A Basic Behavior of CNG DI Combustion in a Spark-Ignited Rapid Compression Machine

摘要: A basic characteristics of compressed natural gas direct-injection (CNG DI) combustion was studied by using a rapid compression machine. Results show that comparing with homogeneous mixture, CNG DI has short duration, high pressure rise due to combustion, and rate heat release, which are considered come from the charge stratification flow generated fuel injection. can realize extremely lean reaches 0.03 equivalence ratio, φ. Combustion maximum efficiency found be insensitive injection modes. Unburned methane showed almost same level as mixture combustion. CO increased steeply increase in φ when greater than 0.8 excessive stratification, NOx peak value shifted region lower inefficiency maintains less 0.08 range 0.1 0.9 increases at very low bulk quenching higher stratification. The estimated products shows good agreement release analysis.