d) Metallic Debris The elemental analyses of Al and Fe reflect the wearing of the engine components. Cr reflects the wearing of piston ring and cylinder liners while Tin, copper and lead reflect that of bearing and titled pads. Comparing between the new and used lubricants, there was more Fe in the oils of Engine3-B5 and Engine1-D100 under full-load durability tests. The results showed that under full-load operation, the components, such as cylinder, crank, and piston rings, were worn more seriously. Oil sample Table 10. Test result of the engine oils New (at 0hr) Engine1- D100 (at 500hr) Engine2- B2 (at 500hr) Engine3- B5 (at 500hr) Test item Viscosity, cst, Viscosity, cst, Viscosity Index Total Acid Number, mgkoh/g Total Basic Number, mgkoh/g Fuel Dilution, <0.7 <0.7 <0.7 <0.7 Remark D445 D664 D2896 D3524

7 wt% N-pentane Insoluble, wt% Toluene Insoluble, wt% P, wt%, XRF Zn, wt%, XRF Ca, wt%, XRF Ba, wt%, XRF Mg, ppm, Cr, ppm, Cu, ppm, Fe, ppm, Al, ppm, Sn, ppm, Pb, ppm, N.D< N.D< N.D< N.D<3 N.D<3 N.D<3 N.D<3 N.D<3 5.1 N.D< N.D< N.D<3 N.D<3 N.D<3 3.6 N.D<3 N.D<3 N.D<3 N.D<3 N.D<3 4.3 N.D<3 3.9 Fuel Supply System In this paper, the rubber fuel hoses of Engine3-B5 under 0 hour and 500 hours were inspected following test standards in Taiwan. Table 12 shows the change of hardness Page 7 of 10 D893 D4927 D5185 The fuel supply system of the diesel engine consists of a fuel tank, fuel pipes, fuel filters, and a low pressure pump. During the durability tests, the fuel supply simulated as the way of onroad vehicles. Diesel fuel, B2 and B5 biodiesel were supplied respectively for the durability tests. The pressure and temperature were measured at the inlet and outlet of the filters and the outlet temperature remained within 40±5. After the durability tests, the fuel tanks and fuel pipes were dissected to evaluate the corrosion of the tanks, pipes and filters caused by biodiesel. Table 11 shows the dissection of the tanks, pipes, and filters of the three engines after the durability tests. It was observed that all the test fuels (D100, B2 and B5) made no corrosion to both the fuel tanks and the fuel pipes. Furthermore, there were not many impurities on the filters. The pressure between inlet and outlet of the filter of Engine3-B5 was 798mmH 2 O. Compared with that of Engine1-D100 and Engine2-B2 under full-load durability test for 500 hours, the differential pressure was smaller Engine3-B5. for the inlet and return hoses, percentage change in elongation rate and volume. It was found there was no evident difference caused by the low pressure operation. For the tensile strength, the properties of biodiesel increased the change in hardness after 500hr operation. In brief, there were no breaks, leaks, or deformation on rubber fuel hoses. The research posted in literature also indicated that using B20 biodiesel for 500 hours operation did not cause the fuel hoses hardening or broken [11]. Fuel tank Fuel pipe Fuel filter Table 11. Components of the fuel supply system (after durability test) * PD: pressure difference Engine1-D100 Engine2-B2 Engine3-B5 Inlet/Outlet PD 792mmH 2 O Inlet/Outlet PD 785mmH 2 O Inlet/Outlet PD 798mmH 2 O Table 12. Comparison of the rubber fuel hoses of Engine3 before and after 500hr durability test Test item Inlet Hose Return hose Remark Change in Hardness (Type A/1 sec) Percentage Change in Tensile Strength (%) Percentage Change in Elongation Rate (%) Percentage Change in Volume (%) Engine Performance The engine performance was evaluated by the test procedure for SAE J1995 requirement. Figure 5 and Figure 6 show the engine torque variation for B2, B5 and D100 fuels and the corresponding durability tests with respect to engine speed. The torque variation for B5 biodiesel at full speed is under ±2% compared with using D100 fuel. For the speed under

