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Design changes in new model cars have resulted in higher under-the-hood temperatures. This has created a demand for rubber components that are more heat resistant. Since ethylene propylene terpolymer (EPDM) is a heat and weather resistant polymer being considered for many of these applications, this paper is presented to show the effect of various cure systems on heat resistance of EPDM compounds. The common sulfur cure system is useful to 300°F and the use of a sulfur donor system can extend that range to 350°F. Above 350°F a peroxide cure is shown to be necessary.

The effects of nonpolymer constituents and antioxidants on the aging behavior of nitrile rubber polymers are discussed. The paper covers experimental work carried out to develop a range of rubbers which are responsive to heat resistant curing systems, the optimization of these systems in terms of antioxidant protection, and the practical use of this type of nitrile rubber in compounding to meet critical specifications. The authors conclude that nitrile rubber polymers produced according to the SP principle offer excellent heat resistance in a variety of curing systems. Furthermore, such polymers have an advantage over nitrile polymers produced with stabilizers which function as efficient antioxidants, since this latter type of polymer can detract from aging resistance, depending on the curing system used.

The use of hydraulics offers a power brake system that provides the higher pressures required to meet the new federal safety stopping distance regulations for some passenger car and truck applications. The design and operating characteristics of the Bendix Hydro-Boost hydraulic power brake booster are explained.

Ion plating and sputtering offer materials engineers versatile coating methods. Both processes use a controlled pressure chamber and vacuum equipment. Sputtering is essentially a line of sight deposition method. The coating material is partially ionized, following electrical lines of force, during ion plating, uniformly coating the substrate configuration. Both processes-their applications and advantages-are discussed. Although the processes are not economically competitive with electroplating or other conventional coating methods, the properties they provide may offset the costs.

Ion plating is a deposition process whereby high energy ions of plating material are extracted from a plasma at high energy and applied as diffusion coatings to a negatively charged substrate. Ion plating is done in a vacuum and offers an extremely wide choice of material combinations and very fast deposition rates. Thick films of refractory compounds can be ion plated onto surfaces without changing the roughness or topography of the surface. Excellent throwing power offers uniform film thickness even with three-dimensional substrates. The economics of ion plating make it attractive both for decorative and functional applications.

Dynamometer tests of a production disc brake provided new information on asbestos fiber emissions during break-in, normal use, and high temperature use conditions. Both ambient air and brake cooling air were sampled isokinetically, using 0.45 μm filters. Examination of test and background filters required a clarification process to maximize fiber detectability, the use of transmission electron microscopy (at 40,000X) for detection, and electron diffraction for positive identification of asbestos fibers. Most of the lining asbestos was found to be converted to a nonfibrous material by the high flash temperatures of the braking surface. Less than 0.02% of the lining wear was released as asbestos fibers. The concentration of asbestos fibers in the urban atmosphere, due to brake usage, was conservatively estimated at less than 0.07 X 10-9 g/m3. Based on this upper bound, the use of brakes was judged to be not significant as a source of atmospheric asbestos.

A review is made of available data on fuel economies of the current internal combustion engine-powered automobiles and of those with alternative powerplants. Comparisons of fuel economies of all these engine systems are made on the basis of the vehicle weight/engine displacement, and the vehicle weight alone. The thermal efficiencies are also compared. It is shown that several versions of the diesel engine which meet the 1975 Clean Air Act Standards and which are on the road today are more efficient than the conventional internal combustion engine of 1973. Moreover, prototypes of other alternative systems, using other cycles (Brayton, Rankine, Stirling) under development are also projected to provide higher efficiencies than the conventional internal combustion engine of 1973. All comparisons are made using the federal driving cycle as a common reference.

Ion plating is a high-energy or plasma deposition method which essentially consists of sputtering and ion implantation (thermal evaporation with ionization). During ion plating, deposition is by ions as opposed to atoms. Ion plating has the two distinct characteristics of high throwing power and high kinetic energy. The high throwing power is responsible for coating complex geometrical surfaces with a uniform film without rotation. The high kinetic energy of the ion flux forms a graded interface; as a result a very adherent film is formed. Mechanical tests (tensile, fatigue, and friction) show a very strong adherence of the film and even an increase in mechanical properties such as tensile strength and fatigue life.

Since 1968, vehicle weight increases and emissions controls have reduced fuel economy substantially. Additional losses in economy and acceleration will be experienced through 1976. Recommendations are made to lessen the impact of the predicted losses. Factors influencing fuel economy and acceleration are examined for an intermediate car. Changes in engine efficiency and displacement, compression ratio, torque converter, transmission, axle ratio, aerodynamic drag, tires, accessories, vehicle weight, and emissions controls are examined. When practical, the effects of 10% changes are analyzed. Comparisons are also made with a subcompact and a luxury vehicle.

