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A methodology for regulating fuel stratification and improving fuel economy of GCI mode via double main-injection

《能源前沿(英文)》 2023年 第17卷 第5期   页码 678-691 doi: 10.1007/s11708-022-0859-z

摘要: Gasoline compression ignition (GCI) combustion faces problems such as high maximum pressure rise rate (MPRR) and combustion deterioration at high loads. This paper aims to improve the engine performance of the GCI mode by regulating concentration stratification and promoting fuel-gas mixing by utilizing the double main-injection (DMI) strategy. Two direct injectors simultaneously injected gasoline with an octane number of 82.7 to investigate the energy ratio between the two main-injection and exhaust gas recirculation (EGR) on combustion and emissions. High-load experiments were conducted using the DMI strategy and compared with the single main-injection (SMI) strategy and conventional diesel combustion. The results indicate that the DMI strategy have a great potential to reduce the MPRR and improve the fuel economy of the GCI mode. At a 10 bar indicated mean effective pressure, increasing the main-injection-2 ratio (Rm-2) shortens the injection duration and increases the mean mixing time. Optimized Rm-2 could moderate the trade-off between the MPRR and the indicated specific fuel consumption with both reductions. An appropriate EGR should be adopted considering combustion and emissions. The DMI strategy achieves a highly efficient and stable combustion at high loads, with an indicated thermal efficiency (ITE) greater than 48%, CO and THC emissions at low levels, and MPRR within a reasonable range. Compared with the SMI strategy, the maximum improvement of the ITE is 1.5%, and the maximum reduction of MPRR is 1.5 bar/°CA.

关键词: gasoline compression ignition     injection strategy     fuel stratification     high efficiency     high load    

Emission components characteristics of a bi-fuel vehicle at idling condition

Sameh M. METWALLEY, Shawki A. ABOUEL-SEOUD, Abdelfattah M. FARAHAT

《能源前沿(英文)》 2011年 第5卷 第3期   页码 322-329 doi: 10.1007/s11708-011-0158-6

摘要: Natural gas (NG) represents today a promising alternative to conventional fuels for road vehicles propulsion, since it is characterized by a relatively low cost, better geopolitical distribution than oil, and lower environmental impact. This explains the current spreading of compressed natural gas (CNG) fuelled spark ignition (SI) engine, above all in the bi-fuel version, which is able to run either with gasoline or with NG. However, the aim of the present investigation is to evaluate the emission characteristics at idling condition. The vehicle engine was converted to bi-fueling system from a gasoline engine, and operated separately either with gasoline or CNG. Two different fuel injection systems (i.e., multi-point injection (MPI)-sequential and closed-loop venturi-continuous) are used, and their influences on the formation of emissions at different operating conditions are examined. A detailed comparative analysis of the engine exhaust emissions using gasoline and CNG is made. The results indicate that the CNG shows low air index and lower emissions of carbon monoxide (CO), carbon dioxide (CO ), and total hydrocarbon (THC) compared to gasoline.

关键词: road vehicle engine     fuel injection systems     carbon monoxide (CO)     carbon dioxide (CO2)     total hydrocarbon (THC)     vehicle idle conditions     air index    

Numerical simulation of biodiesel fuel combustion and emission characteristics in a direct injection

Yi REN, Ehab ABU-RAMADAN, Xianguo LI,

《能源前沿(英文)》 2010年 第4卷 第2期   页码 252-261 doi: 10.1007/s11708-010-0036-7

摘要: The effect of the physical and chemical properties of biodiesel fuels on the combustion process and pollutants formation in Direct Injection (DI) engine are investigated numerically by using multi-dimensional Computational Fluid Dynamics (CFD) simulation. In the current study, methyl butanoate (MB) and -heptane are used as the surrogates for the biodiesel fuel and the conventional diesel fuel. Detailed kinetic chemical mechanisms for MB and -heptane are implemented to simulate the combustion process. It is shown that the differences in the chemical properties between the biodiesel fuel and the diesel fuel affect the whole combustion process more significantly than the differences in the physical properties. While the variations of both the chemical and the physical properties between the biodiesel and diesel fuel influence the soot formation at the equivalent level, the variations in the chemical properties play a crucial role in the NO emissions formation.

