以現階段的技術背景而言,改善機車油耗及污染最適合的方法為使用電子燃油噴射系統,因此當務之急是開發小型引擎的引擎管理系統(Engine Management System, EMS)來提高小型引擎之效率。為了提升火星塞的壽命並且避免噴油嘴於非線性區段作動而造成供油不精準的問題,行程判別是EMS不可缺少的機制。 本研究之行程判別策略首先在起動過程中利用曲軸旋轉加速度迅速判別出引擎行程,接著再次進行確認並判斷當時運轉情況是否適合以歧管壓力差與曲軸旋轉速度作為行程判別之依據,確保引擎可正常起動。最後則是記憶行程判別的結果,當曲軸旋轉速度變異量過大而造成齒訊計數錯誤使行程判別誤判時,便立即進行檢測。在策略初步發展時,利用Matlab/Simulink針對非線性單缸機車引擎建立引擎模型,再使用硬體在迴路中(Hardware In the Loop, HIL)進行策略驗證。初步驗證完成後,為了使策略更加可靠而對實車進行相關訊號量測,並探討各種運轉條件下最適合執行之策略。最後進行實車測試,由測試結果驗證本研究之策略在引擎暫態運轉之下仍可成功的判別出正確之行程。
In order to reduce the emissions and improve the fuel consumption of scooter engines, it is necessary to develop a strategy for engine management system (EMS). For prolonging the life of spark plug, and prevent the injector operating in the nonlinear region, EMS should have the stroke identification. The purpose of this paper is to devep the strategy of stroke identification. At first, the crankshaft angular acceleration is used to identify the engine stroke. Then, it will check the stroke again, and decided whether to use manifold absolute pressure or crankshaft angular velocity for the stroke identification in different operating conditions. Finally, it will save the current result of stroke identification in the memory of ECU (Engine Control Unit). When the stroke identification result mislead by the tooth counting error during the crankshaft angular velocity variation is too large, the system will identify the stroke again. During developing the strategy of stroke identification, this research using Matlab/Simulink to build the engine model and use HIL to test the strategy. After the simulation is finished, the strategy needs to test in real engine, so we analyze the signal from fuel injection system, and build a stronger strategy. Finally, the experiment results proves that the strategy identify the correct stroke during the transient condition.