Development Research On ECU Of Motorcycle EFI

In July 2008 the China III emission legislation (similar to Euro III) for motorcycles will come into force. That will be a profound impact on the domestic motorcycle industry. A lot of low emissions technologies were therefore sourced and developed, among which electronic fuel injection (EFI) system was considered the most effective method to satisfy the Euro III and more strict regulation.In this paper, in order to meet the demands of domestic motorcycle market restricted by Euro III regulation, an Atmel's low-cost 8 bit microcontroller, ATMega 168, is used to develop an EFI system for a single cylinder motorcycle. In view of the stringent cost requirement, the goal of our research is to control the system cost as lower as possible while achieving Euro III regulation.The EFI system developed in this paper is based on A/F open-loop control strategy, and applies throttle position -speed method. Unique injection and ignition control strategies for transient and idle operating mode are also been developed and employed in this system. Segment fuel correction method according to engine speed is proposed in this paper. So the manufacture error of engine and EFI system can be effectively reduced just after limited engine speed points are corrected, and the three-way catalytic converter can work more effectively.A 125ml volume motorcycle is equiped with this EFI system. Emission experiment is carried out after the EFI system is calibrated. The results show that: the EFI system based on A/F open-loop control, equiped with three-way catalytic converter, can satisfy Euro III regulation.