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学者姓名：纪常伟
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Abstract ：
Pre-chamber (PC) jet ignition technology has gained significant attention in engine applications. However, research on passive PC in NH3/H2 zero-carbon fuel engines remains limited. This study experimentally investigates the effects of excess air ratio (lambda) and spark timing (ST) on the performance of a passive PC NH3/H2 engine and uses numerical to analyze flow and combustion in the PC. The engine operates at 1600 rpm with an intake manifold absolute pressure of 60 kPa. The results show that the brake mean effective pressure (BMEP) gradually decreases with the increase of lambda. The thermal efficiency increases first and then decreases with the increase of lambda. Under the fuel-rich condition with lambda of 0.8, BMEP reaches a maximum of 4.17 bar, which is 63 % higher than that of ultra-lean combustion with lambda of 2.4. However, the maximum value of brake thermal efficiency (BTE) is 31.3% when lambda is 1.2. At lambda is 0.8, the flame propagation speed in the PC is highest, while the uniform mixture at the stoichiometric ratio leads to the fastest combustion speed in the main chamber. The rapid combustion period is consistently shorter than the flame development period in the combustion process. While rich combustion significantly reduces NOx, it also increases the escape of unburned NH3. Experiments show that when the ST is set at TDC to the 4 degrees CA ATDC, the performance of the passive PC NH3/H2 engine is significantly improved.
Keyword ：
Spark timing Spark timing Combustion analysis Combustion analysis Excess air ratio Excess air ratio Turbulent jet ignition Turbulent jet ignition Ammonia-hydrogen engine Ammonia-hydrogen engine
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| GB/T 7714 | Qiang, Yanfei , Yang, Xu , Yang, Jinxin et al. Exploration of the application of passive pre-chamber ignition systems in ammonia-hydrogen engines: Rich, stoichiometric, and lean combustion evaluations [J]. | INTERNATIONAL JOURNAL OF HYDROGEN ENERGY , 2025 , 100 : 466-476 . |
| MLA | Qiang, Yanfei et al. "Exploration of the application of passive pre-chamber ignition systems in ammonia-hydrogen engines: Rich, stoichiometric, and lean combustion evaluations" . | INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 100 (2025) : 466-476 . |
| APA | Qiang, Yanfei , Yang, Xu , Yang, Jinxin , Su, Fangxu , Wang, Fuzhi , Wang, Shuofeng et al. Exploration of the application of passive pre-chamber ignition systems in ammonia-hydrogen engines: Rich, stoichiometric, and lean combustion evaluations . | INTERNATIONAL JOURNAL OF HYDROGEN ENERGY , 2025 , 100 , 466-476 . |
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Abstract ：
The oval rotary engine (ORE) has smooth rotation, high power density, and a more flexible combustion chamber shape than the Wankel rotary engine, with a great future in carbon-free power. This ORE numerical model works with the hydrogen direct-injection and spark ignition to study the impact of different spark plug positions, ignition timings, and excess air ratio (2) on the engine performance. The results indicate that high turbulence occurring near the top dead center (TDC) in the combustion chamber edge accelerates flame propagation on trailing spark position in combustion chamber. The case with the spark position on the trailing side of the combustion chamber has the shortest ignition delay period of 3.9 degrees crank angle (CA) and main combustion period of 11.7 degrees CA. In-cylinder vortices become smaller and hydrogen-air mixing becomes poorer with delaying ignition. Mixture stratification in rich mixture results in NOx emission of the case with 2 of 1.4 27 % lower than 2 of 1.6. Overall, the optimal working condition is 2 of 1.8 with ignition at 6 degrees CA before TDC, which is 21 % higher on IMEP, just 0.9 % lower on ITE of 36.4 %, but 19.4 % higher on NOx emission than the case with ultra-lean mixture.
