| With the increase of altitude, the atmospheric pressure and temperature are all decreased. The performance of diesel engine in plateau environment aspects are greatly reduced, even through the turbocharger system to improve the working performance of the diesel engine, the rotational speed of the turbine, excess air coefficient and the fuel consumption rate of each factor are subject to the influence of plateau environment and become the bottleneck to enhance the performance of the diesel engineMJ350 diesel engine is a company developed independently of a heavy duty diesel engine used for power generation. But in the plateau in the process, the emergence of turbocharger failure rate is high, speeding and other issues. Therefore, selection and optimization of pressurization system of MJ350 diesel engine matching as a subject of study, expect to optimize the engine performance at altitude, and summed up the engine altitude performance matching optimization process, for enterprises to further explore the plateau market and provide theory support to enhance the performance of the diesel engine.The following is the main content of this paper:1, this paper analyzes the domestic and foreign research status of high altitude diesel engine, and introduces the research background and significance of the performance optimization based on MJ350 Diesel Engine Turbocharger matching.2, introduced the working principle of MJ350 diesel and its turbocharger system, analyzed the basic characteristics of the plateau environment, summarized the law of atmospheric pressure, temperature, air density and oxygen content along with altitude. Summarized along with the increase of altitude, high engine speed conditions prone to turbocharger speed, low speed conditions prone to compressor surge, low speed conditions prone to turbine exhaust temperature is too high. All these factors greatly affect the safety, stable operation and service life of the turbocharger. The influence of plateau environment on the performance of diesel engine is analyzed. With the increase of altitude, the power of the diesel engine is significantly increased.3, analysis the MJ350 diesel engine turbocharger performance matching principle, namely the design of boost pressure, air flow, engine power and fuel consumption rate can reach the expected requirements; should as far as possible to make the line of diesel engine running through the compressor characteristic curves, area and the surge boundary line approximately parallel. In this paper, the performance matching method of variable cross-section turbocharger is described, and the evaluation principle of the characteristics of the turbocharger and the internal combustion engine is presented.4, combined with the performance of MJ350 diesel engine under the plateau environment, the performance of the diesel engine based on the plain simulation test was studied. First of all, the performance of the M5 and K6 Turbocharger matching test, followed by the K6 turbocharger and MJ turbocharger plateau performance simulation test, the MJ turbocharger plateau speed is close to the limit requirements. The new scheme of MJ1, MJ2 turbocharger and K6 supercharger plateau performance comparison test evaluation. The results show that the MJ1 supercharger does not appear overspeed phenomenon, determine the MJ1 turbocharger as combustion system optimization scheme; at the same time plateau startup performance optimization test is given. Performance comparison test piston compression ratio of two schemes, determined the compression ratio for 17.5:1 piston as the optimal scheme.5, the MJ350 diesel engine of plateau field performance test, through the plains and plateau performance contrast test, confirming the matching MJ1 turbocharger as the final solution, finally the engine configuration state closed throttle test and load test, obtained 4200 m plateau environment power than the flat raw decreased by 10.3%, in line with national standard requirements. |
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