Measurements of the Effect of In-Cylinder Motion on Flame Development and Cycle-to-Cycle Variations Using an Ionization Probe Head Gasket

An ionization probe head gasket (to IPHG) was used to investigate flame development in a 2.0L I4 engine with two in-cylinder fluid motions. A new technique was developed to display accurate flame contours at 2%, 10% and 50% mass fraction burned crank angles using the measurements of flame arrival time from the ion probes in conjunction with cycle simulations. The flame arrival and burn rate information is used to scale the relationship between flame radius and mass fraction burned from the cycle simulation to create accurate contours of the flame for each cycle.

The tumbling motion inside the combustion chamber produced by the production intake ports convected the flame towards the exhaust side of the chamber. The geometry of the flame development was relatively unaffected by changes in speed and load. A swirl generating plate at the port/manifold interface generated more intense in-cylinder motion, a 5-9° faster burn rate and increased lean limit at part throttle operating conditions. The change in the in-cylinder motion resulted in more uniform flame arrival at the chamber periphery.

The IPHG was also used to investigate cycle-to-cycle variations in flame shape and combustion. Cycles where the flume kernel was pushed more strongly towards the exhaust side of the chamber produced a longer flame travel distance to the intake side of the chamber, an earlier truncation of the flame at the chamber walls and a longer 10-90% burn duration.