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Gas concentrations, under different engine operating conditions, different locations relative to the fuel spray are presented. The gas that is sampled is “snatched” from a continuous flow sampling probe. The time of snatching is controlled. The concentrations of CO, CO2, NOx, and O2 are plotted against, crank position. The sampled gases were analyzed for concentration in the as taken state and after the sampled gas had passed through a heated catalytic oxidation converter. Analysis have been performed and plots are presented of the findings. The analytic procedure developed for the data analysis are presented in detail.

A contribution to tire rolling resistance which arises from tire tread impact with the roadway is defined. These impact losses depend on the square of the vehicle speed. The physics of the process is revealed using a realistic, simple model coupled with Newton's second law. It is shown how the losses depend on tire characteristics. It is not feasible to determine to high accuracy the magnitude of the effect from such an uncomplicated model, however. The speed independent losses are also discussed in terms of a simple model. Finally, analytic expressions are presented for rolling resistance (speed dependent + speed independent) as a function of tire characteristics.

Tire rolling resistance losses can be significantly influenced by road surface texture. Data obtained from laboratory tire dynamometer tests and outdoor tests conducted on various paved public type roads indicates that tire rolling resistance losses increase as road surface texture increases. Some tires are more sensitive to surface texture than others, and relative tire comparisons may depend upon the test surface used. Developments in road surface texture may be an additional approach to the question of tire rolling resistance. Other tire performance areas like noise and traction are also affected by surface texture; therefore, future road surface developments should be based on a consideration of the interaction between surface texture and tire performance.

A field measurement was obtained of tire inflation practices representative of typical automobile drivers. Approximately 2000 vehicles were surveyed during a midsummer period, and 400 vehicles during a midwinter period. Inflation pressures covered a wide spectrum with 10 percent being at least 6 psi below manufacturer's recommendation and 10 percent at least 3.5 psi above. During the summer, an average of one tire per vehicle was underinflated by 3 to 6 psi. The winter survey indicated that an average underinflation of 5 to 8 psi was present. A general conclusion is that the typical vehicle has at least one tire in which underinflation could cause serious tire deterioration and substantial increase in the rolling resistance and corresponding fuel usage.

Reflecting the need for field testing of bimetallic automotive body sheet; an extensive program was planned in 1974. Adhesive bonded and weld bonded panels (2036 aluminum and 5182 aluminum with 1010 steel) were prepared and exposed at atmospheric test sites at Pompano Beach, Florida; Phoenix, Arizona; Chicago, Illinois; and Richmond, Virginia. Exposures were made in 1975-76 and 1- and 2-yr removals and evaluations are reported in this paper. “In-plant” and “After-market” repaired aluminum panels were exposed at the same time. These results are reported here.

There is an increasing use of aluminum in automobiles for weight reduction and decreased energy consumption. Recycled aluminum can be utilized in automotive castings with savings in both dollars and energy. The technology for the recovery of aluminum from auto scrap is analogous to the recovery of solid waste and the present and developing unit operations are reviewed and an aluminum recovery demonstration laboratory is described.

A small addition of magnesium (0.3%) to prime 380 die casting alloy (SAE 308) was found to improve the alloy's machinability. Magnesium hardens the matrix and by doing so reduces the tendency to build up on a tool edge, results in shorter and tighter chips, provides a better workpiece surface finish, giving prime 380 desirable machining characteristics similar to those of secondary alloy. However, tool wear rates for the magnesium-modified prime alloy were significantly lower than those for secondary alloy. Other minor/impurity element alloy variations also affected machining characteristics but less dramatically than the magnesium. Some elements traditionally credited with improving machinability were found in this study to be of little benefit.

Mechanically plated finishes primarily used by the automotive industry have been specified for the following reasons: 1) Torque drive relationships. 2) Assured product reliability through elimination of hydrogen embrittlement. 3) Simplicity of coating application and waste treatment. 4) Corrosion protection. 5) Multiple coating applications. Current automotive industry trends are toward weight reduction, involving the use of lighter weight metals in fabrication. Fastener components and their protective coatings must also be compatible to the bimetallic surfaces with which they come in contact. Promising new mechanical plating developments are geared toward supplying finishes with characteristics necessary for bimetallic fastening while keeping cost factors in perspective.

Production equipment has been developed for plating with aluminum by ion vapor deposition. This offers a new dimension in protective finishes to the corrosion engineer. The equipment called the Ivadizer™, deposits a uniform, dense coating of pure aluminum which provides outstanding corrosion protection. In addition there are no embrittlement problems, the coating can be used at temperatures up to 925°F (496°C), and both the process and the coating are environmentally clean. Because of its performance advantages, ion vapor deposited aluminum can be used in a wide range of applications, and is particularly effective as a replacement for cadmium. Interest in and demand for the coating is progressing rapidly in the aerospace and other industries.

Possessing hardness, strength, toughness, dimensional stability, elevated temperature strength and hardness, and resistance to wear, tool steels merit consideration as candidate materials for automotive engine and other components which encounter demanding service requirements. The properties of ten tool steel grades, which are considered to be most promising for selected automotive applications, are discussed.