Keyword ：
Oval rotary engine Oval rotary engine Flow field characteristic Flow field characteristic Hydrogen direct-injection Hydrogen direct-injection Mixture stratification Mixture stratification NO x emission NO x emission Combustion progress Combustion progress
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| GB/T 7714 | Ji, Changwei , Deng, Yutao , Yang, Jinxin et al. Numerical study on the effects of spark plug position and ignition timing on the performance of hydrogen direct-injection oval rotary engine under different excess air ratio conditions [J]. | ENERGY , 2025 , 314 . |
| MLA | Ji, Changwei et al. "Numerical study on the effects of spark plug position and ignition timing on the performance of hydrogen direct-injection oval rotary engine under different excess air ratio conditions" . | ENERGY 314 (2025) . |
| APA | Ji, Changwei , Deng, Yutao , Yang, Jinxin , Zambalov, Sergey , Kasaev, Dmitry . Numerical study on the effects of spark plug position and ignition timing on the performance of hydrogen direct-injection oval rotary engine under different excess air ratio conditions . | ENERGY , 2025 , 314 . |
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Abstract ：
To handle and manage battery degradation in electric vehicles (EVs), various capacity estimation methods have been proposed and can mainly be divided into traditional modeling methods and data-driven methods. For realistic conditions, data-driven methods take the advantage of simple application. However, state-of-the-art machine learning (ML) algorithms are still kinds of black-box models; thus, the algorithms do not have a strong ability to describe the inner reactions or degradation information of batteries. Due to a lack of interpretability, machine learning may not learn the degradation principle correctly and may need to depend on big data quality. In this paper, we propose a physics-informed recurrent neural network (PIRNN) with a fractional-order gradient for fast battery degradation estimation in running EVs to provide a physics-informed neural network that can make algorithms learn battery degradation mechanisms. Incremental capacity analysis (ICA) was conducted to extract aging characteristics, which could be selected as the inputs of the algorithm. The fractional-order gradient descent (FOGD) method was also applied to improve the training convergence and embedding of battery information during backpropagation; then, the recurrent neural network was selected as the main body of the algorithm. A battery dataset with fast degradation from ten EVs with a total of 5697 charging snippets were constructed to validate the performance of the proposed algorithm. Experimental results show that the proposed PIRNN with ICA and the FOGD method could control the relative error within 5% for most snippets of the ten EVs. The algorithm could even achieve a stable estimation accuracy (relative error < 3%) during three-quarters of a battery's lifetime, while for a battery with dramatic degradation, it was difficult to maintain such high accuracy during the whole battery lifetime.
Keyword ：
physics-informed machine learning physics-informed machine learning incremental capacity analysis incremental capacity analysis fractional-order gradient fractional-order gradient backpropagation backpropagation battery degradation battery degradation
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| GB/T 7714 | Wang, Yanan , Wei, Min , Dai, Feng et al. Physics-Informed Fractional-Order Recurrent Neural Network for Fast Battery Degradation with Vehicle Charging Snippets [J]. | FRACTAL AND FRACTIONAL , 2025 , 9 (2) . |
| MLA | Wang, Yanan et al. "Physics-Informed Fractional-Order Recurrent Neural Network for Fast Battery Degradation with Vehicle Charging Snippets" . | FRACTAL AND FRACTIONAL 9 . 2 (2025) . |
| APA | Wang, Yanan , Wei, Min , Dai, Feng , Zou, Daijiang , Lu, Chen , Han, Xuebing et al. Physics-Informed Fractional-Order Recurrent Neural Network for Fast Battery Degradation with Vehicle Charging Snippets . | FRACTAL AND FRACTIONAL , 2025 , 9 (2) . |
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Abstract ：
Ammonia (NH3) and hydrogen (H2) can provide effective assistance for the transportation sector to face the dualcarbon challenge. Ammonia-enriched engines cannot effectively ensure stable and efficient operation due to the combustion inertia of ammonia. Increasing intake air temperature (IAT) and hydrogen volume ratio (HVR) are two effective means of promoting ammonia combustion, but also lead to increased emissions. The purpose of this work is to apply numerical simulation to examine the combined impacts of IAT and HVR on the combustion and emissions of ammonia-enriched hydrogen port fuel injection (PFI) spark ignition (SI) engines. Four IAT conditions of 270K, 300K, 330K and 360K and three HVR conditions of 10%, 20% and 30% are set. The research results indicate that there is an overlapping offset period for the promotion of combustion by the HVR and IAT, which is particularly obvious with the increase of the two. In addition, NOX emissions increase with the increasing HVR and IAT. When the HVR and IAT are increased to 20% and 330K, respectively, the ammonia escape rate is 0.19% and the N2O emission is close to zero. At 30% HVR, the ammonia escape phenomenon disappears. At the IAT of 330K, the HVR can be reduced to 10% while maintaining good performance and low emissions.
