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Technical Paper
2013-04-08
William Barton, Daniel Jason Knapton, Mark Baker, Andrew Rose, Elizabeth A. Schiferl, Michael Huston, Gareth Brown, Gregory Hunt
This paper outlines the second part in a series on the effect of polymeric additives commonly known as viscosity modifiers (VM) or viscosity index improvers (VII) on gear oil efficiency and durability. The main role of the VM is to improve cold temperature lubrication and reduce the rate of viscosity reduction as the gear oil warms to operating temperature. However, in addition to improved operating efficiency across a broad temperature range compared to monograde fluids the VM can impart a number of other significant rheological improvements to the fluid [1]. This paper expands on the first paper in the series [2], covering further aspects in fluid efficiency, the effect of VM chemistry on these and their relationship to differences in hypoid and spur gear rig efficiency testing. Numerous VM chemistry types are available and the VM chemistry and shear stability is key to fluid efficiency and durability. The trend of increased drivetrain power density and reduced sump volume places even more burden on the fluid film protection with increasing load in the contact and increased number of duty cycles per volume of fluid further increasing shear loss severity.
Technical Paper
2010-10-25
Matthew Henley, Shubhamita Basu, Elizabeth Schiferl, David Whitticar, Mark Baker, Stuart Bartley, Michael E. Huston
Wet clutch friction devices are the primary means by which torque is transmitted in many of today's modern vehicle drivelines. These devices are used in automatic transmissions, torque vectoring devices, active on-demand vehicle stability systems, and torque biasing differentials. As discussed in a previous SAE paper ( 2006-01-3270 - Next Generation Torque Control Fluid Technology, Part I: Break-Away Friction Slip Screen Test Development), a testing tool was developed to simulate a limited slip differential break-away event using a Full Scale-Low Velocity Friction Apparatus (FS-LVFA). The purpose of this test was to investigate the fundamental interactions between lubricants and friction materials. The original break-away friction screen test, which used actual vehicle clutch plates and a single friction surface, proved a useful tool in screening new friction modifier technology. This paper describes upgrades to the FS-LVFA as well as improvements in the test method including statistical data analysis.
Technical Paper
2010-10-25
David Whitticar, Shubhamita Basu, Galen Greene, Matthew Henley, Dwight Parham, Christopher Prengaman, Elizabeth Schiferl, Mark Baker, Stuart Bartley, Michael E. Huston
Wet clutch friction devices are the primary means by which torque is transmitted through many of today's modern vehicle drivelines. These devices are used in automatic transmissions, torque vectoring devices, active on-demand vehicle stability systems and torque biasing differentials. As discussed in a previous SAE paper ( 2006-01-3271 - Next Generation Torque Control Fluid Technology, Part II: Split-Mu Screen Test Development) a testing tool was developed to correlate to full-vehicle split-mu testing for limited slip differential applications using a low speed SAE #2 friction test rig. The SAE #2 Split-Mu Simulation is a full clutch pack component level friction test. The purpose of this test is to allow optimization of the friction material-lubricant hardware system in order to deliver consistent friction performance over the life of the vehicle. In this paper we will describe the development of a new test based on the previous work including equipment modifications, data analysis and correlation to full-vehicle split-mu testing.
Technical Paper
2010-05-05
Michael G. Christianson, Ewa Bardasz, William Nahumck
Limited technical studies to speciate particulate matter (PM) emissions from gasoline fueled vehicles have indicated that the lubricating oil may play an important role. It is unclear, however, how this contribution changes with the condition of the lubricant over time. In this study, we hypothesize that the mileage accumulated on the lubricant will affect PM emissions, with a goal of identifying the point of lubricant mileage at which PM emissions are minimized or at least stabilized relative to fresh lubricant. This program tested two low-mileage Tier 2 gasoline vehicles at multiple lubricant mileage intervals ranging from zero to 5000 miles. The LA92 cycle was used for emissions testing. Non-oxygenated certification fuel and splash blended 10% and 20% ethanol blends were used as test fuels. Results collected indicate that both the magnitude and variability of PM mass emissions decrease in the first 2000 miles of lubricant break-in, with potential increases as lubricant ages and decreases its performance activity.
