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Metal Oxide Particle Emissions from Diesel and Petrol Engines

All internal combustion piston engines emit solid nanoparticles. Some are soot particles resulting from incomplete combustion of fuels, or lube oil. Some particles are metal compounds, most probably metal oxides. A major source of metal compound particles is engine abrasion. The lube oil transports these abraded particles into the combustion zone. There they are partially vaporized and ultrafine oxide particles formed through nucleation [1]. Other sources are the metallic additives to the lube oil, metallic additives in the fuel, and debris from the catalytic coatings in the exhaust-gas emission control devices. The formation process results in extremely fine particles, typically smaller than 50 nm. Thus they intrude through the alveolar membranes directly into the human organism. The consequent health risk necessitates a careful investigation of these emissions and effective curtailment.

Ionic Liquids as Novel Lubricants or Lubricant Additives

For internal combustion engines and industrial machinery, it is well recognized that the most cost-effective way of reducing energy consumption and extending service life is through lubricant development. This presentation summarizes our recent R&D achievements on developing a new class of candidate lubricants or oil additives ionic liquids (ILs). Features of ILs making them attractive for lubrication include high thermal stability, low vapor pressure, non-flammability, and intrinsic high polarity. When used as neat lubricants, selected ILs demonstrated lower friction under elastohydrodynamic lubrication and less wear at boundary lubrication benchmarked against fully-formulated engine oils in our bench tests. More encouragingly, a group of non-corrosive, oil-miscible ILs has recently been developed and demonstrated multiple additive functionalities including anti-wear and friction modifier when blended into hydrocarbon base oils.

Traction Coefficient Measurement

Aviation oils provide thin lubricating films between highly stressed bearing, gear and other lubricated contacts. The stresses and shear rates cause rapid rheological changes in the oil which affect the traction (friction) between the surfaces. Thin film dynamic forces are associated with the molecular structure of the oil provided by the oil supplier. Traction force divided by the normal load (i.e. traction coefficient) can be viewed as a fundamental property of aviation oil. Its value is a function of stress, temperature and shear rate. Appropriate measurements are made under dynamic conditions to characterize aviation oil products for engineering design purposes and service performance prediction.

SAE International Journals Complete Set

This set includes: SAE International Journal of Aerospace March 2010 - Volume 2 Issue 1 SAE International Journal of Commercial Vehicles October 2009 - Volume 2, Issue 1 March 2010 - Volume 2, Issue 2 SAE International Journal of Engines October 2009 - Volume 2, Issue 1 March 2010 - Volume 2, Issue 2 SAE International Journal of Fuels and Lubricants October 2009 - Volume 2, Issue 1 March 2010 - Volume 2, Issue 2 SAE International Journal of Materials and Manufacturing October 2009 - Volume 2, Issue 1 March 2010 - Volume 2, Issue 2 SAE International Journal of Passenger Cars - Electronic and Electrical Systems October 2009 - Volume 2, Issue 1 SAE International Journal of Passenger Cars - Mechanical Systems October 2009 - Volume 2, Issue 1 March 2010 - Volume 2, Issue 2
Technical Paper

High-Speed High-Efficiency Engines

MARKED improvement in high-speed high-efficiency engines will be accomplished during the next few years, according to the author. They will have better balance, longer life and greater efficiency, and will develop more power and be more satisfactory to the motoring public. Details of recent developments in this class of engine are given by the author after remarking that the present trend is toward a large number of small changes in design and construction rather than toward radical departures from former design and methods. Mr. Duesenberg comments upon the main features of design of his 91-cu. in. racing-car engine and its parts, and on the troubles that necessitated design changes. The combustion-chamber is stated to be the most important contributor to high efficiency. If the shape of the combustion-chamber, the area of the valves, and the location of the valves and spark-plugs are not right, all the other refinements of detail are of little value.
Technical Paper

