Search Results

A drag dynamometer was used to evaluate the performance of automotive brake drums made from four kinds of materials with different thermal conductivities. In the order of decreasing thermal conductivity they are chromium copper, aluminum/cast iron composite, cast iron, and nickel-aluminum bronze. All of the drums were of the standard configuration used in SAE J 661a, or closely approximated it. The drums were run in conjunction with three types of lining materials: nonabrasive, moderately abrasive, and highly abrasive. Temperatures near the lining/drum interface, coefficients of friction, and lining wear were measured and compared. For a given amount of work done, the temperature near the drum surface was found to be lowest for the chromium copper drums, with progressively higher temperatures in the aluminum/cast iron composite, nickel-aluminum bronze, and cast iron drums. Relative lining wear and coefficient of friction varied with the type of lining tested.

Safety legislation and its implication on equipment design in the agricultural and light industrial equipment industry is mounting at both a state and federal agency level. A need for greater recognition of the contributions which all members can make in the area of health and safety through technical societies such as SAE is in order.

Concern has been expressed over the effects on various industries if electric vehicles obtain an appreciable percentage of the automobile market. Given the state of development of such vehicles, the capability of the power industry, and the availability of off-peak power, it is felt that development of the electric vehicle market will be very gradual with minimum disruption of the automobile industry, the electric power industry, the petroleum industry, or their suppliers.

This paper presents an evaluation of the metric system within the United Kingdom. Psychological, administrative as well as technical aspects of metrication are discussed. At the present time, the British Government supports the metric change, but is relying on industry to execute the program. Implementation and publicity of metrication is discussed in terms of trade and general acceptance.

There are many indications that Canada is moving slowly toward adoption of the metric system. Some groups and industries are making extensive use of it; other groups are laying plans or making preparations. Some metric standards are being published, while the Government of Canada is studying the implications of a change. As yet, no definite decision has been reached, and no national schedule for change has been established. Many Canadians are anxious to get on with the change, but realize that for economic reasons it will have to be coordinated with similar action in the United States.

Cast iron has been used as an engineering material for 2000 years. The concept of an integral hub is not new to the automotive engineer since it dates back at least 40 years. For economic considerations, the use of cast iron has been merged with the concept of an integral hub and disc for passenger car usage. This paper discusses the various problems involved in the utilization of cast iron and includes details of various tests and their results necessary to prove out this design.

This paper covers progress made by General Motors in development and use of the SHED technique since report of its initial development to SAE in January, 1968. Additional details are given on SHED leakage, interior temperature, and car background emission. Auxiliary equipment developed to facilitate evaporative emission testing is described. Methods of emission control hardware evaluation are discussed, for which the SHED technique has unique capability.

NON DESTRUCTIVE TESTING OF BRAKE LINING Every piece of brake lining must meet standards which relate production lining to lining tested on the vehicle for approval. To accomplish this purpose limits have been set on Cure, Strength, Hardness, Specific Gravity and Appearance, and these characteristics must be measured on a production basis. New techniques developed to measure these characteristics rapidly and non-destructively are; Electrical Conductivity for Cure, Loaded Rollers for Strength and Gamma Radiation Gauges for Specific Gravity. These techniques, plus Gogan hardness and visual inspection, have been coupled with systematic recording of measurements on experimental lining.

Catalytic converters have been combined with other emission control methods to arrive at very low emission levels. Two cars with catalytic converters successfully completed 50,000 miles on an AMA driving schedule. However, the catalyst required a nonleaded fuel for acceptable life and contained a noble metal which makes it unsuitable for large volume usage. The search for a physically durable, chemically active, and economical catalyst, which will operate with leaded fuel, continues. In addition, durability of the catalytic converter system under the wide variety of operating conditions in customer service must be established.

This study describes the changes in the chemical composition of the exhaust at various equivalence ratios (air-fuel weight ratios) when pure isooctane, diisobutylene, toluene, and toluene-n-heptane mixture are used as fuels in a single-cylinder engine, operating at constant conditions. Isooctane and diisobutylene combustion produced large concentrations of olefins in the exhaust, while toluene produced small amounts of ethylene as its only olefinic product. The olefins, in general, showed a strong temperature dependence and exhibited maximum emissions near the stoichiometric equivalence ratio. Combustion of the mixture of 25 volume percent n-heptane in toluene reveals interesting information, compared to emissions from pure toluene: concentrations of ethyl-benzene, styrene, and dimethylacetylene surprisingly are increased by factors of 1.9, 1.9, and 2.1, respectively, probably because reactive radicals derived from h-heptane interact with toluene to form unsaturated molecules.