Technical Paper
2009-11-02
Richard J. Vickerman, Kevin Streck, Elizabeth Schiferl, Ananda Gajanayake
The world is firmly focused on reducing energy consumption and on increasingly stringent regulations on CO2 emissions. Examples of regulatory changes include the new United States Environmental Protection Agency's (U.S. EPA) fuel economy test procedures which were required beginning with the 2008 model year for vehicles sold in the US market. These test procedures include testing at higher speeds, more aggressive acceleration and deceleration, and hot-weather and cold-temperature testing. These revised procedures are intended to provide an estimate that more accurately reflects what consumers will experience under real world driving conditions. The U.S. EPA has also proposed changes, which will extend at least to 2016, that will increase the fleet wide corporate average fuel economy (CAFE) standards step wise, year on year and would impose limits on the amount of greenhouse gas emissions.3,8 Typical operating temperatures in automatic transmissions during cold start-up and light-duty operation are between -20°C and 80°C.
Technical Paper
2008-10-06
Patrick Dyke, Mike Sutton, Terry Thiele, Michael Collins
Life Cycle Assessment (LCA) is a methodology used to determine quantitatively the environmental impacts of a range of options. The environmental community has used LCA to study all of the impacts of a product over its life cycle. This analysis can help to prevent instances where a greater degree of environmental harm results when changes are made to products based on consideration of impacts in only part of the life cycle. This study applies the methodology to engine lubricants, and in particular chlorine limits in engine lubricant specifications. Concern that chlorine in lubricants might contribute to emissions from vehicle exhausts of polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF), collectively called PCDD/F, led to the introduction of chlorine limits in lubricant specifications. No direct evidence was available linking chlorine in lubricants to PCDD/F formation, but precautionary principles were used to set lubricant chlorine limits. To complete this study, the LCA was supplemented by detailed emissions testing from the use and disposal phase of lubricants.
Technical Paper
2007-10-29
Sung Choon Yoo, Sang Yeob Cha, Masahiko Ikeda, Isao Nakagawa, Hyun-Soo Hong
Global original equipment manufacturers (OEMs) have requested lower viscosity automatic transmission fluid (ATF) for use in conventional and 6-speed automatic transmissions (AT) to meet growing demands for improved fuel economy. While lower-viscosity ATF may provide better fuel economy by reducing churning losses, other key performance attributes must be considered when formulating lower viscosity ATF(1,2). Gear and bearing performance can be key concerns with lower-viscosity ATFs due to reduced film thickness at the surfaces. Long-term anti-shudder performance is also needed to enable the aggressive use of controlled slip torque converter clutches that permit better fuel economy. And, friction characteristics need to be improved for higher clutch holding capacity and good clutch engagement performance. This paper covers the development of next-generation, low-viscosity ATF technology, which provides optimum fuel economy along with wear and friction durability. Low Velocity Friction Apparatus (LVFA), SAE #2, and FZG pitting tester were used to develop the technology.
Technical Paper
2007-10-29
Ewa A. Bardasz, Elizabeth Schiferl, William Nahumck, Jack Kelley, Lewis Williams, Carolyn P. Hubbard, Eva Thanasiu, Mark Jagner, Ann O'Neill, Dairene Uy
Phosphorus is known to reduce effectiveness of the three-way catalysts (TWC) commonly used by automotive OEMs. This phenomenon is referred to as catalyst deactivation. The process occurs as zinc dialkyldithiophosphate (ZDDP) decomposes in an engine creating many phosphorus species, which eventually interact with the active sites of exhaust catalysts. This phosphorous comes from both oil consumption and volatilization. Novel low-volatility ZDDP is designed in such a way that the amounts of volatile phosphorus species are significantly reduced while their antiwear and antioxidant performances are maintained. A recent field trial conducted in New York City taxi cabs provided two sets of “aged” catalysts that had been exposed to GF-4-type formulations. The trial compared fluids formulated with conventional and low-volatility ZDDPs. Results of field test examination were reported in an earlier paper (1). As a part of our current examinations, Federal Test Procedure (FTP-75) emissions tests were conducted.
