Comparative analysis of water injection and EGR effects on combustion, performance, and emission characteristics of a diesel engine using diesel-biodiesel blends

IF 5.3 Q2 ENGINEERING, ENVIRONMENTAL

Cleaner Engineering and Technology Pub Date : 2025-04-04 DOI:10.1016/j.clet.2025.100965

Maziyar Moeini Manesh , Alireza Shirneshan , Sobhan Emami

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引用次数: 0

Abstract

The pollutants emitted from diesel engines, especially nitrogen oxides (NOx), are one of the fundamental challenges for designers and manufacturers of internal combustion engines. Exhaust gas recirculation (EGR) and water injection are two essential methods for reducing NOx emitted from the engine. The comparison of these two methods when simultaneously utilizing biodiesel in the engine can be considered the most significant gap in previous research. This study investigates the effects of water injection and EGR, along with the application of various diesel-biodiesel blends, on the performance, combustion, and NOx emissions of a Caterpillar 3401 diesel engine. The AVL Fire CFD software package was utilized along with a three-zone extended coherent flame combustion model and k-ζ-f turbulence model for evaluating the impacts of water injection at percentages of 15 %, 30 %, 45 %, and 60 %, and EGR at rates of 0 %, 10 %, 15 %, 20 %, and 25 % for the B0, B10, B20, and B50 (50 % diesel-50 % biodiesel) blends. According to the results, increasing water injection by up to 45 % reduces the maximum in-cylinder pressure by 4.4 % and engine power by 3.2 %–4.4 % for different fuel mixtures. However, a slight increase in power is observed when the water injection percentage reaches 60 %. Additionally, the specific fuel consumption (SFC) rises by 6.4 % for these mixtures. Similarly, as the EGR rate increases, the maximum in-cylinder pressure decreases by up to 5.5 %, with power declining by 3.5 %–4.3 %, comparable to the water injection scenario. The SFC also increases by 3.7 %–4.6 % across different fuel blends, though slightly less than with water injection. The results also reveal that a water injection of 60 % reduces specific NOx by about 57 %; furthermore, increasing the EGR rate to 25 % reduces nitrogen oxides by approximately 78 %. It was found that a 0.18 mm diameter is the most suitable for water droplets to reduce NOx emissions during water injection. Based on the results, considering both engine performance and the reduction of nitrogen oxides, the EGR method is recommended over water injection.

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使用柴油-生物柴油混合物的柴油发动机，注水和EGR对燃烧、性能和排放特性的影响比较分析

柴油发动机排放的污染物，尤其是氮氧化物（NOx），是内燃机设计师和制造商面临的基本挑战之一。废气再循环（EGR）和注水是减少发动机NOx排放的两种重要方法。在发动机中同时使用生物柴油时，这两种方法的比较可以被认为是以往研究中最显著的空白。本研究调查了注水和EGR，以及各种柴油-生物柴油混合物的应用，对卡特彼勒3401柴油发动机的性能、燃烧和氮氧化物排放的影响。AVL Fire CFD软件包与三区扩展相干火焰燃烧模型和k-ζ-f湍流模型一起使用，以评估15%、30%、45%和60%的注水比例以及0%、10%、15%、20%和25%的EGR对B0、B10、B20和B50（50%柴油- 50%生物柴油）混合物的影响。结果表明，对于不同的燃料混合物，将注水量增加45%可使最大缸内压力降低4.4%，发动机功率降低3.2% - 4.4%。然而，当注水比例达到60%时，观察到功率略有增加。此外，这些混合燃料的油耗（SFC）增加了6.4%。同样，与注水工况相比，随着EGR速率的提高，最大缸内压力下降5.5%，功率下降3.5% - 4.3%。SFC在不同燃料混合物中也增加了3.7% - 4.6%，尽管比注水稍微少一些。结果还表明，当水注入量为60%时，比NOx降低约57%；此外，将EGR率提高到25%可以减少约78%的氮氧化物。研究发现，0.18 mm直径的水滴最适合减少注水过程中NOx的排放。综上所述，考虑到发动机性能和氮氧化物的减少，建议采用EGR方法，而不是注水方法。

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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