Mixture control for ic engine with temperature limiting - has proportion of exhaust gases recycled when engine torque is high and with stoichiometric mixture

摘要

The engine operates with an air to fuel ratio of between 16:1 to 13:1, with the latter representing the richer mixture for cold starting. When the engine torque requirement is higher than a set level the mixture is set at a stoichiometric value. To prevent undue rise in temperature of the valves and of the exhaust system, a set proportion of exhaust gasses are recycled to the inlet manifold. The rate of recycling depends on the engine torque. The recycled gasses pass through a first cooler before entering the inlet manifold. For turbocharged inlet manifolds a second cooler is set behind the compressor. ADVANTAGE - Improved engine management, no high temperatures in valves and in exhaust system.