Quantified Analysis of a Production Diesel Injector Using X-Ray Radiography and Engine Diagnostics
2015-10-21T00:00:00Z (GMT) by
The work presented in this thesis pursues further the understanding of fuel spray, combustion, performance, and emissions in an internal combustion engine. Various experimental techniques including x-ray radiography, injection rate measurement, and in-cylinder endoscopy are employed in this work to characterize the effects of various upstream conditions such as injection rate profile and fuel physical properties. A single non-evaporating spray from a 6-hole full-production Hydraulically Actuated Electronically Controlled Unit Injector (HEUI) nozzle is studied under engine-like ambient densities with x-ray radiography at the Advanced Photon Source (APS) of Argonne National Laboratory (ANL). Two different injection pressures were investigated and parameters such as fuel mass distribution, spray penetration, cone angle, and spray velocity were obtained. The data acquired with x-ray radiography is used for the development and validation of improved Computational Fluid Dynamic (CFD) models. Rate of injection is studied using the same HEUI in a single cylinder Caterpillar test engine. The injection rate profile is altered to have three levels of initial injection pressure rise. Combustion behavior, engine performance, and emissions information was acquired for three rate profile variations. It is found that NOx emission reduction is achieved when the SOI timing is constant at the penalty of lower power generated in the cycle. However, if CA50 is aligned amongst the three profiles, the NOx emissions and power are constant with a slight penalty in CO emissions. The influence of physical and chemical parameters of fuel is examined in a study of the heavy alcohol, phytol (C20H40O), in internal combustion engine application. Phytol is blended with diesel in 5%, 10%, and 20% by volume. Combustion behavior is similar between pure diesel and the phytol/diesel blends with small differences noted in peak cylinder pressure, ignition delay, and heat release rate in the premix burn phase. Diesel/phytol blends yield marginally lower power values. In-cylinder soot radiation images show combustion instability at the start of the event for the 20% phytol/diesel blend. Overall, NOx emissions are comparable across the different fuels used and no discernible trend is found in CO emissions.