Technical Paper
2007-10-29
Mike Sutton, Jody A. Kocsis, Isao Nakagawa
Requirements to improve vehicle fuel economy continue to increase, spurred on by agreements such as the Kyoto Protocol. Lubricants can play a role in aiding fuel economy, as evidenced by the rise in the number of engine oil specifications that require fuel economy improvements. Part of this improvement is due to achieving suitable viscometric properties in the lubricant, but additional improvements can be made using friction modifier (FM) compounds. The use of FMs in lubricants is not new, with traditional approaches being oleochemical-based derivatives such as glycerol mono-oleate and molybdenum-based compounds. However, to achieve even greater improvements, new new friction modifying compounds are needed to help deliver the full potential required from next generation lubricants. This work looks at the potential improvements available from new FM technology over and above the traditional FM compounds. This is explored from bench screening tests through to standard industry engine tests and quantifies the potential benefit that these compounds may have on improving vehicle fuel economy.
Technical Paper
2007-10-29
W. Michael Burk, Brigdon D. Domonkos, Kieron Donnelly, David A Duncan, Matthew D. Gieselman, Darryl T. Gundic, Jess R. Hamilton, Douglas T. Jayne, Michael Sutton
With the increasing use of modern, EGR-equipped, heavy-duty diesel engines and the use of lower sulfur and alternate fuels, such as biodiesel, lubricants are being exposed to a range of different compositions of acids. To complement the traditional detergent bases, todays lubricants have evolved to include a higher proportion of basic materials from amine-derived sources to aid in oxidation and soot control. This paper explores the impact of the different sources of acids, some of the issues they create and how they can be addressed, exemplified in a prototype CJ-4 lubricant formulation.
Technical Paper
2007-10-29
Jonathan S. Vilardo, David Arters, Keith Corkwell, Carlos L. Cerda de Groote
Ethanol-gasoline blends are widely understood to present certain technical challenges to engine operation. Despite widespread use of fuels ranging from E5 (5% ethanol in gasoline) in some European countries to E10 (10% ethanol) in the United States to E100 (100% ethanol; “alcool”) in Brazil, there are certain subjects which have only anecdotally been examined. This paper examines two such issues: the effect of ethanol on intake valve deposits (IVD) and the impact of fuel additive on filter plugging (a measure of solubility). The effect of ethanol on IVD is studied along two lines of investigation: the effect of E10 in a multi-fuel data set carried out in the BMW 318i used for EPA and CARB certification, and the effect of varying ethanol content from 0% to 85% in gasoline carried out in a modern flex-fuel vehicle. While different detergent types are shown to effectively reduce IVD in a range of ethanol concentrations, the potential effects of fuel additive solubility on fuel filter plugging are shown to vary with dose and type of detergent additive, including variations within a single additive type.
Technical Paper
2006-10-16
Chris Schenkenberger, Elizabeth Schiferl, Gary Garling, Mark Baker, Michael E. Huston, Dwight Parham, Chris Prengaman, Gabe Rhoads, Denise Vermilya
The popularity of SUVs and light trucks in North America, combined with the return to rear-wheel-drive cars globally, is significantly increasing the installation of torque control devices that improve vehicle stability and drivability. As with other driveline hardware, it is important to optimize the friction material-lubricant-hardware system to ensure that a torque control device provides consistent performance over the life of the vehicle. While there are many publications on friction tests relevant to automatic transmission fluids, the literature relating to torque control testing is not as well developed. In this paper, we will describe a split-mu vehicle test and the development of a split-mu screening test. The screening test uses the SAE#2 friction test rig and shows how results from this test align with those from actual vehicle testing.
