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The UACL JT15D-1 engine is a 2200 lb thrust turbofan engine of the high bypass ratio type, the first small engine of the type to be certified and placed in production. The engine is briefly described, and the scope of development testing and resources applied is reviewed. A selection of major development problems is covered, and future developments are indicated.

The battery electric vehicle has had limited success except in the United Kingdom, where large fleets operate mainly for the dairy industry. Changing social conditions are now bringing modifications to these fleets where many vehicles are used as traveling shops dealing in a wide variety of domestic goods. The development is seen as the forerunner of wider use of general-purpose vehicles, requiring improved performance and range. The operating costs and high reliability of the vehicles have been proved. Some typical costs are given, together with those for backup mechanical handling industrial trucks. Improvements in energy sources and other components are now becoming apparent. These, together with growing worldwide interest, predict a vast growth in the industry, particularly in commercial applications for battery electric trucks and vehicles.

This paper describes the development of the pumps, blowers, and electronic control systems for a fuel-cell/lead-acid-battery hybrid electric car. Wherever possible, commercially available equipment was used in order to reduce costs and expedite the completion of the vehicle. With the chosen components and their associated control circuits, a vehicle was completed which behaves much like conventional cars with two-pedal controls. It is concluded that if low-cost fuel cells were to become available, the construction of auxiliaries to provide a satisfactory vehicle would not prove difficult.

Hybrid powertrain configurations were evaluated for several classes of vehicles. This paper presents a discussion of the type of hybrid powertrain configurations evaluated, their respective mode(s) of operation, a discussion of computer simulation of powertrain/vehicle performance, and the effect of the performance of several key powertrain components such as heat engine, battery, and electric drive motor on vehicle emissions. Based on power and torque requirements for various classes of vehicles as derived from basic specifications and performance guidelines, it was found that the necessary hybrid powertrain configurations would be composed of major components of a relatively feasible efficiency and size. It was also found that vehicle emissions are relatively sensitive to electric drive motor efficiency and relatively insensitive to battery recharge efficiency. Driving-cycle characteristics were shown to have a significant effect on theoretical average emission levels.

This paper presents a new approach to the problem of handling a vehicle under emergency conditions, showing that the parameter plane method gives a clearer insight into the handling characteristics of vehicles under emergency braking conditions. The value of this method lies in the selection of the two independent parameters. For the particular problem considered, cornering stiffness at the front wheel may be taken as one independent parameter and cornering stiffness at the rear wheel is taken as the other. In other problems, suitable choice of the parameters may be made in order to obtain the necessary information. An illustrative example is included. The effect of wheel locking on the handling characteristics of the vehicle is studied; the degree of instability is redefined as a nondimensional number, and its utility is indicated.

The development of windshields and their methods of mounting are covered. By performing tests in which a single head form strikes against the windshield, two model heads strike against the windshield at the same time, and an unrestrained test dummy strikes the windshield, it has been shown that reinforcement of the interlayer and, at the same time, limiting of the windshield edge mounting would improve the safety factor when accidents occur. The necessity of further development is however dependent on the restraint system used. Apparently, development of the windshield is not necessary if inflatable restraint systems are used and if their performance is sufficient enough.

A fuel direct-injection system was applied to a 2-stroke engine for the purpose of reducing exhaust gas emissions, especially exhaust hydrocarbons. It was observed that fuel injection only, as an alternative to the carburetor, was not an adequate means for exhaust gas purification. Therefore, a combined throttle and spark timing control device and a thermal reactor were also adopted. On an automotive injection engine with a swept volume of 21.7 in3, these changes succeeded in reducing hydrocarbons to 5 ppm and carbon monoxide to 0.21% in the Japanese four-mode test. The durability of the thermal reactor is not yet adequate.

This paper describes a new stratified-charge combustion system called the Mitsubishi Combustion Process (MCP), accomplished by controlling the air swirl and improving the injection nozzle in regulating fuel injection, which reduces poisons from exhaust emissions of small engines. Experiments proved that the MCP engine reduces the emission level; for example, with gasoline the concentrations of HC, CO, and NO are 80 ppm, 0.20%, and 600 ppm, respectively, at the rated horsepower. The engine shows excellent performance in multifuel and starting characteristics. The improvement of spray formation that has an important effect on exhaust emissions and other engine performance is also described.

Modern design trends are placing greater demands on welded structures. This paper discusses the present state of the art and provides recommendations for dealing with some of the more commonly encountered structural problems. Emphasis is placed on stress concentration and fatigue strength and the relation of these factors to welding practices and methods. Formulas needed to compute stress and strength are presented. Characteristics of various types of materials, of fillet size, and of good bonding welds are described and compared.

