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Technical Paper

Understanding Soot Mediated Oil Thickening Part 6: Base Oil Effects

One of the key functions of lubricating oil additives in diesel engines is to control oil thickening caused by soot accumulation. Over the last several years, it has become apparent that the composition of the base oil used within the lubricant plays an extremely important role in the oil thickening phenomenon. In particular, oil thickening observed in the Mack T-8 test is significantly affected by the aromatic content of the base oil. We have found that the Mack T-8 thickening phenomenon is associated with high electrical activity, i.e., engine drain oils which exhibit high levels of viscosity increase show significantly higher conductivities. These findings suggest that electrical interactions are involved in soot-induced oil thickening.
Technical Paper

The Use of Life Cycle Assessment with Crankcase Lubricants to Yield Maximum Environmental Benefit – Case Study of Residual Chlorine in Lubricant

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.
Technical Paper

The Role of Engine Oil Formulations on Fluid Diagnostics

Historically, vehicle fluid condition has been monitored by measuring miles driven or hours operated. Many current vehicles have more sophisticated monitoring methods that use additional variables such as fuel consumption, engine temperature and engine revolutions to predict fluid condition. None of these monitoring means, however, actually measures a fluid property to determine condition, and that is about to change. New sensors and diagnostic systems are being developed that allow real time measurement of some lubricant physical and/or chemical properties and interpret the results in order to recommend oil change intervals and maximize performance. Many of these new sensors use electrochemical or acoustic wave technologies. This paper examines the use of these two technologies to determine engine oil condition and focuses on the effects of lubricant chemistry on interpreting the results.
Technical Paper

The KA24E Engine Test for ILSAC GF-3.Part 2. Valve Train Wear Response to Formulation Variables

The work presented here is the second of two papers investigating the KA24E engine test. The first paper characterized the KA24E engine in terms of the physical and chemical operating environment it presents to lubricants. The authors investigated oil degradation and wear mechanisms, and examined the differences between the KA24E and the Sequence VE engine tests. It was shown that while the KA24E does not degrade the lubricant to the extent that occurs in the Sequence VE, wear could be a serious problem if oils are poorly formulated. This second paper examines the wear response of the KA24E to formulation variables. A statistically designed matrix demonstrated that the KA24E is sensitive to levels of secondary zinc dialkyldithiophosphate (ZDP), dispersant and calcium sulfonate detergent. This matrix also showed that the KA24E appears to have good repeatability for well formulated oils and is a reasonable replacement for the wear component of the Sequence VE.
Technical Paper

The KA24E Engine Test for ILSAC GF-3 Part 1: Engine Design, Operating Conditions and Wear Mechanisms

The Nissan KA24E engine test is designated to replace the Ford Sequence VE engine test as the low temperature valve train wear requirement for ILSAC (International Lubricant Standardization and Approval Committee) GF-3. The KA24E (recently designated the Sequence IV A) represents much of the current world-wide material and design technology while retaining the sliding cam/follower contact found in earlier engine designs. The work presented here is the first of two reports. In this first report, the physical and chemical environment the KA24E engine presents a lubricant is characterized and compared to those of the Sequence VE engine. Valve train materials and wear modes are investigated and described. Although chemical analysis of drain oils indicate the KA24E procedure does not degrade the lubricant to the extent seen in the Sequence VE test, valve train wear appears to proceed in a similar manner in both tests.
Technical Paper

The Impact of Passenger Car Motor Oils on Emissions Performance

Throughout the evolution of the automobile, passenger car motor oils have been developed to address issues of wear, corrosion, deposit formation, friction, and viscosity stability. As a result, the internal combustion engines are now developed with the expectation that the lubricants to be used in them will deliver certain performance attributes. Metallurgies, clearances, and built-in stresses are all chosen with certain expectations from the lubricant. A family of chemicals that has been universally used in formulating passenger car motor oils is zinc dithiophosphates (ZDPs). ZDPs are extremely effective at protecting highly stressed valve train components against wear failure, especially in engine designs with a sliding contact between cams and followers. While ZDPs' benefits on wear control are universally accepted, ZDPs have been identified as the source of phosphorus, which deactivates noble metal aftertreatment systems.
Technical Paper

The Effect of Heavy Loads on Light Duty Vehicle Axle Operating Temperature

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.
Technical Paper

The Development of Predictive Models for Non-Acidic Lubricity Agents (NALA) using Quantitative Structure Activity Relationships (QSAR)

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

The Development of CVT Fluids with Higher Friction Coefficients

The development of new transmission designs continues to affect the vehicle market. Continuously variable transmissions (CVTs) remain one of the more recent designs that impact the vehicle market. A desire for high belt-pulley capacity has driven studies concentrating on metal-on-metal (M/M) friction as a function of the CVT fluid. This paper describes the statistical techniques used to optimize the fluid friction as a function of additive components in a bench-scale, three-element test rig.
Technical Paper

Test Techniques for the Evaluation of Lubricant Effects on Axle Break-in Temperature - Investigation with an Integrally Built Rear Axle of a European Sedan