Technical Paper
2006-10-16
Mark R. Baker, Chris Schenkenberger, Gabe Rhoads, Bryan A. Grisso
The popularity of light trucks and sport utility vehicles (SUVs), coupled with growing consumer demand for vehicles with more size, weight and horsepower, has increased the impact of these vehicle classes on the manufacturer's CAFE (Corporate Average Fuel Economy) numbers. Consumers often use light trucks and SUVs in applications such as prolonged towing at highway speeds, resulting in heavy loading and/or high operating temperatures in the axle. These conditions require superior axle lubricant protection, often provided by choosing a higher viscosity fluid (e.g., SAE 75W-140). Traditionally, the choice of these higher viscosity fluids for enhanced durability performance often results in reduced city-highway efficiency. This paper will describe the use of controlled axle dynamometer laboratory testing methods to develop fluids that maximize both fuel efficiency and durability performance across the wide spectrum of the new proposed viscosity classifications. The impact of viscosity grade and additive chemistry will be explored using controlled laboratory axle testing in an effort to build fluids that maintain durability performance while they maximize efficiency.
Technical Paper
2006-10-16
George Szappanos, Stuart Bartley, Elizabeth Schiferl, Michael E. Huston, Edward Akucewich, Mark Baker, Mitchell Gentile, Jerry Mount, Gabe Rhoads, Denise Vermilya, Dave Whitticar
The popularity of SUVs and light trucks in North America, combined with the return to rear-wheel-drive cars globally, is significantly increasing the installation rates of torque control devices that improve vehicle stability and drivability. As with other driveline hardware, it is important to optimize the friction material-lubricant-hardware system in order to ensure that a torque control device provides consistent performance over the life of the vehicle. While there are many publications on friction tests relevant to automatic transmission fluids, the literature relating to torque control testing is not as well developed. In this paper we will describe the development of a break-away friction screening test using a Full-Scale Low-Velocity Friction Apparatus (FS-LVFA). Additionally, we will illustrate how this screening test can be used to investigate the fundamental friction material-lubricant interactions that occur in continuously engaged limited slip differentials.
Technical Paper
2005-10-24
Doug M. Barr, Chris L. Friend
This study describes the use of Quantitative Structure Activity Relationships (QSAR) to develop predictive models for non-acidic Lubricity agents. The work demonstrates the importance of separating certain chemical families to give better and more robust equations rather than grouping a whole data set together. These models can then be used as important tools in further development work by predicting activities of new compounds before actual synthesis/testing.
Technical Paper
2005-10-24
B. M. O'Connor, C. Schenkenberger
With the continued growth of the sport utility vehicle (SUV) market in North America in recent years more emphasis has been placed on fluid performance in these vehicles. In addition to fuel economy the key performance area sought by original equipment manufacturers (OEMs) in general has been temperature reduction in the axle. This is being driven by warranty claims that show that one of the causes of axle failure in these type vehicles is related to overheating. The overheating is, in turn, caused by high load situations, e.g., pulling a large trailer at or near the maximum rated load limit for the vehicle, especially when the vehicle or its main subcomponents are relatively new. The excessive temperature generally leads to premature failure of seals, bearings and gears. The choice of lubricant can have a significant effect on the peak and stabilized operating temperature under these extreme conditions. Several laboratory methods evolved with time and experience to assess lubricant performance.
Technical Paper
2005-10-24
Mark R. Baker, Bryan A. Grisso, Gabe Rhoads, Chris Schenkenberger, Farrukh S. Qureshi, Andrew Gelder
The popularity of light trucks and sport utility vehicles (SUVs), coupled with growing consumer demand for vehicles with more size, weight and horsepower, has challenged the original equipment manufacturers' (OEM) ability to meet the Corporate Average Fuel Economy (CAFE) specifications due to the increased contribution of these vehicle classes on fleet averages. The need for improved fuel economy is also a global issue due to the relationship of reduced fuel consumption to reduced CO2 emissions. Vehicle manufacturers are challenged to match the proper fluid with the application to provide the required durability protection while maximizing fuel efficiency. Recent new viscosity classifications outlined under SAE J306 aid in more tightly defining options for lubricant choice for a given application. Changes to the SAE J306 viscosity classification define new intermediate viscosity grades, SAE 110 and SAE 190. This paper will describe the use of controlled laboratory testing methods for the development of axle fluids that maximize both the fuel efficiency and durability performance across the wide spectrum of these new proposed viscosity classifications.