Keyword ：
Combustion and emissions Combustion and emissions Ammonia-enriched engine Ammonia-enriched engine Hydrogen volume ratio Hydrogen volume ratio Numerical simulation Numerical simulation Intake air temperature Intake air temperature
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| GB/T 7714 | Zhao, Shihao , Qiang, Yanfei , Ma, Tianfang et al. Numerical investigation on the synergistic effect of intake air temperature and hydrogen volume ratio on combustion and emissions of ammonia-enriched hydrogen spark-ignition engine [J]. | INTERNATIONAL JOURNAL OF HYDROGEN ENERGY , 2025 , 103 : 999-1012 . |
| MLA | Zhao, Shihao et al. "Numerical investigation on the synergistic effect of intake air temperature and hydrogen volume ratio on combustion and emissions of ammonia-enriched hydrogen spark-ignition engine" . | INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 103 (2025) : 999-1012 . |
| APA | Zhao, Shihao , Qiang, Yanfei , Ma, Tianfang , Yang, Jinxin , Wang, Shuofeng , Ji, Changwei . Numerical investigation on the synergistic effect of intake air temperature and hydrogen volume ratio on combustion and emissions of ammonia-enriched hydrogen spark-ignition engine . | INTERNATIONAL JOURNAL OF HYDROGEN ENERGY , 2025 , 103 , 999-1012 . |
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Abstract ：
Turbulent jet ignition (TJI) effectively achieves lean and stable combustion in hydrogen engines. However, research on injection strategies for TJI hydrogen engines is still lacking. In this study, experimental methods investigated the effects of single and split injection strategies on the combustion and emissions of TJI hydrogen engines under medium loads. The numerical simulation reveals the operational characteristics of fuel distribution, ignition capability, and energy conversion in the pre-chamber at different injection times in a single injection strategy. This work is conducted at 1600 rpm with a manifold absolute pressure of 70 kPa. The experimental results indicate that the delay of the start of injection (SOI) can enhance the performance of the TJI hydrogen engine. However, as SOI approaches TDC, emissions worsen, and combustion stability decreases. When SOI is 90 degrees CA BTDC, the brake mean effective pressure (BMEP) and brake thermal efficiency (BTE) can achieve 3.1 bar and 32.9%, with the coefficient of variation of the IMEP (COVIMEP) of 1.6% and lower emissions. For the split injection strategy, delaying the secondary end of injection (SEOI) can increase BMEP and BTE. As SEOI gradually delays the TDC, emissions deteriorate sharply. Under the split injection strategy, COVIMEP is higher, which is unfavorable for hydrogen engine applications.
