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USING a high-speed motion picture camera, flame photographs were taken of the combustion process associated with the starting of hot gasoline engines. Compression ignition at isolated points followed by normal combustion caused peak cylinder pressures to occur prior to top dead-center under some low-speed engine conditions. In addition, an abnormal combustion phenomenon was observed in the last part of the charge to burn. The reaction rate was appreciably faster than normal for the engine speed and much slower than is usually observed in knocking combustion at normal engine speeds.

TURBOGLIDE is the deluxe automatic transmission of the General Motors Chevrolet. One of its most important features is that its performance ratio is available at any throttle position, enabling control of torque ratio and engine output by the throttle pedal. The system includes a five-element torque converter, pump, three turbines, and the dual stator. The entire installed unit weighs 148 lb, a result of the general arrangement and the use of aluminum in the case and bell housing. The authors discuss the basic operating principle of the transmission, the arrangement, performance, torque distribution, control system, and valve body.

CHEVROLET has made its new air-suspension system easily interchangeable in production line assembly with standard full-coil suspension by adopting a 4-link-type rear suspension with short and long arms. A feature of the system is the mounting of the leveling valves within the air-spring assemblies. These valves correct riding height continually at a moderate rate, regardless of whether the springs are leveling or operating in ride motion. The system provides constant frequency ride—ride comfort remains the same whether the car is occupied by the driver alone or is fully loaded.

IN 1957 Ford introduced in its passenger cars a new rear axle incorporating a straddle-mounted pinion. This paper describes the development and features of the 2¼-in. offset axle. The author thinks the most interesting feature of the development problem was the design of the hypoid gears. The 1957 gears were designed with the deepest possible teeth to give maximum fatigue strength. They maintained the conventional scheme of 50 deg on the pinion and about 15 deg on the gear.

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.

TECHNIQUES, based on panel estimates, were developed for evaluating the odor and irritation intensities of undiluted diesel-engine exhaust gases or of various dilutions of these gases in air. Along with the estimates, chemical analyses were made to determine the concentrations of total aldehydes, formaldehyde, and oxides of nitrogen. Statistically significant correlations were found between odor or irritation intensity estimates and the analytical data, but these correlations were too weak to permit accurate prediction of odor or irritation from chemical analyses. Effects of some engine variables on diesel odor were studied. Possible means of reducing diesel odor are discussed.

ONE plastic model is worth 40 lb of blueprints and 40 hr of the explaining that goes along with the prints, according to engineers who have worked with the new plastic “toys” which can serve as perfectly scaled miniatures for virtually every phase of automobile design and manufacture. The extensive benefits occasioned by this revolution in methods may be summarized thus: 1. Shortens design development time by providing a third-dimension evolvement of structure and form. 2. Used in advance discussions for compromising engineering and manufacturing problems, showing construction so clearly that troublesome problems are foreseen; thus enabling clear-cut, reliable decisions with a minimized chance of encountering major revisions. 3. Show in one minute what could not be found on prints for hours, saving time over any other methods, while generating valuable counterproposals reducing costs, operations, man-hours, and so forth. 4.

THE study of engine life, carried out by investigating engine wear in typical service, and by then striving to find the most effective ways of controlling it, forms the basis of this paper on contaminants in lubricants. The investigation involved a study of engine wear in 20,000 miles of operation typical of the average driver. The average driver was selected by using test cars from an employee transportation car pool. At the conclusion of the tests it was found that the use of the full-flow oil filter proved to be the best method for restricting engine wear caused by contaminants that get inside the engine. It was also shown that after successfully eliminating large, solid particles, further restriction of engine wear would depend upon the ability of the oil to lubricate, and upon the engine design to provide the oil supply in a manner suitable for lubrication of each part of the engine.

NODULAR cast iron, so called because the graphite is present as finely dispersed, well-rounded particles, is made in two stages: The first stage consists of the addition of magnesium or other carbide formers, which promote the formation of white iron in one normally solidifying gray. In the second stage a ferrosilicon type of inoculant overcomes the tendency toward white iron and causes the graphite to precipitate out in the form of small spherulites. The methods of making nodular iron, the effect of composition on physical properties, economic factors involved, and potential applications are discussed in this paper.

THIS description of the hydraulic control used with the hydra-matic transmission reveals how the control operates to change ratios under power without direction from the driver. The control's pattern of automatic shifting for ordinary, high-range driving has been selected as the best compromise between top performance and low ratio of engine noise to wind noise. The control's low range shifts gears according to performance dictates alone, furnishing greater power for extreme conditions at low speeds and enabling the driver to use his engine as a brake on steep descents. Heart of the control system is a double hydraulic governor, sensitive both to car speed and throttle opening. THIS paper, as well as the two that follow, one by Messrs. Nutt and Smirl and the other by Mr. Kimberly, make up a symposium on automatic transmission components presented at the 1947 SAE Summer Meeting.

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.