It has been recognized for many years that multipurpose axle lubricants give rise to much higher axle break-in temperatures than lead-soap, active-sulfur or sulfur-chlorine-lead lubricants. Evaluation of differences in axle lubricant break-in temperature between the various multipurpose gear lubricants has been complicated by lack of repeatability and reproducibility. The work described in this paper shows that one of the most important variables affecting axle break-in temperature, under the conditions of the test technique used, was torsional axle preload and that control of dimensional preload in itself is not sufficient to ensure good test repeatability. The test technique described here has been used to evaluate the axle lubricant break-in temperature properties of several sulfur-phosphorus multipurpose gear lubricants.
Technical Paper

Review of Exhaust Emissions of Compression Ignition Engines Operating on E Diesel Fuel Blends

Recently, research and testing of oxygenated diesel fuels has increased, particularly in the area of exhaust emissions. Included among the oxygenated diesel fuels are blends of diesel fuel with ethanol, or E diesel fuels. Exhaust emissions testing of E diesel fuel has been conducted by a variety of test laboratories under various conditions of engine type and operating conditions. This work reviews the existing public data from previous exhaust emissions testing on E diesel fuel and includes new testing performed in engines of varied design. Emissions data compares E diesel fuel with normal diesel fuel under conditions of different engine speeds, different engine loads and different engine designs. Variations in performance under these various conditions are observed and discussed with some potential explanations suggested.
Technical Paper

Polymer Additives as Mist Suppressants in Metalworking Fluids Part IIa: Preliminary Laboratory and Plant Studies - Water Soluble Fluids

Mist generated from water-soluble fluids used in machining operations represents a potentially significant contribution to worker exposure to airborne particles. Part I of this study [1], discussed polymer additives as mist suppressants for straight mineral oil metalworking fluids (MWF), which have been successfully employed at several locations. This paper focuses on recent developments in polymer mist suppressants for water-based MWF, particularly in the production environment. The polymer developed and tested in this study functions on a similar basis to that for straight oil anti-mist additives. This water soluble polymer suppresses the formation of small mist droplets and results in a distribution of larger droplet sizes. These larger droplets tend to settle out near the point of machining, resulting in a significant decrease in the total airborne mist concentration.
Technical Paper

Over a Decade of LTMS

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.
Technical Paper

Opportunity for Diesel Emission Reductions Using Advanced Catalysts and Water Blend Fuel

This paper features the results of emission tests conducted on diesel oxidation catalysts, and the combination of diesel oxidation catalysts and water blend fuel (diesel fuel continuous emulsion). Vehicle chassis emission tests were conducted using an urban bus. The paper reviews the impact and potential benefits of combining catalyst and water blend diesel fuel technologies to reduce exhaust emissions from diesel engines.
Technical Paper

Next Generation Torque Control Fluid Technology, Part IV: Using a New Split-μ Simulation Test for Optimizing Friction Material-Lubricant Hardware Systems

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.
Technical Paper

Next Generation Torque Control Fluid Technology, Part III: Using an Improved Break-Away Friction Screen Test to Investigate Fundamental Friction Material-Lubricant Interactions

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.
Technical Paper

Next Generation Torque Control Fluid Technology, Part II: Split-Mu Screening Test Development

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

Lubricity and Injector Pump Wear Issues with E diesel Fuel Blends

The search for alternative energy sources, particularly renewable sources, has led to increased activity in the area of ethanol blended diesel fuel, or E diesel. E diesel offers potential benefits in reducing greenhouse gases, reducing dependence on crude oil and reducing engine out emissions of particulate matter. However, there are some concerns about the use of E diesel in the existing vehicle fleet. One of the chief concerns of the use of E diesel is the affect of the ethanol on the lubricating properties of the fuel and the potential for fuel system wear. Additive packages that are used to formulate E diesel fuels can improve fuel lubricity and prevent abnormal fuel system wear. This work studies the lubricity properties of several E diesel blends and the diesel fuels that are used to form them. In addition to a variety of bench scale lubricity tests, injector pump tests were performed as an indicator of long term durability in the field.
Technical Paper

Low Volatility ZDDP Technology: Part 2 - Exhaust Catalysts Performance in Field Applications

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).
Technical Paper

Jet Fuel Thermal Stability Additives - Electrical Conductivity and Interactions with Static Dissipator Additive

The primary goal of the USAF JP-8+100 thermal stability additive (TSA) program is to increase the heat-sink capacity of JP-8 fuel by 50%. Current engine design is limited by a fuel nozzle temperature of 325°F (163°C); JP-8+100 has been designed to allow a 100°F increase in nozzle temperatures up to 425°F (218°C) without serious fuel degradation leading to excessive deposition. Previous studies have shown that TSA formulations increase the electrical conductivity of base jet fuel. In the present paper, further characterization of this phenomenon is described, as well as interactions of newer TSAs with combinations of SDA and other surface-active species in hydrocarbons, will be discussed.