2004-01-0098
Effect of Various Lubricating Oils on Piston Deposits in Biodiesel Fueled Engines Thomas R. Sem Thermo-King Corporation, Division of Ingersoll Rand Copyright © 2004 SAE global
ABSTRACT Some customers of Transport Refrigeration Units (TRU’s) powered by 2.1 liter diesel engines in Europe are requesting to run 100% biodiesel fuel in their TRU’s. The purpose of this paper was to find a way for users of 100% biodiesel fuel to maintain reliable diesel engine operation through selection of a better engine lubricant. Diesel engines that have been run with 100% biodiesel fuel have been found to have deposits inside the engine that are not found when running on fossil petroleum diesel fuel. This paper examines the effect of various engine-lubricating oils on engines engines running with 100% biodiesel fuel. The comparison of various engine oils was accomplished by evaluating the piston skirt and ring groove deposits when running 4 different engine oils for 1000 hours each on identical engines that are fueled by Soybean Biodiesel fuel.
The result is a fuel with a viscosity slightly higher than 2 2 petroleum diesel (4.08mm /s for biodiesel, 2.7mm /s for petroleum diesel). These short chain oils are called methyl esters and there are several acronyms to describe these ‘short chain’ biodiesel fuels: SOME or SME (Soybean Oil Methyl Ester), RME (Rapeseed Methyl Ester, common in Europe. In the US rapeseed is called canola), and FAME (Fatty Acid Methyl Ester, a name which encompasses oils from many sources: all types of vegetable oils and animal fats).
INTRODUCTION WHAT IS BIODIESEL FUEL? - Biodiesel fuel is a diesel fuel substitute that is made from vegetable oils or animal fats. Vegetable oils that are used for cooking are too thick and viscous to run properly in a diesel engine and so a process was developed to take the very long molecules found in cooking oils, and shorten those molecules so the cooking oils can become similar in viscosity to petroleum diesel fuel. In vegetable oils, the glycerin portion of the molecule connects three long chain (mostly 18 carbons long) molecules together (Figure 1). The glycerin is what makes vegetable oil thick and sticky. The process of ‘transesterification’, which is the conversion of vegetable oil into biodiesel, releases those three long chain carbon molecules from being stuck together by the glycerin portion of the vegetable oil. In order to reduce the viscosity to make the fuel usable in a diesel engine, the pure oil is converted from a natural oil triglyceride (three long chain carbon molecules stuck together by the glycerin) into three monoalkyl esters (three separate long chain carbon molecules).
FIGURE 1: Soybean 1: Soybean Vegetable Oil Molecule Compared to the Biodiesel Molecules WHAT KIND OF ENGINE PROBLEMS HAVE THERE BEEN WITH B100 BIODIESEL? - The literature has explored various problems on B100 biodiesel fueled engines, most of which are related to various residues
and deposits caused by B100 that can result in engine damage. Injector and piston deposits: - Some problems have been encountered with injector deposits [1] when running with B100. At temperatures of 430ºC to 480ºC, decomposition of soybean biodiesel occurs [2], therefore the possibility exists for the biodiesel to decompose during the ignition delay period, resulting in injector tip deposits. In addition to temperature decomposition, oxidation of the B100 over time can form soluble gums that can cause the formation of deposits on the injector tips [3] or piston surfaces. Oil Pan Deposits: - B100 has been shown to cause significant residue formation and viscosity decreases [4] in the engine oil, requiring a shortening of the normal oil change interval for the engine. Fuel System Deposits: - There have been some problems associated with fuel filter clogging [5] as well. Biodiesel has a detergent effect which releases the deposits accumulated within the fuel system (from the petroleum diesel fuel used prior to the biodiesel) and can cause filter clogging from those released deposits. If the B100 releases deposits that have accumulated after the fuel filter, then those deposits can end up within the injection pump and cause problems on those very precise, tight clearance components. This would not be a problem on engines that have only been run with Biodiesel. Fuel Instability: - Due to the high internal oxygen content of biodiesel, B100 oxidizes and degrades in storage and requires special handling to insure that the fuel quality will meet ASTM D6751-02 