Full-field IC engine flow measurement using particle image velocimetry

Particle image velocimetry (PIV) has been used to study the in-cylinder flow within a single-cylinder optical Spark ignition engine. The engine had a standard four-valve pentroof cylinder head geometry, a compression ratio of 10.5:1, and was motored at a crank speed of 1000 rpm. Double exposed PIV images were recorded from a range of vertical and horizontal measurement planes within the engine's glass cylinder. The images were interrogated using digital autocorrelation to give maps of two-dimensional instantaneous velocity. Successful PIV measurements have also been made under firing conditions in the unburned gas ahead of the flame front, with the engine being skip-fired using a propane/air mixture. The use of PIV for the characterization of realistic in-cylinder flow fields under a variety of inhospitable conditions has therefore been demonstrated. Limitations in the current technique are briefly discussed and methods for overcoming these limitations are described. (C) 1996 Society of Photo-Optical instrumentation Engineers.