Study on Performance of Highland Heavy-duty Natural Gas Engine by Pressurization Method
National six-equivalent heavy-duty natural gas engines commonly use a single-stage exhaust gas turbine to pressurize the fresh charge.Under the low-pressure environment of plateau,with relatively low intake air density,the single-stage exhaust gas turbine supercharging method is unable to provide the supercharging requirement for stable and efficient operation of the working conditions,resulting in the prominent problem of engine power degradation.In order to study the influence of different boosting methods on the plateau performance of National Ⅵ-equivalent heavy-duty natural gas engines,the performance of engines with single-stage exhaust gas turbocharging and two-stage supercharging in the simulated plateau low-pressure environment was analyzed through simulated plateau bench tests of the engines.The test results show that the two-stage supercharging method can significantly improve the power degradation problem of heavy-duty natural gas engine in plateau low-pressure environment.Compared with the single-stage exhaust gas turbocharging method,the power density of the two-stage supercharging method can be improved by 13.7％in the plain environment within the boundary conditions of safe engine operation;the engine realizes no power loss at 2km altitude,and the power drop is improved by 13％;there is no loss of power in the engine at 2.5km altitude,and the torque is recovered by 17％;the power drop is improved by a larger extent at 3km altitude,and the maximum drop is reduced by 27.5％to 10.5％.27.5％to 10.2％.In addition,the increase of the safety margin of the engine supercharger speed under the low-pressure environment of plateau greatly reduces the risk of supercharger over-speed shaft breakage,and improves the durability and reliability of engine operation.
Equivalent natural gas enginePlateau environmentPressurization methodEngine performance
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