biodiesel fuel specification. Biodiesel should be used within 6 months after it is produced [4]. Aged or poor quality biodiesel can contain organic acids, water, peroxides and products of polymerization that can reduce the service life of fuel injection equipment [6]. Material Incompatibilities: - Due to the high oxygen content of B100, the ability of B100 to break down or ”oxidize” rubbers and plastics is enhanced. Changes to the engine seals (both lube oil and fuel system o-rings) and fuel hoses are then needed because of material incompatibility with the B100. The hydroperoxides formed during the oxidation of the biodiesel are unstable and attack elastomeric materials [7]. Biodiesel has incompatibilities with nitrile rubber, nylon 6/6 and high density polypropylene. However, teflon and viton have good compatibility [8] with B100. Due to a high fuel dilution rate into the lube oil it is recommended to make all lube system elastomers compatible with biodiesel. Temperature considerations: - B100 turns to jelly at subfreezing conditions and requires blending with petroleum diesel or additives for operation below freezing conditions.
Energy content: - B100 has an 11% lower energy content than petroleum diesel, however the higher viscosity (compared to petroleum diesel) results in better injector efficiency. The net result can be about 5-7% less fuel energy and therefore 5-7% reduction in maximum power output and higher fuel consumption. A range of 8 to 12% increase in fuel consumption rate was found when running with B100 biodiesel fuel in a Transport Refrigeration Unit as compared with petroleum diesel. There are enough problems with B100 to prevent a full endorsement from all engine manufacturers, however there is widespread approval for running diesel engines with B5 (5% biodiesel, 95% petroleum diesel blended). John Deere [9], Cummins [10], Yanmar [11], the Engine Manufacturers Association (EMA) [12], and a consortium of FIE (fuel injection equipment) [13] manufacturers have all issued position statements approving the use of biodiesel blends up to B5 as long as the biodiesel portion of the fuel blend meets ASTM D6751-02 to insure that the biodiesel fuel is maintained to a high quality level. Some German (MAN, Daimler-Chrysler, Mercedes-Benz, Volkswagen) and European engine manufacturers have approved operation with B100 in certain engine models, however they may require special service including more frequent oil changes, synthetic oil and the installation of compatible seals and hoses. PISTON DEPOSITS - This paper is specifically looking at the effect of various lubricating oils to reduce piston deposits, specifically on the piston skirt and in the ring grooves. These deposits could either be formed from the fuel that is moving past the rings from the combustion chamber or formed from the fuel diluted within the lube oil. In either case, a high quality lube oil coating the piston surfaces and ring groove may have a positive effect on reducing or eliminating these deposits from the biodiesel fuel. HOW DOES B100 BIODIESEL FUEL GET PAST THE RINGS INTO THE OIL PAN? - Under normal engine operation, a small amount of any diesel fuel, including petroleum diesel and biodiesel, will get into the oil pan due to incompletely combusted fuel. There are several reasons why the B100 biodiesel has a greater tendency than petroleum diesel to get into the oil pan. B100 has about 50% higher viscosity than petroleum diesel [2], which means that when the injectors try to atomize the thicker fuel, larger droplets will form in the fuel spray [14]. The droplet size is affected by several fuel properties including surface tension, specific gravity, and viscosity. These three properties have higher values for B100 compared with petroleum diesel (Table 1). Increases in these properties interfere with the droplet ‘breakup’ mechanism, resulting in generally larger size droplets for B100 fuels [15]. For reference, the properties of the very
thick, unprocessed vegetable oil are also included in Table 1. #2 Petroleum Diesel
Rapeseed Methyl Ester Biodiesel
Neat Rapeseed vegetable oil (not methyl ester) 28.1
rates and soybean oil methyl esters have higher content of unsaturated fats than rapeseed methyl esters. Soybean biodiesel has been shown to cause increases in viscosity of 18 to 25 times the rate of Rapeseed (or canola) biodiesel fuels [19]. Some engine and equipment manufacturers view soybean biodiesel as posing a greater risk of causing lubricating oil problems than rapeseed biodiesel [20].