关键词: biodiesel     diesel engine     CFD simulation     combustion     pollutant formation    

A new approach for fuel injection into a solar receiver/reactor: Numerical and experimental investigation

M Helal Uddin, Nesrin Ozalp, Jens Heylen, Cedric Ophoff

《化学科学与工程前沿(英文)》 2018年 第12卷 第4期   页码 683-696 doi: 10.1007/s11705-018-1782-z

摘要:

An innovative and efficient design of solar receivers/reactors can enhance the production of clean fuels via concentrated solar energy. This study presents a new jet-type burner nozzle for gaseous feedstock injection into a cavity solar receiver inspired from the combustion technology. The nozzle design was adapted from a combustion burner and successfully implemented into a solar receiver and studied the influence of the nozzle design on the fluid mixing and temperature distribution inside the solar receiver using a 7 kW solar simulator and nitrogen as working fluid. Finally, a thorough computational fluid dynamics (CFD) analysis was performed and validated against the experimental results. The CFD results showed a variation of the gas flow pattern and gas mixing after the burner nozzle adaptation, which resulted an intense effect on the heat transfer inside the solar receiver.

关键词: solar reactor     nozzle     CFD     heat transfer     mixing and recirculation    

Effects of Fischer-Tropsch diesel fuel on combustion and emissions of direct injection diesel engine

HUANG Yongcheng, WANG Shangxue, ZHOU Longbao

《能源前沿(英文)》 2008年 第2卷 第3期   页码 261-267 doi: 10.1007/s11708-008-0062-x

摘要: Effects of Fischer-Tropsch (F-T) diesel fuel on the combustion and emission characteristics of a single-cylinder direct injection diesel engine under different fuel delivery advance angles were investigated. The experimental results show that F-T diesel fuel exhibits shorter ignition delay, lower peak values of premixed burning rate, lower combustion pressure and pressure rise rate, and higher peak value of diffusion burning rate than conventional diesel fuel when the engine remains unmodified. In addition, the unmodified engine with F-T diesel fuel has lower brake specific fuel consumption and higher effective thermal efficiency, and presents lower HC, CO, NO and smoke emissions than conventional diesel fuel. When fuel delivery advance angle is retarded by 3 crank angle degrees, the combustion duration is obviously shortened; the peak values of premixed burning rate, the combustion pressure and pressure rise rate are further reduced; and the peak value of diffusion burning rate is further increased for F-T diesel fuel operation. Moreover, the retardation of fuel delivery advance angle results in a further significant reduction in NO emissions with no penalty on specific fuel consumption and with much less penalty on HC, CO and smoke emissions.

关键词: combustion pressure     further     HC     operation     single-cylinder    

Effect of distributions of fuel concentration and temperature on ignition processes in a diesel PCCI

Yang YU, Wanhua SU,

《能源前沿(英文)》 2010年 第4卷 第2期   页码 269-279 doi: 10.1007/s11708-009-0046-5

摘要: The distributions of fuel concentration and temperature have significant effect on the ignition processes of diesel premixed charge compression ignition (PCCI) combustion. It was found in this study that the ignition process of PCCI combustion organized by multi-pulse injection was strongly influenced by conditions of fuel stratification. The start of low temperature reactions occurred in the leaner area of the combustion chamber in the test engine because the temperature here first reached the point of low temperature reactions. Ignition always occurred in the position where the mixture featured with equivalence ratios close to the mean equivalence ratio of the overall mixture, while the neighboring area of the initial ignition area accumulate heat with a finite speed until finally autoigniting. Moreover, the appearance of highest combustion temperature occurred in the same area at the combustion chamber. For more homogeneous mixture, a higher amount of mixture reached ignition simultaneously, resulting in a larger initial ignition area and a higher temperature at the ignition area. Furthermore, V-type distribution of equivalence ratio was found to be beneficial to retarding high temperature reaction.

