The major goal of the study is the improvement of the ignition characteristics of lean, premixed natural gas (NG) combustion under engine-like conditions. A new process is investigated involving the oxidative coupling of methane reaction (OCM) for the in situ production of C-2 hydrocarbons to be used as ignition enhancers during lean combustion of methane in internal combustion (IC) engines. Addition of the OCM product mixture enhances the ignition characteristics of lean methane/air mixtures, the beneficial effect resulting from the C2H4/C2H6 components. OCM in both conventional plug flow and packed-bed membrane reactors is modelled and optimised with respect to reactor conditions and ignition characteristics. An additional ignition technique that includes flowing a jet of a fuel/air stream against a hot inert surface has been implemented for quantifying the effect of the proposed ignition enhancers. (c) 2006 Elsevier Ltd. All rights reserved.