A Comparison of Transient Air-Fuel Measurement Techniques 2002-01-2753

Universal Exhaust Gas Oxygen (UEGO) sensors are widely used in engine exhaust streams to measure the recently burned air-fuel (A/F) mixture ratio. UEGO sensors are also frequently used to characterize transient A/F behavior during throttle or fuel variations. This study experimentally compares a UEGO exhaust based sensor response to that obtained from an in-cylinder Fast Flame Ionization Detector (FFID) during engine transients. UEGO sensor transient response time is seen as a limitation to the type of transient measurement that can be accurately characterized. A brief comparison of conventional transient fuel x-τ model parameters based upon the different measurement techniques shows that the transient fuel compensation calibration can be a function of measurement technique and method.