Fuel-air mixture control for carburettor of IC engine - calculates engine speed from measured crankshaft speed and compares it with required speed

摘要

The mixture control measures the fluctuations in speed of the engine crankshaft and calculates the variation in engine speed. The calculated engine speed is compared with a reference command signal. The fuel/air mixture in the carburettor is altered until the engine speed is equal to the selected reference. The mixture is altered by controlling the amount of air admitted or by controlling a secondary jet, the main jet providing the greater part of the mix. Alternatively the mixture is altered by controlling a bypass connection between the air inlet of the carburettor and a point directly downstream of a large nozzle in the carburettor.