The failure to realize a more widespread application of the diesel engine is the result of the manner of fuel combustion in the diesel engine. As long as engine rotative spreads do not become high (1000 to 2000 RPN) the combustion is fairly satisfactory. However, at higher engine speeds a greater velocity of fuel injection is required and the time lag between injection and ignition becomes a greater percent of the engine cycle. These two conditions lead to a rapid initial combustion in the engine cylinder producing engine vibration, rough running and objectionable noise.
To obtain the high power output per unit of weight required for transportation service of all types of necessitates engine operation at high rotative speeds. The slow speed type of diesel engine is entirely satisfactory for stationary and marine power but is unsuitable for automotive, railroad or aircraft propulsion.
Thus all of the major difficulties encountered in the use of high speed diesel engines are a direct result of the manner of combustion of the fuel in the engine cylinder. Correction of these difficulties could be most intelligently accomplished if information were available as to the combustion process and how it is affected by the operating variables.
In an effort to obtain some information concerning the combustion process, diesel engine experimental work has been in progress for several years at the University of Wisconsin. This thesis concerns itself with the experimental work carried out during the school year 1940-1941 and the conclusion available from the data accumulated up to the present time. This thesis includes some analysis of engine test data which was obtained previously at the University of Wisconsin and elsewhere. In each case due acknowledgement has been made.
Copyright 1941
Engine Research Center
University of Wisconsin-Madison