A numerical investigation on the effects of gaseous fuel composition in a pilot ignited direct injection natural gas engine. (15th February 2021)

• Record Type: Journal Article
• Authors: Li, Menghan; Wei, Zhangning; Liu, Xiaori; Wang, Xiaoyan; Zhang, Qiang; Li, Zhenguo
• Is Part Of: Energy. Volume 217(2021)
• Publication Date: 2021-02-15
• Subjects: Pilot ignited direct injection natural gas engine -- Gaseous fuel composition -- Mechanism -- Simulation -- Thermal efficiency -- Emissions; ATDC after top dead center -- BTDC before top dead center -- BMEP brake specific effective power -- CO carbon monoxide -- CA10 the phase angle of 10% energy released -- CA50 the phase angle of 50% energy released -- CFD computational fluid dynamic -- DNI injection interval between diesel and natural gas -- DPW diesel pulse width -- DRGEP directed relation graph with error propagation -- DRGEPSA directed relation graph with error propagation and sensitivity analysis -- EGR exhaust gas recirculation -- GPW natural gas pulse width -- HC hydrocarbon -- IMEP indicated mean effective pressure -- ITE indicated thermal efficiency -- NGSI natural gas single injection -- NOx nitrogen oxides -- HCCI homogenous charge compression ignition -- HCDI homogenous charge direct injection -- NSOI start of natural gas injection -- PAH polycyclic aromatic hydrocarbon -- PM particulate matter; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Energy consumption -- Periodicals; 333.7905
• DOI: 10.1016/j.energy.2020.119467
• Languages: English
• ISSNs: 0360-5442

Abstract

Abstract: Pilot ignited direct injection natural gas engines have the potential to obtain both high efficiency and low emissions, thus, are considered as promising alternations for diesel engines. In order to assess the effects of gaseous fuel composition on this type of engines, a three-dimensional model was constructed based on a new mechanism developed for the high-precision prediction of soot precursors. The numerical results showed that thermal efficiency could be improved by increasing nitrogen proportion at medium and high loads as well as increasing propane proportion at low load. Regarding emissions, it was found that ethane addition will lead to deteriorated NOx and CO emissions at high and medium loads along with increases in soot emissions at all loads. When propane is blended, though notable increased NOx emissions and higher soot emissions could be observed at all loads, improved CO emissions are revealed at high load with small blending ratios and at low load with all blending ratios. In contrast to ethane and propane addition, nitrogen addition is favorable for NOx control at all engine loads and is beneficial for soot control at high and medium loads. CO emissions, however, will suffer from nitrogen addition at high and low loads. Highlights: A dual fuel mechanism including pathways for ethane and propane was constructed. The effects of gaseous fuel composition was numerically studied. Promoted gas ignition is obtained by increasing the ratios of C2 H6, C3 H8 and N2 . Improved thermal efficiency could be achieved by nitrogen addition at higher loads. Propane addition has significant detrimental effects on NOx and soot emissions.