Fuzzy Logic Control System for Fuel Mixture Quality in Spark Ignition Engines.(Dept.M)

Spark ignition engine performance and exhaust emissions are strongly affected by the fuel/air ratio used. A considerable amount of investigations have been carried out by engine manufacturers to control engine performance and meet exhaust emission standards of governmental agencies by developing control systems for some operating variables such as ignition timing(IT), Fuel Air Ratio(FAR), and Exhaust Gas Recirculation (EGR) This paper presents a fuzzy control system that measures exhaust temperature and operates a needle valve on the engine earburetor jet that enables the fuel to air ratio lo oscillate about a desired value. A group of experiments have been carried out to obtain the relationship between fuel to air ratio or (ɸ), Exhaust temperature and exhaust emissions. A group of fuzzy logic rules which relate exhaust temperature, to the desired speed with the position of a needle valve actuated by a stepping motor are proposed. A beneficial of fuzzy control method was that the rules determined the characteristics of control system are interpreted by the operator. Experimental and simulated results show that the proposed fuzzy system improves the fuel/air mixture quality.