Cycle-Resolved Multipoint Ionization Probe Measurements in a Spark Ignition Engine

Ionization probes installed in the head gasket of a spark ignition engine are used to measure the cycle-resolved arrival time of the flame at eight discrete points at the perimeter of the cylinder bore. Simultaneous data acquisition of the ionization probe and cylinder pressure measurements permits the flame burn pattern, the combustion rate, and the cyclic variability of these quantities to be observed on a video monitor m real-time as engine operating parameters are varied. To demonstrate the technique, measurements are presented for uniformly-spaced and clustered arrangements of ionization probes and differing conditions of fluid motion, spark location, spark plug configuration, and equivalence ratio.