Technical Paper
2005-10-24
David A. Duncan, Mark Rees, Amy L. Szabo, Lewis Williams
SAE 2004-01-3009 reported on work conducted to investigate the correlation between the Mack T-11 laboratory engine tests and vehicle field tests. It concluded that the T-11 test provides an effective screening tool to investigate soot-related viscosity increase, and the severity of the engine test limits provides a substantial margin of safety compared to the field. This follow-up paper continues the studies on the 2003 Mack CV713 granite dump truck equipped with an AI-427 internal EGR engine and introduces experimentation on a 2003 CX613 tractor unit equipped with an AC-460P cooled EGR engine. The paper further assesses the correlation of the field trials to the Mack T-11 engine test and reviews the impact of ultra low sulfur diesel (ULSD) and prototype CJ-4 lubricant formulations in these engines.
Technical Paper
2005-10-24
W. Rocco Pistillo, Carlos L. Cerda de Groote
Cloud point depressants (CPD) have been successfully used for many years in low-sulfur diesel fuels. For over ten years, custom-designed, specialty polymer chemistry has enabled refiners to meet cloud point (CP) guidelines with substantially less kerosene. This translates into greater refined yields through cut-point adjustment upgrades and the potential for diverting kerosene to more lucrative market opportunities, such as jet fuel. The practice of cut-point downgrades to gas oil can be costly because diesel fuel generally has greater value. Kerosene dilutions have historically been as high as 30%-40% by volume with low-sulfur diesel fuels [1, 2]. While kerosene addition enables fuels to reach CP guidelines, it may negatively impact the fuel's energy content, cetane number, lubricity, flash point and density. Properly designed CP additives are able to substantially reduce or even eliminate the need for kerosene, thus substantially reducing refinery costs. With ultra-low-sulfur diesel (ULSD) fuels being mandated throughout the mass market distribution system by June 2006, the need for CP control may be greater than ever.
Technical Paper
2005-05-11
B. M. O'Connor, R. P. Jacobs, F. C. Jacoby
The constant velocity joint (CVJ) has seen increased usage driven by the growth of front wheel drive vehicles over the last 30 years. The CVJ provides a smooth, dynamic connection between the output of the axle or gearbox and the driving wheels of the vehicle. The seemingly simple device, however, requires specially designed greases to maximize protection of the internal components from distress and provide optimum performance and service life. One measure of potential distress in the CVJ can be related to temperature rise which is a reflection of the friction and wear properties of the grease employed. A test rig was designed and a method created to evaluate the temperature response of different greases used in a CVJ. The test rig was designed to allow a wide range of speeds, torques and shaft angles to be used. The rig uses a unique temperature pickup system to allow for dynamic measurement of the grease temperature in the boot. The test method described here is based on calculated road load power requirements needed to move a compact vehicle over a wide range of speeds and road grade conditions.
Technical Paper
2005-05-11
B. M. O'Connor, F. C. Jacoby, R. W. Cain
Laboratory testing is an essential part of product development. However, it usually only reflects a small portion of the experience that a lubricant may see in actual service conditions. Many laboratory tests are designed to only address one or two facets of what is deemed to be critical performance areas. Since it is difficult to cover all of the critical performance conditions problems sometimes arise in service that were not anticipated by the laboratory test. Or, conversely, some above average performance evolves during service that was not observed in a specific laboratory test. This paper highlights the overall performance of four manual transmission fluids approved or accepted by the manufacturer for this application. The evaluations were conducted in a city bus fleet with the test buses assigned to the same route for approximately 300,000 km over 30 months. The route chosen for this operation was the most severe for the fleet and included several long, steep grades on the outbound and inbound legs from the garage.
