Burn Rates in Natural Gas Fueled Single Cylinder Spark Ignition Engine

An experimental study was undertaken to investigate burn characteristics of homogeneous charge natural gas fueled, single cylinder, spark ignition engine. The engine was instrumented with flame detection sensors, pressure transducer, a wide-range exhaust oxygen sensor and several other devices to measure parameters associated with charge and combustion. The pressure data was used in a model to estimate mass of charge burned during the combustion events. Engine compression ratio was varied within a small range. The flame kernel development time was influenced by mixture stoichiometry, engine load and speed. Very lean equivalence ratio had pronounced effect on kernel development. The combination of light load and very lean air-to-fuel ratio provided less favorable environment for the formation of stable flame kernel. An increase in compression ratio helped to shorten flame development time. The rapid burn combustion process with natural gas fuel was a little slower than that was observed with gasoline mixtures at corresponding conditions. The engine data was used to calculate turbulent burning speed of natural gas-air mixtures. The information would be useful in simulation and modeling of combustion processes in natural gas fueled, medium speed, industrial engine.