More Efficient Combustion in Small Open Chamber Diesel Engines

Until quite recently, it appeared that there was an effective lower limit on bore size in open-chamber diesel engines. This paper presents a technique for improving combustion in the small open-chamber diesel engine.

Recent work at MIT on a 2-1/2 in bore, short-stroke diesel engine has demonstrated that good efficiency can be obtained through a combination of a large-hole nozzle and the use of air swirl to prevent overpenetration. There is some indication that good efficiency can be obtained over a wider operating range than standard diesel practice.

A method of design analysis for this type of engine is presented, along with techniques for estimating the swirl and nozzle design parameters.