22.5 25.4 Surface Tension, mM/m at 100C .852 .874 .906 Specific Gravity 1.3 2.4 Viscosity, cs at 100C TABLE 1: Comparison of the fuel properties that affect droplet size for Rapeseed Biodiesel and for Petroleum Diesel Fuel [15] [analysis done by Phoenix Chemical Laboratory]
WHICH OIL ADDITIVES CAN COUNTERACT THE RING GROOVE DEPOSIT FORMATIONS? - Antioxidants can reduce residue formation, also known as polymerization, significantly. Oils can have various levels of oxidative stability. The oils with the higher oxidative stability will allow for more of the additives to be available to control oxidation and polymerization of the biodiesel fuel [21]. A CI-4 premium full synthetic oil can have four times the oxidative stability of a CI-4 fleet grade mineral oil as measured by the Sequence IIIE and IIIF Engine Oil Oxidation tests. Also, lube oils with high dispersancy additives should help reduce residue formation [1,18].
Emission tests confirm that the emitted particulates from B100 exhaust are 10 times greater in size than petroleum diesel particulates and these larger particles are considered to be unburned biodiesel [16].
WHAT EFFECT DOES THE CONCENTRATION OF ANTI-OXIDANTS HAVE ON THE FORMATION OF PISTON DEPOSITS? - The following test determined that there is a significant effect from oils with higher levels of oxidative stability in controlling the piston surface and ring groove deposits.
Heavy fuel components have more potential for incomplete combustion and can cause more combustion deposits at partial loads than petroleum diesel fuels [9]. The higher density and narrow, high boiling curve for B100 confirms the presence of heavier fuel components (molecules that are primarily 18 carbons long for biodiesel) than petroleum diesel (molecules that are primarily 14 to 18 carbons long). The smaller petroleum diesel fuel droplets will burn more completely during the short time period for combustion than the larger biodiesel droplets, therefore some portion of the unburned larger biodiesel droplets will find their way past the rings and into the oil pan. Another reason for larger droplets, is that the engine used in our Transport Refrigeration Unit is direct-injected and it has been shown that direct injected engines exhibit a greater tendency for fuel dilution with B100 than indirect injection engines [1,5]. Also, lighter load conditions, typical for Transport Refrigeration Units, can also result in higher fuel dilution into the oil [17]. Finally, deposits on the tips of injectors from B100 fuel can result in imperfect atomization and in additional fuel dilution into the crankcase oil. IS THE DEPOSIT FORMATION PROPERTY THE SAME FOR SOYBEAN AND RAPESEED BIODIESEL FUELS? - The potential for residue formation is greater for methyl esters derived from oils that are high in linoleic and linolenic acids, such as soybean oil. These types of methyl esters will react more rapidly towards polymerization [18]. Biodiesel fuels with higher levels of unsaturated fats will result in higher residue formation
EXPERIMENTAL APPROACH TEST PLAN - The following test was designed to compare the effect of various engine lubricating oils on the piston surface and ring groove deposits of engines running on 100% biodiesel fuel. For this test, 4 Yanmar 2.1 liter direct injection diesel engines were run on 100% soybean biodiesel (SOME). It was decided to run this test using the soybean biodiesel because the deposit formation capability is greater for soybean biodiesel than for rapeseed biodiesel. Each of the 4 engines was run with a different lubricating oil: two mineral oils, one synthetic oil and one synthetic-mineral blend. In addition, a fifth engine was run under the same operating conditions but with petroleum diesel fuel and the mineral lube oil with the lowest level of anti-oxidant. TEST PROCEDURE - Five new Yanmar 4TNE86 direct injection 4 cylinder 2.1 liter diesel engines (Table 2) were tested on Stusska water brake dynamometers for 1000 hours each on identical duty cycles simulating TRU (transport refrigeration unit) operation: 15 minutes at 2200 rpm and 21hp (which is 62% of rated load at 2200 rpm), then 44 minutes at 1450 rpm and 10 hp (which is 37% of rated load at 1450 rpm), then 1 minute shutdown, restart at high speed and repeat. Oil sump temperature during this duty cycle was found to be about 205ºF. One engine was fueled on petroleum diesel and four engines were fueled on B100 SOME biodiesel which slightly exceeded ASTM D6751-02 in acid number. The
fuel was sourced from West Central Soy in Ralston, Iowa (see certificate of analysis in Appendix).
