A New Fuzzy Logic Approach to EGR Control

Abstract This paper presents a control scheme for the exhaust gas recirculation of a spark ignition engine based on the engine smoothness. The emission of nitrogen oxid of a spark ignition engine can be drastically reduced by recirculating the exhaust gas. This also improves engine efficiency. Engine smoothness, pollutant emission, and engine efficiency get worse if the amount of exhaust gas in the combustion mixture exceeds a certain level. In this contribution a fuzzy system determines the quality of combustion and engine smoothness by evaluating cylinder-pressure-signals. A control scheme maximizes the rate of exhaust gas recirculation without effecting the engine smoothness adversely. The control scheme was tested in a test vehicle.