8 1200 rpm, however, the variation is more than ±2% but in the range of ±3%. This shows that B5 biodiesel has little influence on engine torque and durability performance. The power difference has the same trend as torque performance. Figure 7 shows the change of fuel consumption, having the same conclusion as engine performance. For example, with speed lower than 700 rpm, the difference of fuel consumption of Engine3 in B5 biodiesel before and after the durability tests, 0 hour and 500 hours, is about 2.5%. For other speed, the variation is within ±2%. In summary, the engine performance and fuel consumption in B5 biodiesel for various durability tests are within ±3%. Torque difference(%) D100_500hr B2_500hr B5_500hr Engine Speed(rpm) Figure 5. The effect on engine torque using different fuels under durability tests (SAE J1995) Power difference(%) D100_500hr B2_500hr B5_500hr Engine Speed(rpm) Figure 6. The effect on power using different fuels under durability tests (SAE J1995) FC difference (%) D100_500hr B2_500hr B5_500hr Engine Speed(rpm) Figure 7. The effect on fuel consumption using different fuels under durability tests (SAE J1995) Exhaust Emissions and Fuel Consumption The main pollutants emitted by diesel vehicles are nitrogen oxides (NOx) and particular matter (PM). Figure 8, Figure 9 and Figure 10 show the diesel emissions analyzed in this paper. The amounts of CO, HC, and NMHC from the diesel engine were much lower, about 1% of the emission standard. The emission of CO and HC was slightly increased; it indicated the little effect on deterioration after the durability tests. However, the NOx emission was 92% of the standard and the emission of PM is 95% compared with the standard which is 0.1 g/bhphr. Based on the emissions of engine1-d100. From the figure 10, it was found that the NOx of Engine2-B2 for 0 hour and 500 hours increased slightly and there was no obvious difference on PM, CO 2 and fuel consumption. The NOx emission of Engine3-B5 for 0 hour and 500 hours decreased a little and there was no obvious difference on PM, CO 2, and fuel consumption. These results indicate that B5 biodiesel affected the emissions of diesel engines slightly under durability tests. There was limited effort of the low percentage biodiesel on the emissions of PM and NOx. According to past researches, the decrease of emissions due to biodiesel was related with the percentage of the biodiesel and the emission control strategy. Using B100 biodiesel and old diesel vehicles fueled with biodiesel have the best effect upon the decrease of the exhaust emission. Page 8 of 10

9 emission(g/bhp-hr) B2-0hr B5-0hr D100-0hr B2-500hr B5-500hr D hr because of its increased on the CO, HC and NMHC emissions. But higher blend shows the lower increased compare to the D100 at the both 0 hour and 500 hour conditions. There was the most advantage of the decrease of PM which compare with D100 and B5 was up to 13.9% that after 500 hour durability test Engine1-D100(0hr&500hr) Engine3-B5(0hr&500hr) B5 vs D100(500hr) Engine2-B2(0hr&500hr) B2 vs D100 (500hr) B2 vs B5(500hr) CO HC NMHC Figure 8. CO,HC and NMHC emission of test engines before and after durability tests (FTP Transient Cycle) emission difference(%) emission(g/bhp-hr) CO2 FC B2-0hr B5-0hr D100-0hr B2-500hr B5-500hr D hr Figure 9. CO 2 and fuel consumption(fc) of test engines before and after durability tests (FTP Transient Cycle) 0.0 CO HC NMHC Figure 11. The effect on CO,HC and NMHC emission using different fuels under durability tests (FTP Transient Cycle) emission difference(%) Engine1-D100(0hr&500hr) Engine1-D100(0hr&500hr) B5 vs D100(500hr) Engine2-B2(0hr&500hr) B2 vs D100 (500hr) B2 vs B5(500hr) CO2 NOx PM FC emission(g/bhp-hr) B2-0hr B5-0hr D100-0hr B2-500hr B5-500hr D hr Figure 12. The effect on CO2,NOx,PM emission and FC using different fuels under durability tests (FTP Transient Cycle) CONCLUSIONS NOx Figure 10. NOx and PM emission of test engines before and after durability tests (FTP Transient Cycle) Figure 11 and Figure 12 show the percentage changes of using different biodiesel blend under durability tests. There were some disadvantages of using biodiesel whether B2 or B5, PM The results obtained in this work indicate the influence of B5 biodiesel on diesel engines and answer the public s concerns in order to gain more trust and support from vehicles users in Taiwan for the use of biodiesel. The conclusions are presented detailed as follows. After the durability tests, either for the 500hr long term fullload operation B5 biodiesel did not have obvious influence on the dimensions of the engine components. From the microscopic observation, on the other hand, the wear behavior Page 9 of 10

