Search Results

Vibrations encountered in motor vehicles operated at speeds in excess of 60 mph are discussed in terms of source analysis, component response, and vehicle sensitivity relative to customer acceptance standards. Two actual case histories are used to illustrate the utility of component order alignment charts, the effectiveness of component response control and the use of sensitivity charts for comparative analysis of subjective data.

The California Steam Bus Project demonstrated the potential of low-emission, quiet external combustion engines in public transit service. Three contractors supplied and installed steam powerplants in urban buses, replacing the original diesel engines. Exhaust emissions were found to be considerably lower than the 1975 California requirements for heavy-duty vehicles. Substantial reductions in sound levels were measured in one of the buses. Powerplant weights can be lower than present diesel engines. Road performance was similar to that with diesel engines, but very high fuel consumption was experienced with these nonoptimized demonstration vehicles. Prospects for future improvements are given in this paper, including the outlook for large reductions in fuel consumption and exhaust emissions.

This paper presents major developments in urban bus design which are currently in progress under the sponsorship of the Urban Mass Transportation Administration. The paper describes trends in mass transportation since 1945 to illustrate the decline of the transit industry. The needs of the transit industry for a new workhorse vehicle are delineated. The features that are specified for the new 40 ft urban bus (Transbus) are compared with the features of current buses. Three competing prototype bus designs, which are currently under development, are described. Emphasis is placed upon features to improve transit speed, passenger safety, passenger comfort, vehicle aesthetics, environmental impact, vehicle reliability, and maintainability at realistic costs. The program is presented for prototype testing, public demonstration, and pilot production leading to the full-scale introduction of Transbus into the United States urban bus fleet in the latter half of the 1970s.

The proposed federal and California regulations affecting emissions from on-highway diesel-powered vehicles have stimulated a critical examination of many forms of combustion chambers in search for a solution to the 5 g/bhp·h combined HC + NO2 requirement. Results of tests made on indirect and direct injection systems are presented. It has been shown that with a simple modification to the injection timing of a production engine equipped with a swirl chamber combustion system, combined emission on the order of 4 g/bhp·h can be achieved under both naturally aspirated and turbocharged conditions. These results are achieved without significant sacrifice of smoke-limited power. Data on heat loss to coolant with the engine tuned for low emissions are presented.

The Automobile Manufacturers Association (AMA) and the Engine Manufacturers Association (EMA) contracted with Ethyl Corp. to determine the effects of humidity and temperature on HC, CO, CO2, NOx, and smoke emissions on six different manufacturers' engines run over a 13-mode cycle. Emission procedures used are similar to “California Procedures for Diesel Engines in 1973 and Subsequent Model Year Vehicles Over 6001 Pounds Gross Vehicle Weight” as adopted November 18, 1970 and amended February 17, 1971. Equations are recommended to correct NOx emissions back to standard conditions of 75 grains of H2O/lb dry air and 85 F. Humidity had no significant effect on other emissions. Temperature substantially affected the HC, CO, and smoke emissions of some engines. The correlations between four NO/NOx instruments and between two smoke measurement techniques are reported.

Understanding obtained through a research study of corrosion of decorative chromium plating systems is reviewed. From this knowledge, the development of an electrolytic corrosion test (the EC test) is traced. Measurements of corrosion sites show that electrolysis for 2 min (6 min elapsed time) in the EC test produces corrosion sites more like those from one year of Detroit service than those produced in 16 h of CASS test exposure. The EC test has been employed for four years with satisfactory results as a monitor of durability of automotive parts plated in a production line. The paper outlines the mechanism by which nickel corrodes, describes the EC test equipment, and gives the results of an evaluation made by GM production personnel.

The development of smoke measurement procedures and instruments has been one of the significant factors contributing to the reduction of smoke from diesel-powered trucks. There is a need, however, for better information on the relation between measurements and the appearance of the smoke plume, for improved smokemeters, and for common international test procedures. Studies of smoke plumes using jet theory, alumina tracer, and hydraulic analog techniques indicate that the plumes are sometimes unstable and subject to large-scale shedding in the region where free-plume smokemeters are located. This introduces a significant random variation into smoke measurements made in this location. A future test procedure based on smoke measurements made with a long path (500 mm) in-line smokemeter during a dynamic cycle is suggested for consideration. Smoke limits would be based on tests similar to those conducted by MIRA to relate smoke levels and engine size to human response.

The neutral salt spray as an accelerated corrosion test to predict the service performance of decorative, bright-plated automobile trim gave such unsatisfactory results that the American Electroplaters' Society sponsored development of more rapid and reliable testing methods. The Corrodkote and CASS tests were successfully developed to duplicate the extent and type of corrosion occurring on parts in one winter's service in Detroit. It is suggested that unsatisfactory experience with the neutral salt spray as an accelerated test was due to failure to define service performance properly, and that the CASS test has proved to be more satisfactory mainly because performance criteria have been more realistically defined.

Current state periodic motor vehicle inspection (PMVI) programs vary widely both in items inspected and inspection criteria. Many performance parameters not tested could have a significant impact on highway safety. New automotive emissions standards will achieve their goal of reducing air pollution only if periodic inspections are instituted to verify vehicle system performance. Thus, a trend is apparent toward more effective and uniform safety inspection coupled with emissions inspection. Such an inspection is feasible only if inspection automation can provide high throughput, effective testing, and component fault diagnosis. The diagnostic requirement is crucial in protecting the consumer from exposure to a potential ticket to still higher automotive repair bills.