engine is designed to run 6 liters low before warning the customer of a low oil level condition.
4 cylinder, in-line vertical
Oil was not added to engines during the entire 1000 hour test. At each 200 hour oil sample interval, the length on the dipstick of oil level was recorded so that the comparative oil consumption rates of the engines could be determined. At the completion of the 1000 hour test, engines were disassembled and condition of rings and ring grooves were inspected.
direct-injection combustion 4 stroke, water cooled 86mm bore X 90mm stroke 2.09 liter displacement 33.9 hp @ 2200 rpm power rating 10 degrees BTDC fuel injection timing 2800 to 3000 psi nozzle injection popping pressure 18:1 compression ratio 2 valves per cylinder naturally aspirated TABLE 2: YANMAR 4TNE86 TEST ENGINE DETAILS The lubricating oils used in these four engines were commercially available API CI-4 diesel engine oils 1. Test Oil A: Mineral Fleet Grade 15W40 2. Test Oil B: Mineral Premium 15W40 3. Test Oil C: Semi-synthetic 15W40 4. Test Oil D: Full Synthetic 5W40 A fifth Yanmar 4TNE86 engine was set up to run on the exact same duty cycle as the biodiesel engines, however fueling this engine with 2-D petroleum diesel fuel. This engine also ran for 1000 hours and was used for comparing the deposits. The A oil was used in this petroleum diesel-fueled engine, as it has the lowest level of additives of the four test oils. OIL ANALYSIS - Standard oil analysis included viscosity at 100ºC, as well as TBN, metals, fuel/water dilution and was performed by Cleveland Technical Center labs. Oil samples were collected at 200 hour intervals beginning with "0" hours. 2 oil samples were collected at each 200 hour interval from each engine. This allowed averaging of the variation due to the oil analysis lab procedures. Frequency and multiplicity of samples was determ ined by limiting the total oil removed for samples to 10% of the total oil sump capacity. A total of ten 120cc oil samples were removed from an oil sump capacity of 12 liters during the 1000 hour test from each engine, and two more samples at 1000 hours (12 total). Normal oil consumption rate is about 5 liters/1000 hours. This
ENGINE OILS - All the engine oils contain a metallic additive detergent and dispersancy component mixture of primarily calcium and magnesium chemistry. The different levels of performance between the oils are obtained by supplemental additives and base stock differences. Mineral Test Oil A - Contains a level of dispersant, detergent, and inhibitors needed to provide basic API CI4 performance in a mineral oil base stock, system, i.e. Group I and Group II base stocks. This product will give good performance when used at standard recommended drain intervals in diesel engines. Mineral Test Oil B - The additive system has been supplemented with some selective boosting of dispersant, detergent, and oxidation inhibitor additives. This, in combination with an optimized base stock system increases oil performance beyond the basic CI-4 level. Test Oil B will provide better protection against wear and oxidation, and improved engine cleanliness compared to Test Oil A. Semi-Synthetic Test Oil C - The dispersant and oxidation inhibitor in the additive is boosted above the Test Oil B level, and contains semi-synthetic base stock system. These changes will provide benefits in the areas of oxidation stability and engine cleanliness. Full Synthetic Test Oil D - The metallic additive level is similar to that in Test Oil B and C. Test Oil D also contains supplemental additive boosters and a fully synthetic polyalphaolefin (PAO) base stock system, which is built up from ethylene. This oil is manufactured from discrete chemical feedstocks. Aside from the obvious low temperature advantages that come with the synthetic base stock system, the most apparent performance benefits for Test Oil D are observed in the areas of oxidation stability and engine cleanliness. Additionally, Test Oil D may provide improvement in piston deposit protection in some circumstances. PERFORMANCE DIFFERENCE OF THE ENGINE OILS IN RELATION TO OXIDATION STABILITY - Overall it is hard to exactly quantify on a additive basis the differences between the oils since the basic chemistry is similar, but primary performance differences are attributed to the blending with different engine oil base stocks and supplemental performance additives.
