Evaluation of the Atomized Jet of Common-Rail Injectors Nozzles Working with Biodiesel 2017-36-0415

The atomization process in a Diesel engine is directly involved with its efficiency, emissions and damage. The biodiesel insertion brought with it interactions not expected by the components involved in the injection process and, consequently, different wear mechanisms. This paper aims to evaluate the injector nozzle hole wear and the consequences to the atomized jet profile by using a high-speed camera. The tests were run in a common rail test rig using two injectors, one to each biodiesel formulation during the period of 20 hours, non-continuous, for each one The injection parameters were set to 800 bar, 700 μs and 18 Hz (representing partial load in a usual common rail engine), for the pressure, time and frequency of injection, respectively. The injectors were placed in a chamber at 1 atm and were filmed in its new condition and after the tests using the camera at 10,000 frames per second (fps) in two different pressures (350 bar and 1400 bar) with the injection frequency at 12 Hz. The results were analyzed using a software to measure the jet length, speed, cone angle and jet density. The wear mechanisms were different for each fuel resulting in a jet profile change and, consequently, modifying the engine efficiency.