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摘要 ：
This paper aims to predict the intake characteristics of a side-ported Wankel rotary engine implemented by a novel dual-layer machine learning (ML) structure. The Sobol sequence coupled with a parametric phase control model is performed to generate samples using a three-dimensional dynamic simulation model. Two ML structures are compared to determine the input features, in which the input features of structure A are the port phases, while structure B also contains the geometric features. Compared with Structure A, the regression and generalization abilities of Structure B with different ML methods are generally favorable. Based on structure B, a novel dual-layer structure prediction model is developed using the Gaussian process regression method in which geometric features are used as intermediate variables. The results show that for the prediction of intake loss and volumetric efficiency, the coefficients of determination are greater than 0.99, and the prediction error is less than 1%. In addition, the port full closing timing determines the intake characteristics compared with other port phases. This paper provides novel solutions for predicting intake characteristics to guide practical optimization.(c) 2022 Elsevier Masson SAS. All rights reserved.
关键词 ：
Intake characteristics Intake characteristics Wankel rotary engine Wankel rotary engine Machine learning Machine learning
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| GB/T 7714 | Wang, Huaiyu , Ji, Changwei , Yang, Jinxin et al. Implementation of a novel dual-layer machine learning structure for predicting the intake characteristics of a side-ported Wankel rotary engine [J]. | AEROSPACE SCIENCE AND TECHNOLOGY , 2023 , 132 . |
| MLA | Wang, Huaiyu et al. "Implementation of a novel dual-layer machine learning structure for predicting the intake characteristics of a side-ported Wankel rotary engine" . | AEROSPACE SCIENCE AND TECHNOLOGY 132 (2023) . |
| APA | Wang, Huaiyu , Ji, Changwei , Yang, Jinxin , Ge, Yunshan , Wang, Shuofeng . Implementation of a novel dual-layer machine learning structure for predicting the intake characteristics of a side-ported Wankel rotary engine . | AEROSPACE SCIENCE AND TECHNOLOGY , 2023 , 132 . |
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摘要 ：
In this study, a double spark plugs direct injection rotary engine is used to investigate the effects of synchronous and asynchronous changes of ignition timing on combustion and emission performance. The three-dimensional dynamic model was established by CONVERGE software and validated by the experimental data. The results indicate that setting the fuel injector toward the spark plug can reduce the fuel distribution at the tail of the combustion chamber, and the in-cylinder mixture inhomogeneity index gradually increases with the advance of the ignition timing. Compared with the synchronous change of ignition timing, advancing the ignition timing of the tailing spark plug can promote the combustion process. When the ignition timing of the leading spark plug is too early, the flame front will be irregular. With the advance of ignition timing, CA 0-10 corresponding to synchronous and asynchronous change all gradually increase, and the change of CA 10-90 is more stable than that of CA 0-10. Whether the ignition timing is changed synchronously or asynchronously, with the advance of the ignition time, the in-cylinder pressure shows an upward trend. The mean in-cylinder pressure corresponding to the synchronous change with the same change amplitude is slightly higher than that of asynchronous change. The peak pressure of 16.4% higher than that of the original engine can be obtained by adopting the ignition strategy of the synchronous advance of 30 degrees CA. Under this ignition strategy, the temperature and NOx mole fraction in the combustion chamber are all the lowest.