Technical Paper
2005-05-11
Ewa A. Bardasz, Susan Cowling, Avtar Panesar, John Durham, Ted N. Tadrous
Forthcoming on-highway 2005/2007 European and North American emission regulations will require modern diesel engines to be equipped with Diesel Particulate Filters (DPF) capable of trapping up to 99% of the exhaust particulate matter. Since diesel particulates (soot) accumulate in the filter over time, the overall system needs to be regenerated by attaining the ignition temperature of soot, which in the presence of oxygen is >600 °C. Catalyzed DPFs regenerate at temperatures as low as ∼300 °C. One of the major issues facing OEMs, aftertreatment system manufacturers, and lubricant formulators is the potential effects of the lubricant-derived ash deposits and their impact on a pressure increase across filters, as well as overall filter performance and its service characteristics. In the present study, several lubricant-formulating additive variables, metal detergent type, antiwear additive (ZDP) type and level, the presence of boron as well as the effect of noble metal concentration in catalyzed DPF were examined.
Technical Paper
2004-10-25
James N. Vinci, Bryan A. Grisso, Chris Schenkenberger, Farrukh S. Qureshi, Michael P. Gahagan, Hirohito Hasegawa
Consumer demand for size, weight and horsepower has dictated a prominent role for sport utility vehicles and light trucks in the product lines of major North American automobile manufacturers. Inherently less efficient than passenger cars, these vehicles will be facing more stringent light duty CAFE (Corporate Average Fuel Economy) standards beginning in 2005 when mileage targets will be elevated to 21 mpg; this figure will be further increased to 22.2 mpg by 2007. In order to accommodate both public demand and CAFE requirements, vehicle manufacturers are seeking ways to improve fuel economy through design and material modifications as well as through improvements in lubrication. The axle lubricant may have an important impact on fuel economy, and axle lubricants can be tailored to deliver higher levels of operating efficiency over a wide range of conditions. Improvements in city-highway axle efficiency can be gained through the lubricant when appropriate rheological properties are coupled with lighter (SAE 75W-90) viscosity grades to minimize frictional churning losses.
Technical Paper
2004-10-25
S. A. Goodlive, V. F. Lvovich, B. K. Humphrey, F. P. Boyle
Soot is a typical byproduct of the diesel fuel combustion process, and a portion of the soot inevitably enters an engine's crankcase. A key functionality of a diesel engine lubricant is to disperse and suspend soot so that larger-particle agglomerations are prevented. The role of soot agglomeration in abrasive engine wear and lubricant viscosity increase is the subject of a continuing investigation; however, what is generally known is that once an engine lubricant loses its ability to control soot and a rapid viscosity increase begins, the lubricant has reached the end of its useful life and should be changed to maximize engine performance and life. This issue of soot related viscosity increase is of such importance that the Mack T-11 engine test was developed as a laboratory tool to evaluate lubricants. The newly proposed Mack EO-N Premium Plus - 03 specification includes a T-11 performance requirement. Recently, a study was run using a variety of lubricants to compare the T-11 test to a carefully controlled field test.
Technical Paper
2004-10-25
David A. Duncan, Mark Rees, Amy L. Szabo, Lewis Williams
Soot related viscosity increase has been reported as a field issue in some diesel engines and this led to the development of the T-11 engine test, incorporated in the Mack EO-N Premium Plus 03 specification (014 GS 12037). This study compares T-11 laboratory engine tests and vehicle field tests and seeks to confirm the correlation between them. The findings are that the T-11 test provides an effective screening tool to investigate soot related viscosity increase, and the severity of the engine test limits gives a substantial margin of safety compared to the field. A complementary study was conducted in conjunction with this work that focuses on the successful application of electrochemical sensor technology to diagnose soot content and soot related viscosity increase. This will be the subject of a separate paper.
Technical Paper
2004-10-25
Ewa A. Bardasz, Fred A. Antoon, Elizabeth A. Schiferl, Jerry C. Wang, Warren Totten
Global emission legislations for diesel engines are becoming increasingly stringent. While the exhaust gas composition requirements for prior iterations of emission legislation could be met with improvements in the engine's combustion process, the next issue of European, North American and Japanese emission limits greater than 2005 will require more rigorous measures, mainly employment of exhaust gas aftertreatment systems. As a result, many American diesel OEMs are considering NOx adsorbers as a means to achieve 2007+ emission standards. Since the efficacy of a NOx adsorber over its lifetime is significantly affected by sulfur (“sulfur poisoning”), forthcoming reductions in diesel fuel sulfur (down to 15 ppm), have raised industry concerns regarding compatibility and possible poisoning effects of sulfur from the lubricant. Since relatively little is known about the interaction between lubricant derived sulfur and NOx adsorbers, a joint technical program was conducted using a Cummins 5.9L engine and NOx adsorbers supplied by Delphi.
