Effects of intake parameters and compression ratio on ammonia combustion and emissions in SI engines

Hu, Xiaozhong; Pan, Jiaying; Zhang, Ren; Li, Jinguang; Li, Wei; Wei, Haiqiao

doi:10.1016/j.fuel.2023.129382

Cited by 29 publications

(4 citation statements)

References 42 publications

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“…The effects of initial temperature on ammonia flames were also investigated by Kanoshima et al 23 and they found that the temperature exponents of ammonia flames were more prominent than methane flames, while the H-abstract reaction was strongly influenced by temperature exponents. Besides, our previous numerically work 24 also demonstrated the promotion effect of elevated intake temperature on ammonia combustion. The above studies have demonstrated the strong sensitivities of ammonia combustion to thermodynamic boundary conditions.…”

Section: Introductionmentioning

confidence: 79%

“…Considering the asymmetry and stretch during flame propagation, the turbulent flame propagation is calculated based on an effective front method S T = ( d A d t ) / L where S T is the turbulent flame propagation speed, A is the flame projected area, L is the length of the flame front that propagates freely, and t is the time. More details on image processing can be found in refs and .…”

Section: Experimental Setup and Methodologiesmentioning

confidence: 99%

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Optical Study on the Effects of Wall and Intake Temperatures on Ammonia Combustion and Emissions

Zhang,

Chen,

et al. 2024

Energy Fuels

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Ammonia (NH3) as an alternative carbon-free fuel suffers from poor combustion and emission performance, limiting its large-scale commercial utilization in the automobile industry. It has been shown that ammonia combustion is sensitive to operating boundary conditions of actual engines. In this work, the effects of thermodynamic boundary conditions (i.e., wall and intake temperature) on ammonia combustion and emissions were investigated using an optical spark-ignition engine with a high compression ratio. Wall and intake temperatures were regulated by a coolant and an intake heater, respectively. The results show that raising the wall temperature can significantly improve combustion stability, combustion efficiency, and thermal efficiency, while intake temperatures can enhance ammonia combustion only when the wall temperature reaches beyond some thresholds. Combustion visualization shows that the intake and wall temperature affect different stages of the combustion process. Specifically, the intake temperature might predominantly influence the early stages of combustion, whereas the wall temperature might have a more significant impact on the entire combustion process. Elevating the intake temperature increases the flame propagation speed, while there are no obvious changes in terms of the wall temperature. Flame analysis shows that a high wall temperature corresponds to a lower flame stretch sensitivity, indicating reduced cyclic variations in flame propagation and alleviating the possibility of flame quenching. While a high intake temperature features a stronger flame response to turbulence at the early stage of flame development. Besides, NH3 and N2O emissions are significantly reduced due to the improvement of flame propagation instability and incomplete combustion based on the crevice mechanism, but there is an increase in NO and NO2 emissions. The chemical kinetic analysis indicates that increasing NO x emissions mainly comes from the temperature and pressure sensitivities of fuel-type NO x .

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Section: Introductionmentioning

confidence: 79%

Section: Experimental Setup and Methodologiesmentioning

confidence: 99%

Optical Study on the Effects of Wall and Intake Temperatures on Ammonia Combustion and Emissions

Zhang,

Chen,

et al. 2024

Energy Fuels

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“…However, the low combustion rate and high spontaneous combustion temperature of ammonia lead to a poor combustion effect of pure ammonia. Additionally, ammonia easily produces harmful NOx under lean combustion conditions [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

A Study on the Thermal Behavior of Series and Parallel Connection Methods in the Process of Hydrogenation of Ship-Borne Hydrogen Storage Cylinder

Li,

Wang,

et al. 2024

Processes

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As a subdivision of the hydrogen energy application field, ship-borne hydrogen fuel cell systems have certain differences from vehicle or other application scenarios in terms of their structural type, safety, environmental adaptability, and test verification. The connection method of the ship-borne hydrogen storage cylinder (SHSC) is very important for the hydrogen fuel cell ship, and the structural parameters of the SHSC are particularly important in the hydrogen refueling process. To ensure the safe and reliable operation of the hydrogen-powered ship, research on the filling of the SHSC under different connection modes was carried out during refueling. In our study, a thermal flow physical model of the SHSC was established to research the hydrogen refueling process of the series and parallel SHSCs. The influence of series and parallel modes of the SHSCs on the hydrogen refueling process was explored, and the evolution law of the internal flow field, pressure, and temperature of series and parallel SHSCs under different filling parameters was analyzed by numerical simulation. Our results confirmed the superiority of the parallel modular approach in terms of thermal safety during refueling. The results can supply a technical basis for the future development of hydrogen refueling stations and ship-board hydrogenation control algorithms.

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“…However, the low combustion rate and high spontaneous combustion temperature of ammonia lead to a poor combustion effect of pure ammonia. And, ammonia easily produces harmful NO x under lean combustion conditions [23][24][25]. The use of exhaust gas recirculation or the addition of other, more reactive fuels as combustion aids, that is, the dual fuel combustion mode [26], can improve ammonia combustion, thereby improving fuel efficiency and reducing emissions.…”

Section: Introductionmentioning

confidence: 99%

Effects of Methanol–Ammonia Blending Ratio on Performance and Emission Characteristics of a Compression Ignition Engine

Huang,

Lyu,

Luo

et al. 2023

JMSE

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Sustainable ammonia is one of the leading candidates in the search for alternative clean fuels for marine applications. This paper aims to build a simulation model of a six-cylinder, four-stroke diesel engine to investigate the effects of increasing the ammonia proportion in methanol–ammonia fuel blends on engine performance and emissions. In the present study, the conditions of different speeds and different proportions of ammonia in fuel blends are investigated. The results show that the average effective pressure, brake power, and brake torque increase by about 5% with an increased ammonia substitution ratio. In terms of economic performance, the changes under medium and low speed conditions are not obvious. However, the change in high speed conditions is significant. The brake specific fuel consumption (BSFC) is reduced by 6.6%, and the brake thermal efficiency (BTE) is increased by 4%. It is found that the performance of the engine is best at medium speed. The best performance is achieved with higher efficiency and lower emissions. The present results can provide guidance for the optimization of ammonia–methanol blends and their applications in engines.

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Effects of intake parameters and compression ratio on ammonia combustion and emissions in SI engines

Cited by 29 publications

References 42 publications

Optical Study on the Effects of Wall and Intake Temperatures on Ammonia Combustion and Emissions

Optical Study on the Effects of Wall and Intake Temperatures on Ammonia Combustion and Emissions

A Study on the Thermal Behavior of Series and Parallel Connection Methods in the Process of Hydrogenation of Ship-Borne Hydrogen Storage Cylinder

Effects of Methanol–Ammonia Blending Ratio on Performance and Emission Characteristics of a Compression Ignition Engine

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