A numerical study on the effects of constant volume combustion phase on performance and emissions characteristics of a diesel-hydrogen dual-fuel engine
A numerical study on the effects of constant volume combustion phase on performance and emissions characteristics of a diesel-hydrogen dual-fuel engine
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DOI：
10.1016/j.ijhydene.2020.09.021
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发表时间：
2020-09
影响因子：
7.2
通讯作者：
C. Ramsay;K. Dinesh;W. Fairney;N. Vaughan
中科院分区：
文献类型：
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作者：
C. Ramsay;K. Dinesh;W. Fairney;N. Vaughan
对柴油机-氢双燃料（DF）压缩点火发动机在柴油机喷射和大部分燃烧发生在定容下的新型燃烧策略下的性能进行了详细的数值研究。对柴油-氢发动机运行的数值模型进行了详细的验证。然后进行了一项参数研究，以研究高达90%氢能量份额（HES）的恒体积燃烧阶段（CVCP）对发动机低负荷和高负荷下性能和排放的影响，并与传统发动机进行了比较。结果表明，CVCP策略可以在低碳排放的情况下提高所有HESs和负载条件下的热效率。传统的DF发动机在低负荷高HESs下挣扎，因为减少的柴油喷射无法点燃稀薄的预混燃料。通过在低负荷下使用CVCP热效率90%，HES从11%提高到38%，由于温度和压力的增加，允许氢-空气混合物的大规模点火，大大减少了氢气排放。研究人员还发现，通过提高柴油喷射，增加CVCP内的燃烧时间，可以进一步提高热效率，同时不会对排放产生负面影响。
A detailed numerical study is carried out to investigate the performance of a diesel-hydrogen dual fuel (DF) compression ignition engine operating under a novel combustion strategy in which diesel injection and most of the combustion occur at a constant volume. A detailed validation of the numerical model for diesel-hydrogen DF engine operation has been carried out. Then a parametric study has been performed to investigate the effects of the constant volume combustion phase (CVCP) at up to 90% hydrogen energy share (HES) on engine performance and emissions at low and high load with comparisons to the conventional engine. The results demonstrate that the CVCP strategy can improve thermal efficiency at all HESs and load conditions with far lower carbon-based emissions. Conventional DF engines struggle at low load high HESs due to the reduced diesel injection failing to ignite the leaner premixed charge. Through use of a CVCP thermal efficiency at low load 90% HES increased from 11% to 38% with considerably reduced hydrogen emission due to the increased temperatures and pressures allowing for the wholesale ignition of the hydrogen-air mix. It was also found that increasing the time allowed for combustion within the CVCP, by advancing the diesel injection, can lead to even further thermal efficiency gains while not negatively impacting emissions.