International Journal of Automotive Technology, Vol. 17, No. 2, pp. 289−298 (2016) DOI 10.1007/s12239−016−0029−6

Copyright © 2016 KSAE/ 089−11 pISSN 1229−9138/ eISSN 1976−3832

COMPREHENSIVE EXPERIMENTAL STUDY ON THE EFFECT OF BIODIESEL/DIESEL BLENDED FUEL ON COMMON-RAIL DI DIESEL ENGINE TECHNOLOGY S. JAROONJITSATHIAN1, 2)*, N. NOOMWONGS1) and K. BOONCHUKOSOL1) 1)

Department of Mechanical Engineering, Chulalongkorn University, Phayathai, Bangkok 10220, Thailand 2) PTT Research & Technology Institute, PTT Public Company Limited, 555 Vibhavadi Rangsit Rd., Chatuchak, Bangkok 10900, Thailand (Received 27 March 2015; Revised 10 July 2015; Accepted 11 August 2015)

ABSTRACT−This research work aims to study the aspects of using biodiesel or FAME as a component blended in diesel fuel for common-rail DI engine technology. The specific engine experiments were designed for LD commercial engine [Toyota 2KD-FTV] to understand engine combustion process, engine performance and thermal efficiency when applying FAME blended fuel. In addition, the exhaust emission in HD diesel engine [HINO J08E] was evaluated by standard HD engine emission ESC and ELR test cycles. Furthermore, the severe 400-hour of HD engine durability tests for determining the limitation on using FAME blended fuel, have been conducted with B0, B10, B20 and B50. The result shows that using of FAME blended fuel in the HD common-rail DI engine, can be applied with some guidelines experimentally discovered by this research such as filter plugging that may occur when the content of biodiesel is up to 20 % or higher, and the critical fuel injector surface polishing wear, can be observed from B50 sample. In general, the higher biodiesel content will contribute to lower power output as well, thus too high biodiesel content will cause low engine power output. KEY WORDS : FAME, Biodiesel, Engine combustion, Engine performance, Engine durability test, Emission test

used in many countries especially those producing oil crops. Usually FAME, can be derived from various kind of feedstock such as rapeseed, soy bean, palm, jatropha, cotton or karanja and so on. Wide varieties of biodiesel’s originality leading to fuel quality differences, for example oxidation stability, cold flow property or pour point and cetane number, etc. However, there are some common fuel qualities of FAME which are mainly suitable for use as a diesel fuel such as viscosity, density, high quality fuel lubricity enhancer, high cetane number and sulfur free. The most promising raw material of FAME production, is palm oil in Thailand as well as Malaysia and Indonesia. Palm oil methyl ester has very high oxidation stability when compared with rapeseed and soy bean regarding its high saturated vegetable oil. But, its cloud point and cold flow properties are too high to use in cold climate. In addition, Palm oil is one of the best cooking oil for fried food, thus some people disagree to use food as a fuel. By the way, a net importer of crude oil like Thailand, still needs energy security policies to reduce the dependency on imported oil. Thus, Thailand has announced the B3.5 – B7 mandatory use nationwide since early 2014. Basha et al. (2009) have been reviewing the biodiesel papers and commented that most biodiesel gives shorter ignition delay than that of diesel fuel, and also gives lower peak of heat released rate in direct injected diesel engines.

NOMENCLATURE FAME : fatty acid methyl ester Common-rail DI : common-rail direct injection Bsfc : brake specific fuel consumption BTE : brake thermal efficiency IMEP : indicated mean effective pressure LD Engine : light-duty engine HD Engine : heavy-duty engine ECE R85 : European Commission – engine performance test code of conduct ESC : european stationary cycle ELR : european load response PM : particulate matter NOx : Oxide of Nitrogen TGF : total groove flocculation, % JPI : Japan Petroleum Institute TAN : Total Acid Number CRC : Coordinating Research Council WWFC : 5th Edition World-wide Fuel Charter,

1. INTRODUCTION Biodiesel or Fatty Acid Methyl Ester (FAME) is widely *Corresponding author. e-mail: [email protected] 289