关键词 ：
Double spark plugs Double spark plugs Ignition timing Ignition timing Direct injection Direct injection Synchronous and asynchronous Synchronous and asynchronous
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| GB/T 7714 | Chang, Ke , Ji, Changwei , Wang, Shuofeng et al. Numerical investigation of the synchronous and asynchronous changes of ignition timing in a double spark plugs direct injection rotary engine [J]. | ENERGY , 2023 , 268 . |
| MLA | Chang, Ke et al. "Numerical investigation of the synchronous and asynchronous changes of ignition timing in a double spark plugs direct injection rotary engine" . | ENERGY 268 (2023) . |
| APA | Chang, Ke , Ji, Changwei , Wang, Shuofeng , Yang, Jinxin , Wang, Huaiyu , Meng, Hao et al. Numerical investigation of the synchronous and asynchronous changes of ignition timing in a double spark plugs direct injection rotary engine . | ENERGY , 2023 , 268 . |
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摘要 ：
Hydrogen is regarded as one of the most potential alternatives for high-efficiency and eco-friendly combustion. The influences of hydrogen fractions and equivalence ratios on chamber pressure, combustion phases, wall heat loss, brake thermal efficiency, and cyclic fluctuation of Wankel engines were studied by testbench measurement. The intrinsic mechanisms of these effects were analyzed through numerical investigation. Results indicated that increasing hydrogen fraction increased the mass fraction of high-temperature regions, the timings taken for formations of intermediate products were advanced, and the peak H2O2 and CH2O reduced while OH concen-tration increased. These factors were responsible for increased chamber pressure and the shortened flame development and propagation periods in experiments. A close inverse relationship can be drawn between the wall heat loss and brake thermal efficiency with respect to hydrogen addition. A larger hydrogen fraction coupled with a smaller equivalence ratio manifested lower wall heat loss and higher thermal efficiency. Compared with hydrogen-free regimes, brake thermal efficiency of 6% hydrogen fraction was increased by 64.6%. There was a positive proportional correspondence between the initial flame development and cycle-to-cycle fluctuation. Increasing the hydrogen content caused the enhanced turbulent intensity during the initial combustion stage, which contributed to the stability improvement of engine operations.
关键词 ：
Hydrogen Hydrogen Wankel engine Wankel engine Numerical simulation Numerical simulation Equivalent ratio Equivalent ratio Combustion Combustion
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| GB/T 7714 | Shi, Cheng , Chai, Sen , Di, Liming et al. Combined experimental-numerical analysis of hydrogen as a combustion enhancer applied to wankel engine [J]. | ENERGY , 2023 , 263 . |
| MLA | Shi, Cheng et al. "Combined experimental-numerical analysis of hydrogen as a combustion enhancer applied to wankel engine" . | ENERGY 263 (2023) . |
| APA | Shi, Cheng , Chai, Sen , Di, Liming , Ji, Changwei , Ge, Yunshan , Wang, Huaiyu . Combined experimental-numerical analysis of hydrogen as a combustion enhancer applied to wankel engine . | ENERGY , 2023 , 263 . |
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摘要 ：
The Wankel rotary engine (WRE) is widely used in the fields of unmanned aerial vehicles and range extenders due to its superior power-to-weight ratio. However, the rotor piston bears an intense thermal load during operation. This study focuses on the implementation of the coupled 1D-3D model. The influence of ECFs on WRE performance characteristics and emissions and improving WRE performance characteristics and emissions at different operating parameters (speeds and hydrogen enrichment) with ECFs are studied. The simulation results demonstrated that radial-fins have a more significant effect, reducing the fire-face's average temperature by 49.03 K and increasing the in-cylinder mass by 6.4 %. Compared with no-fins, radial-fins can increase pressure by 4.4 % and HRR by 5.6 %. At the same time, the NOx is reduced by 15.60 %, and the CO is slightly increased by 0.93 %. At different speeds, the ECF structure can improve the engine performance. The ECFs are more evident at low speeds, which can increase the indicated power by 3.13 % compared with the original engine. Compared with the gasoline-fueled WREs, using radial-fins can lead to more apparent performance improvement for hydrogen-enriched WREs. This paper will provide insight into the feasibility of ECF configuration to improve the performance of WREs in engineering applications.
