EGR cooler

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The EGR cooling system is a device for reducing the NOx emission setting of automobile exhaust, and is an exhaust gas recirculation system. At a higher speed of the car, a small amount of exhaust gas is reintroduced into the intake valve. The temperature of the exhaust gas is related to the NOx emissions. The lower the temperature of the exhaust gas, the better the NOx suppression effect on the engine. The EGR cooler can reduce the temperature of the exhaust entering the cylinder. The low temperature is definitely good for the engine’s thermal load. Lower the engine temperature.

An exhaust gas recirculation (EGR) system is used to reduce the amount of nitrogen oxides (NOX) emitted from the exhaust gas. Nitrogen and oxygen only react under high temperature and high pressure conditions, and the temperature and pressure in the engine combustion chamber satisfy the above conditions, especially during forced acceleration.

When the 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 with the combustible mixture. The EGR valve is closed at idle and almost no exhaust gas is recirculated to the engine. Automotive exhaust is a non-flammable gas (excluding fuel and oxidant) that does not participate in combustion in the combustion chamber. It reduces combustion temperature and pressure by absorbing some of the heat generated by combustion to reduce the amount of nitrogen oxides produced. The amount of exhaust entering the combustion chamber increases as the engine speed and load increase.

One of the common brazing methods for EGR coolers is the use of vacuum brazing.

The vacuum brazing process is: stamping–cleaning–core assembly fin-clamping–machine-coated paste-like solder resist–drying–shell assembly–upper core subassembly cooling tube–assembly flange — TIG welding water pipe – overall vacuum brazing – pressure test – inspection – packaging. An important part of this is vacuum brazing.

The EGR stainless steel cooler can be made of copper and BNi-5 as the solder.