Technical Paper
2004-06-08
Simon C. Tung, Michael L. McMillan, Gao Hong, Ewa Bardasz
The effects of lubricating oil on friction and wear were investigated using light-duty 2.2L compression ignition direct injection (CIDI) engine components for bench testing. A matrix of test oils varying in viscosity, friction modifier level and chemistry, and base stock chemistry (mineral and synthetic) was investigated. Among all engine oils used for bench tests, the engine oil containing MoDTC friction modifier showed the lowest friction compared with the engine oils with organic friction modifier or the other engine oils without any friction modifier. Mineral-based engine oils of the same viscosity grade and oil formulation had slightly lower friction than synthetic-based engine oils. In the comparison of wear on cylinder bores lubricated with the same viscosity of lubricant, the lubricant containing the MoDTC friction modifier had the lowest wear depth, probably because of a wear-resistant reaction film formed by the reaction of sulfur from ZnDTP (Zinc Dialkyl Dithiophosphate) and MoDTC.
Technical Paper
2004-06-08
Philip R. Scinto
The Lubricant Test Monitoring System (LTMS) is the calibration system methodology and protocol for North American engine oil and gear oil tests. This system, administered by the American Society for Testing Materials (ASTM) Test Monitoring Center (TMC) since 1992, has grown in scope from five gasoline engine tests to over two dozen gasoline, heavy duty diesel and gear oil tests ranging from several thousand dollars per test to almost one-hundred thousand dollars per test. LTMS utilizes Shewhart and Exponentially Weighted Moving Average (EWMA) control charts of reference oil data to assist in the decision making process on the calibration status of test stands and test laboratories. Equipment calibration is the backbone step necessary in the unbiased evaluation of candidate oils for oil quality specifications. Given that calibration of test equipment is both expensive and vital to the evaluation of candidate oil capability, it is worth reviewing current issues and concerns, and to consider enhancements to the LTMS.
Technical Paper
2004-06-08
Elisa Santos, Josephine Martinez, Philip R. Scinto
The Sequence IIIG is a newly developed 100 hour test used to evaluate the performance of crankcase engine oils in the areas of high temperature viscosity increase, wear, deposits, pumpability, and ring sticking for the North American GF-4 standard. Data from the ASTM Precision Matrix, completed in the spring of 2003, along with early reference data from the Lubricant Test Monitoring System (LTMS) showed unexpected test results for selected oils and indicated that percent viscosity increase and pumpability were highly correlated with oil consumption. This correlation led to an intensive study of the factors that influence oil consumption and an attempt to compensate for non-oil related oil consumption through a model based adjustment of the results. The study and scrutiny of the IIIG data has led to more uniform oil consumption in the test and improved test precision, and has eliminated the need for a correction equation based on non-oil related oil consumption. While the adoption of a bias correction should not routinely substitute for quality root cause analysis, it can be a temporary practical solution that leads to reduced variability of a test, and therefore to better performance evaluation of the oil.
Technical Paper
2004-06-08
Christopher T. Gray, Peter J. Zemroch, Derek Mackney
The Coordinating European Council, CEC, develops performance tests for the motor, oil, petroleum, additive and allied industries. In recent years, CEC has moved away from using round robin programmes (RRP's) for monitoring the precision and severity of test methods in favour of regular referencing within a test monitoring system (TMS). In a TMS, a reference sample of known performance, determined by cross-laboratory testing, is tested at regular intervals at each laboratory. The results are plotted on control charts and determine whether the installation is and continues to be fit to evaluate products. Results from all laboratories are collated and combined to monitor the general health of the test. The TMS approach offers considerable benefits in terms of detecting test problems and improving test quality. However, the effort required in collating data for statistical analysis is much greater, and there are technical difficulties in determining precision from TMS data. This paper describes the test monitoring framework that has been developed and how it fits into the CEC test development process.
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