Study Of Small EFI Gasoline Generator Set Control Strategies

With the increasing environmental pollution,emission regulations are becoming more and stringent for engines;meanwhile,energy is depleting,energy conservation & emission reduction has become a theme of modern world.Nowadays,small gasoline generator sets still use carburetors as the fuel supply means and also mechanical devices for speed regulation.Carburetor has the disadvantage of high fuel consumption,and gasoline engine with carburetor shows shortcomings with the stringent regulatory requirements,and its mechanical speed control device has accommodative lag,low accuracy and poor stability shortcomings.EFI(Electronic fuel injection)technology has a huge advantage over carburetor in terms of energy conservation,provides a way to replace the carburetor.FAI(finely atomized injection)technology is designed to provide EFI solutions for small gasoline engine,but for the application of FAI to gasoline generator sets,the mechanical speed regulation device cannot be coupled with the EFI platform,which restricts the improvement of gasoline generator,so it is urgent to develop a practical,reliable,reasonably priced digital speed control system for EFI system.This thesis focuses on the development of digital speed control system for EFI generator set.In order to improve the performance of digital speed control system,various speed control strategies were specially studied.Firstly,based on the application requirement of generator set,further improvement of the EFI system was conducted,including current sampling,MCU,electronic throttle drive,control strategies etc;In terms of FAI calibration system,ignition/fuel injection and relevant MAPs of the transformed EFI engine were calibrated.Secondly,based on V-development model for electrical control system,GT-POWER and Matlab / Simulink were used to establish engine model and electronic throttle model;their characteristics were separately compared with actual engine and electronic throttle.The GT-POWER engine model was coupled with electronic throttle model in the Simulink environment and different control strategies including PID,fuzzy PID,feed-forward fuzzy PID were designed and performances were compared and analyzed,the superiority of feed-forward fuzzy PID was verified.Thirdly,according to the optimized control strategy,digital speed control system was fulfilled.The detailed hardware design was given,including the speed signal processing circuit,the current sampling circuit,the motor drive circuit etc;and the detailed software design was given,including acceleration module,constant speed control module,fault monitoring & alarm module and communication module.Furthermore,multi-tooth speed control strategy was proposed,the relevant software and hardware design was given;Based on the DATAVIEW platform of FAI,CAN communication module was programmed,which equips the product with bus interface.Finally,bench tests were conducted with the designed digital speed control system.PID,fuzzy PID,feed-forward fuzzy PID and multi-tooth control strategies were compared and analyzed.Meanwhile,the emission and fuel consumption of EFI generator set were tested and also compared with the performances of original machine.The results show that FAI system applied to the small gasoline generator set achieves the goal of energy saving and better emission,the performance of designed digital speed control system is superior,of which the quality meets the relevant international standards.