10 of the piston ring of the engine using B5 biodiesel was slightly better than that of using B2 and D100 diesel fuel. More carbon deposits on the top of piston were observed for B2 fuel. However, the results of fewer carbon deposits on the cylinder wall and nozzle for using B5 were as in contrast. Such outcome showed that the carbon deposits on the top of the piston of D100 engine were looser and could be easily peeled off because of generated from burning of engine oil. The amounts of phosphorous, sulfur and zinc of carbon deposits for B5 biodiesel were fewer than those of D100 as well as B2 and the deterioration of lubricant was slower. This showed that the less wear loss for the engine components than those of D100 and B2. With respect to the engine emission and performance, B5 biodiesel has slight effects on the exhaust emission under durability tests. The changes of engine performance and fuel consumption were within ±3%. REFERENCES 1. C.A. Sharp, S.A. Howell, J. Jobe, 2000, The Effect of Biodiesel Fuels on Transient Emissions from Modern Diesel Engines, Part I Regulated Emissions and Performance, SAE paper V. Camobreco, J. Sheehan, J. Duffield, M. Graboski, 2000, Understanding the Life-Cycle Costs and Environmental Profile of Biodiesel and Petroleum Diesel Fuel, SAE paper M.A. Kalam, H.H. Masjuki, 2002, Biodiesel from palmoil - An analysis of its properties and potential, Biomass Bioenergy, Vol. 23, pp K.S. Wain, J.M. Perez, E. Chapman, A.L. Boehman, 2005, Alternative and low sulfur fuel options: Boundary lubrication performance and potential problems, Tribol. Int., Vol. 38, pp A.K. Agarwal, J. Bijwe, L.M. Das, 2003, Wear assessment in a biodiesel fueled compression ignition engine, J. Eng. Gas Turbines Power, Vol. 125, pp A.K. Agarwal, J. Bijwe, L.M. Das, 2003, Effect of biodiesel utilization of wear of vital parts in compression ignition engine, J. Eng. Gas Turbines Power, Vol. 125, pp A.K. Agarwal, 2005, Experimental investigations of the effect of biodiesel utilization on lubricating oil tribology in diesel engines, Proc. Inst. Mech. Eng. Part D J. Automob. Eng., Vol. 219, pp S. Kaul, R.C. Saxena, A. Kumar, M.S. Negi, A.K. Bhatnagar, H.B. Goyal, A.K. Gupta, 2007, Corrosion behavior of biodiesel from seed oils of Indian origin on diesel engine parts, Fuel Process. Technol., Vol. 88, pp Yasunori TAKEI, 2007, JAMA s Recommendation on Bio Diesel Specification, The Fourth Meeting of the APEC Biofuels Task Force, Oct , Bangkok, Thailand. 10. Automotive Research & Testing Center, 2008, The Durability Test of Biodiesel Engine (B2) Final Report, authorized by Industrial Technology Research Institute. 11. Industrial Technology Research Institute, 2006, Development & Dissemination of Bio-fuel Technologies, final report, 95-D0133. Industrial Technology Research Institute, 2006, The Environmental Benefits and Strategy Analysis of the Biodiesel Vehicles, final report, EPA-95-FA01-03-A124. CONTACT INFORMATION Yong-Yuan Ku Project Engineer Automotive Research and Testing Center, Taiwan tom@artc.org.tw Ke-Wei Lin Project Engineer Automotive Research and Testing Center, Taiwan linkewei@artc.org.tw Ya-Lun Chen Project Engineer Automotive Research and Testing Center, Taiwan ellen@artc.org.tw Ching-Fu Liao Project Engineer Automotive Research and Testing Center, Taiwan chingfu@artc.org.tw ACKNOWLEDGMENTS The authors would like to acknowledge the financial support by Bureau of Energy, Ministry of Economic Affairs (R.O.C.) under contract 102-D0107 which has made this report successful. Page 10 of 10