Investigation of a railplug ignition system for lean-burn large-bore natural gas engines.

摘要

The characteristics of three ignition systems, such as inductive ignition, capacitor discharge ignition, and railplug ignition system, are investigated. Based on the characteristics, the railplug is a very promising ignition system for lean burn natural gas engines with its high-energy deposition and high velocity plasma arc. Parallel railplugs are designed, fabricated and tested on an operating natural gas fueled engine. The engine tests shows that the lean-stability-limit (LSL) can be extended from a fuel/air equivalence ratio of ϕ = 0.62 for spark plugs down to ϕ = 0.535 using a railplug. Thus, engine-out NOx emission is also reduced using railplugs. A heat transfer model is proposed to aid the railplug design. A parameter study is performed both in a constant volume bomb and in an operating natural gas engine to improve and optimize the railplug designs.