Single Cylinder Motored SI IC Engine Intake Runner Flow Measurement Using Time Resolved Digital Particle Image Velocimetry 2006-01-1043

Time resolved intake runner flow field data is presented for a motored single cylinder four stroke, direct injection spark ignition (DISI) optical internal combustion (IC) engine with an optically accessible intake runner. Previous studies have shown the fundamental influence in-cylinder air motion has on engine performance, exhibiting a controlling factor on the mixing process and early flame kernel development. An improved understanding of the in-cylinder flow fields during the intake and compression process leading up to ignition is required. However, knowledge of the intake runner flow field during the intake phase of the engine cycle is required to establish the effect of intake runner flow variation on in-cylinder flow field development. This paper presents the use of a new time resolved digital particle image velocimetry system within the intake runner to study runner flows and their variation over many engine cycles.

A high speed time resolved digital particle image velocimetry (TRDPIV) system was employed to measure the flow field within an optical intake runner of the same geometry as the standard runner employed. Measurements of the fluid flow within the runner were achieved at an engine speed of 1500 rpm and diagnostic acquisition rate of 5 kHz, providing a temporal resolution of 1.8 crank angle degrees between measurement fields. Multiple cycle captures are obtained for the intake runner flow during the intake and compression phase. Further examples of intake runner flow over consecutive, full, engine cycles were captured for the engine range 0 to 720 crank angle degrees (CAD), and comparisons to the runner pressure history are made. Results show a clear link between the intake flow field magnitude and the gradient of runner pressure. The presence of clear high velocity pulses can be seen, correlating to the region of maximum piston speed. Variation in intake runner flow direction and magnitude are investigated for improved understanding of cyclic variation.