Search Results

A new, low cost method to determine the accumulated structural loads in service (not to predict component fatigue life) that requires practically no on-board instrumentation is discussed. This method makes use of S/N fatigue life gages with high-gain mechanical multipliers bonded to a component. Permanent change in gage resistance results from the number of component load cycles and their magnitudes. These resistance change data are then used to reconstruct the load range history. The computer program on this method is listed in the Appendix. Results of laboratory tests conducted to validate the new method and evaluate the behavior of the multipliers over a practical range of operating temperature and strain magnitude and frequency are presented. The component load range distribution estimated by this method is compared to that measured by conventional methods for a vehicle operating on a proving ground route.

The analysis presented in this paper indicates that while 1700 lbf (7560 N) is a realistic femur fracture load for 30-50 ms duration impacts, the human femur can withstand higher loads for shorter-duration impacts. Experimental femur fracture data from cadaver and bone specimen tests are reviewed. These data are used to develop femur load fracture tolerance as a function of impact duration. On the basis of a measured 10% amplification of 1-2 ms input forces by the dummy, the cadaver fracture tolerance is proportionately adjusted to arrive at equivalent load levels for forces measured on current dummy test devices. Experimental dummy test device data are included and compared to the theoretical response of a mathematical model of the human upper leg. This comparison demonstrates that even neglecting the 10% amplification, there are still significant differences in the response of dummy and human upper leg structures for impact durations less than 3 ms.

IIEC efforts to develop NOx catalysts with improved durability have continued. Properties of several nickel oxide catalysts on pelleted, monolithic ceramic, and metallic supports are discussed and the engineering requirements for their effective use are defined. Some promoted nickel oxide, pelleted catalysts show good low-temperature activity, and produce minimal amounts of ammonia but are strongly deactivated by sulfur in the feed gas. Monolithic and metallic catalysts, on the other hand, although not active at temperatures below 1000 F, are very active at higher temperatures where deactivation by sulfur and ammonia formation are not troublesome.

This paper discusses the development of adequate criteria and evaluation methods for seat belt restraint design. These criteria should include the effect of seat belts in abdominal injury as well as head injury. It is concluded that belt load limiters and energy-absorbing devices should limit head-to-vehicle contact, ensure that the lap belt maintains proper contact with the bony pelvic girdle, and limit the belt loads. Studies are made of pulse shape and belt fabrics. Currently available mathematical models are used for the studies included in the paper.

The Kinematic Analysis Methods Computer Program that has been used by Ford Motor Co. to evaluate mechanisms for the past four years has been modified to generate performance curves for windshield wiper linkages directly using a Calcomp Plotter. Problems such as stalling, “jerky” operation, and excessive phase lag between wipers can be detected early in the design stages by careful evaluation of the curves.

This project developed and evaluated a catalyst system for oxides of nitrogen control to achieve target reduction levels established for the Inter-Industry Emission Control (IIEC) Program, with concurrent control of the hydrocarbons and carbon monoxide. The major effort described is the evaluation of catalysts and the development of a suitable exhaust gas-temperature environment. The objective was met, with the exception of long-term durability, by using a pelleted, nonnoble metal catalyst and a special container design.

Two types of catalysts were tested in a fleet of twenty-four 1969 vehicles, operated in customer-type urban driving regimes, on both leaded and nonleaded fuels over a period of 18 months. The two catalyst types and the converter systems chosen for this evaluation were selected on the basis of information obtained from an earlier test program involving four cars that were durability tested on a more rapid “test track mileage accumulation cycle.” Comparisons are made between the vehicles running rapid mileage accumulation and the vehicles running slower customer-type mileage accumulation. Catalyst life and system performance depreciation were relatively similar in both fleets and did not seem to be significantly affected by the method of mileage accumulation. The 24-vehicle fleet was equipped with a programmed protection system (PPS) designed to protect the catalysts from damage due to over-temperature operation. Problems with this prototype protection system are discussed.

This study was undertaken to determine to what extent the passenger car eye ellipses have applicability in van-type truck package design and to produce a new practical design tool, if necessary. Eye positions of van drivers were found to be distributed differently from those for passenger car drivers and from those obtained by the procedure outlined in SAE J941b, Motor Vehicle Driver's Eye Range. There were produced in this study, tables of parameter values that a van-package designer can use readily to position eye-location distributions in space as a function of the azimuth and elevation angles of many targets in the forward field of view. These tables are available upon request from SAE.

When Ford decided to offer a midrange diesel engine family in medium trucks, it was recognized that the power-train had to be considered as a complete system in order to assure optimum compatibility. This paper describes how program objectives were established and the necessary validation programs for the truck, engine, and the chassis were conducted.

