The gasoline engine converts the energy of gasoline into kinetic energy to drive the car. The simple way is to obtain kinetic energy by burning gasoline inside the engine. Therefore, the automobile engine is an internal combustion engine -- combustion occurs inside the engine.

有兩點需注意：

There are two points to note:

1． 內燃機也有其他種類，比如柴油機，燃氣輪機，各有各的優點和缺點。

1. There are other types of internal combustion engines, such as diesel engine and gas turbine, which have their own advantages and disadvantages.

2． 同樣也有外燃機。在早期的火車和輪船上用的蒸汽機就是典型的外燃機。燃料（煤、木頭、油）在發動機外部燃燒產生蒸氣，然后蒸氣進入發動機內部來產生動力。內燃機的效率比外燃機高不少，也比相同動力的外燃機小很多。所以，現代汽車不用蒸汽機。

2. There are also external combustion engines. The steam engine used in early trains and ships was a typical external combustion engine. Fuel (coal, wood, oil) burns outside the engine to produce steam, which then enters the engine to generate power. The efficiency of internal combustion engine is much higher than that of external combustion engine, and much smaller than that of external combustion engine with the same power. Therefore, modern cars do not use steam engines.

相比之下，內燃機比外燃機的效率高，比燃氣輪機的價格便宜，比電動汽車容易添加燃料。
  這些優點使得大部分現代汽車都使用往復式的內燃機。

In contrast, internal combustion engines are more efficient than external combustion engines, cheaper than gas turbines, and easier to add fuel than electric vehicles< br/> & nbsp; These advantages make most modern cars use reciprocating internal combustion engines.

二、燃燒是關鍵

2、 Combustion is the key

汽車的發動機一般都采用4沖程。（馬自達的轉子發動機在此不討論，汽車畫報曾做過介紹）

Automobile engines generally use 4-stroke. (Mazda's rotor engine will not be discussed here, which has been introduced by auto illustrated)

4沖程分別是：進氣、壓縮、燃燒、排氣。完成這4個過程，發動機完成一個周期(2圈)。

The four strokes are: intake, compression, combustion and exhaust. After completing these four processes, the engine completes one cycle (2 turns).

理解4沖程

Understand 4-stroke

活塞，它由一個活塞桿和曲軸相聯，過程如下：

The piston is connected with the crankshaft by a piston rod. The process is as follows:

1．活塞在頂部開始，進氣閥打開，活塞往下運動，吸入油氣混合氣

1. The piston starts at the top, the intake valve opens, and the piston moves downward to suck in the oil-gas mixture

2．活塞往頂部運動來壓縮油氣混合氣，使得爆炸更有威力。

2. The piston moves to the top to compress the oil-gas mixture, making the explosion more powerful.

3．當活塞到達頂部時，火花塞放出火花來點燃油氣混合氣，爆炸使得活塞再次向下運動。

3. When the piston reaches the top, the spark plug releases sparks to ignite the oil-gas mixture, and the explosion makes the piston move downward again.

4．活塞到達底部，排氣閥打開，活塞往上運動，尾氣從汽缸由排氣管排出。

4. When the piston reaches the bottom, the exhaust valve opens, the piston moves upward, and the tail gas is discharged from the cylinder through the exhaust pipe.

注意：內燃機終產生的運動是轉動的，活塞的直線往復運動終由曲軸轉化為轉動，這樣才能驅動汽車輪胎。

Note: the motion generated by the internal combustion engine is rotation, and the linear reciprocating motion of the piston is finally converted from the crankshaft to rotation, so as to drive the automobile tire.

