| The process of hot surface ignition of direct injected natural gas using a shielded glow plug was studied in an optically accessible combustion apparatus by varying combustion chamber design and operational parameters. Parameters studied were glow plug temperature, relative angle of the fuel injector and the glow plug shield, and the fuel injector nozzle orifice size, shape, and angular spacing. Results were analyzed using ignition delay time, fuel utilization, rate of heat release, and acquired high speed combustion images. Glow plug temperature had a dominant effect on ignition delay in comparison to all other parameters. Fuel injector nozzle design, along with the geometric interaction between the fuel injector and the glow plug shield, had a strong effect on the air fuel mixture available for ignition in the vicinity of the glow plug. Results will be used to inform the design and operation of a hot surface assisted natural gas engine. |
