Abstract

This study examines the laser ignition of methane-air mixtures in a Rapid Compression Machine (RCM). The lean limit and the minimum ignition energy (MIE) were investigated in the engine-like conditions provided by the RCM. A lean limit of ϕ₉₀=0.47 was found experimentally for a laser spark energy of 5 mJ (corresponding to 90% combustion efficiency). MIE was found to exhibit a stochastic behavior and results can only be interpreted statistically. The MIE study was conducted at an equivalence ratio of ϕ=0.4 yielding an MIE (90% probability) of MIE₉₀=7.2 mJ.

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