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Technical Paper

“Understanding Diesel Engine Lubrication at Low Temperature”

Oil pumpability in passenger car gasoline engines was well-characterized by an ASTM program and by individual researchers in the 1970's and early 1980's. Oil pumpability in diesel engines however, was not investigated to any significant extent until the mid-1980's. This study was initiated to define the performance of several commercial viscosity modifiers in different formulations containing 3 detergent-inhibitor (DI) additive packages and 4 basestock types. The test oils were run at -18°C (0°F) in a Cummins NTC-400 diesel engine. The results, when statistically analyzed, indicated that a new, second generation olefin copolymer (OCP) viscosity modifier had better performance than a first generation OCP and, furthermore, had performance equal to a polymethacrylate (PMA) viscosity modifier. The analysis also showed that one DI/base stock combination had a significant effect on performance.
Technical Paper

“Smart sensing” of Oil Degradation and Oil Level Measurements in Gasoline Engines

Proper lubrication of moving parts is a critical factor in internal combustion engine performance and longevity. Determination of ideal lubricant change intervals is a prerequisite to ensuring maximum engine efficiency and useful life. When oil change intervals are pushed too far, increased engine wear and even engine damage can result. On the other hand, premature oil changes are inconvenient, add to vehicle maintenance cost, and result in wasted natural resources. In order to determine the appropriate oil change interval, we have developed an oil condition sensor that measures the electrical properties of engine oil, and correlates these electrical properties to the physical and chemical properties of oil. This paper provides a brief background discussion of the oil degradation process, followed by a description of the sensor operational principles and the correlation of the sensor output with physical and chemical engine oil properties.
Technical Paper

“Seizure-Delay” Method for Determining the Seizure Protection of EP Lubricants

IT does not yet seem to be recognized fully that it is the local temperature at the surface of contact and not the local specific pressure that chiefly determines the occurrence of seizure under extreme-pressure-lubrication conditions. This local temperature is the result of the temperature level of the parts lubricated, considered as a whole (“bulk” temperature) and of a superimposed instantaneous temperature rise (temperature “flash”) which is localized in the surface of contact. It appears typical for extreme-pressure-lubrication conditions, as met in gear practice, that the temperature flash is much higher than the bulk temperature. With existing conventional test methods for the determination of the protection against seizure afforded by EP lubricants, a considerable rise of the bulk temperature mostly occurs; as it cannot be controlled sufficiently; thus, leaving an unknown margin for the temperature flash, it renders impossible a reliable determination.
Technical Paper

“Second-Generation” SAE 5W-30 Passenger Car Engine Oils

Abstract High performance lubricant additive systems have been developed to formulate SAE 5W-30 passenger car engine oils which meet current and anticipated requirements of the North American original equipment manufacturers. The trend in North America is to recommend SAE 5W-30 oils that not only meet the API SF requirements for gasoline engines (“first-generation” oils), but also meet the stringent API CC requirement for light duty diesel engines (“second-generation” oils). Furthermore, the engine builders have issued “world specifications” for motor oils which incorporate additional “second-generation” SAE 5W-30 characteristics, such as enhanced API SF limits, improved fuel efficiency, an increased margin of bearing protection, and lower finished-oil phosphorus levels. The additive systems described herein exceed API SF and CC requirements as well as “second-generation” performance hurdles.
Technical Paper


Research information on solid lubricants has been compiled for consideration in the possible use of such materials in aircraft electrical equipment. Solid lubricants are capable of lubricating at the maximum temperatures (600° F) for aircraft electrical equipment. Many solids that adhere well to metals may be useful lubricants; those with layer-lattice structure usually give low friction. Solid lubricants are most commonly used as bonded films but the use of fluid carriers and surface reaction products have considerable merit.
Technical Paper

“MBE 4000-A New Engine for the US Class 8 Truck Market”

Due to ever soaring fuel costs and even more stringent emission regulations which require more elaborate technical efforts and unfortunately lead to a negative trend on fuel economy as well, todays and future trucking business is extremely challenged. These facts create an urgent requirement for the engine manufacturer to offer an engine with an optimized cost-benefit-ratio for the trucking business. Mercedes-Benz, as the leader in the European commercial vehicle market - of which e. g. high fuel costs, long maintenance intervals and high engine power-to-weight ratios have always been key characteristics - has developed a new class 8 engine for the US market. The MBE 4000 is a 6 cylinder inline engine in the compact size and low weight category, but due to its displacement of 12,8 liters it offers high performance characteristics like heavier big block engines.
Technical Paper

“Hot Tube Test”-Analysis of Lubricant Effect on Diesel Engine Scuffing

To prevent engine scuffing in the field a new laboratory test called the Hot Tube Test has been established in order to evaluate the high temperature stability of diesel engine oils. In a strip mining application field test using 47 bulldozers powered by the same engine type, half of the engines suffered from piston scuffing failures when operated on a variety of commercially available API CD quality SAE 30 Grade engine oils. All the field test oils have been investigated using the Hot Tube Test, and an analysis of the results indicates that it would be possible to accurately predict scuffing failures by this test method. Furthermore, the reliability of this analysis has been verified by bench engine testing on reference oils. The reasons why the Hot Tube Test predicts the anti-scuffing performance of engine oils are discussed.
Technical Paper

new Fluoroester Lubricants for high-temperature applications

THE NEED for greater speed in military aircraft and missiles is, without question, the primary force behind the current quest for lubricants of increased thermal and oxidative stability. Turbojet engines soon to be available will require improved lubricants for trouble-free operation. Once developed, these oils may find use in the engines of future civilian aircraft as well as in a variety of special applications. It is the purpose of this paper to discuss the results of an experimental program in the field of high-temperature lubricants. Problems of relating chemical structure to the physical properties and performance of highly fluorinared ester lubricants will be described. Background information in the field of turbojet engine lubrication will be presented.
Technical Paper