A small-scale oxidation test for automatic transmission fluids has been developed. In the test air flow rates, temperature and catalytic activity can be closely controlled at desired levels. A test procedure for screening automatic transmission fluids is described. Data are presented illustrating the ability of the test to distinguish between different levels of oxidation resistance, the repeatability of the test, and the correlation achieved thus far with a presently used full-scale transmission oxidation test.

The design requirements for the frame as a load carrying member are discussed in relationship to a highway truck and its basic vehicle package. The theoretical and experimental procedures are given in detail to demonstrate the techniques for frame design. The features of a method to laboratory test a frame with correlation to service miles is discussed.

In 1962 and 1964 the Coordinating Research Council (CRC) evaluated the vapor locking characteristics of about 40 selected new model cars during centralized programs at Yuma, Arizona. Volatility tolerances were determined during acceleration following a hot soak at approximately 100 F ambient using two reference fuel series with diverse front-end volatilities. Fifty per cent of the 1962 model cars tested had a limiting vapor pressure equal to or less than 8.4 lb with the high volatility fuels and 9.7 lb with the low volatility fuels. Comparable values in the 1964 program were 8.9 lb for the high and 10.4 lb for the low volatility fuels. Analytical results obtained on vehicle tank samples for the first time during 1964 showed that limiting temperature at a given vapor-to-liquid ratio also was a useful parameter in defining car volatility tolerances.

Discussion of four factors pertinent to any overall ride evaluation. These factors are frame beaming, fifth wheel location, special body mountings, and variable loading conditions on tandem truck and tractor ride. The methodology for measuring the characteristics of these factors is reviewed and practical solutions for improved ride are given.

This paper gives a comprehensive analysis of vehicle understeer-oversteer, utilizing theoretical and experimental approaches. It departs from the conventional by defining understeer-oversteer in the transient as well as in the steady-state condition under various types of inputs. The relationship between understeer-oversteer and directional and oscillatory stability is stated within this concept. The paper introduces new definitions, based on transient condition analysis, for direct and indirect understeer, directional and oscillatory stability, side-slip velocity, and others. It employs a computer program evolved from the equations of motion, shown in the comprehensive Appendix, to analyze the basic nature of understeer-oversteer. New procedures are outlined for quantitative determination of vehicle understeer and stability. The paper discusses the relationships between understeer, oscillatory stability, and the subjective “feel” of passenger automobiles.

Most automobiles, at certain speeds with at least one window open, develop a pulsating pressure which is felt mainly through the ears and is objectionable to the occupants. While this “aerodynamic wind throb” is noticeable over a range of speeds, there is a fairly pronounced peak in the effect at one speed. This problem is studied analytically and experimentally. It is established that the car is a dynamic system consisting of a Helmholtz resonator excited by an edge tone. It is shown that the trouble can be corrected by changing the natural frequency, minimizing or eliminating the excitation, or increasing damping of the system.

THE Free-Piston Engine Program described in this paper was concerned with determining thermodynamic relationships of small, high-speed engines. The purpose was to establish proper engine geometry and mechanical design which could then be applied to developing larger automotive engines. The author outlines the problems encountered during the Program's beginnings: starting system, powerplant assembly, cooling system, and lubrication. The results indicated that the free-piston engine would be particularly applicable to the farm tractor. The author thinks that such a powerplant may equal or better the diesel engine in economy.

THIS paper describes the development and utilization of a new Ford free-piston power-plant, the model 519. Mr. Noren traces the development of the engine from the initial idea to the point where commercial utilization could be considered. Mr. Erwin describes one commercial use: in the Typhoon tractor. The ratio of size and weight to horsepower is favorable for farm tractors, being smaller and lighter than equivalent diesel engines. The performance of the tractor has been satisfactory thus far, operating smoothly and being practically vibration-free, with little noise. The advantages of the free-piston gasifier, as reported by the authors, are: flexibility, fuel economy, no need for auxiliary starting engine, economical manufacture of a wide range of engine sizes, adaptability to a wide range of fuels, and good torque characteristics.

AS a basis for the analyses of this symposium, a hypothetical car has been used to evaluate the engine power distribution in performance. Effects of fuel,-engine accessories, and certain car accessories are evaluated. The role of the transmission in making engine power useful at normal car speeds is also discussed. Variables encountered in wind and rolling resistance determinations are reevaluated by improved test techniques. Net horsepower of the car in terms of acceleration, passing ability and grade capability are also summarized.

PROPER protection of metal parts operating as bearing surfaces, or in contact under relatively heavy loads, during the break-in period often means the difference between successful operation and failure. Various surface coatings have been investigated to discover which ones will give this protection. The authors discuss here three types of surface treatment for cast-iron and steel that do give superior wear and scuff resistance.