Specification-Writing for Petroleum Lubricants

ALL large users of petroleum lubricants are endeavoring to reduce to printed form their individual ideas of what the lubricants they want should contain and what their physical and mechanical properties should be. The lubricants manufacturer finds, however, that anarchy prevails among the requirements and that the technique of writing the specifications is distinctly amateurish. One method followed is to analyze a satisfactory lubricant and embody the results in the specifications, but the specifier does not know that the product is the best for his purpose and does not possess the facilities for accurate analysis and the ability to determine the pertinent from the irrelevant factors. Another method is to select from a number of analyses and specifications items that seem important and incorporate them in the writer's specification. The result calls for a non-existent hybrid that may be impossible to produce.
Technical Paper

Load-Carrying Capacity of Extreme-Pressure Lubricants

THE choice of a suitable lubricant for a given mechanism involves a study of the relation between the various factors of design, operation and lubricant characteristics. One of the most important phases of the extreme-pressure-lubricant problem is the development of laboratory apparatus and test methods for the determination of the characteristics of a lubricant that are significant measures of its service performance. During the last year the U. S. Bureau of Standards has undertaken a comprehensive study of the problem of extreme-pressure lubricants in cooperation with the S.A.E. Lubricants Research Subcommittee. Since the primary requisite for an extreme-pressure lubricant is that “it lubricate under high load,” it was decided that a start on this program be made with an investigation of the load-carrying capacity. The preliminary tests are described, the effect of speed and temperature is considered, and the apparatus and procedure are explained.
Technical Paper

Journal-Bearing Friction in the Region of Thin-Film Lubrication1

AUTOMOTIVE engineers, who have to deal with high-speed high-load journal bearings and are confronted with fear of the consequences of “ragged-edge” thin-film lubrication, will find much of interest and value in this report. It covers the information obtained and conclusions reached as a result of the extension of research into the region of thin-film lubrication, in which little investigation has heretofore been made. Tests made in a four-bearing machine, using both high-tin babbitt and high-lead bronze bearings and operated on lubricants of various viscosities over a wide range of speed and load, showed conclusively that the coefficient of friction depends directly upon the viscosity even in the thin-film region. They indicated defnitely that the friction coefficient is more likely a function of ZN/√P than of ZN/P.
Technical Paper

Fundamentals of Automotive Lubrication

SATISFACTORY performance of a lubricant depends upon characteristics of the lubricant, operating conditions and design of the device in which the lubricant is used. Applied lubrication requires a study of the relation among these factors in their effect upon performance. The authors treat journal bearings, ball and roller bearings and gears. Equations are given for journal bearings operating under various conditions of design, lubrication, friction and heat dissipation. The authors conclude that neither ZN/P nor PV alone is adequate as a measure of the power dissipated by a bearing, a composite relation involving both terms being required over a large part of the operating range. They show that each bearing has a minimum value of ZN/P below which it may get into the unstable region of thin-film lubrication and fail.
Technical Paper

Factors Controlling Engine-Carbon Formation

THE Conradson carbon-residue test is the generally accepted method for predicting the relative quantities of carbon an oil will deposit in an engine. This belief arises from the fact that, although publication of results of earlier researches in this field have shown that volatility of the oil is a controlling factor, it has been assumed that in all cases volatility is measured by the carbon-residue test. The results of tests conducted by the authors, covering a period of about two years, show that no such general relationship exists when the carbon-forming characteristics of a wide variety of oils are considered. This conclusion is drawn from 50-hr. tests of a large number of commercial lubricating oils in an engine operating under fairly heavy load and at moderate speed. The authors found that the volatility of the oil is the primary factor in engine carbon-deposition, and a laboratory method was developed for indicating the total volatility of a motor oil.
Technical Paper

