EGR的作用： 廢氣再循環（EGR）系統用于降低廢氣中的氧化氮（NOx）的排出量。氮和氧只有在高溫高壓條件下才會發生化學反應，柴油機燃燒室內的溫度和壓力滿足了上述條件，在強制加速期間更是如此。 當柴油機在負荷下運轉時，EGR閥開啟，使少量的廢氣進入進氣歧管，與可燃混合氣一起進入燃燒室。怠速時EGR閥關閉，幾乎沒有廢氣再循環至柴油機。

The function of EGR: The exhaust gas recirculation (EGR) system is used to reduce the emission of nitrogen oxides (NOx) in the exhaust gas. Nitrogen and oxygen only undergo chemical reactions under high temperature and pressure conditions, and the temperature and pressure in the combustion chamber of a diesel engine meet the above conditions, especially during forced acceleration. When the diesel engine is running under load, the EGR valve opens, allowing a small amount of exhaust gas to enter the intake manifold and enter the combustion chamber together with the combustible mixture. When idling, the EGR valve closes and there is almost no exhaust gas recirculation to the diesel engine.

汽車廢氣是一種不可燃氣體（不含燃料和氧化劑），在燃燒室內不參與燃燒。 它通過吸收燃燒產生的部分熱量來降低燃燒溫度和壓力，以減少氧化氮的生成量。進入燃燒室的廢氣量隨著柴油機轉速和負荷的增加而增加。 電控柴油機EGR系統

Automotive exhaust gas is a non combustible gas (excluding fuel and oxidants) that does not participate in combustion in the combustion chamber. It reduces the production of nitrogen oxide by absorbing some of the heat generated by combustion to lower the combustion temperature and pressure. The amount of exhaust gas entering the combustion chamber increases with the increase of diesel engine speed and load. Electronic control diesel engine EGR system

工作原理： EGR系統的主要元件是數控式EGR閥。數控式EGR閥安裝在右排氣歧管上，其作用是獨立地對再循環到柴油機的廢氣量進行的控制，而不管歧管真空度的大小。 EGR閥通過3個孔徑遞增的計量孔控制從排氣歧管流回進氣歧管的廢氣量，以產生7種不同流量的組合。每個計量孔都由1個電磁閥和針閥組成，當電磁閥通電時，電樞便被磁鐵吸向上方，使計量孔開啟。旋轉式針閥的特性保證了當EGR閥關閉時，具有良好密封性。

Working principle: The main component of the EGR system is a CNC EGR valve. The CNC EGR valve is installed on the right exhaust manifold and its function is to independently and accurately control the amount of exhaust gas recirculated to the diesel engine, regardless of the vacuum level in the manifold. The EGR valve controls the amount of exhaust gas flowing back from the exhaust manifold to the intake manifold through three metering holes with increasing apertures, in order to generate a combination of seven different flow rates. Each measuring hole is composed of one solenoid valve and a needle valve. When the solenoid valve is energized, the armature is attracted upwards by a magnet, causing the measuring hole to open. The characteristics of the rotary needle valve ensure good sealing when the EGR valve is closed.

閥通常在下列條件下開啟：

Valves typically open under the following conditions:

①柴油機暖機運轉。

① Warm up operation of diesel engine.

②轉速超過怠速。 ECM根據柴油機冷卻水溫傳感器、節氣門位置傳感器和空氣流量傳感器來控制EGR系統。

② The speed exceeds idle. The ECM controls the EGR system based on the diesel engine cooling water temperature sensor, throttle position sensor, and air flow sensor.