Influence of rail pressure on a two-stage turbocharged heavy-duty diesel engine under transient operation

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• 作者：Z. C. Liu ; K. B. Yu ; J. Tian ; Y. Q. Han…
• 关键词：Key WordsDiesel engine ; Two ; stage turbocharger ; Transient operation ; Full ; stage rail pressure ; Sectional ; stage rail pressure
• 刊名：International Journal of Automotive Technology
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：18
• 期：1
• 页码：19-29
• 全文大小：670 KB
• 刊物类别：Engineering
• 刊物主题：Automotive and Aerospace Engineering and Traffic
  
• 出版者：The Korean Society of Automotive Engineers
• ISSN：1976-3832
• 卷排序：18

文摘

The demand for continually improving the transient performance of diesel engines requires higher rail pressure and more efficient turbocharger. Before the test, a two-stage turbocharger with a turbine by-pass valve (TBV) had been matched reasonably with the base engine. In order to reduce smoke emission under the typical 5-second transient process of constant speed and increasing torque, the influence of rail pressure on combustion, emissions and performance characteristics was experimentally investigated. The results showed that the two-stage turbocharger was helpful in improving transient performance. Moreover, the full-stage rail pressure (FSRP) strategies (increasing rail pressure during the whole transient process) could reduce smoke emission when the TBV was closed. However, smoke deteriorated once TBV opening got larger. Then the sectional-stage rail pressure (SSRP) strategies (increasing rail pressure from a pre-set load to 100 % load) were presented under small TBV opening to improve in-cylinder thermal condition. Hence, the air-fuel mixing process was improved at medium and large loads. Then the maximum decline of smoke opacity peak was 56.3 %, which happened under 10 % TBV opening. In addition, fuel consumption of FSRP strategies got worse under larger TBV opening. However, this deterioration situation could be effectively restrained by the utilization of SSRP strategies.