High-Energy Spark-Flow Coupling in an IC Engine for Ultra-Lean and High EGR Mixtures 2001-01-0548

The role of high-energy ignition in the combustion of ultra-lean and high EGR air-fuel mixtures has been misunderstood as a result of neglecting a critical component to ignition: the coupling of the spark to a flowing mixture. Coupling of a suitably designed high-energy spark to the mixture flow in an engine not only increases spark energy delivery but significantly increases the lean burn capability of an engine. Tests in a single cylinder, two-valve, homogeneous charge gasoline engine designed with high squish flow and dual high-energy spark plugs located in the high flow field have resulted in considerable extension of the lean misfire limit of the engine to 30 to one air-fuel ratio (λ=2), with significantly improved fuel economy at light engine loads and lower emissions throughout the entire engine operating range.