This paper describes the complexity of service systems for the maintenance and repair of automobiles and outlines the functions and responsibilities of government, automobile manufacturers, the service industry, and vehicle owners. It also provides an analysis of the need to develop standardized plug-in diagnostic testing equipment and presents a proposal for the design of function test equipment for possible joint application by government agencies and the automotive service industry.

With the increasing emphasis on vehicle safety and proper engine performance to assure low levels of exhaust emissions, automatic diagnostic systems will be required to service the large vehicle population in use. Techniques are described which use a combination of on-vehicle and off-vehicle sensors and equipment to check the condition of engine, drive train, brake, steering, and suspension components. The tradeoff considerations for selecting on-vehicle versus off-vehicle sensors are discussed, and types of testing which can be practically implemented are outlined. In addition, the use of results from vehicle handling and brake-system component degradation studies for establishing limits of acceptable performance for automatic diagnostic testing are presented.

The methods to achieve standardization of automotive diagnostic testing are the subject of this paper. Current diagnostic technology is described by definition and example. The requirements for nationwide implementation of diagnostic testing is analyzed and a preliminary system concept for a standardized diagnostic center is presented. The benefits of such a system are discussed and some future recommendations given. The paper excludes any specific detailed economic tradeoffs which must be done regarding the distribution of centers for optimum consumer travel expense.

The use of plastics by the automotive industry is gaining momentum, but their ultimate application as material for an all-plastic car, including the body and associated operating functions, hovers in the background. This paper examines carefully, and supports by test data and known materials properties, the practicability of this development. It points out the range of problems that must be solved before functional implementation, producibility, and economic manufacture on a mass-volume basis can be achieved. The conclusion reached is that compromises must be made and that these objectives are attainable in the present only by a happy marriage of metal and plastics, with each type of material contributing its superior qualities.

Personal Rapid Transit (PRT) is a new member of the transportation family primarily oriented toward short-haul and distributor/circulator operations. It can also be used in a quasi line-haul situation. The system utilizes small vehicles on a separate guideway (on, above, and below ground) to convey individuals from origin to destination without intermediate stops. Vehicles are operated entirely automatically and respond directly to passenger demand without any significant waiting period. They are rubber-tired and electrically powered, and therefore nonpollutant and silent in operation. The system is centrally controlled and supervised. The PRT project was inaugurated in Morgantown, West Virginia, on Oct. 24, 1972. The installation is a combination line-haul and circulatory system over exceptionally difficult terrain, providing a testing ground for the design and implementation of this new technology.

This paper gives a description of the Bay Area Rapid Transit (BART) system in San Francisco. The design and construction of the system depended upon the geography of the area and upon the equipment and skills of the many contractors involved-all of which are described. Details are given of the excavation for tunnels and stations and the equipment used in these operations. The design of the vehicles on the BART system was aimed toward passenger safety and comfort, and some details of the cars are shown. BART may be a model for rapid-transit development in communities where mass-transit systems will help solve urban transportation problems.

The contamination level of the fluid within a hydraulic system is a reflection of not only the particle removal capability of the filter element, but also the contaminant ingression characteristics of the system. Furthermore, the amount of contaminant permitted to enter the fluid past exclusion devices has a direct influence on the filter requirements-separation efficiency and capacity. Thus, without some means of establishing the effectiveness of contaminant exclusion devices, no realistic analysis can be made regarding the contamination level of a hydraulic system. This paper presents the analytical expressions that can be used to describe rigorously the contamination control of a hydraulic system. The importance of contaminant ingression is dramatically illustrated by realistic test results. The correlation of the theoretical considerations with characteristic field conditions is accomplished using the results of a wiper seal study.

This paper outlines a seal manufacturer's development of a single lip seal for reciprocating hydraulic cylinders. It traces the development of functional test equipment and a uniform method for evaluating the performance of seals.

Product design engineers have the responsibility for developing a product yielding satisfactory life for some given duty, at a reasonable cost. In the absence of an immediate failure, a product is many times subjected to loading which exceeds the design parameters, resulting in unanticipated short life and possibly poor product acceptance. Often, the ultimate user of a product, with little knowledge of the extensive effects of overloading, justifies this practice with false economics. It is the purpose of this paper to illustrate the relationship of loading to product life. With this basic understanding, it is hoped that products will be used more effectively and not abused.

This paper discusses the design and development of the Funk two-speed planetary input drive. A detailed description of the “power shift” concept through the use of hydraulically actuated spring returned clutch packs is presented. Diagrams which display the internal operation and trace the power flow through the drivetrain are presented for clarification along with simplified circuitry diagrams of the developmental hydraulic system. Developmental testing to substantiate product reliability and unit performance is reported, along with some typical applications where the two-speed input drive could be employed.

The expansion of the New York City Rapid Transit System, funded by a voter-approved $25 billion transportation bond issue in 1967, is described. Fifty-two miles of new subway routes will be constructed, along with other on-going modernization of the system. Eleven new routes will be constructed under the program. The work and type of equipment presently used in constructing four of these routes is described in some detail.