The automobile engines can be classified according to :1.number of cylinders ;2.arrangement of cylinders ;3.arrangement of valves ;4.type of cooling ;5.number of cycles (two or four );6.type of fuel burned ;7.type of ignition .
The engine is the source of power that makes the wheels go around and the car move .the automobile engine is an internal-combustion engine because the fuel (gasoline ) is burned inside it .the burning of gasoline inside the engine produces high pressure in the engine combustion chamber .this high pressure in the engine combustion chamber .this high pressure forces piston to move ,the movement is carried by connecting rods to the engine crankshaft .the crankshaft is thus made to rotate ;the rotary motion is carried through the power train to the car wheels so that they rotate and the car

汽車發(fā)動(dòng)機(jī)可以按以下幾種情況分類：
1、按氣缸的數(shù)量分類；2。按氣缸排列的方式分類；3。按進(jìn)氣方式分類；4。按冷卻方式分類；5。按工作循環(huán)的行程分類（二行程或四行程）；6。按所用的燃料分類；7。按點(diǎn)火方式分類。
發(fā)動(dòng)機(jī)是使車輪轉(zhuǎn)動(dòng)，從而驅(qū)動(dòng)汽車的動(dòng)力的來源。汽車發(fā)動(dòng)機(jī)是一種內(nèi)燃機(jī)，因?yàn)槿加停ㄆ停┦窃诎l(fā)動(dòng)機(jī)內(nèi)燃燒的。汽車的燃燒　在發(fā)動(dòng)機(jī)燃燒　室中產(chǎn)生的高壓力，推動(dòng)活塞運(yùn)動(dòng)，并通過連桿傳到發(fā)動(dòng)機(jī)曲軸。曲軸轉(zhuǎn)動(dòng)，動(dòng)力傳動(dòng)系統(tǒng)發(fā)動(dòng)機(jī)的轉(zhuǎn)動(dòng)運(yùn)動(dòng)傳給汽車車輪，從而使車輪及整車轉(zhuǎn)動(dòng)起來。