Experimental Investigation On The Spray And Ignition Characteristics Of Diesel Spray

With the development and more requirement of modern society on dynamicperformance and emission characteristics of engines, more attention is paid to fuelatomization and ignition characteristics. Atomization quality of fuel is the most importantfactor in diesel combustion process, and ignition characteristics have important influenceon cold starting performance and emission characteristics of engines. So it is important tograsp the influence of different environmental conditions and injections on the spray andignition characteristics of diesel.A constant volume combustion device with high temperature and pressure wasdesigned to test spray and ignition characteristics of diesel with the use of high-pressurecommon rail fuel injection system and high-speed cameras and schlieren system. Matlabdigital image processing techniques was applied for image processing to get the spraypenetration distance, spray angle and ignition information. It also could improving theefficiency of the test image processing.In this test condition, investigation showed that with the ambient temperature rising,the liquid spray penetration distance was shortened and the spray angels were increased.High ambient temperature promoted the formation of mixture and shortened the ignitiondelay. With the ambient density increasing, spray penetration distance was shortened andthe spray angels got bigger. High ambient density promoted the diffusion and mixing ofmixture, and shorten the ignition delay. Under the conditions of low ambient temperatureand density, the higher injection pressure resulted longer spray penetration, and the sprayangle did not change obviously, and the ignition delay became longer.