Research On Air/Fuel Ratio Fuzzy Self-tuning PID Control System For Carburetor Engine

With increasingly stringent emission regulations, the motorcycle industry needs ahighly cost-effective solutions to solve the emission problem. Electronic carburetortechnology is one of the recommended routes for the country Ⅲ emission. due to smallchanges to the original carburetor engines, and performance-cost into account, it’s more inline with the status of China’s motorcycle market, and will become one of the mainstreamtechnologies for motorcycles to cope State Ⅲ emission regulations.152QMI carburetor engine was used as the prototype for electronic carburetor systemdevelopment. Firstly determined the overall conversion program for electronic carburetorsystem, and made component selection and installation to accomplish systemtransformation; then carried out hardware development work for electronic carburetorsystem, chose control microcontroller and designed the circuit for the sensors andactuators to produce low-cost ECU. explored control strategy for the electronic controlsystem to determine the condition division and air supply pulse width calculation process,established the basic architecture of the software, and then developed the control softwarefor the electronic carburetor system; the closed-loop control algorithm based on theoxygen sensor is the focus of the development. After introducing the PID control andfuzzy control basic principles, on the foundation of PID control algorithm, introducedfuzzy self-tuning capabilities of PID parameters, and achieved it in the microcontroller;Finally, carried out the control algorithm experimental studies, used FOLPDapproximation and unstable system PID tuning formula to determine the basic PIDparameters, did experimental optimization, then added fuzzy self-tuning function,comparative experiments show that the fuzzy self-tuning PID has better control effect,which benefits conversion efficiency of three-way catalytic converters.