EGR的作用： 废气再循环（EGR）系统用于降低废气中的氧化氮（NOx）的排出量。氮和氧只有在高温高压条件下才会发生化学反应，柴油机燃烧室内的温度和压力满足了上述条件，在强制加速期间更是如此。 当柴油机在负荷下运转时，EGR阀开启，使少量的废气进入进气歧管，与可燃混合气一起进入燃烧室。怠速时EGR阀关闭，几乎没有废气再循环至柴油机。

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.

汽车废气是一种不可燃气体（不含燃料和氧化剂），在燃烧室内不参与燃烧。 它通过吸收燃烧产生的部分热量来降低燃烧温度和压力，以减少氧化氮的生成量。进入燃烧室的废气量随着柴油机转速和负荷的增加而增加。 电控柴油机EGR系统

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系统的主要元件是数控式EGR阀。数控式EGR阀安装在右排气歧管上，其作用是独立地对再循环到柴油机的废气量进行准确的控制，而不管歧管真空度的大小。 EGR阀通过3个孔径递增的计量孔控制从排气歧管流回进气歧管的废气量，以产生7种不同流量的组合。每个计量孔都由1个电磁阀和针阀组成，当电磁阀通电时，电枢便被磁铁吸向上方，使计量孔开启。旋转式针阀的特性保证了当EGR阀关闭时，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.

阀通常在下列条件下开启：

Valves typically open under the following conditions:

①柴油机暖机运转。

① Warm up operation of diesel engine.

②转速超过怠速。 ECM根据柴油机冷却水温传感器、节气门位置传感器和空气流量传感器来控制EGR系统。

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.