Engine oil performance parameters (oxidation stability, detergency, dispersancy, anti-wear, rust and corrosion protection, cold pumpability, etc) will vary somewhat between each engine oil. Some parameters will have a large difference in overall performance and others
PISTON SKIRT DEPOSITS - Oil A, which had the lowest additive level, exhibited the worst piston skirt deposits (Figure 3).
less. Oxidation stability is probably the easiest to put a relative measure between the different oils (Figure 2) and it also is a primary factor to the capability of the engine oil for severe or extended service type use. Comparison of Oxidative Stability of the 4 Tested oils Full Synthetic Oil D e p y T l i O
Semi-synthetic Oil C Premium Mineral Oil B Fleet Grade Mineral Oil A 0%
100% 200% 300% 400% 500%
FIGURE 3: Piston skirt deposits from engine run on B100 soybean biodiesel fuel and Oil A fleet grade mineral lubricating oil
Relative Percentage of Oxidative Stability
FIGURE 2: Relative oxidative stabilities of the 4 tested oils
Oil B premium mineral oil had significantly reduced piston skirt deposits (Figure 4) as compared to fleet grade mineral oil A (Figure 3).
As for the use of these products with biodiesel fuel, there is reason to believe that the higher performing oils will provide some level of improved performance. It has been shown that some biodiesel fuels can have a significant negative impact on the lube oil condition and engine durability. In general, the higher the degree of unstaturation in the fatty acid used to manufacture the fuel, the greater the impact on lube performance. There are some other fuel composition factors that can also impact the oil. The impact on the lube oil is believed to be due to the introduction of unburned fuel components into the lube oil which promote deposit formation and oil degradation.
RESULTS AND DISCUSSION OVERVIEW OF THE TEST RESULTS - The purpose of this test was to determine whether there was some differentiation found between the piston skirt and ring groove deposits of the biodiesel engines running with 4 different engine oils. There was evidence from the inspection of the pistons that there was some benefit to the higher additive-level oils. However, there were enough deposits in the top ring grooves of all four biodiesel engines to cause a sticking ring condition.
FIGURE 4: Piston skirt deposits from engine run on B100 soybean biodiesel fuel and Oil B premium mineral lubricating oil
The semi-synthetic oil C (Figure 5) and fully synthetic oil D (Figure 6) had no visible piston skirt deposits.
FIGURE 5: Piston skirt deposits from engine run on B100 soybean biodiesel fuel and Oil C semi-synthetic lubricating oil
RING GROOVE DEPOSITS - All four of the biodiesel engines had black sticky deposits in the top ring groove and sticking top ring condition found on the #1 cylinder.
FIGURE 7: Typical black, sticky deposits in ring groove and on land between top and second ring grooves on all four biodiesel engines Figure 7 shows the typical black, sticky ring groove deposit found in the top ring groove of all four biodiesel engines, however the synthetic oils had a portion of the ring groove without this deposit (see Table 3).
