Abstract
Data on exhaust-gas composition, obtained in a study of the hazards that might attend the use of Diesel engines underground, are discussed in relation to combustion in the Diesel engine. Two engines were tested throughout a wide range of fuel-air ratios, and the results indicated that combustion was essentially complete in the normal operating range although even under these conditions low but significant concentrations of carbon monoxide, aldehydes, and free carbon were present in the exhaust gases. The concentration of carbon monoxide, determined by precise analytical methods, was a minimum at a fuel-air ratio of approximately 0.03 lb per lb and was affected by engine design and to a slight extent by factors that varied with speed. The coexistence of aldehydes and free carbon indicated that direct oxidation and destructive combustion of the fuel were occurring simultaneously. The calculation of combustion efficiency from data on the products of incomplete combustion is illustrated.
