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Factors influencing the effectiveness of exhaust port air injection in oxidizing the hydrocarbons and carbon monoxide in engine exhaust gas have been investigated in order to establish guidelines for the engineering of vehicle emission control systems. Single-cylinder engine and vehicle studies have demonstrated that the temperature, composition, and residence time of the exhaust gas-air mixture are basic factors determining both the effectiveness of air injection and the type of oxidation process which occurs in the exhaust system. Both luminous and nonluminous oxidation have been observed. These basic factors are affected by such variables as: engine spark timing and air-fuel ratio, insulation and size of exhaust manifolds, injection air temperature and airflow rate, and the warmup characteristics of the air injection system. The warmup characteristics can be influenced particularly by spark timing and exhaust manifold design.

In any statistical prediction problem involving items being used by customers in the field, it is important to attach the correct percentile number to each case of a failure. The method of “suspended items,” that is, treating unfailed items together with failed ones, is presented as one solution in this difficult problem of placing failures in correct order within a population. Once this has been done, the prediction problem can be solved in a straightforward manner, either graphically or numerically in a computer.

A rapid and precise oil consumption measurement in an automotive engine can be made in 5-7 minutes by a radiometric method. Several hours are usually required for conventional methods. The radiometric method consists of tagging the engine oil with a radioactive tracer, 1,2-dibromo-octadecane containing bromine-82. This material undergoes combustion with the oil, and the radioactive hydrogen bromide is extracted from the exhaust gas with one molar sodium hydroxide. Scintillation counting is employed to determine the amount of radioactivity recovered, which in turn is proportional to oil consumption. Oil consumption measurements were determined over a speed range of 1500-3000 rpm and over manifold vacuum ranges of 22-2 in. Hg. It was found that the presence of lead, either as engine deposits or in the gasoline, interfered with the recovery of hydrogen bromide. Therefore, this method is restricted to nonleaded engines.

In order to determine transmission fluid requirements, fluid performance in automatic transmissions has been investigated using engine-transmission-dynamometer test apparatus. It was found that the rate of fluid oxidation was essentially the same using two-speed and three-speed transmissions. Further, the rate of fluid oxidation was very similar in part throttle and full throttle cycling tests. In addition, the effect of fluid frictional deterioration on shift performance was similar between the two transmission types. It is concluded that fluid performance in the two-speed transmission can be evaluated using the three-speed transmission, or vice versa. The significance of the full-scale laboratory test results was confirmed by establishing a correlation with car test results.

Since General Motors introduced the Stirling thermal engine to the American engineering community at the 1960 SAE Annual Meeting, it has accumulated 6500 hr operating experience with full-size, practical Stirling engines. Most of this experience has been in dynamometer operation which generated quantities of performance curves that define the operation of the engine under normal and abnormal conditions and which permitted critical evaluation and refinement of our computer analogs of the engine. Much knowledge has been acquired in development of controls and peripheral apparatus needed to make the Stirling engine a complete entity like the Ground Power Unit recently accepted and tested by the U. S. Army. Attention has also been given to Stirling engine systems of 5–5000 hp for applications ranging from below the sea to outer space.

Results of a psychophysical experiment indicated that “jerk” (that is, rate of change of fore and aft acceleration) associated with the clutch-actuated gear ratio change in an automatic transmission correlated well with subjective evaluations of shift-feel. A portable device, the GMR Jerkmeter, was constructed to measure acceleration and jerk during on-the-road evaluations of transmission performance. Techniques for using Jerkmeter data in automatic transmission fluid research and development projects are discussed. Examples are given of the use of Jerkmeter data to: 1. Produce a detailed characterization of shift performance. 2. Measure effect of fluid on shift performance. 3. Study effect of changes in fluid characteristics with use.

The effect of fuel composition on automotive evaporative emissions has been studied using five cars, not equipped with evaporative emission controls, and a total of 31 fuels. The amount of evaporative emissions increased with increasing fuel volatility. Also, the evaporative emission photochemical reactivity per gram increased with increasing C4 and C5 olefins in the fuel and decreased with increasing C4 and C5 paraffins. For an assessment of the smog potential of evaporative emissions, the amount and reactivity per gram should not be considered independently, since they both are simultaneously dependent on fuel composition. The product of amount and reactivity per gram (the Evaporative Reactive Index) is a good measure of the contribution of evaporative emissions to photochemical air pollution. An empirical equation for predicting the Evaporative Reactive Index from fuel properties has been derived.