Keyword ：
Hydrogen Hydrogen Combustion analysis Combustion analysis Injection strategies Injection strategies Passive pre-chamber ignition Passive pre-chamber ignition
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| GB/T 7714 | Qiang, Yanfei , Cai, Xiaoqian , Xu, Song et al. Effect of injection strategy on the hydrogen mixture distribution and combustion of the hydrogen-fueled engine with passive pre-chamber ignition under lean burn condition [J]. | FUEL , 2024 , 375 . |
| MLA | Qiang, Yanfei et al. "Effect of injection strategy on the hydrogen mixture distribution and combustion of the hydrogen-fueled engine with passive pre-chamber ignition under lean burn condition" . | FUEL 375 (2024) . |
| APA | Qiang, Yanfei , Cai, Xiaoqian , Xu, Song , Wang, Fuzhi , Zhang, Lijun , Wang, Shuofeng et al. Effect of injection strategy on the hydrogen mixture distribution and combustion of the hydrogen-fueled engine with passive pre-chamber ignition under lean burn condition . | FUEL , 2024 , 375 . |
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Abstract ：
Knock-free operation of direct-injection (DI) hydrogen engines at stoichiometric and wide-opening throttle (WOT) conditions is attractive, but combustion knock hinders the implementation of this idea, which inspires the present study. In this work, ammonia, as a combustion inhibitor, is added to the DI hydrogen engine, which is expected to utilize the low reactivity of ammonia and the crowding out of the intake charge to suppress knock and extend speed and lambda corresponding to knock limits. All tests are conducted at WOT conditions. In Part 1, lambda is 1.6, and the speed corresponding to the knock limit is elevated from below 1600 rpm to 2000 rpm by injecting ammonia. In Part 2, the speed is kept at 1600 rpm, and the realization process of the engine shifting from lean operation to stoichiometric operation reflects the effectiveness of ammonia addition in suppressing knock. Then, using the critical knocking state as a boundary, dynamically adjusted ammonia injection enables the engine to achieve stoichiometric operation and prominent power expansion at various speeds. Especially at 3000 rpm, the brake power varies from below 21.0 kW to about 44.2 kW. Furthermore, the suppression mechanism of knock by ammonia addition is revealed by analyzing the mapping relationship between combustion characteristic parameters and knock.
Keyword ：
Power expansion Power expansion Stoichiometric operation Stoichiometric operation Combustion knock Combustion knock Hydrogen Hydrogen Ammonia addition Ammonia addition
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| GB/T 7714 | Hong, Chen , Xu, Song , Zhao, Shihao et al. Analysis of ammonia as a combustion inhibitor for combustion knock and power expansion in a DI hydrogen engine [J]. | FUEL , 2024 , 375 . |
| MLA | Hong, Chen et al. "Analysis of ammonia as a combustion inhibitor for combustion knock and power expansion in a DI hydrogen engine" . | FUEL 375 (2024) . |
| APA | Hong, Chen , Xu, Song , Zhao, Shihao , Zhang, Huachuan , Su, Fangxu , Wang, Shuofeng et al. Analysis of ammonia as a combustion inhibitor for combustion knock and power expansion in a DI hydrogen engine . | FUEL , 2024 , 375 . |
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Abstract ：
Adopting the low-temperature hydrogen evaporated from the liquid hydrogen is capable of improving volumetric efficiency for the Wankel rotary engine (WRE). Considering the difficulty in ignition and slow flame propagation of low-temperature hydrogen-air mixtures, the passive pre-chamber is used to improve ignition and combustion. A three-dimensional computational fluid dynamics model for a turbulent jet ignition (TJI) WRE fueled by lowtemperature hydrogen was established. The effects of low temperature and TJI on the in-cylinder flow field, combustion, emissions and leakage in the TJI-WRE fueled by low-temperature hydrogen were studied under different ignition timings. The results indicated that low-temperature tends to suppress the flame propagation, whereas TJI can accelerate the flame speed and promote flame propagation to the unburned zone in the combustion chamber. Combining low-temperature hydrogen with the passive pre-chamber can achieve high engine thermal efficiency and power while significantly reducing leakage. With the ignition timing set at 18 degrees CA before the top dead center, the indicated thermal efficiency reached 39.49 % and the indicated mean effective pressure peaked at 0.77 MPa. Compared to the original engine, fresh mixture leakage through spark plug cavities and adjacent chambers was reduced by 72.13 % and 78.79 %, respectively.
