Study On The Exhaust Gas Recirculation (EGR) System

The pollution of automobile emissions has become a severe social problem whenautomobiles are more popularized in our country. Among those emissions, nitrogenoxide (NOx) is particularly harmful. The technology of exhaust gas recirculation(EGR) is known as an effective method to reduce the emission of NOx by the engine.An EGR system was fixed on a DA462 carburetor engine, and many tests have been done on the engine test bed.The results showed that EGR can reduce NOx emission under various operation conditions, but the effective power ( Pe) , the effective torque ( Me) and the effective gasoline consume rate (ge) will be affected. So there will be an optimum working state of the EGR valve under various operation conditions.It also showed that when the engine worked at a low load, EGR can effectively reduce NOx emission, but the power of the engine is seriously affected, so EGR was not advised to use in such case; when the engine worked at a moderate load, EGR can significantly reduce NOx emission under wide velocity range and had little effect on the power and economic performance of the engine, so EGR was encouraged to use in such condition; when a higher load was added to the engine, EGR can effectively reduce NOx emission under some velocity range, and the engine power was slightly affected, so EGR can be used in some conditions; when the engine worked at high load and full load, EGR can also reduce the NOx emission, but the power and economic performance of the engine badly influenced , so EGR shouldn't be used.Through tests, a high-performance data acquisition card with programmable gain was used to gain the parameters of the engine operation conditions in real time, and the automation on the EGR system was realized.