Production of Gasoline and Lubricants by Hydrogenation

AFTER briefly describing the hydrogenation process and its three characteristic reactions, purification, stabilization and homogenizing, that remain unaltered in direction although they all change in extent, the authors discuss the possibilities of applying the process to the production of motor-fuel and lubricating oil. The possibilities offered by the process of reforming the molecular structure of petroleum hydrocarbons along directed lines to obtain products of the so-called paraffinic or naphthenic type are stressed. This presentation is supplemented by data on the actual properties and performance characteristics of hydrogenated gasolines and lubricating oils as tested by the fuel and lubrication laboratories of the Standard Oil Development Co. Two series of tests were run, one on a White motor-truck engine and the other on a Mack motor-truck engine, the latter being under abnormally severe conditions.
Technical Paper

Air-Cooled Cylinder-Head Design

THE TWO MAJOR REQUIREMENTS for good cooling of an air-cooled cylinder-head are (a) adequate conductivity from the zones of maximum heat-flow, that is, the spark-plug bosses and the exhaust-valve seats, elbows and guides, to a sufficient area of finning, and (b) the maintenance of a high-velocity air-flow over the entire length and depth of all fins. Solution of the problem of (b) depends upon many items in the engine installation outside of the cylinder-head. A limit to possible power output of the cylinder is set by detonation, which, with a given fuel, depends upon the cylinder-head temperatures. As these temperatures are the basic index of operating conditions of air-cooled engines, the author states that a head thermocouple instrument should be standard equipment on every airplane, and pilots should be trained to respect head temperatures as much as they now respect oil pressures and temperatures.
Technical Paper

The Field for Synthetic Lubricating Oils

ONE method employed in a fundamental investigation of the composition of lubricating oils as it affects the viscosity characteristics has involved the synthesis of viscous oils by polymerizing a wide range of olefins with a condensing agent, such as aluminum chloride. Many thousand gallons of synthetic lubricating oils have been made within the last two or three years from olefins produced by cracking paraffin waxes. Details of the process have been published previously and hence are not included. The present paper deals with the characteristics of two such oils that have been synthesized in commercial quantities. The raw materials and the process of manufacture make these more expensive than ordinary motor oils, but their temperature-viscosity characteristics make them desirable for use in transmission and steering mechanisms and in hydraulic shock-absorbers, as they are less susceptible than the usual oil to viscosity changes with changes of temperature.
Technical Paper


Very few data seem to be available on the frictional losses in automobile engines caused by the failure of the oil to perform its function as a lubricant. The researches of the Lubrication Inquiry Committee in England indicate that the friction of a flooded bearing is proportional to the speed of the engine, the area of the bearing and the viscosity of the lubricant and is independent of the pressure and of the materials of which the opposing surfaces are composed. The principal sources of friction in an engine are the crankshaft, the camshaft and the connecting-rod bearings, which rotate; the pistons and the valves, which slide; and the auxiliaries, such as the generator, the pump and the distributor.
Technical Paper


Methods adopted and results obtained in an investigation of the formation of carbon in an internal-combustion engine and its influence on the performance of the engine, as carried out by a series of tests, are described by the author. It was found that special methods of controlling the character and quantity of lubricating oil that reached the combustion-chamber were necessary to obtain concordant results on successive tests. Four factors are believed to control the formation of carbon in an engine, namely, (a) quantity of oil that reaches the combustion-chamber, (b) quality of the oil, (c) rate of breakdown of the oil in the chamber, and (d) time. Secondary factors are important only insofar as they influence these primary factors. Certain substances are shown to accelerate or retard the rate of formation of carbon. Carbon is shown to increase materially the indicated thermal efficiency of an engine operating under conditions such that no detonation or preignition occurs.
Technical Paper


Always prominent in the thoughts of automotive engineers, the lubrication of an internal-combustion engine presents continuous interest in that characteristic and elusive lubrication difficulties exist which largely baffle correction. Many of these difficulties are still existent because, according to the authors, more energy has been expended in correcting diseases of the lubricating system than has been spent in preventing the diseases by original design. When analysis is made of what has been done in the last few years of study on lubrication, it is irksome to realize that we still have to contend with all the former troubles such as oil-pumping or over-lubrication, fuel dilution of the oil supply, lubrication failures under certain conditions of engine operation, excessive wear on engine parts, and high maintenance-costs.