Keyword ：
Passive pre-chamber Passive pre-chamber Combustion Combustion Turbulent jet ignition Turbulent jet ignition Wankel rotary engine Wankel rotary engine Low-temperature hydrogen Low-temperature hydrogen
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| GB/T 7714 | Ji, Changwei , Li, Hanlin , Yang, Jinxin et al. Numerical investigation on the effect of ignition timing on a low-temperature hydrogen-fueled Wankel rotary engine with passive pre-chamber ignition [J]. | ENERGY , 2024 , 313 . |
| MLA | Ji, Changwei et al. "Numerical investigation on the effect of ignition timing on a low-temperature hydrogen-fueled Wankel rotary engine with passive pre-chamber ignition" . | ENERGY 313 (2024) . |
| APA | Ji, Changwei , Li, Hanlin , Yang, Jinxin , Meng, Hao . Numerical investigation on the effect of ignition timing on a low-temperature hydrogen-fueled Wankel rotary engine with passive pre-chamber ignition . | ENERGY , 2024 , 313 . |
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Abstract ：
To achieve sustainable transportation, ammonia (NH3) and hydrogen (H2) should be applied in internal combustion engines. The adoption of turbulent jet ignition (TJI) can improve ignition and combustion stability. The present study aims to explore the combustion characteristics of NH3/H2/air adopting TJI, and the effect of nitrogen (N2) dilution on factors such as ignition mechanism and flame propagation process was analyzed. The results indicate that N2 dilution worsens the combustion of NH3/H2/air. When the H2 volume fraction is 50%, a dilution ratio of 30% can increase the ignition delay and combustion duration by 3-6 times. With the increase of the dilution ratio, sensitivities of ignition delay and combustion duration to dilution ratio are enhanced in both passive TJI and active TJI modes. Compared to passive TJI, the injection of auxiliary gas in active TJI mode reduces the sensitivity of jet velocity to dilution, which can accelerate the early stage of flame development. However, the high turbulence intensity provided by active TJI makes the ignition position closer to the bottom and causes an extended final stage of combustion. For ultra-low reactivity mixtures, the active TJI with the scavenging system can provide sufficient ignition energy, but ignition occurs after prolonged accumulation of heat and radicals, as well as dissipation of turbulence.
Keyword ：
Turbulent jet ignition Turbulent jet ignition Combustion characteristics Combustion characteristics Hydrogen Hydrogen Ammonia Ammonia Nitrogen dilution Nitrogen dilution
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| GB/T 7714 | Wang, Zhe , Zhang, Tianyue , Yang, Haowen et al. Effects of N2 2 dilution on NH3/H2/air 3 /H 2 /air combustion using turbulent jet ignition [J]. | INTERNATIONAL JOURNAL OF HYDROGEN ENERGY , 2024 , 82 : 685-692 . |
| MLA | Wang, Zhe et al. "Effects of N2 2 dilution on NH3/H2/air 3 /H 2 /air combustion using turbulent jet ignition" . | INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 82 (2024) : 685-692 . |
| APA | Wang, Zhe , Zhang, Tianyue , Yang, Haowen , Wang, Shuofeng , Ji, Changwei . Effects of N2 2 dilution on NH3/H2/air 3 /H 2 /air combustion using turbulent jet ignition . | INTERNATIONAL JOURNAL OF HYDROGEN ENERGY , 2024 , 82 , 685-692 . |
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Abstract ：
Ammonia (NH 3 ) and hydrogen (H 2 ) mixture are expected to replace traditional fossil fuels in the transportation industry to achieve zero-carbon emissions. Adopting turbulent jet ignition (TJI) is a reliable way to enhance the ignition and combustion of NH 3 /H 2 . The present study aims to explore the effects of initial pressure and temperature on the ignition and combustion characteristics of NH 3 /H 2 ignited by TJI. It can be found that the increased initial pressure reduces the jet velocity. Due to the joint effect of weakened turbulence and inherent flame propagation characteristics caused by the elevated pressure, the combustion duration is extended. However, the ignition performance can be enhanced by increasing the initial pressure. Improvement is reflected in the emergence of flame ignition mechanisms and the obvious radial propagation of jet flames in early development. The increase in initial temperature slightly increases the peak jet velocity, while the auxiliary H 2 in active mode will reduce the sensitivity of jet velocity to the initial temperature. Although the increased initial temperature has shown the promotion for achieving rapid ignition and combustion, there is no significant improvement in the ignition mechanism, the ignition is caused by accumulated heat and radicals provided by the reacted jet.