关键词 ：
Enhanced cooling fins Enhanced cooling fins Performance and emissions Performance and emissions Hydrogen-enriched Hydrogen-enriched Wankel rotary engine Wankel rotary engine Thermal load Thermal load
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| GB/T 7714 | Ji, Changwei , Huang, Xionghui , Yang, Zhengyu et al. Potential improvement in performance and emissions of air-cooled rotary engine using novel enhanced cooling fins [J]. | FUEL , 2023 , 334 . |
| MLA | Ji, Changwei et al. "Potential improvement in performance and emissions of air-cooled rotary engine using novel enhanced cooling fins" . | FUEL 334 (2023) . |
| APA | Ji, Changwei , Huang, Xionghui , Yang, Zhengyu , Yang, Jinxin , Wang, Shuofeng . Potential improvement in performance and emissions of air-cooled rotary engine using novel enhanced cooling fins . | FUEL , 2023 , 334 . |
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摘要 ：
As a promising power system, hydrogen-fueled Wankel rotary engine with excellent power and emission characteristic have received attention increasingly, which makes it of great interest to investigate it. To make up for blanks, this work was conducted to experimentally investigate the effect of spark plug position on the combustion and emission characteristic of hydrogen-fueled Wankel rotary engine under 1500 r/min, 66 kPa manifold absolute pressure and 1.5 excess air ratio. The results indicate that compared to the trailing spark plug, the leading spark plug is more suitable to hydrogen-fueled Wankel rotary engines, which can realize a wider ignition range, higher maximum brake torque, lower cyclic variation and better nitric oxide emission. The maximum brake torque of adopting trailing spark plug is 31.2 N.m, which is only 87% of the maximum brake torque of 36.0 N.m with adopting leading spark plug. At the maximum brake torque ignition timing, adopting leading trailing spark plug achieves lower cyclic variation and slightly higher thermal load than adopting trailing spark plug. Besides, the optimum central heat-release point of both spark plug positions locate between 35 and 40 degrees CA after the top dead center, and that of leading spark plug is later 2 degrees CA than that of trailing spark plug. Moreover, both spark plug positions obtained 0 nitric oxide emission at maximum brake torque ignition timing, which means that emission will not be a problem to limit the selection of spark plug position under tested conditions.
关键词 ：
Wankel rotary engine Wankel rotary engine Emission Emission Hydrogen Hydrogen Combustion Combustion Spark plug position Spark plug position
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| GB/T 7714 | Yang, Jinxin , Meng, Hao , Ji, Changwei et al. Comparatively investigating the leading and trailing spark plug on the hydrogen rotary engine [J]. | FUEL , 2022 , 308 . |
| MLA | Yang, Jinxin et al. "Comparatively investigating the leading and trailing spark plug on the hydrogen rotary engine" . | FUEL 308 (2022) . |
| APA | Yang, Jinxin , Meng, Hao , Ji, Changwei , Wang, Shuofeng . Comparatively investigating the leading and trailing spark plug on the hydrogen rotary engine . | FUEL , 2022 , 308 . |
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摘要 ：
Ammonia is considered as a promising hydrogen carrier, which is seen as a reliable carbon-free fuel. Improving the combustion properties of ammonia is the focus of current research. The hydrogen could be dissociated from the ammonia in real applications. For purpose of combustion, partially dissociated ammonia could be combusted directly without using extra hydrogen. Laminar burning velocity is an important combustion parameter, but there are only a few data of partially dissociated ammonia are reported. To fill the data gap, the laminar burning velocity was measured at various equivalence ratios and dissociation degrees of ammonia by the constant pressure spherical flame method in this study. Besides, fifteen kinetic models were compared with experimental data, and the model with the best consistency was obtained. The experimental results show that the laminar burning velocity increases monotonically with the increase of the dissociating degree. When ammonia is completely dissociated, the maximum laminar burning velocity increases from 7.9 cm/s to 228 cm/s, and the equivalence ratio corresponding to the peak value also shifts from 1.1 to 1.6. The laminar burning velocity predicted by the model constructed by Stagni is in best agreement with the experimental data. Moreover, data calculated by the five correlations for predicting laminar burning velocity were compared with the numerical data to verify that whether they are suitable for the mixtures with additional nitrogen. The results show that the correlation based on the activation tem- perature is the most accurate. However, it still has a maximum relative error of +/- 20% within the calculated range. (c) 2021 Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC.
