A Critique of the Theory for Gussac's “LAG Process” Engine

The theory of the LAG process (1)* is examined, especially the claim that radicals resulting from rich combustion in the pre-chamber reduce the induction time in the main chamber resulting in more rapid combustion. Recent calculations are presented which show that flame propagation is dominated by diffusion of radicals which eliminates any induction time. Additional radicals from the pre-chamber would be superflous. Assuming more rapid combustion in an actual engine, as Gussac claims, tentative alternate explanations are given. The Appendix reviews and extends Semenov's theory (2) of branching chain reactions. It is shown that buildup of radical concentrations governs the induction period, and that the rate of fuel consumption is determined by the steady state radical concentration.