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In addition, FAME always has combustion duration periods shorter than those of straight vegetable oil. Chauhan et al. (2013) studied on the use of Karanja biodiesel in mechanical fuel injected diesel technology and founded that the higher bulk modulus of elasticity of biodiesels, results in advancing the fuel injection timing that will cause higher NOx emission when compared with diesel fuel. Sharon et al. (2012) conducted the direct injection diesel test rig with used palm oil methyl ester at constant engine speed and concluded that FAME always has shorter ignition delay when compared with diesel and higher content of FAME results in lower engine power output by which the B75 and B100 gave 10 % and 19 % power reduction at full load respectively. Palash et al. (2013) had reviewed the formation of NOx from using biodiesel and concluded that the higher NOx formation from biodiesel, composing of thermal NOx and prompt, may be a contribution between the presence of Oxygen leading to higher heat released combustion, the high cetane number and bulk modulus of elasticity leading to the shorter ignition delay and the higher adiabatic flame temperature. While, additional EGR is the most effective way to reduce NOx. An et al. (2012) has conducted an experiment on Euro IV Common-rail DI with biodiesel derived from wasted cooking oil and reported that FAME contributes to shorter burn duration and also lower heat released rate when compared with diesel especially at full load. The reduction in CO2 and HC has been observed. Can (2014) studied the effect of 5 % and 10 % FAME blended fuels on the single cylinder diesel engine with N.A. system and found that FAME helps reduce the ignition delay and thermal efficiency while increasing the burn duration. Al_Dawodi and Bhatti (2014) can estimate the result from simulation and can also achieve the good correlation with the engine experiment by concluding that soybean methyl ester helps reduce 43 % smoke and result in 14 % higher specific fuel consumption. Harch et al. (2014) also modeled the N.A. mechanical fuel injection engine for FAME blended fuel study and found that B10 can deliver the highest performance and efficiency, while reducing the emission. Kuti et al. (2013) investigated the FAME spray characteristics in common-rail DI diesel engine which related to the engine combustion and concluded that FAME has shorter ignition delay and shorter flame lift-off length, The oxygen content in the FAME helps reduce the soot formation effectively. Mohan et al. (2014) studied the FAME characteristics in constant volume chamber and commented that B100 has higher spray tip penetration and velocity, while narrowing the spray angle when compared with B20. Moreover, B100 has lean equivalence ratio along the axial direction of spray which contributes to the lower soot formation in exhaust gas. Rajasekar and Selvi (2014) reviewed comprehensively on biodiesel combustion and concluded that the behavior of biodiesel combustion will relate to the engine technology whether in combustion and

or emission. Anyway, they stated that biodiesel could be used as the C.I. engine alternative fuel. Bari (2014) conducted an experiment on a MAN metrobus with mechanical fuel injection system running with biodiesel B20. The result was concluded that B20 gives a comparable vehicle performance as well as combustion characteristics. The increasing of NOx emission was observed, whereas PM, CO and HC were decreased. According to the reviewed literatures, there are none of research articles that cover all aspects of biodiesel utilization. Therefore, this research work is emphasis on the conclusion of the biodiesel utilization for common-rail DI diesel engine by covering the fuel properties analysis including limit of blending, engine performance change with the content of biodiesel blended, fuel combustion, mainly on common-rail DI, exhaust emission followed by a European standard protocal and the most important section which is engine durability test. The design of engine durability test is intended to accelerate the severely effects of biodiesel oxidation on engine parts for 400-hour operation.

2. FUEL PROPERTIES All engine experiments were conducted by using diesel/ biodiesel derived from palm oil. The antioxidant was treated with B100 before being blended with diesel fuel to achieve the target of 20-hour oxidation stability according to the EN15751 analytical method. The blended fuels have no lubricity additives, since the FAME itself already helps improve the fuel lubricity. The heating value of FAME blended fuel is lower, when higher FAME is applied regarding the 14 % lower heating value of B100 compared to diesel fuel. By the way, the cetane number measured by ASTM D613 of FAME is higher than diesel. WWFC limits the content of water in blended fuel to less than 200 ppm (ASTM D6304), while the TAN is limited to 0.08 mgKOH/g (ASTM D664).