关键词 ：
Ammonia Ammonia Laminar burning velocity Laminar burning velocity Dissociated ammonia Dissociated ammonia Constant pressure combustion Constant pressure combustion
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| GB/T 7714 | Ji, Changwei , Wang, Zhe , Wang, Du et al. Experimental and numerical study on premixed partially dissociated ammonia mixtures. Part I: Laminar burning velocity of NH3/H-2/N-2/air mixtures [J]. | INTERNATIONAL JOURNAL OF HYDROGEN ENERGY , 2022 , 47 (6) : 4171-4184 . |
| MLA | Ji, Changwei et al. "Experimental and numerical study on premixed partially dissociated ammonia mixtures. Part I: Laminar burning velocity of NH3/H-2/N-2/air mixtures" . | INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 47 . 6 (2022) : 4171-4184 . |
| APA | Ji, Changwei , Wang, Zhe , Wang, Du , Hou, Ruifeng , Zhang, Tianyue , Wang, Shuofeng . Experimental and numerical study on premixed partially dissociated ammonia mixtures. Part I: Laminar burning velocity of NH3/H-2/N-2/air mixtures . | INTERNATIONAL JOURNAL OF HYDROGEN ENERGY , 2022 , 47 (6) , 4171-4184 . |
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摘要 ：
This work aims to investigate experimentally the asynchronous ignition in a hydrogen-fueled Wankel rotary engine. This work was carried out at 1500 r/min and lean combustion. The experimental results showed that a suitable asynchronous ignition may realize better power performance than synchronous ignition and earlier ignition timing of the leading plug than that of the trailing plug is more preferable. When the leading plug and the trailing plug spark at 5 degrees CA ATDC and 20 degrees CA ATDC, respectively, the highest torque is obtained, 36.4 N.m, higher than 35.2 N.m, the highest torque when the synchronous ignition is adopted. Besides, a declined tendency of knock also can be achieved by asynchronous ignition. Compared with synchronous ignition at 35.2 N.m, a reduction of 19.5% maximum pressure rising rate can be achieved by asynchronous ignition at 36.4 N.m. In addition, for hydrogen-fueled WRE, the CA50 should be located at 35 to 40 degrees CA ATDC to obtain the highest output torque.
关键词 ：
Hydrogen-fueled Hydrogen-fueled Asynchronous ignition Asynchronous ignition Wankel rotary engine Wankel rotary engine Combustion Combustion
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| GB/T 7714 | Meng, Hao , Ji, Changwei , Yang, Jinxin et al. Experimentally investigating the asynchronous ignition on a hydrogen-fueled Wankel rotary engine [J]. | FUEL , 2022 , 312 . |
| MLA | Meng, Hao et al. "Experimentally investigating the asynchronous ignition on a hydrogen-fueled Wankel rotary engine" . | FUEL 312 (2022) . |
| APA | Meng, Hao , Ji, Changwei , Yang, Jinxin , Wang, Shuofeng , Xin, Gu , Chang, Ke et al. Experimentally investigating the asynchronous ignition on a hydrogen-fueled Wankel rotary engine . | FUEL , 2022 , 312 . |
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摘要 ：
In order to improve the performance, reduce the emissions and enhance the calibration efficiency of a gasoline Wankel rotary engine (WRE), three advanced machine learning (ML) methods, including artificial neural network (ANN), support vector machine (SVM), and Gaussian process regression (GPR), were applied to develop the prediction model of the torque, fuel flow, nitrogen oxide, carbon monoxide, and hydrocarbon. The effect of feature numbers was examined using the recommended parameters of the ANN, SVM, and GPR models. It was concluded that using speed, manifold absolute pressure, and air fuel ratio as input parameters to build the prediction model performed best. The generalization ability of the three ML models was compared on the interpolative and extrapolative data sets using the extended recommendation parameters. The results showed that the GPR model performed the best generalization ability in scarce data sets and was simpler to train compared with ANN and SVM. The response surfaces constructed using the GPR model were very smooth and accurate, in which the coefficient of determination for all the predicted parameters was more than 0.99. It is strongly proposed that the GPR approach is a universal approach which will be an essential direction for WRE system control and surrogate model modeling.
