特殊背压下高增压柴油机增压器匹配性能研究

基于GT-power搭建了某高增压柴油机一维仿真模型,并通过试验数据对模型进行标定。利用该模型计算分析了柴油机在不同排气背压下的性能,利用计算结果配合试验,分析了排气背压高且波动范围大工况下的压气机和涡轮的匹配。研究表明:背压升高会导致柴油机性能恶化,通过增压器的合理匹配可以实现高排气背压柴油机功率的恢复,稳态工况下可以恢复至59.8%,背压波动工况可以恢复至66%;高排气背压工况应提高压气机低压比区域的效率和流量,并适当控制高压比区域的压比;涡轮喷嘴环流通面积对性能影响较大,过大或过小均不利于功率恢复,通过选择合适的涡轮,可使功率恢复提升10.9%;柴油机性能参数随排气背压波动做规律波动,但存在一定的延迟,波动的幅值与该性能参数的迟滞时间负相关。

Study on Turbocharger Matching Performance of High-turbochargedDiesel Engine under Specific Back Pressure

Certain one-dimensional simulation model of high-turbocharged diesel engine was established based on GT-power, and calibrated by experimental data. The performances of the engine at different exhaust back pressure were predicted using the model, the results of which were then being used incorporated with the experimental data to analyze the matching between compressors and turbochargers at high and fluctuating back pressure. The results of the study showed that the rising back pressure would worsen the performance of the engine. And the performance of engine at higher back pressure was reversed by an appropriate matching of turbocharger, which recovered the engine power to 59.8% and 66%, respectively, at steady and fluctuating conditions. The efficiency and flow of compressor in the low boost ratio area should be increased, and the boost ratio in the high boost ratio area should be appropriately controlled under the high back pressure. Such recovery was strongly determined by the flow area of nozzle ring, too big or too small of which would not be effective. An appropriate selection of turbocharger increased the recovery rate by 10.9%.The fluctuation of the engine performance parameters reflected the changes in back pressure with a certain delay. And, the amplitude of fluctuates was correlated inversely with the length of delay.