3. ENGINE PERFORMANCE & THERMAL EFFICIENCY LD Engine Performance test standard ECE R85 was performed in comparison between B0 vs B5 and B0 vs B100 by calculating their brake thermal efficiency, power and specific fuel consumption Figure 1, the new engines were removed from the rented vehicles for installing in the engine test bench and run-in for 10 hours before starting the ECE R85 engine performance test. Each engine was compared in 2 fuel basis; one engine compared base diesel with B5, while the other compared base diesel with B100. The installation and data correction were made in accordance with ECE R85 regulation. The instrument specifications are listed in Table 1. The test engine, Euro III Common-rail Direct Injection –

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Table 1. Test equipment specifications. Equipment

Specification

Dynamometer

AVL DC, 240 kw

Fuel consumption meter Engine coupling Gear shift

AVL 735, flex-fuel via transmission 4th gear

Fuel conditioning unit

AVL 753 Figure 2. Performance comparison B0 vs B5 – ECE R85.

Figure 3. Performance Comparison B0 vs B100 – ECE R85. Figure 1. Test bed configuration for LD engine test.

Table 3. Engine performance & efficiency at 2,000 rpm. Parameter

2KD-FTV, has the maximum common-rail fuel pressure controlled at 160 MPa. This engine control version has a pilot injection before main injection during idling and part load, at low to medium engine speed, which help reduce combustion noise during cold run. Detailed specifications of the test engine are shown in Table 3. At 2,000 rpm, the maximum torque output location, B100 performs about 16 % less power, 16 % higher brake specific fuel consumption resulting from the 14 % lower in heating value, while 2 % better brake thermal efficiency. For B5, all parameters were almost comparable with base diesel, since the physical and chemical properites are comparable with B0.

B5 vs B0

B100 vs B0

− 0.85

− 15.77

Bsfc

0.65

15.06

BTE

− 0.01

2.33

Max. power

Remark

At 3,600 rpm, the maximum torque output located, B100 performs about 6 % less power, 16 % higher brake specific fuel consumption, and 1 % better brake thermal efficiency. B100 actually has 14 % lower in heating value, by the way, the only 6 % less in power may be effected from both physical and chemical fuel properties.

4. ENGINE COMBUSTION ANALYSIS Table 2. LD engine specifications. Engine specification

TOYOTA, 2KD–FTV

Configuration

In-line, 4 cylinders

Fuel injection 3

Common-rail DI 3

Volume, cm (in )

The FAME blended fuel combustion has been studied via AVL IndiCom – The high resolution combustion indicating system by a piezo-electric pressure sensor embedded inside glow plug adapter at cylinder no.4. In addition, the high

2.494 (152.2) 2

2

Bore × Stroke, mm (inch ) 92.0 × 93.8 (3.62 × 3.69)

Table 4. Engine performance & efficiency at 3,600 rpm. Parameter

B5 vs B0

B100 vs B0

Max. power

0.07

− 6.10

Max. torque, [SAE–NET] 200 Nm@1,400 ~ 3,200 rpm

Bsfc

2.01

16.49

Emission standard

BTE

− 1.34

1.08

Compression ratio

18.5 : 1

Max. power, [SAE–NET] 75 kW@3,600 rpm Euro 3

Remark

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precision speed encoder was equipped with the crankshaft to determine the angle position up to 0.1 degree. The values shown in the figures were averaged from 100 consecutive cycles. At full load conditions, the 3 selected engine speeds, of 1,200 rpm, 2,400 rpm and 3,600 rpm, were measured. Their cylinder pressure and heat release were compared with base diesel, B5, B15, B20 and B50. The result are shown in Figure 5, only insignificant differences between B0 and B50, have been observed. The combustion parameters were analyzed based on the cylinder pressure data, all tested fuels have comparable cylinder pressure data as an effect of common-rail DI. From Figure 6, biodiesel blended fuel helps shorten the ignition delay especially at low speed conditions i.e. 1,200 and 1,800 rpm. In addition, biodiesel blended fuels can improve the burn duration or burn faster than diesel fuel, while the IMEP of higher biodiesel blended fuel is lower than diesel fuel according to the lower heating value. The maximum rate of pressure rise or the source of combustion noise comparing biodiesel blended fuel with diesel fuel, has no difference. For part load, 3 load ranges were performed for combustion analysis i.e. 40 Nm, 75 Nm and 110 Nm by varying the 3 engine speeds: which were 1,200 rpm, 2,400 rpm and 3,600 rpm. Almost the same result as the full load condition was shown. There is very slightly difference when comparing base diesel with B50. It should be noted that result at 1,200 rpm is different from 2,400 rpm and 3,600 rpm since there is a pilot injection.

Figure 4. Cylinder pressure & heat release profile.

Figure 5. Combustion analysis of biodiesel blended fuel at full load condition.