The durability requirements of the diesel engine exhaust valve have been satisfied through the use of several iron, nickel, and cobalt base alloys. There have been cases where iron base austenitic alloys were found deficient in one or more physical or mechanical properties, and they were replaced with a nickel or cobalt base super alloy, often with a wide margin of design safety. Strategic alloying elements such as cobalt, tungsten, and nickel have escalated in price at a significant rate, thus increasing the cost of the super alloys. An improved austenitic alloy has been developed to provide adequate performance while retaining the cost effectiveness of iron base systems. During this development program, the alloy was designed to minimize its susceptibility to manufacturing problems which have been associated with prior valve materials.

The engineer and metallurgist, working as a team, have made a tremendous step forward in worldwide conservation of energy. Replacing cast and malleable iron castings with aluminum castings in the automotive industry has greatly reduced the weight of the car. Designing castings in one piece where there is an assembly of component parts is a more economical and mechanically sound procedure.

High integrity aluminum castings are potential replacements for cast iron in current vehicle weight reduction programs. Domestically, several cast aluminum structural-type components are already realities, saving weight and contributing to improved fuel economy; wheels, brake drums, master brake cylinders and power steering housings. In Europe, suspension components, wheel hubs and disc brake calipers are cast in aluminum for some car models, indicating the functional and economic feasibility of such parts. Alloy and process technology already exist to enable production of realiable, high strength aluminum castings. Domestic automotive product engineers are urged to carefully consider and thoroughly test such aluminum castings along with the many other weight reduction possibilities currently being investigated.

The design, construction, testing, and competition of the Mini Baja 77 winning vehicle was performed as an academic assignment by senior Mechanical Engineering students. The nature of the course is explained; the educational benefits explored. The vehicle design criteria and their relationship to the morphology of the design process are developed. The tradeoffs and compromises by the group required to develop an optimum design were extensive. The actual design is presented in a series of photographs, and examples of the required tradeoffs are illustrated thereby. An analysis of the educational benefits of this type of competition is presented along with recommendations for expanding the concept.

Mini-Baja 1977 represents an attempt on the part of the academic community to increase the industrial readiness of engineering students. The object of this simulated industrial design and fabrication project is to construct a marketable, manufacturable, high-performance one-man, all-terrain vehicle for the least possible cost. Each university started with the same air cooled engine and a $550 manufactured cost limitation. The designs evolved from a series of performance vs. cost, styling vs. cost, and design features vs. cost decisions. Because of the close simulation to the actual industrial design process, engineering students have found this type of competition to be a valuable addition to their education.

In Japanese automotive industry considerable changes have been done in not only design of exhaust train but also materials to be used due to non-leaded gasoline as well as emission controls. Especially application ratio of heat-resisting and stainless steel has increased rapidly and at the same time manufacturing technique and performance improvement of raw-materials have been made for heat-resisting steel for passenger cars. We have explained for the current trend in materials used for exhaust train such as reactor, catalytic convertor, other part of exhaust train, engine valves, valve seat inserts.

A Rough Terrain Vehicle has been designed, constructed and tested by Mechanical Engineering Students for the Mini-Baja 77 Races. This one seat vehicle has an eight horsepower engine, five speed transmission, independent front wheel suspension and disc brake. The gear train has been matched to the engine performance curves. A wooden mockup was used to establish the man-machine interface. The design and construction of this vehicle was the assigned problem in “Mechanical Engineering Practice”. This paper presents the design of this vehicle and then comments on the effectiveness of this project in achieving the objectives of this course.

The Vehicle Maintenance Reporting Standards of the American Trucking Associations can be used by manufacturers to improve heavy-duty vehicles. After verifying the accuracy and significance of the data the manufacturing, engineering, technical service and marketing departments can all use the information to improve vehicles and provide better service to the user.

DuPont operates a medium-sized fleet consisting of 200 tractors and 450 trailers. These units are based in Wilmington, Delaware, and at six other terminals. We have three basic goals in specifying our fleet and in establishing programs for its operation: low maintenance costs, fuel economy, and safety. To maintain our program and to work toward improved results, we make use of a variety of management tools. A major contributor is the Burlington reports. Every maintenance dollar we spend is programmed into the system. These reports provide us with all fuel and maintenance data to accurately determine costs and to develop methods to improve existing cost and fuel savings programs. Three examples will be given to show how we use the reports to make some significant decisions in our operation. The first two will deal with replacement of equipment and the third with driver influence.

The flow around a bluff body with a slanted rear surface is influenced very dramatically by changing the angle of the rear surface slant and at some slant angles an excessively high drag is generated. To learn more about this critical behavior a series of detailed experiments was conducted on a vehicle-like bluff body, investigating the effect of ground proximity, Reynolds number, free-stream turbulence and of rounding of the upper edge of the slanted surface. The results of these experiments showed that although these various factors could change the critical slant angle and the size of the drag overshoot, the basic critical behavior was always present.