三、汽缸數

3、 Number of cylinders

發動機的核心部件是汽缸，活塞在汽缸內進行往復運動，上面所描述的是單汽缸的運動過程，而實際應用中的發動機都是有多個汽缸的（4缸、6缸、8缸比較常見）。
  我們通常通過汽缸的排列方式對發動機分類：直列、V或水平對置（當然現在還有大眾集團的W型，實際上是兩個V組成）。見下圖

The core component of the engine is the cylinder, and the piston moves back and forth in the cylinder. The above description is the movement process of a single cylinder, while the engine in practical application has multiple cylinders (4, 6 and 8 cylinders are common)< br/> & nbsp; We usually classify the engine by the arrangement of cylinders: in-line, V or horizontal opposed (of course, there is now the W-type of Volkswagen Group, which is actually composed of two V). See the figure below

直列4缸

In line 4 cylinder

水平對置4缸

Horizontal opposed cylinder 4

不同的排列方式使得發動機在順滑性、制造費用和外型上有著各自的優點和缺點，配備在相應的汽車上。

Different arrangement makes the engine have their own advantages and disadvantages in smoothness, manufacturing cost and appearance, which are equipped on the corresponding vehicle.

四、排量

4、 Displacement

混合氣的壓縮和燃燒在燃燒室里進行，活塞往復運動，你可以看到燃燒室容積的變化，大值和小值的差值就是排量，用升（L）或毫升（CC）來度量。汽車的排量一般在1。5L~4。0L之間。每缸排量0。5L，4缸的排量為2。0L，如果V型排列的6汽缸，那就是V6 3。
  0升。一般來說，排量表示發動機動力的大小。

The compression and combustion of the mixture are carried out in the combustion chamber. The piston moves back and forth. You can see the change of the volume of the combustion chamber. The difference between the large value and the small value is the displacement, which is measured in liters (L) or milliliters (CC). The displacement of a car is generally 1. 5L~4。 Between 0l. Displacement per cylinder 0. 5L, the displacement of cylinder 4 is 2. 0l, if there are 6 cylinders arranged in V-shape, it is V6 3< br/> & nbsp; 0 liter. Generally speaking, the displacement represents the power of the engine.

所以增加汽缸數量或增加每個汽缸燃燒室的容積可以獲得更多的動力。

Therefore, increasing the number of cylinders or increasing the volume of combustion chamber of each cylinder can obtain more power.

五、發動機的其他部分

5、 Other parts of the engine

凸輪軸 控制進氣閥和排氣閥的開閉

The camshaft controls the opening and closing of the inlet and exhaust valves

火花塞 火花塞放出火花點燃油氣混合氣，使得爆炸發生。火花必須在適當的時候放出。

The spark plug is ignited by the mixture of oil and gas. Sparks must be released at the right time.

閥門 進氣、出氣閥分別在適當的時候打開來吸入油氣混合氣和排出尾氣。在壓縮和

The inlet and outlet valves of the valve shall be opened at an appropriate time to suck in the oil-gas mixture and discharge the tail gas. In compression and

燃燒時，這兩個閥都是關閉的，來保證燃燒室的密封。

During combustion, both valves are closed to ensure the sealing of the combustion chamber.

活塞環 在氣缸壁和活塞中提出密封：

The piston ring raises the seal in the cylinder wall and piston:

1．防止在壓縮和燃燒時油氣混合氣和尾氣泄漏進潤滑油箱。

1. Prevent the oil-gas mixture and tail gas from leaking into the lubricating oil tank during compression and combustion.

2．防止潤滑油進入汽缸內燃燒。

2. Prevent lubricating oil from entering the cylinder for combustion.

大多“燒機油”的汽車就是因為發動機太舊：活塞環不再密封引起的（尾氣管冒青煙）

Most "oil burning" cars are caused by the old engine: the piston ring is no longer sealed (the exhaust pipe emits blue smoke)

活塞桿 連接活塞環和曲軸，使得活塞和曲軸維持各自的運動。

The piston rod connects the piston ring and the crankshaft so that the piston and the crankshaft maintain their respective motion.

潤滑油槽 包圍著曲軸，里面有相當數量的油。

The lubricating oil groove surrounds the crankshaft and contains a considerable amount of oil.