5. HEAVY-DUTY ENGINE EMISSION TEST The heavy-duty (HD) common-rail DI engine was installed in the engine test bench for measuring its emission regarding to ESC and ELR cycles by comparing the base diesel with B5, B10, B20 and B50. The engine with a special adapter and a modified exhaust pipe, was connected to the engine dynamometer, Furthermore, a specifically water-cooled intercooler was installed to allow for higher engine performance test and the high speed engine durability test. The exhaust back pressure control valve is adjusted until the output power is acceptable, while installing an actual 200 liter fuel tank inside the test bench for simulating the fuel circulation system like an actual vehicle (Figure 6). The period of 1 cycle high speed engine durability test, is about 3.3 hours determined by the capacity of fuel tank and the fuel consumption rate (about 60 liter per hour). The results in Figure 7 show that the higher FAME content did not explicitly contribute to the change in HC and PM emission. However, the smoke reduction is wellcorrelated to the increase of FAME content; B50 can

Figure 6. Test bed configuration for HD engine Test.

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Table 5. Equipment specification. Equipment

Specification

Dynamometer

AVL AC, 400 kw

Fuel consumption Engine coupling Gear shift Emission analyzer

AVL 733 Via transmission 4th Gear AVL AMA i60

Fuel conditioning

AVL 753

Table 6. HD engine specification. Engine specification

HINO J08E

Configuration

In-line, 6 cylinders

Fuel injection

Common-rail DI

Volume, cm3

7,684 2

2

Bore × Stroke, mm (inch )

112 × 130

Compression ratio

18.0 : 1

Max. power, [SAE–NET]

184 kw@2,500 rpm

Max. torque, [SAE–NET]

739 Nm@1,500 rpm

Emission standard

Euro 3

Figure 9. % emission comparison vs B0 by ESC, ELR. expected to lower than that of diesel fuel as studied by Lee et al. (2013) but the ESC cycle are actually composed of 13 speeds and loads measuring conditions which are determined by full load curve. The curve of B20 and B0 are different, thus the results may not directly compared. Figure 8, the NOx and CO were not dominated by the higher FAME content. NOx content in common-rail DI engine was not influenced by the higher bulk modulus of the FAME like the mechanical fuel injection system, thus it was not changed when FAME content was increased.

6. HD ENGINE DURABILITY TEST

Figure 7. Emission concentration ESC / ELR.

The HD engines were tested with 4 different fuels namely base diesel, B5, B10 and B20 by running a pre-determined severe test condition for 400 hours. The test condition is always run at full load 2,500 rpm for 10 hours a day, following with a soak of empty fuel tank for 14 hours. The 200 liter standard fuel tank from a truck, was removed and installed in the test bench for accelerating the high fuel return temperature up to 90 oC especially when the fuel level is almost empty. The 10-hour cycle is composed of 3 loops, each loop consume about 190 liters of the fuel. OEMs believe that this critical running condition is the best condition for evaluating the effect of using bio-fuel on engine part

Figure 8. Emission concentration according to ESC. significantly reduce smoke by 57 % when compared with the base diesel. PM of higher biodiesel blended fuels are

Figure 10. Severity of engine durability test cycle.

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Figure 11. Filter plugging tendency on FAME blended fuels. deterioration. The total fuel consumption for each 400-hour test, is about 22,800 liter where it could be compared with running the vehicle on-road of about 70,000 km. However, the extremely severe running condition results in the higher part wear, deposit formation and used oil degradation. From Figure 11, the filter plugging tendency of the 400hour HD engine durability test, shows that the higher FAME blended fuel will significantly result in the shorter filter plugging as seen from B20 and B50. A further investigation was done by extracting the main filter paper and comparing the B0 with B20, as seen in Figure 12. The only difference in appearance when comparing between B0 and B20, is the darker color deposit of B20. In the previous research work, the filter element was inspected by SEM as seen in the Figure 13. However, the result is not clear, the further study is needed for deposit formation of FAME blended fuel. By the way, the filter plugging problem can be solved

Figure 12. Filter papers after durability test B0/ B20.

Figure 13. Deposit in filter elements by SEM (Jaroonjitsathian et al., 2009).

