1) The engine is the power plant that produces the energy needed to propel the vehicleand operate other systems. It converts the heat energy of a fuel (gasoline, diesel，alcohol,etc) into movement. The burning and expansion of the gases in the combustion chamberproduces pressure. The engine piston, connecting rod and crankshaft convert this pressureinto motion for moving the car and operating other systems.

    譯：發動機是驅動汽車和運行車上其他系統所需能量的動力源。發動機將一種燃料（汽油、柴油、乙醇等）的熱能轉化為運動。燃氣在燃燒室燃燒并膨脹，產生壓力。發動機活塞、連桿和曲軸將這種壓力轉換為運動，從而推動汽車行進并使其他系統運行。

    2) Four separate piston strokes are needed to produce one cycle, which are intakestroke，compression stroke, power stroke and exhaust stroke.

    譯：（發動機）一個工作過程（周期）包括四個不同沖程：進氣沖程、壓縮沖程、做功沖程和排氣沖程。

    3) Valvetrain opening/closing and duration, as well as the geometry of the valvetrain,controls the amount of air and fuel entering the combustion chamber at any given point intime.

    譯：配氣機構通過開閉和持續時間及其幾何形狀來控制進人燃燒室的空氣和燃油的總量。