FIGURE 6: Piston skirt deposits from engine run on B100 soybean biodiesel fuel and Oil D synthetic lubricating oil
Engine Oil and Fuel
% of Piston Diameter with Black, Sticky Deposit in Top Ring Groove
Fleet grade mineral oil A and B100 fuel
100%
Premium mineral oil B and B100 fuel
100%
Semi-synthetic oil C and B100 fuel
40 to 50%
Fully synthetic oil D and B100 fuel
40 to 50%
Fleet grade mineral oil A and petroleum diesel
none
TABLE 3: A Qualitative Comparison of the Ring Groove Condition for Mineral and Synthetic Oils Used in the Test The combustion bowl on this engine is not directly in the center of the piston head, and the two engines with synthetic oils only had black, sticky deposits on about 40 to 50% of the top ring groove that is in the closest proximity to the hot combustion bowl.
This qualitative comparison of the condition of the ring groove deposits did give an indication that the synthetic oils were performing better than the mineral oils, however the synthetics were still unable to prevent ring sticking from occurring in the top ring groove. FUEL DILUTION INTO THE ENGINE LUBE OIL - The viscosity data from the oil analysis showed significant viscosity reductions in the biodiesel engines (Figure 8). In the first 400 hours of operation, there was about 3 cST average reduction in viscosity, which correlates with an 8% fuel dilution rate (new oil samples were pre-blended with increments of 1% through 10% biodiesel fuel and measured to be .35 cSt viscosity reduction for every 1% of biodiesel fuel). 8% of the oil sump after 400 hours operation is about .80 liter of fuel in the oil. This fuel in the oil indicates there was liquid fuel leaving the combustion chamber, past the rings and into the oil pan. If the ring grooves or ring surfaces are hot enough, some of this liquid biodiesel fuel can decompose and form hard deposits. Viscosity is the best indicator of fuel dilution since standard lab procedures (measuring the presence of fuel vapor in a heated lube oil sample) used to detect percent fuel dilution cannot detect the presence of biodiesel in the engine lube oil due to the high boiling curve of biodiesel (320ºC to 350ºC) [18].
Viscosity vs Hours Fleet Grade Mineral Oil A and B100 fuel
18
The viscosity of the lube oil changes in a curvilinear manner for the biodiesel engines, therefore viscosity can only be used as a casual indicator of the amount of biodiesel found in the oil pan [18]. To get more a precise determination of biodiesel fuel in oil, a higher resolution Gas Chromatography method could be used to detect the specific distribution of hydrocarbons in the fuel. It is possible that this type of detailed analysis could accurately detect the level of biodiesel fuel in used oil. The issue of "new" versus "aged or polymerized" biodiesel may not be fully resolved on the first attempt at measuring fuel content. This is also an issue with petroleum diesel fuel analysis because of the distribution of hydrocarbons in the fuel and fractionation that occurs in the engine [21]. Oil “B” viscosity was rising significantly near the end of the test, however this engine had a completely stuck top and second ring which would have caused excessive blowby, resulting in soot loading of the oil and viscosity increase. SOOT SOLIDS ANALYSIS - The soot solids oil analysis (Figure 9) gave an indication at what time the rings may have become completely stuck, since the soot loading of the oil from exhaust gases going past the stuck rings increases significantly. If it is assumed that the petroleum diesel solids level had a “normal” rate of increase, then Oil B (with B100 fuel) became stuck after 600 hours and Oil A (with B100 fuel) became stuck after 800 hours. The synthetic Oils C and D (with B100 fuel) exhibit a soot solids level similar to the petroleum fueled engine with Oil A.
16 Premium Mineral Oil B and B100 fuel
t 14 S c , 12 C 0 0 10 1 @ y t i 8 s o c 6 s i V 4
Semi-synthetic Oil C and B100 Fuel Full synthetic Oil D and B100 fuel
2 0 0
200
400
600
Hours
800 1000
Fleet Grade Mineral Oil A and Petroleum Diesel fuel
FIGURE 8: Viscosity data from oil analysis showing significant viscosity reduction for the Biodiesel engines The engine run on petroleum diesel showed a statistically significant more stable viscosity level than the engines running with biodiesel (Figure 8). One noticeable trend was the flattening out of the Biodiesel engine viscosities after 400 hours. It has been previously described that after the initial induction phase, the viscosity will begin to rise after the process of oxidation of the biodiesel fuel in the lube oil begins [22].
