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The objectives of this study are twofold. First, engine data are presented which indicate how the three major automotive exhaust pollutants are affected by the distribution of the inducted fuel. Nonuniform fuel distribution prohibits lean engine operation without increasing hydrocarbon emissions. Nitrogen oxide emissions are lower at a given fuel-air ratio with nonuniform fuel distribution, this condition being particularly true near stoichiometric conditions. Carbon monoxide emissions are lower with more uniform fuel distribution. The primary objective of this paper is to demonstrate a new method of studying the mixing conditions that take place in an induction system. This method involves the use of a conventional water table, a facility to demonstrate pictorially the salient flow field characteristics and mixing patterns that were encountered at typical engine operating conditions. Also, several different geometric configurations and their resultant flow patterns are included.

A theoretical model for the determination of surface ignition has been established on the basis of thermal and chemical properties of deposits as related to heat transfer rates in an internal combustion engine. It is used in conjunction with fuel ignition temperature and ignition delay, as obtained using an adiabatic compression machine. The model, in conjunction with the experimental data, has the flexibility of determining the effects of various parameters which are prevalent in surface ignition. The fuels most prone to surface ignition were benzene, diisobutylene, toluene, and isooctane, in that order. The results agree favorably with those obtained by other experimenters using actual engines.

A single-cylinder, 4-1/2 in. by 5-1/2 in. diesel engine was modified to direct injection. It was supercharged, simulating turbocharging with aftercooling to 89.6 in. Hg absolute manifold pressure and 200 F manifold air temperature. The maximum bmep was 302 psi at 2400 rpm, which gave an output of 0.915 bhp/cu in. of piston displacement. In order to achieve 1 hp/cu in., a manifold pressure of 98.5 in. Hg absolute would be required at 2400 rpm. The economy was found to improve with high supercharging. The maximum gas pressure encountered was 2700 psi. This could be moderated by changing either the combustion system or the compression ratio. Changing the compression ratio affected the brake specific fuel consumption only slightly.