电控燃油喷射系统相位识别新方法

本文提出利用进气压力传感器及摩托车磁电机触发信号为电控燃油喷射系统提供相位基准的新方法。磁电机每个工作循环产生两个触发信号，仅根据该信号不可能精确控制喷油及点火时刻。进气过程中进气压力传感器输出信号先减小，后升高，而这一变化过程正好位于两次触发信号之间，根据这一特征可以区分两次触发信号。在低转速工况，将当前采集的进气压力值同预设的参考值进行比较，通过判断进气过程是否到来，区分两个触发信号；高转速时在进气冲程只是保存进气压力数据，根据上一循环确定的触发信号进行喷油和点火控制，为防止电磁干扰带来的判断失误，在每个循环的“空闲时间”将采样的压力值进行校验，保证最多只有一个循环系统工作异常。利用该方法进行电控系统MAP图标定试验，整个过程中，系统工作正常，表明该方法是可行的。

New method of phase recognition in EFI system

A new method of phase recognition in EFI system is proposed, which utilizes intake air pressure sensor value and trigger signal generated from motorcycle magnetor as phase signal for EFI system. Motorcycle magnetor generates two trigger signals in one cycle, so it is impossible to control injection and ignition timing accurately only according to these signals. Output of intake air pressure sensor decreases at the beginning of intake stroke and then increases, this process locates just between two adjacent trigger signals . This feature can be used to distinguish two trigger signals. When the engine runs at low speed, the system compares the current intake air pressure value with a preset threshold value to decide whether the intake stroke comes, and to distinguish two trigger signals. When the engine runs at high speed, the intake air pressure value in the intake stroke is only saved, and the injection and ignition timings are controlled by trigger signals that were identified in the former cycle. To avoid mis-judgement of trigger signals due to electromagnetic interference, intake air pressure sampled in intake stroke is checked in the idle time of every cycle, this ensures that the system may work abnormally only in one cycle at most. MAP calibration experiment of EFI system was carried out using this method. The results show that the system works normally during the entire process, which indicates the method is feasible.