A Two-Tracer LIF Strategy for Quantitative Oxygen Imaging in Engines Applied to Study the Influence of Skip-Firing on In-Cylinder Oxygen Contents of an SIDI Engine

The effect of skip-firing (which is often applied in optical engine work) on the available in-cylinder oxygen concentration was investigated with a laser-induced fluorescence imaging setup that combines the measurement of fluorescence signals from toluene and 3-pentanone to quantitatively determine the distribution of molecular oxygen. We describe in detail the image processing procedure for this measurement. The reduction of in-cylinder oxygen when switching from skip-fired to continuous-fired engine operation is measured and compared to traditional exhaust measurements.