Figure 14. Piston detergency rating after durability test. Table 7. Diesel piston rating result. Piston merit rating

B0

B10

B20

B50

TGF (%) [< 60 %]

28.3

40.0

39.0

29.6

Underside [> 6.0]

9.7

9.6

9.7

9.6

easily by changing fuel filter. After running the 400-hour of engine durability test, each engine was disassembled for overall part inspection by professional rater. The standard piston rating according to JPI–5S–15–05 JPI Diesel Piston Rating Method, was performed for comparing the cleanliness of FAME blended fuels with base diesel. The most critical part of diesel piston rating in accordance with the use of biofuel, are TGF and piston underside. The TGF can indicate how much deposit forms in the combustion chamber and clogs in the piston groove. The higher TGF accumulated in the groove reveals the higher tendency of piston rings to stick and ring-liner to wear. On the other hand, the piston underside deposit is the best indicator for engine oil degradation. When the engine oil degrades, the oxidized part of engine oil will stick to the piston underside surface. A severe condition of engine oil degradation can cause severe breaking of connecting rod. Based on the experiment, there were no correlations between the higher FAME content and the piston cleanliness. Fuel injection equipment, especially the injector is the most critical part when evaluating the effect of using biofuel in the common-rail Di engine technology. Formerly, when the mechanical distributor type fuel injection technology was widely used in LD engine, the most sensitive part for fuel quality, were cam plate and roller which required fuel lubricity property for lubricating the whole metal-to-metal contact parts inside fuel pump. When the current diesel technology with common-rail DI becomes common both in LD and HD engines, the most critical part for fuel quality are the injector nozzle holes, plunger and the command piston. After 400 hours of

COMPREHENSIVE EXPERIMENTAL STUDY ON THE EFFECT OF BIODIESEL/DIESEL BLENDED FUEL

Figure 15. Common-rail injector part inspection. engine durability tests, the fuel injection system of each engine was disassembled, and visual inspection was performed. From all parts inside the injector and supply pump, the only part sensitive to FAME blended fuels, is the command piston as seen in Figure 15. Only the command piston of B50 can be observed to have severe surface polishing wear which is the beginning of metal surface wear. 6.1. Used Oil Analysis The standard heavy-duty diesel engine oil grade API CH4, SAE 15w-40, was used for this severe engine test. The drain interval was set at 200 hours. The used oil analysis was performed to inspect the effects of FAME on fuel dilution and engine part wear. The results are shown in Figures 16 ~ 20. The used engine oil at each 200-hour drain interval, has the viscosity and TAN increased compared with the initial oil , however the viscosity at 100 oC and TAN, was still in the limit of its viscosity grade (12.5 ~ 16.3 cSt). The wear metal Fe, Cu and Al in the used engine oil, were analyzed and found that all wear metals detected in the used oil, were in the recommended limit from the OEM (100 ppm). Therefore, the used engine oil analysis result gives the information that FAME blended fuel up to B50, can be used in the HD engine with standard engine oil 15w-40 by controlling the drain interval to guarantee the viscosity and TAN quality.

Figure 17. TAN of used engine oil.

Figure 18. Fe wear metals from used engine oil.

6.2. Engine Parts Inspection Valve cover sludge formation was investigated and found that there was no abnormal sludge formation for all fuel

Figure 19. Cu wear metals from used engine oil.

Figure 16. Viscosity at 100 oC of used engine oil.

Figure 20. Al wear metals from used engine oil.

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Table 8. Test fuels properties. Properties Methyl ester content o