Soot Solids vs Hours Fleet grade Mineral Oil A and B100 fuel
0.7 0.6 e m u 0.5 l o V %0.4 , s d 0.3 i l o S t 0.2 o o S 0.1
Premium Mineral Oil B and B100 fuel Semi-synthetic Oil C and B100 fuel Full synthetic Oil D and B100 fuel
0 0
200 400 600 800 100 0
Hours
Fleet grade mineral Oil A and Petroleum Diesel fuel
FIGURE 9: Comparison of the Soot Accumulation in the Oils Showing Significant Increases for Oils “A” and “B” Which Both Had the Most Severe Ring Groove Deposits
SUMMARY OF THE RESULTS AND DISCUSSION Piston skirt and ring groove deposits were discovered on the four biodiesel engines and those deposits did not occur on the petroleum diesel engine. The deposits on the piston skirt and ring grooves on the four biodiesel-fueled engines were found to be affected by the type of lubrication oil. The oils with higher additive levels had a significant impact on eliminating the deposits on the piston skirt. In addition, both of the mineral Oils A and B had the most severe deposits in the ring groove resulting in completely stuck top rings. The semi-synthetic and synthetic Oils C and D had a significant impact on reducing top ring groove deposits, however even these synthetic oils still had the formation of a top ring sticking condition at the completion of the 1000 hour test. The synthetic base oils are more stable, and more responsive to the additives used to extend oil life and therefore it is expected that the synthetic formulation will allow for more of the additives to be available to control oxidation of the biodiesel fuel. Additionally, the synthetic formulation should be better able to maintain its properties and protect against engine deposits caused by degraded or oxidized biodiesel fuel components.
CONCLUSIONS All four of the B100 Biodiesel fueled engines had at least one stuck top ring at the completion of the 1000 hour test. As discussed in the introduction, the light loading of the TRU application and the direct-injection combustion could have contributed to excessive unburned fuel getting past the rings and decomposing to form a deposit in the ring grooves. The type of lube oil would have a very limited effect in reducing deposits in the top ring groove. The synthetic Oil D, and the semi-synthetic Oil C, had better top ring groove condition for the Biodiesel fueled engines than the mineral Oils A and B, however even the synthetics were not able to protect the engines from the formation of a stuck ring condition. The higher additive level Oils B, C and D contributed to the reduction in piston skirt deposits of the B100 Biodiesel fueled engines.
