Experimental Investigation On The Exhaust Gas Recirculation (EGR) System For Cooled Turbocharged Diesel Engines

The technology of exhaust gas recirculation (EGR) is known as an effective method to reduce the emission of NOx in the diesel engine. But it is only studied experimental investigation in our country. With the increasingly stringent regulations on emissions from automotive industries, also the reality that the diesel engine manufactures have to compete with the foreign counterparts worldwide, EGR will soon be put into use in our country, consistently with the developing trend of the diesel engine in economic and ecologic requirements. Under this circumstance, an EGR system was fixed on a YC6105ZLQ Turbo-charged diesel engine, and many tests had been done on the engine test bed in order to decrease NOx.At first, the author devised a set of electronic controlled and cooled EGR system with ventuti pipe. Then, the experimental investigation on YC6105ZLQ Turbo-charged diesel engine with the EGR system had been carried out.The results showed that EGR can reduce NOx emission under various operation conditions, but the effective gasoline consume rate, the effective power and the smoke will be affected. So there will be an optimum working state of the EGR valve under various operation conditions. And then cooling therecirculating exhaust gas can reduce the NOx emission more effectively.Because the EGR system with ventuti pipe is very complex, under this basis, the author devised a set of EGR system with non-return valve and the experimental investigation has been carried out.From the test results, we come to the conclusion that it is difficult for simple EGR technique to optimize the integer performance of the diesel. All in all, the performance of the EGR system with ventuti pipe is better than the EGR system with non-return valve. But compared with diesel without EGR system, non-return valve EGR system can make good use of exhaust manifold pressure wave and increase EGR rate, it is very low and effective.