关键词 ：
Gasoline Wankel rotary engines Gasoline Wankel rotary engines Advanced machine learning methods Advanced machine learning methods Performance and emissions prediction Performance and emissions prediction Scarce data sets Scarce data sets
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| GB/T 7714 | Wang, Huaiyu , Ji, Changwei , Shi, Cheng et al. Comparison and evaluation of advanced machine learning methods for performance and emissions prediction of a gasoline Wankel rotary engine [J]. | ENERGY , 2022 , 248 . |
| MLA | Wang, Huaiyu et al. "Comparison and evaluation of advanced machine learning methods for performance and emissions prediction of a gasoline Wankel rotary engine" . | ENERGY 248 (2022) . |
| APA | Wang, Huaiyu , Ji, Changwei , Shi, Cheng , Ge, Yunshan , Meng, Hao , Yang, Jinxin et al. Comparison and evaluation of advanced machine learning methods for performance and emissions prediction of a gasoline Wankel rotary engine . | ENERGY , 2022 , 248 . |
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摘要 ：
The development of hydrogen-fueled Wankel rotary engine is restricted by the leakage problem, especially the apex seal leakage (ASL). In the study, the ASL area is divided into the geometric leakage area (GLA) and the dynamic leakage area (DLA). The models of under-seal pressure prediction and vibration of apex seal are established. The mechanism of GLA and DLA and the effects of key parameters on them are analyzed. Results show that the DLA decreases with the increase of discharge coefficient, clearance between apex seal and slot. There is no DLA when the rotation speed is slower than 2000 rpm or higher than 7000 rpm. Besides, the value of DLA is only 11.23% of GLA and the GLA can be reduced by 88.57% when using a corner-piece structure. The total leakage decreases with the increase of rotation speed. Finally, some measures to reduce the leakage are given.(c) 2022 Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC.
关键词 ：
Under-sealpressure Under-sealpressure Sealing performance Sealing performance Hydrogen Hydrogen Wankel rotary engine Wankel rotary engine Apex seal leakage Apex seal leakage
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| GB/T 7714 | Ji, Changwei , Yang, Zhenyu , Yang, Jinxin et al. Apex seal bottom pressure prediction and leakage analysis of The Hydrogen Fueled Wankel Rotary Engine based on dynamics [J]. | INTERNATIONAL JOURNAL OF HYDROGEN ENERGY , 2022 , 47 (52) : 22226-22242 . |
| MLA | Ji, Changwei et al. "Apex seal bottom pressure prediction and leakage analysis of The Hydrogen Fueled Wankel Rotary Engine based on dynamics" . | INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 47 . 52 (2022) : 22226-22242 . |
| APA | Ji, Changwei , Yang, Zhenyu , Yang, Jinxin , Wang, Shuofeng . Apex seal bottom pressure prediction and leakage analysis of The Hydrogen Fueled Wankel Rotary Engine based on dynamics . | INTERNATIONAL JOURNAL OF HYDROGEN ENERGY , 2022 , 47 (52) , 22226-22242 . |
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摘要 ：
Hydrogen-fueled Wankel rotary engine (HWRE) as a promising power device overcomes some of the drawbacks of the hydrogen-fueled reciprocating engine. However, its elongated combustion chamber makes it prone to knock, and little research has been done in this area. Hence, to understand the knock characteristics of HWRE, the present work focus on parameters of HWRE knock at 2000r/min, an excess air ratio of 1.2 and an ignition timing of -7 degrees CA ATDC. The main results are as follows: As with knock intensity, knock duration and maximum pressure rising rate also can characterize the knock of HWRE because of the logarithmic or linear relationship among three parameters. For the knock intensity, two parameters are needed to precisely characterize the HWRE knock, while only one parameter is needed for the knock duration and the maximum pressure rising rate. Considering the computing cost, the maximum pressure rising rate is better than others. The knock intensity has a significant influence on the timed sequence of peak knock pressure and peak in-cylinder pressure. Besides, the mechanism of backfire caused by the knock of HWRE is different from that of the hydrogen-fueled reciprocating piston engine, which results from the inter-cylinder flame leakage. (C) 2022 Elsevier Ltd. All rights reserved.
关键词 ：
Wankel rotary engine Wankel rotary engine Knock characteristics Knock characteristics Hydrogen Hydrogen
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| GB/T 7714 | Meng, Hao , Ji, Changwei , Su, Teng et al. Analyzing characteristics of knock in a hydrogen-fueled Wankel rotary engine [J]. | ENERGY , 2022 , 250 . |
| MLA | Meng, Hao et al. "Analyzing characteristics of knock in a hydrogen-fueled Wankel rotary engine" . | ENERGY 250 (2022) . |
| APA | Meng, Hao , Ji, Changwei , Su, Teng , Yang, Jinxin , Chang, Ke , Xin, Gu et al. Analyzing characteristics of knock in a hydrogen-fueled Wankel rotary engine . | ENERGY , 2022 , 250 . |
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