Combustion efficiency with a change in ignition plug type using a new plasma energy generator in a constant volume combustion chamber

摘要

At present, the combustion condition inside the cylinder of a spark ignition engine is formed as a high-pressure and rare condition due to the application of supercharger and turbocharger technologies. This study verified the validity of the ignition technology for plasma energy generator (PEG) via flame propagation speed (FPS) and inflammability limit in a constant volume combustion chamber. The control board and internal circuit of an ignition system with the application of PEG were personally designed and produced. Propane gas was used as the experimental fuel, and air/fuel ratio (AFR) was controlled by setting the theoretical AFR to 15.6:1. Experiments were performed using a camera that could measure 1000 frames per second at an optimum resolution for the precise analysis of flames. FPS and inflammability were compared based on two sets of experimental variables, namely, an ignition system using PEG and an AFR of 1.0 to 1.9 from a 0.1 unit. On the basis of the FPS analysis results, the FPS values for the existing ignition system and for the C-type and J-type ignition systems with mounted PEG were not considerably different at AFR(lambda) 1. However, the difference between the existing ignition system and the ignition system using PEG was observed to be 5 ms at AFR(lambda) 1.3, and differences in FPS increased with AFR. Experimental results on inflammability limit showed that the conventional type ignition system failed to generate ignition from AFR 1.5, whereas the ignition system using PEG exhibited combustion up to AFR(lambda) 1.9 due to the increased inflammability limit. For the C-type and J-type plugs using PEG, the J-type plug was demonstrated to be efficient at higher AFR, which was the lean burn area, although no substantial difference was observed between AFR(lambda) 1.0 and 1.3. In the present study, FPS was improved by using the new ignition system, and the inflammability limit could be increased.