Specific gravity @ 15.6/15.6 C o

Standard

Unit

B0

B5

B15

B20

B50

EN 14078

% volume

0.0

5.4

15.8

22.0

53.0

0.8271

0.8295

0.8338

0.8367

0.8514

0.8094

0.8117

0.8159

0.8187

0.8331

ASTM D4052 3

Density at 40 C

ASTM D4053

kg/m

Cetane number

ASTM D613

Number

63.5

64.2

65.9

66.4

69.9

Viscosity at 40 C

ASTM D445

cSt

3.222

3.264

3.353

3.416

3.784

Sulfur content

ASTM D5453

%wt

0.0049

0.0048

0.0043

0.0040

0.0028

IP 391

%wt

15.9

15.0

13.6

12.4

7.8

Carbon

PTT In-house

% mass

85.99

85.39

84.79

83.59

80.00

Hydrogen

PTT In-house

% mass

14.01

13.91

13.81

13.61

13.01

Oxygen

PTT In-house

% mass

0.00

0.65

1.30

2.60

6.50

o

Aromatic content

H/C ratio

Calculation

1.955

1.955

1.954

1.954

1.952

O/C ratio

Calculation

0.000

0.006

0.011

0.023

0.061

Gross heating value

ASTM D240

J/g

46,178

45,888

45,347

45,095

42,919

Total acid number

ASTM D664

mgKOH/g

0.02

0.02

0.04

0.06

0.13

TAN growth

Modified ASTM

mgKOH/g

0.260

0.000

0.005

0.010

0.070

Water content

ASTM D6304

%wt

0.007

0.009

0.012

0.014

0.020

Lubricity by HFRR

CEC F-06-96

mm

445

216

237

227

197

Copper strip corrosion

ASTM D130

number

1a

1a

1a

1a

1a

Carbon residue

ASTM D4350

%wt

0

0

0

0.006

0.006

Pour point

ASTM D5950

°C

−3

−3

−3

−3

6

ASTM D86

°C

350.7

349.3

348.4

345.1

340.2

Water and sediment

ASTM D2709

%wt

< 0.025

< 0.025 < 0.025 < 0.025

< 0.025

Ash content

ASTM D874

%wt

< 0.005

< 0.005 < 0.005 < 0.005

< 0.005

Flash point

ASTM D93

°C

65

66

68.5

70

79.5

2.3

3.1

4.9

5.7

8.0

Distillation at 90 % recovery

Oxidation stability

EN 015751

g/m

3

samples. The bearing wear and corrosion were also inspected and concluded that there was no abnormal bearing wear either. The cam lobe wear and cylinder bore wear, were rated and proved that no abnormal wear occured. All items are rated according to the CRC Manual No. 21. The part inspections are shown in Figures 21 ~ 24.

7. CONCLUSION The FAME derived from palm oil has high cetane number – up to 69, while having a benefit of shorter ignition delay and burn duration especially when running the engine at low speed condition. The 14 % lower in heating value of FAME, directly result in the lower maximum engine power output when running by full load power as well as brake specific fuel consumption. Besides, the present of some oxygen content in the molecule helps improve a few

Figure 21. Valve cover sludge rating according to CRC manual no. 21.

COMPREHENSIVE EXPERIMENTAL STUDY ON THE EFFECT OF BIODIESEL/DIESEL BLENDED FUEL

Figure 22. Oil pan sludge rating according to CRC manual no. 21.

Figure 23. Cam lobe wear rating according to CRC manual no. 21.

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matter, while the smoke emission positively decreased in proportion with the higher FAME content i.e. 56 % for B50 when compared with B0. The severe HD engine durability tests were performed completely, and could be summarized as follows. The higher FAME blended fuels tend to cause the faster fuel filter plugging. In addition, there will be no sign of fuel dilution problem occurred even when running on B50, if the drain interval is maintained by controlling the viscosity at 100 oC stay within the engine oil grade. Furthermore, the piston cleanliness according to the JPI standard of FAME blended fuels, can be comparable to base diesel both TGF and piston underside. The only factor that limits the proportion of FAME blended in the diesel fuel, is the deterioration of fuel injection system part. The experimental result shows that 50 % FAME blended fuel causes deterioration of the command piston surface polishing wear. Meanwhile, the former experiment also revealed that the metal fuel tank corrosion occurred, when the level of emulsified water in the fuel were higher than 150 ppm. The FAME blended fuel, in conclusion, can be used in high pressure diesel common-rail DI Euro III engine with some concerns about FAME quality such as water and TAN. The proportion of FAME blended fuel up to B20, may not contribute to the different engine maintenance periods. While, the higher FAME blended fuel may result in the shorter engine maintenance schedule such as fuel filter plugging, engine oil drain and fuel injection system overhaul. ACKNOWLEDGEMENT−A part of these multiple tasks of engine experiment, has been technologically transfered from HINO Motors Ltd. All the experimental works have been done at PTT Research and Technology Institute in Thailand. I would like to thank for all PTT specialists, researchers, engineers and technicians who devoted their times for setting up and running the engines.

REFERENCES

Figure 24. Cylinder bore wear rating according to CRC manual no. 21. percent brake thermal efficiency at full load. The effects of FAME blended fuels on HD emission test, were evaluated by running the ESC and ELR engine test cycles. And the result was concluded that there was insignificantly change in the total hydrocarbon, the oxide of nitrogen, the carbon monoxide and the particulate

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