With the advent of disc brakes as standard equipment on some vehicles, an integral ductile iron steering knuckle has been developed to replace the assembly of a separate forged knuckle, steering arm, and disc brake housing bracket. The flexibility of the casting process has been applied to take advantage of the properties of ductile iron and to permit combination of components. The simplicity of the integral knuckle concept, which eliminates assembly operations and fasteners, makes the design inherently more reliable. A series of non-destructive tests has been devised to assure casting quality. The paper describes the general approach to designing castings in ductile iron for this application, considering both functional and manufacturing requirements.

Auto exhaust emission surveys and surveillance programs have shown 10:1 ranges in amounts of hydrocarbon and carbon monoxide emitted by individual cars. Low levels of hydrocarbon and carbon monoxide emissions can be maintained from properly tuned engines. The most practical method to reduce auto pollution would be to identify the high emitters and require proper maintenance. The purpose of this investigation was to examine existing data from auto exhaust emission surveys and surveillance programs in order to recommend a practical and efficient testing procedure for auto smog inspection. A new mathematical approach is used to discover which modes of the seven mode standard test are most discriminating for the high emitters of carbon monoxide and hydrocarbons. The idle mode is shown to be the best mode for identifying the high emitters. A 40 sec idle test is developed and applied to tune-up data.

It is necessary to establish separate test procedures that evaluate the many different performance parameters required of pneumatic tires. The ability to operate at high speeds is one of the more important requirements. This paper describes the physical properties needed for various high speed performance potentials. It also shows that, with a relationship established between laboratory and road, laboratory testing permits more accurate evaluation.

A comprehensive method for predicting the mass and composition of evaporative losses from fuel tanks and carburetors and a computer program embodying the method are presented. This method was developed as one phase of the work on automotive evaporative emissions in the Inter-Industry Emission Control program*. It is presented as a tool to assist in the design and evaluation of fuels and vehicle evaporation control systems; it is not intended as a substitute for compliance testing. The prediction method makes use of published equations for carburetor loss, tank loss, and loss composition. Calculated losses are compared with measured losses from several published studies. The accuracy and the limitations of the method are described, and some relationships between losses and fuel and fuel system parameters are shown.

Treadwear is the most important aspect of tire performance to the consumer. Despite this, little is known about the fundamental mechanism of wear and no suitable laboratory methods are available for evaluation. Testing of treadwear must be done on the road and, as a result, is subject to a wide variety of ambient, vehicle, road, traffic, and driver differences. Typical mileages obtained in various parts of the country are reported here and current techniques used by tire companies to measure treadwear are summarized. Various possibilities of improving wear and the effect these would have on other properties are also discussed.

Diesel smoke measurements were made over a broad range of smoke intensities with seven different commercially available smokemeters using a 4-cycle engine and a 2-cycle engine operated under steady-state conditions on two fuels of different smoking tendencies. Exhaust soot concentrations were also measured by two filtering methods, and smoke was rated visually by two trained raters. Correlations among the smokemeter readings did not differ with either fuel or engine. A nomograph correlating smokemeter readings was prepared, and agreement with published data appears generally good except for high readings from one continuous filtering smokemeter exposed to high sampling pressure, and unexplained low readings from a light-dispersion meter. The CRC Smokemeter Group believes these correlations, with the exceptions mentioned, give a firm basis for comparing measurements made with different smokemeters.

Product problems can be divided into two general categories: “vital few” and “trivial many.” This paper suggests ways to identify the two types of problems and different approaches to solving each type. Recommendations are made for obtaining complete, accurate, and timely problem definition from the field. A system for identifying cause and responsibility for solution, and improving the efficiency of arriving at a satisfactory solution is recommended for “vital few” problems. A task force approach for solving “trivial many” problems is recommended. Specific field problems are used throughout the paper to illustrate the suggestions and recommendations.

This paper discusses and compares manual and on-line computer systems for evaluating the performance of exhaust emission control systems for motor vehicles. Also discussed in detail are two applications for an on-line data acquisition and reduction system with step-by-step procedures to aid those interested in reducing the delays normally experienced with manual reduction.

The “identification of systems” is a generalized form of curve fitting pertaining to systems for which a mathematical model is known, and for which input/output data is empirically available, but for which actual values of parameters in the model are unknown and are sought. A technique for identification (that is, determination of parameters) in second-order, dynamic systems is presented and applied to a typical system; namely, a two-axle rubber-tired vehicle. The scheme is based on establishing a set of system model equations and their use with system response data to define one or more residue functions in a manner analogous to the defining of an error function in curve-fitting by the collocation method. A performance index is defined by treating the residue as a measure of least squares fit, and the parameters are then determined by finding the set of values which simultaneously makes all the first partial derivatives of this index with respect to the parameters vanish.

A new concept of a ductile iron integral steering arm, brake caliper support, and steering knuckle has been developed. This has inherently higher reliability, fewer fasteners, and fewer human variables than the assembly it replaces.