(1) Working cycle - a closed cycle consisting of four working processes: intake, compression, work and exhaust. Only by carrying out these processes repeatedly can the internal combustion engine work continuously.

（2）上、下止點——活塞頂離曲軸回轉更遠處，即活塞位置，稱為上止點；活塞頂離曲軸回轉更近處，即活塞點，稱為下止點。在上、下止點處，活塞的運動速度為零。

(2) Top and bottom dead center - the farthest distance between the piston crown and the rotation center of the crankshaft, that is, the highest position of the piston, which is called the top dead center; The place where the piston crown is closest to the rotation center of the crankshaft, that is, the lowest point of the piston, is called the bottom dead center. At the top and bottom dead center, the movement speed of the piston is zero.

（3）曲柄半徑——曲軸的回轉半徑R。

(3) Crank radius - the turning radius r of the crankshaft.

（4）活塞行程——上、下止點間的距離S。S=2R。

(4) Piston stroke - distance s between top and bottom dead center. S=2R。

（5）氣缸工作容積——活塞從上止點到下止點所掃過的容積Vh

(5) Working volume of cylinder - the volume VH swept by the piston from TDC to BDC

（6）燃燒室容積——活塞位于上止點時活塞頂面以上與氣缸蓋底面以下之間形成的容積Vc。

(6) Combustion chamber volume - the volume VC formed between the top surface of the piston and the bottom surface of the cylinder head when the piston is at the top dead center.

（7）氣缸總容積——氣缸工作容積和燃燒室容積之和Va。Va＝Vc＋Vh。

(7) Total cylinder volume - sum of cylinder working volume and combustion chamber volume, Va. Va＝Vc＋Vh。

（8）壓縮比——氣體壓縮前的容積與氣體壓縮后的容積之比值，即氣缸總容積與燃燒室容積之比ε。壓縮比是發動機中一個非常重要的概念，它表示了氣體的壓縮程度。

(8) Compression ratio - the ratio of the volume before gas compression to the volume after gas compression, that is, the ratio of the total volume of the cylinder to the volume of the combustion chamber ε。 Compression ratio is a very important concept in engine, which indicates the compression degree of gas.

（9）發動機排量——多缸發動機各氣缸工作容積的總和VL。VL=Vh×I；其中，Vh—氣缸工作容積；I—氣缸數目。

(9) Engine displacement - the sum of the working volumes of each cylinder of a multi cylinder engine, VL. VL=Vh × I； Where, VH - working volume of cylinder; I - number of cylinders.

我們又進入了緊張有序的工作狀態，這時候，如果天然氣發電機組突然不轉動了，這會給工作帶來很大的麻煩，特別是生產制造單位，耽誤工作就要延誤發貨日期。這對廠家來說是一種損失。因此，發電機組突然不轉動了，就要拿出合理有效的解決方案。一般來說：發電機組突然出現不轉動的現象是因為以下兩個方面：

We have entered a tense and orderly working state again. At this time, if the natural gas generator unit suddenly stops rotating, it will bring great trouble to the work, especially the production and manufacturing units. If we delay the work, we will delay the delivery date. This is a loss for the manufacturer. Therefore, if the generator set suddenly does not rotate, it is necessary to come up with a reasonable and effective solution. Generally speaking, the sudden non rotation of the generator set is due to the following two aspects:

1.是較長時間停放后次啟動，發電機不能轉動。

1. It is the first start after parking for a long time, and the generator cannot rotate.

2.發電機組在運行中出現異常響聲突然熄火，再啟動時發電機不能轉動。

2. The generator set suddenly stalls due to abnormal noise during operation, and the generator cannot rotate during restart.

如果出現上述兩個方面的問題，我們應當考慮是什么原因導致造成的。

If there are problems in the above two aspects, we should consider what causes them.

1. 發電機組在運行過程中突然出現異響并導致熄火，原因多為：抱瓦、黏缸、曲軸或連桿折斷導致發電機不能啟動。如果進氣門和出氣門卡死，以至于不能進氣、出氣，或者是活塞項部有異物，也會造成啟動時發電機不轉動而無法啟動。

1. Abnormal noise occurs suddenly during the operation of the generator set and leads to flameout. Most of the reasons are: bearing, sticking cylinder, broken crankshaft or connecting rod, resulting in the failure of the generator to start. If the inlet valve and outlet valve are stuck so that the inlet and outlet cannot be started, or there is foreign matter in the piston neck, the generator will not rotate and cannot be started during startup.

2.發電機組如果停滯長時間不用，次使用也會出現故障：比如蓄電池極柱接觸不良，啟動線路未接通或蓄電池線路內部斷路，線路不通；蓄電池存電量不足，不能帶動啟動機旋轉等。或啟動線路本身有斷路之處；啟動機磁力開關有故障；啟動機齒輪未能與發電機飛輪齒圈嚙合而導致啟動不了。

2. If the generator set is not used for a long time, it will also fail in the first use: for example, the battery pole is in poor contact, the starting line is not connected, or the internal circuit of the battery line is open, and the line is not connected; The storage capacity of the battery is insufficient to drive the starter to rotate, etc. Or there is an open circuit in the starting line itself; The magnetic switch of the starter is faulty; The starter gear fails to mesh with the flywheel ring gear of the generator, resulting in failure to start.

如果天然氣發電機組突然不轉動了，我們可以下兩種方式調整：

If the natural gas generator set suddenly stops rotating, we can adjust it in the following two ways:

一是可分別對極柱，蓄電池線路、啟動機磁力開關、啟動線路進行檢修。

First, the pole post, battery circuit, starter magnetic switch and starting circuit can be overhauled respectively.