A high pressure EGR system was adopted to a turbocharged inter-cooled diesel engine, to analyze its combustion and emission\r\ncharacteristics under the condition of different loads and constant speed. Under the same steady operating mode, with the increase\r\nof EGR rate, the temperature of compressed gas ascended, the ignition delay was shortened, the pressure and temperature of the\r\nburned gas descended, and the combustion process was prolonged. According to the experimental data, it was found that, at the\r\nsame EGR rate, lower the load of engine was, lower the temperature in cylinder, and higher the increase rate of CO was. However,\r\nthe increase rate of HC present a falling trend. The decrease rate of the specific emission of NOx linearly varied with EGR rate with\r\na slope of 1.651. The increase rate of smoke opacity behaved a second-order polynomial uprising trend, and the higher the load\r\nwas, the sharpener the smoke opacity deteriorated, with the increase of EGR rate. Fromthe point of emission view, the engine with\r\nEGR system can achieve the lesser exhaust emissions in some operations by adjusting the engine parameters.
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