Research And Development Of ECU On 50cc Two-Stroke GDI Engine

Two-stroke engine for motorcycles is reaching an important appointment for its survival due to its high emission level and poor fuel economy. Electronically controlled in-cylinder direct fuel injection system is becoming the key solution to solve these emission and fuel consumption problems.A simple, reliable and cost effective FAI (Free Armature Injection) system is applied to a 50cc two-stroke engine in this dissertation. A carbureted two-stroke engine was converted to a FAI prototype engine, which is good at high pulse-pressure injection; the hardware and software of the Electronic Control Unit (ECU) were designed; then this prototype engine was calibrated, tested and optimized on an engine test bench. A great number of dynamometer experiments are carried out to investigate the effects of fuel injection phasing on the performance, emission, fuel consumption of the engine during all load operating conditions. After a final optimization and other practical considerations, the control MAPs for the two-stroke DISI prototype engine are obtained. The torque performance, fuel consumption and emission economy of the engine is tested and compared with those of the original carbureted engine.In a conclusion, the FAI system can completely remove the fuel short-circuiting, and within the full operating range, the fuel consumption is reduced by 40-50%, and HC emission is greatly reduced.