Study of a Micro-Pulsation Fuel Injection System for Small Gasoline Engine

A new fuel injection concept called micro-pulsation fuel injection (μPFi) system had been developed for an internal combustion engine. The μPFi system composes an engine management system, a fuel-circulating device, and thermal-bubble fuel injectors with micropumps. The μPFi system had been installed in a commercial 4 stroke, 125cc motorcycle and tested in engine and chassis dynamometers. The measured CO and HC+NOx emissions were 1.5g/km and 1.14g/km respectively in ECE-40 test mode without catalyst converter and secondary air. The results showed that the motorcycle with μPFi system achieves superior exhaust CO emissions than the carburetor system while keeping comparable vehicle performance.