This paper discusses fuel economy in present automobiles and shows that as vehicle weight has increased and emission controls have become more stringent, fuel economy has deteriorated and will probably continue to do so. Weight is seen as the significant factor in reduction of fuel economy and performance, and smaller cars are seen as a possible solution to the problem.

A methodology is presented for analyzing springback of biaxially stretched panels as found in automobile exterior body panels, thus permitting determination of draw die overcrown. Good correlation is shown between the computer generated theoretical predictions and experimental data.

This paper presents the outlook for gasoline supply and demand in the United States as now envisioned. It includes discussions of present oil supplies as well as future ones, of refinery capacity and its projected shortage, and of gasoline consumption and supply through 1976 and beyond. Without government and public support, it is doubtful that the necessary refinery capacity can be accomplished.

The United States petroleum supplies cannot keep up with the demands made upon them by the use of automobiles. Increased importation of oil is not a satisfactory long-term solution. Supplies of coal, nuclear, and solar energy, however, are abundant. We suggest that “clean” fuels could be synthesized from these resources by using these abundant materials. This paper examines the possibilities of making methanol, ethanol, hydrogen, and ammonia for use as vehicle fuels. In the short term, methanol and mefhanol-gasoline blends appear attractive. In the long term, hydrogen is ideal if its handling problems can be solved.

This paper discusses the present automobile situation in the United States, in terms of environmental damage, excess weight and low fuel economy, and how the public is forced to deal with traffic. The paper stresses that the automotive engineering industry can alleviate some of the problems by designing and marketing smaller, more efficient cars and by being attuned to the effects of present-day automobiles. Several suggestions are made, including a miles-per-gallon tax and environmental stickers on new cars, next to price stickers.

Modern electronic diagnostic equipment, which displays fuel injection pressure curves, combustion pressure patterns and compression quality, has been used to improve the reliability and repeatability of laboratory engine tests used for lubricant development and evaluation. Major savings in man hours per test engine and greater engine availability have been obtained, along with great improvement in test repeatability. The same equipment used in fleet maintenance has provided significant savings by detecting incipient breakdowns in time to make repairs and avoid engine replacement and on-the-road failures. The fleets tested showed 10-25% of the vehicles had specific malfunctions which could produce costly failures if not immediately repaired.

Comparative test results are presented covering the following four types of truck compressed air dryers; aftercoolers, centrifugal filters, dessicant dryers, and wet tank heat exchangers. The purpose of this paper is to discuss the operating characteristics of each of these types of dryers under varying operating conditions expected in truck usage and to determine the most appropriate use of each dryer type. The results of these tests show, that except for unusually slow vehicles with heavy brake use, the wet tank heat exchanger is the best overall dryer available. This dryer is useable on even slow moving delivery trucks. The aftercooler is the second best overall choice and can be used on slow vehicles with excellent results.

This paper describes a new 2-cyl, reciprocating type, air compressor designed for use as an air source for heavy-duty truck air brake systems. It explains the objectives of a new design and how these objectives were met. A short history of present compressor deficiencies is given, together with recommendations to avoid these shortcomings. Emphasis is placed on positive design features to control oil consumption and minimize the formation of carbon. Also described are design features to eliminate structural failures on highly stressed, critical components found in present-day air compressors.

A test method for accurately determining the noise levels of truck cooling fans, as a function of their performance, has been developed. Correlation between the calculated results, using this test method, and experimental results of tests with a simulated truck cooling system environment has been demonstrated. Since fan noise is a major component noise source for trucks, this procedure is of particular interest to engineers involved in meeting legislated vehicle noise levels.

Combustors suitable for both simple- and regenerative-cycle automotive gas turbine engines have been designed and rig developed for low exhaust emissions. The simple-cycle combustor has demonstrated potential for meeting the EPA 1976 automotive emission standards, employing simple practical hardware with no variable geometry. Low emissions have been rig demonstrated with the regenerative combustor, but techniques such as variable geometry and/or regenerator bypass will probably have to be used to achieve target emission levels. Severe transients under actual driving conditions of the regenerative engines are expected to make it particularly difficult to duplicate rig results.

The development of two low emission combustors for an automotive Rankine cycle engine is described. Emphasis has been placed on low emissions, fast response, compactness, and low parasitic power. Air atomization and rotary atomization of fuel have been incorporated, leading to two different combustor configurations. Emission characteristics of hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx) are described for both concepts. HC and CO emissions have been generally found to be well below 1976 federal standards for automotive emissions. Fine atomization of fuel and thorough air-fuel mixing have been found to be the keys to low NOx emissions. The use of exhaust gas recirculation reduced NOx emissions significantly. Effects of excess air and cooled primary zone are also shown.