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| Effect of Intake Pipe Structure on Exhaust Gas Recirculation Uniformity of Natural Gas Engine |
| DOI：10.13949/j.cnki.nrjgc.2020.03.006 |
| Key Words:natural gas engine exhaust gas recirculation (EGR) numerical simulation uniformity |
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| Abstract:In order to solve the issue of excessive difference in combustion consistence among the cylinders of a China Ⅵ natural gas engine, an analysis of the exhaust gas recirculation(EGR) rate uniformity of the intake system was carried out by a computational fluid dynamics(CFD) software called STAR-CCM+. It was found that the EGR rates of from No.1 to No.3 cylinders were larger than those of from No.4 to No.6 cylinders, and the relative deviation of EGR rate at 1200r/min with full load was from -29.9% to 34.2%. The analysis showed that there was a large fluctuation at the EGR inlet due to EGR being extracted only from No.1 to No.3 cylinders, which mainly caused the uneven distribution of EGR rate among the cylinders. Two optimizations of intake pipe were put forward to reduce the fluctuation of EGR in the intake pipe. By using the two kinds of optimized intake pipe, the recirculated exhaust is fully mixed before entering the intake manifold, which improves the uniformity of EGR rate in each cylinder obviously and brings the relative deviation of EGR rate to within ±5%. |
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