Numerical studies on a novel air path design featured with the sequential turbocharging and the low-pressure exhaust gas recirculation for the marine two-stroke engine fulfilling the IMO Tier Ⅲ regulation

IF 9 1区工程技术 Q1 ENERGY & FUELS

Energy Pub Date : 2025-05-14 DOI:10.1016/j.energy.2025.136574

Yujun Tang , Jinbao Liu , Min Liu , Jinfeng Feng , Kangyao Deng , Sipeng Zhu , Shuzhan Bai , Guoxiang Li

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引用次数: 0

Abstract

As an effective technology for reducing NO_x emissions, exhaust gas recirculation (EGR) has been extensively applied to comply with Tier Ⅲ regulations in marine two-stroke engines. Nevertheless, the high-pressure EGR (HP-EGR) system imposes higher requirements on the design and control of the turbocharging system, particularly when sequential turbocharging is employed to enhance fuel efficiency. In this paper, a novel sequential turbocharging low-pressure EGR (LP-EGR) scenario is proposed. Detailed thermodynamic and numerical analyses of sequential turbocharging combined with LP-EGR and HP-EGR are then conducted and compared with a special focus on scavenging and combustion processes. The results show that optimal fuel economy in multi-mode operations is achieved by sequential turbocharging LP-EGR and HP-EGR employing the equivalent flow area ratio of large and small turbines of 6:4 and 7:3, respectively. Meanwhile, a reduced large turbine throttle valve opening and an increased cylinder bypass rate are required for the NO_x emission reduction in LP-EGR and the scavenging air pressure restoration in HP-EGR at part loads, respectively. Compared to sequential turbocharging HP-EGR, the combined fuel consumption of sequential turbocharging LP-EGR featuring a simpler structure is improved by 1∼4 g/kW·h and 1–3 g/kW·h in Tier Ⅱ and Tier Ⅲ operation, respectively.

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符合IMO TierⅢ规定的船用二冲程发动机序贯增压和低压废气再循环新型气路设计数值研究

废气再循环（EGR）作为一种有效的降低NOx排放的技术，已广泛应用于船舶二冲程发动机中，以符合Ⅲ级法规。然而，高压EGR （HP-EGR）系统对涡轮增压系统的设计和控制提出了更高的要求，特别是当采用顺序涡轮增压来提高燃油效率时。本文提出了一种新的序贯增压低压EGR方案。然后对顺序涡轮增压与LP-EGR和HP-EGR相结合进行了详细的热力学和数值分析，并与特别关注的扫气和燃烧过程进行了比较。结果表明，采用大、小涡轮等效流面积比分别为6:4和7:3的序贯涡轮增压LP-EGR和HP-EGR可获得最佳的多工况燃油经济性。同时，在部分负荷下，LP-EGR的NOx减排和HP-EGR的扫气压力恢复需要减小大涡轮节流阀开度和增大气缸旁道率。与HP-EGR相比，结构更简单的HP-EGR在Ⅱ级和Ⅲ级工况下的综合油耗分别提高了1 ~ 4 g/kW·h和1 ~ 3 g/kW·h。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Energy 工程技术-能源与燃料

CiteScore

15.30

自引率

14.40%

发文量

审稿时长

14.2 weeks

期刊介绍： Energy is a multidisciplinary, international journal that publishes research and analysis in the field of energy engineering. Our aim is to become a leading peer-reviewed platform and a trusted source of information for energy-related topics. The journal covers a range of areas including mechanical engineering, thermal sciences, and energy analysis. We are particularly interested in research on energy modelling, prediction, integrated energy systems, planning, and management. Additionally, we welcome papers on energy conservation, efficiency, biomass and bioenergy, renewable energy, electricity supply and demand, energy storage, buildings, and economic and policy issues. These topics should align with our broader multidisciplinary focus.