Zinc Dialkyldithiophosphate-Dispersant Interactions: Effects on Solution Behavior and Wear

Interactions between a Zinc dialkyldithiophosphate (ZDP) and three different commercially available succinimide dispersants were observed through changes in solutions behavior, as determined by viscometry and Fourier Transform Infrared spectroscopy (FTIR), and four-ball tests. The viscometric response observed for two component blends of ZDP and succinimide dispersant in white oil changed as a function of the molar Zn to N ratio, indicative of specific interactions. The break in the viscometric response curve occurred at Zn:N=0.13 for all three succinimide dispersants. FTIR spectra of the same ZDP-dispersant blends were examined and similar Zn:N dependencies were observed. Four-ball tests measuring wear scar diameter, seizure load and weld load showed a dependence on the Zn to N ratio similar to that observed by viscometry. At very low Zn to N ratios wear and seizure load were decreased, while at higher ratios the seizure and weld loads were increased over that for ZDP alone.
Technical Paper

Zero-dimensional Model and Pressure Data Analysis of a Variable-Displacement Lubricating Vane Pump

A zero-dimensional dynamic model was developed in the Matlab/Simulink® environment to predict the behaviour of a variable-displacement lubricating vane pump for internal combustion engine applications. Based on the geometric and kinematic characteristics of the pump, the model allows predictions of the pressure evolution in each chamber of the pump and in the delivery piping, by employing an integrative-derivative approach. Simulation results were compared with experimental data of pressure transducers, which were fitted along the periphery of the pump case and in the delivery channel. The analysis of the experimental data shows that the pressure dynamics, which is experienced by the transducers, is in some cases quite different from the pressure dynamics in the pump chambers and produces pressure peaks which are not actually present in the original signal. The pressure transducers output was then also modelled in order to properly compare simulation results and experimental data.
Technical Paper

Worldwide Environmental Regulations and Their Impact on Lubricant Additives

Legislation in countries from all parts of the globe have been proposed or enacted in an effort to protect man and the environment from the effects of harmful chemicals. Since their inception these proposed or enacted laws have been effective safeguards in protecting man and the environment on a global basis. This paper reviews several of these regulations, including those enacted by the United States, the European Economic Community, Japan and Australia. General guidelines on what it takes to comply with these regulations and their impact on the lubrication industry will be discussed. Proposed regulations on marine pollution (MARPOL) and the effect of these regulations on the transport of lubricant additives and finished lubricants will also be reviewed.
Technical Paper

Wind-Tunnel Investigation of Commercial Transport Aircraft Aerodynamics at Extreme Flight Conditions

A series of low-speed static and dynamic wind tunnel tests of a commercial transport configuration over an extended angle of attack/sideslip envelope was conducted at NASA Langley Research Center. The test results are intended for use in the development of an aerodynamic simulation database for determining aircraft flight characteristics at extreme and loss-of-control conditions. This database will be used for the development of loss-of-control prevention or mitigation systems, pilot training for recovery from such conditions, and accident investigations. An overview of the wind-tunnel tests is presented and the results of the tests are evaluated with respect to traditional simulation database development techniques for modeling extreme conditions to identify regions where simulation fidelity should be addressed.
Technical Paper

Will It Run at 70 Below? A Progress Report on Arctic Winter Operation of Automotive Equipment

This paper describes special winterization aids and petroleum products that have been developed to make possible the operation of automotive machinery, on an emergency basis, at temperatures as low as -70 F. A package of five basic petroleum products appropriate for use on the North Slope of Alaska has served there successfully for several years at temperatures consistently in the -40 F range. The products may be blended to obtain additional properties. The motor gasoline and diesel fuels developed for this package are discussed, along with the pour point and viscosity properties of Arctic winter lubricants-motor oils, ATF and torque fluids, hydraulic oils, gear oils, and greases.
Technical Paper

Why Some Passenger Car Motor Oils Are No Longer Suitable for Motorcycles: Gear Pitting Issues

The new American Petroleum Institute (API) categories for passenger car motor oils have focused on improving fuel economy and reducing emissions. This has resulted in more fuel efficient oils being developed by lowering the viscometrics and by adding friction modifiers. The emissions reductions have resulted from lowering the percent phosphorus (%P) in the engine oils because phosphorus has been found to poison the catalyst in the catalytic converter. When friction modifiers were introduced, researchers from four Japanese motorcycle manufacturers published the results of their studies (SAE 961217) which indicated that low friction oil can cause too much slippage in starter motor clutches, one-way limited slip clutches, and wet multi-plate clutches. In that same study they reported that engine manufacturers use 10W-30 grade oil to develop new engine technology, and gear pitting was observed with oils of viscosity grades lower than 10W-30 in all four manufacturers' motorcycle engines.
Technical Paper

Wheel Bearing Lubrication Development for Low Friction and Water Resistance

Recently, vehicle production volumes have been increasing, particularly in newly developing countries that often lack adequate infrastructure. These regions utilize many unimproved roads and frequently experience heavy rainfall, requiring robust product features. In contrast, developed countries, with well-maintained infrastructure, have emphasized protection of the environment, requiring automobile manufacturers to target reductions in carbon dioxide emissions. Hub unit bearings, which enable smooth wheel rotation, are mounted at the wheel center. The hub bearing is a critical part which supports the automotive body and requires high reliability. To make environmental progress, hub unit bearings have increasing requirements for low friction. NSK has developed effective grease technologies to meet the diverse requirements of hub unit bearings, such as high reliability and low friction under severe environmental conditions.