Twin jet spray and droplet stream impact injectors for novel combustion processes in Otto and Diesel engines
There have been numerous studies of fuel sprays for internal combustion engines with an emphasis on Single-Jet Sprays (SJS). Various measuring techniques have been employed to acquire quantitative information on different spray properties, including droplet size and droplet speed, as functions of the supply pressure, the jet nozzle diameter and the jet nozzle geometry. Correlating the measured spray properties, e.g. the spray droplet size, with the performance of a particular engine, it has been discovered that droplet size reductions have very positive effects on the combustion process. Reducing the jet nozzle diameter and increasing the supply pressure yield smaller droplets.
Smaller droplets are needed for improving the engine performance, through improved combustion. It is therefore understandable why diesel engines are aiming these days for pressures up to 3,000 bar. Injectors operating with such high pressures require material properties that are difficult to handle in manufacturing processes. This raises questions regarding other ways of producing sprays with small droplet diameters, achievable with much smaller supply pressures. Searches for such ways have resulted in additional and different methods for spray production referred to in this paper as:
“Twin-Jet Sprays” (TJS) production method,
“Droplet-Impingement Spray” (DIS) production method.
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