An inherent characteristic of the rotary engine geometry is its high surface-to-volume ratio. This results in a high quenching effect at the trailing portion of the charge. Combination of rich mixtures in the end gases together with high quenching effects reduces the octane requirement. It also means, however, that the unburned hydrocarbon (HC) concentrations are relatively high, whereas the NOx concentrations are quite low. Thermal reactors have been the Toyo Kogyo Co.'s principal approach to the control of CO and HC exhaust emissions.

This material reports findings of an exploratory experimental study designed to add information on the contribution to air pollution of exhaust emissions from small, utility engines, and to evaluate the procedures used to test small engines. Gross measurements of hydrocarbon, carbon monoxide, and nitric oxide are reported for 29 4-cycle and 7 2-cycle engines; sizes of the engines ranged 2-22 hp. Emission measurements were made on each engine for nine combinations of load and air-fuel adjustments; only one speed point-full governed-was covered in the tests. Test procedures are described. An overall average of the data indicate that, operated at full-load and optimum air-fuel ratio, the 4-cycle engines emitted about 8 g HC, 180 g CO, and 5 g NO2 per horsepower-hour. Under comparable conditions, the 3-6 hp 2-cycle engines emitted an average of 140 g HC, 240 g CO, and 2 g NO2 per horsepower-hour.

The importance of the stress concentration factor in design of structures is emphasized. Design for static stress concentration and design for fatigue stress concentration with ductile and brittle materials has been described. Changes in the critical areas to minimize stress concentration, and examples with typical cases of critical areas of discontinuities are given. Table with design techniques for improving fatigue strength and a few stress concentration charts have been enclosed which are typical in the construction.

This paper describes the work of the Small Engine Emissions Subcommittee of the SAE Engine Committee in determining the characteristics of emissions from small utility engines. The study concentrated on utility and off-highway vehicle engines (for example, lawn and garden equipment), not motorcycles. Results of the study indicate that emissions from garden type engines presently constitute less than 1% of the total from all United States sources. Although the data are less reliable on large two-cycle engines such as snowmobiles, there is an indication that such vehicles may contribute a disproportionately large share of the total small engine hydrocarbons. A test procedure for the measurement of small engine exhaust emissions is included.

This report presents the results of the SAE Human Factor Committee Driver Control Reach Study conducted in June-August 1971. Over 100 test subjects were measured on three test fixtures representing a sports car, a typical passenger car, and a heavy truck. Finger grasp reach was recorded to 40 locations in front of the driver. The report presents the background information for a forthcoming SAE Recommended Practice on Driver Arm Reach.

The role of the engineer, the engineering profession, and professional societies such as the SAE are discussed against a backdrop of domestic and international trade. Questions are posed regarding individual responsibility and future shock handling.

In May 1970, President Nixon signed the Public Law 91-258, The Airport and Airway Development Act of 1970. The Act authorizes a $5.4 billion federal expenditure for improvements to the National Aviation System during the decade of the Seventies. The Airport Development Aid Program (ADAP) portion of the Act projects a $2.5 billion expenditure to match state and local funds for the improvement of existing airport facilities and to construct new airports. This paper describes the government's participation through the Federal Aviation Administration in airport construction.

Acoustic emission technology has developed to the state where broad applications to materials testing and evaluation are evident. The unique characteristics of acoustic emission as they bear on applicability to nondestructive testing are emphasized. Among the advantages anticipated for the acoustic emission method, two are especially noteworthy: 1. Moving inspection upstream in the production process so that bad production can be eliminated before large fabrication and assembly costs are accumulated. 2. Economical 100% NDT inspection of finished components or products.

The record of the nation's cities in implementing plans for significant changes in their public transportation systems is strikingly poor. However, there is substantial evidence to suggest that all the important pieces necessary for major programs are available. This paper covers forces of change in urban transport development-sources of financing, institutional arrangements and their impact on decisionmaking; also discussed is urban transportation technology-options for the future, and transit implementation projects in cities.

This paper deals with a new concept of transportation system development based on well-established psychophysical principles. It reviews briefly the traditional method of transportation system development and modification. The point is made that it now becomes necessary to reverse the usual trend of declining public transportation system usage. The “new philosophy” of system development utilizing user-oriented techniques in the form of attitude surveys is presented as a possible aid in enhancing public transit use. As an exemplar to illustrate four techniques (paired comparison, semantic scaling, branch-and-bounds interview, and document attitude analysis) the methods and some representative data of General Motors Research Laboratories' Transportation Research Department case study of a door-to-door (demand-actuated) public transportation system are discussed.

The evaluation of new friction materials at Caterpillar includes small scale, full scale, and field tests. These tests and the equipment used for them are discussed, as well as the philosophy behind the program. The quality assurance of production materials, the equipment used, and the tests run are directed at measuring the performance of incoming materials to be sure they meet our standards. New tools being developed to improve the program are described.