Fuel Stratification Process in the Cylinder of an Axially Stratified Engine 2000-01-2842
The Fuel stratification process has been investigated in the cylinder of an axially stratified lean burn engine by visualizing fuel behavior. Planar laser light sheet from an Nd:YAG laser has been illuminated through the transparent quartz cylinder of a single cylinder optical engine. Mie scattered light has been captured through the quartz window in the piston head with an ICCD camera. Fuel has been replaced with an ethanol droplets to utilize an atomized fuel spray for visualization purposes. Swirl ratios have been varied by changing cylinder heads with different swirl numbers and injection time has been varied to find the effect of fuel stratification. A higher lean mixture limit was achieved when the fuel remained at the combustion chamber as stratified with the proper combination of fuel injection timing swirl flow. The stratification was governed by tumble motion in no/low swirl ports on the other hands this is determined by short penetration depth and strong swirl of the middle cylinder area, which plays a role of supporting upper-rich state, in high swirl port.