Keyword ：
Initial pressure and temperature Initial pressure and temperature Ammonia Ammonia Turbulent jet ignition Turbulent jet ignition Hydrogen Hydrogen Combustion characteristics Combustion characteristics
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| GB/T 7714 | Wang, Zhe , Zhang, Tianyue , Wang, Du et al. Effects of initial pressure and temperature on the ignition and combustion characteristics of ammonia/hydrogen/air adopting turbulent jet ignition [J]. | INTERNATIONAL JOURNAL OF HYDROGEN ENERGY , 2024 , 78 : 1382-1390 . |
| MLA | Wang, Zhe et al. "Effects of initial pressure and temperature on the ignition and combustion characteristics of ammonia/hydrogen/air adopting turbulent jet ignition" . | INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 78 (2024) : 1382-1390 . |
| APA | Wang, Zhe , Zhang, Tianyue , Wang, Du , Wang, Huaiyu , Yang, Haowen , Wang, Shuofeng et al. Effects of initial pressure and temperature on the ignition and combustion characteristics of ammonia/hydrogen/air adopting turbulent jet ignition . | INTERNATIONAL JOURNAL OF HYDROGEN ENERGY , 2024 , 78 , 1382-1390 . |
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Abstract ：
Internal combustion engines fueled with mixtures of hydrogen (H2) and ammonia (NH3) are potential power devices for reducing carbon emissions. To improve the ignition and combustion performance of NH3/H2, turbulent jet ignition (TJI) can be used. This study aims to investigate NH3/H2/air combustion under TJI modes at low equivalence ratios. Considering that the adoption of the scavenging system is beneficial for improving the reactivity of the pre-chamber, the effect of active TJI with scavenging is also explored. The results show that injecting 1.2 times the initial mixture volume of air is optimal for scavenging, and the scavenging effect becomes significant as the NH3 fraction increases. Using conventional active TJI and active TJI with scavenging effectively improves ignition performance and flame propagation, reducing sensitivity to the equivalence ratio compared to passive TJI mode. Although the adoption of active TJI modes improves the lean flammability limit of NH3/H2, weak flame propagation may occur in the early stage of combustion under ultra-lean conditions. Appropriately increasing the injection of auxiliary H2 can effectively improve this phenomenon.
Keyword ：
Hydrogen Hydrogen Pre-chamber Pre-chamber Turbulent jet ignition Turbulent jet ignition Ammonia Ammonia Combustion characteristics Combustion characteristics
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| GB/T 7714 | Wang, Zhe , Zhang, Tianyue , Wang, Du et al. A comparative study on the combustion of lean NH3/H2/air ignited by pre-chamber turbulent jet ignition modes [J]. | INTERNATIONAL JOURNAL OF HYDROGEN ENERGY , 2024 , 86 : 208-215 . |
| MLA | Wang, Zhe et al. "A comparative study on the combustion of lean NH3/H2/air ignited by pre-chamber turbulent jet ignition modes" . | INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 86 (2024) : 208-215 . |
| APA | Wang, Zhe , Zhang, Tianyue , Wang, Du , Yang, Haowen , Wang, Huaiyu , Wang, Shuofeng et al. A comparative study on the combustion of lean NH3/H2/air ignited by pre-chamber turbulent jet ignition modes . | INTERNATIONAL JOURNAL OF HYDROGEN ENERGY , 2024 , 86 , 208-215 . |
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