Closed Loop Control of Automotive Engines

PDFTech ReportDOT-TSC-NHTSA-81-12HS-805 874DOT-TSC-1466Air quality managementExhaust gasesInternal combustion enginesLoops (Control systems)Control systemsFeedback controlAutomatic controlOptimizationComputer programsElectronic controlFuel consumptionVehicle power plantsUnited StatesUnited States. National Highway Traffic Safety AdministrationPowell, J. DavidGlaser, ItshakRandall, KentHosey, RickStanford UniversityJohn A. Volpe National Transportation Systems Center, (U.S.)United States. National Highway Traffic Safety AdministrationNTL-ENERGY AND ENVIRONMENT-ENERGY AND ENVIRONMENTNTL-ENERGY AND ENVIRONMENT-Air QualityNTL-SAFETY AND SECURITY-Vehicle DesignVolpe National Transportation Systems Center, Technical Reference CenterInternal combustion engine economy and emissions are known to be sensitive to changes in engine control variables. Two of the most important variables are fuel/air ratio (f/a) and spark advance. These variables are affected by environmental changes, manufacturing tolerances, and time degradation. The combined effect of all these changes can cause as much as a 15% loss in economy and a 30% increase in emissions. This research concerns the application of optimization theory to develop control laws for use in closed loop control strategies to minimize the effect of the variables discussed above. The report describes the automated dynamometer facility developed for the acquisition of engine mapping data. This data was used to develop analytical functions describing the fuel consumption and emissions at each of 10 torque/RPM points. The functions were used by an optimization procedure to arrive at control strategies and driving cycle predictions of fuel consumption and emissions. The optimum schedules were then used to determine a closed-loop control strategy