What does EGR stand for, and what is its function?

EGR stands for Exhaust Gas Recirculation, and its primary function is to reduce nitrogen oxide (NOx) emissions in internal combustion engines. The system operates by recirculating a portion of the engine's exhaust gases back into the intake manifold. This has the effect of lowering the combustion temperature, which in turn significantly reduces the formation of NOx gases, which are a major contributor to air pollution and smog.

By introducing exhaust gases back into the intake air, the EGR system displaces some of the oxygen that would otherwise be available for combustion. This mixture generally burns at a lower temperature, which is critical since higher combustion temperatures are responsible for increased NOx formation. Thus, through its design and function, the EGR system plays a crucial role in meeting emissions standards and improving air quality, while also contributing to the overall efficiency of the engine by optimizing the combustion process.