Abstract
In order to control the combustion in direct-injection gas engines, characteristics of spark-ignition combustion of high-pressure natural-gas jets injected into a constant-volume vessel were investigated under various conditions. Particularly in this study, effects of the jet impingement into the cavity wall on the combustion processes were exhibited based on the pressure histories and shadowgraph images. From the experimental results for different shapes and positions of cavity, locations and timings of spark, injection pressures, it was shown that a large-scale vortex flow formed in the cavity greatly contributed to a stable combustion due to the preparation of flammable mixture and the suppression of shear flow.
Keywords: Spark ignition engine, Gaseous fuel, Combustion, Natural-gas, Unsteady jets