An air/fuel mixture is received in an oxidation reaction chamber. The air/fuel mixture has a low concentration of fuel, for example, below a lower explosive limit (LEL). The mixture is received while a temperature of a region in the oxidation reaction chamber is below a temperature sufficient to oxidize the fuel. The temperature of the region is raised to at least the oxidation temperature (the temperature sufficient to oxidize the fuel) primarily using heat energy released from oxidizing the air/fuel mixture in a different region in the reaction chamber.