Effect of addition of hydrogen and exhaust gas recirculation on characteristics of hydrogen gasoline engine

• Published in: International journal of hydrogen energy 2017-03, Vol.42 (12), p.8288-8298
• Main Authors: Du, Yaodong, Yu, Xiumin, Liu, Lin, Li, Runzeng, Zuo, Xiongyinan, Sun, Yao
• Format: Article
• Language: English
• Subjects: Combustion; Emission; Exhaust gas recirculation; Gasoline engine; Hydrogen direct injection
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2017.02.197

The effects of exhaust gas recirculation (EGR) on combustion and emissions under different hydrogen ratios were studied based on an engine with a gasoline intake port injection and hydrogen direct injection. The peak cylinder pressure increases by 9.8% in the presence of a small amount of hydrogen. The heat release from combustion is more concentrated, and the engine torque can increase by 11% with a small amount of hydrogen addition. Nitrogen oxide (NOx) emissions can be reduced by EGR dilution. Hydrogen addition offsets the blocking effect of EGR on combustion partially, therefore, hydrogen addition permits a higher original engine EGR rate, and yields a larger throttle opening, which improves the mechanical efficiency and decreases NOx emissions by 54.8% compared with the original engine. The effects of EGR on carbon monoxide (CO) and hydrocarbon (HC) emissions are not obvious and CO and HC emissions can be reduced sharply with hydrogen addition. CO, HC, and NOx emissions can be controlled at a lower level, engine output torque can be increased, and fuel consumption can be reduced significantly with the co-control of hydrogen addition and EGR in a hydrogen gasoline engine. •Hydrogen direct injection avails enhancing ignition stability.•Slight hydrogen addition obviously improves the power and economic performance.•EGR introduced can reduce the risen level NOx caused by hydrogen addition.•Hydrogen addition combined with EGR contains the lower amount of emissions.