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How does the diesel EGR system work?

Model: (Various brands) Various
Part: EGR valve

In this short video, we see the operation of the diesel EGR system with the role of the MAF sensor and the throttle valve: the MAF constantly measures the incoming air mass from the engine, while the throttle valve regulates the air flow. The ECU calculates the optimal amount of exhaust gas to be recirculated, controlling the opening of the EGR valve. Inert exhaust gases are mixed with fresh air; the throttle valve is partially closed to create a vacuum, which helps the EGR gases enter the intake manifold. The MAF detects the reduction in fresh air, the ECU compensates by adjusting the throttle opening, the amount of EGR gas, and the diesel injection. The result is the optimal mixture of air and EGR gas, lower combustion temperature, and reduction of NOx.

Posted on 30 October 2025 by ScegliAuto

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