Study Of Combustion Performance And Power Recovery For Heavy Duty Diesel Engine At High Altitudes

Our country has a broad distribution of plateaus and mountain, large number of vehicles run in these areas. The plateau has a low atmospheric pressure and ambient temperature change, which have a serious impact on the performance of power equipment. For diesel engine, the performance decrease was manly described as decreasing of power, increasing of fuel consumption rate. Therefore, It is necessary to carry out the study of environmental worthiness and power recovery for diesel engine at high altitudes.Firstly, we established and validated the one-dimensional simulation model for the heavy-duty diesel engine based on GT-POWER, analysed the effects of plateau environment on the engine. Then established and validated the three-dimensional simulation model for the engine, builded several characteristic parameters and then deeply studied the mechanism of the working process in cylinder under high altitudes.In order to improve the performance of heavy-duty diesel engine on plateau, basing on the original combustion system parameters, we optimized the combustion chamber profile shape, the radius of the chamber, the spray angle and swirl ratio, applied three optimization program to the plateau environment, finaly, we found the best optimization program which can improve the dynamic performance on plain environment and partly recovery power of the engine on plateau environment.After analyzing and demonstrating, we selected adjustable turbocharging system to achieve the goal of power recovery for the heavy-duty diesel engine. Firstly, we studied the influence of adjustable turbine flow area on the turbo charger itself, then achieved a good match of the diesel engine and adjustable turbocharging system at different altitudes. Results showed that, after matching adjustable turbocharging system, power performance of the diesel engine was improved significantly. The power at different engine speed conditions under altitude of4km only decreased less than4%. Dynamic performance recovered close to the plains environment, able to meet the power requirement of the heavy-duty diesel engine working in high altitudes.