REFERENCES 1. Blackburn, J.H.; Pinchin, R.; Nobre, J.I.T.; Crichton, B.A.L.; Cruse, H.W.; “Performance of lubricating oil in vegetable oil ester-fueled diesel engines”, SAE 831355, 1983 2. Choi, C.Y.; Bower, G.R.; Reitz, R.D.; “Effects of Biodiesel Blended Fuels and Multiple Injections on DI Diesel Engines”, SAE 970218, 1997
3. “Determination of Additive Compatibility and Efficacy Project”, A final report to the National Biodiesel Board, 1997 4. Ali, Y.; Hanna, M.A.; “Durability Testing of a Diesel Fuel, Methyl Tallowate and Ethanol blend in a Cummins N14-410 Diesel Engine” 5. Staat, Frederic and Gateau, Paul, “The Effects of Rapeseed Oil Methyl Ester on Diesel Engine Performance, Exhaust Emissions and Long-Term BehaviorA Summary of Three Years of Experimentation”, SAE 950053, 1995 6. Babu, A.K.; and Devaradjane, G.; “Vegetable oils and their derivatives as fuels for CI engines: an overview”, SAE 2003-01-0767, 2003 7.Van Gerpen, J.; “Determining the Influence of Contaminants on Biodiesel Properties”, SAE 971685, 1997 8. Besee, G.B., Fay J.P., 1997 “Compatibility of Elastomers and Metals in Biodiesel fuel blends”, SAE 971690, 1997 9. John Deere New Release, www.deere.com, February 21, 2002 10. Cummins Field Announcement, “Cummins Position on the use of Biodiesel Fuel”, August 30, 2001 11. Yanmar Diesel Service Advisory, “Can Bio-Diesel Fuel be used in Yanmar Engines”, April 16, 2002 12. Engine Manufacturers Association (EMA), “Technical Statement on the use of Biodiesel Fuel in Compression Ignition Engines”, February 2003 13. Consortium of FIE (fuel injection equipment) Manufacturers, Delphi/ Stanadyne/ Denso/ Bosch, “Fatty Acid Methyl Ester Fuels as a Replacement or Extender for Diesel Fuels”, Diesel Fuel Injection Equipment Manufacturers Common Position Statement, June 2000 14. EMA FQP-1A, Engine Manufacturers Association, Recommended Guideline on Diesel Fuel, http://www.enginemanufacturers.org, April 2002 15. Peterson, C.L.; Auld, D.L.; “Technical Overview of Vegetable Oil as a Transportation Fuel”, FACT-Vol.12, Solid Fuel Conversion for the Transportation sector, ASME, 1991 16. Hansen, K.F.; Jensen, M. G.; “Chemical and Biological Characteristics of Exhaust Emissions from a DI Diesel Engine Fuelled with Rapeseed Oil Methyl ester (RME)”, SAE 971689, 1997
17. Worgetter, M.; “Durability test of a tractor engine on a test bench in pilot project Biodiesel”, Austrian Institute for Agricultural Engineering Research Report 25, Wieselburg/Austria, 1991
APPENDIX CERTIFICATE OF ANALYSIS FOR THE TEST FUEL ASTM D6751 LIMITS for biodiesel blendstock
18. Schumacher, L.G., “Engine Oil Impact Literature Search and Summary: A research activity designed to determine biodiesel engine oil interactions”, Submitted to National Biodiesel Board, November 1996
BD020403
LOT NUMBER
19. McCormick, R.: “Renewable Diesel Fuels: Status of th Technology and R & D Needs”, US DOE, 8 Diesel Emissions Reduction Conference (DEER), San Diego, CA, August 2002 20.Schafer, A. “Plant oil-methyl-esters as fuels for diesel engines”, Seminar of the Technical Academy, Esslingen/Germany, 1991 21. Kennedy, Steve, Development, 2003
ExxonMobil
Research
and
22. Wexler, H. "Polymerization of drying oils", Chemical Reviews 64(6), 591-611. 1964
.02
0.00008
TOTAL GLYCERINE %
.24
0.1297
130 MIN
136.29
WATER & SEDIMENT, % VOLUME
.050
0.01
CARBON RESIDUE % MASS
.05 MAX
.0292
SULFATED ASH % MASS
.02 MAX
.001
1.9-6.0
4.2138
FLASHPOINT, Cº
.00004
Total sulfur by UV fluorescence % mass
Thomas R. Sem Engine Applications Engineer Corporation since 1981, MSME
FREE GLYCERINE %
KINEMATIC VISCOSITY Cst, 40ºC
CONTACT
at
Thermo
King
FUEL SAMPLE
CETANE NUMBER
47 MIN
49.86 0
CLOUDPOINT Cº
[email protected] 952-887-2603
COPPER CORROSION ACID NUMBER mg KOH/gm PHOSPHOROUS BY ICP% MASS
3 MAX
1A
.80
.89
.001 MAX
0.0007
47.2
SOAP IN OIL, PPM DISTILLATION AT REDUCED PRESSURE Cº IODINE NUMBER
360 MAX
350
131
