Development Research Of FAI System Applied In Different Small Engine

Small gasoline engine has been widely used in motorcycle, scooter and moped area. Recently, China’s small engine industry is developing quickly, export of the generator and garden machinery accounting for more than 70% of the total product. Small engines are applied to the fields of industry, agriculture, recreation industry and garden machinery, which impacts on the growth of national economy. Since air pollution and energy shortage are getting more and more serious, many countries are implementing stringent emission standards for engines and their applications, such as China III emission standards for motorcycles, and more strict emission regulation on small engines of European and United States in these years. Domestic enterprises undoubtedly face huge challenges of global engine export.A simple, reliable and cost-effective FAI fuel injection system is applied to a 50cm3 two-stroke engine to decrease such engine’s fuel consumption rate and emission in this paper, which is a semi-direct injection system. Bench experiments were carried out to evaluate the influence of injection and ignition phase on the performance, emission and fuel consumption of the engine in various load conditions. The chassis test on a scooter showed that the HC emission and fuel consumption was decreased a lot compared with the original carbureted engine.Another research is the FAI system development of a representative 384 cm3 four-stroke engine for general use, which is a Champion brand gasoline electricity generator, to study advantages of fuel injection technology on such engines. The original carburetor engine test is carried out firstly. The results of speed stability test and load change test on the carbureted engine indicate that, the mechanical speed controller makes the speed stay within 1%, the speed fluctuate within 10% on high load condition. The comparison provides the basis to the EFI development.Using PROE software, throttle assembly for the FAI system used on gasoline electricity generator is designed, which including throttle body, stepped motor basement. The prototype of throttle body is produced and fixed on the generator. The result of preliminary experiments demonstrates that the fuel consumption of the FAI system engine can be reduced by 15%.