关键词: PCCI     fuel stratification     multi-pulse injection     ignition    

Dimethyl ether as alternative fuel for CI engine and vehicle

Zhen HUANG , Xinqi QIAO , Wugao ZHANG , Junhua WU , Junjun ZHANG ,

《能源前沿(英文)》 2009年 第3卷 第1期   页码 99-108 doi: 10.1007/s11708-009-0013-1

摘要: As a developing and the most populous country in the world, China faces major challenges in energy supply and environmental protection. It is of great importance to develop clean and alternative fuels for internal combustion engines. On the basis of researches on DME engine and vehicle at Shanghai Jiaotong University in the last twelve years, fuel injection, combustion, performance and exhaust emissions of DME engine and DME vehicle are introduced in this paper. The results indicate that DME engines can achieve high thermal efficiency and ultra low emissions, and will play a significant role in meeting the energy demand while minimizing environmental impact in China.

关键词: dimethyl ether (DME)     fuel injection     combustion process     emission control     CI engine     vehicle    

Significant potential of Solid Oxide Fuel Cell systems for distributed power generation and carbon neutrality

《能源前沿(英文)》 2022年 第16卷 第6期   页码 879-882 doi: 10.1007/s11708-022-0850-8

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Fuel poverty and low carbon emissions: a comparative study of the feasibility of the hybrid renewableenergy systems incorporating combined heat and power technology

《能源前沿(英文)》 2022年 第16卷 第2期   页码 336-356 doi: 10.1007/s11708-021-0748-x

摘要: Fuel poverty is most prevalent in North East England with 14.4% of fuel poor households in Newcastle upon Tyne. The aim of this paper was to identify a grid connected renewable energy system coupled with natural gas reciprocating combined heat and power unit, that is cost-effective and technically feasible with a potential to generate a profit from selling energy excess to the grid to help alleviate fuel poverty. The system was also aimed at low carbon emissions. Fourteen models were designed and optimized with the aid of the HOMER Pro software. Models were compared with respect to their economic, technical, and environmental performance. A solution was proposed where restrictions were placed on the size of renewable energy components. This configuration consists of 150 kW CHP, 300 kW PV cells, and 30 kW wind turbines. The renewable fraction is 5.10% and the system yields a carbon saving of 7.9% in comparison with conventional systems. The initial capital investment is $1.24 million which enables the system to have grid sales of 582689 kWh/a. A conservative calculation determined that 40% of the sales can be used to reduce the energy cost of fuel poor households by $706 per annum. This solution has the potential to eliminate fuel poverty at the site analyzed.

关键词: greenhouse gas control     low carbon target     grid connected     renewable fraction     fuel poverty     combined heat and power     HOMER Pro    

喷射策略对低负荷下天然气——柴油双燃料预混压燃燃烧的影响研究 Article

Hyunwook Park, Euijoon Shim, Choongsik Bae

《工程(英文)》 2019年 第5卷 第3期   页码 548-557 doi: 10.1016/j.eng.2019.03.005

摘要:

双燃料预混压燃(dual-fuel premixed charge compression ignition, DF-PCCI)燃烧因其氮氧化物(NOx)和颗粒物

关键词: 双燃料     反应可控压燃     预混压燃     天然气     喷射策略     废气再循环    

Three-dimensional numerical simulation for plastic injection-compression molding

Yun ZHANG, Wenjie YU, Junjie LIANG, Jianlin LANG, Dequn LI

《机械工程前沿(英文)》 2018年 第13卷 第1期   页码 74-84 doi: 10.1007/s11465-018-0490-1

摘要:

Compared with conventional injection molding, injection-compression molding can mold optical parts with higher precision and lower flow residual stress. However, the melt flow process in a closed cavity becomes more complex because of the moving cavity boundary during compression and the nonlinear problems caused by non-Newtonian polymer melt. In this study, a 3D simulation method was developed for injection-compression molding. In this method, arbitrary Lagrangian-Eulerian was introduced to model the moving-boundary flow problem in the compression stage. The non-Newtonian characteristics and compressibility of the polymer melt were considered. The melt flow and pressure distribution in the cavity were investigated by using the proposed simulation method and compared with those of injection molding. Results reveal that the fountain flow effect becomes significant when the cavity thickness increases during compression. The back flow also plays an important role in the flow pattern and redistribution of cavity pressure. The discrepancy in pressures at different points along the flow path is complicated rather than monotonically decreased in injection molding.

关键词: injection-compression molding     simulation     injection molding     melt flow     cavity pressure    

Real-world fuel consumption of light-duty passenger vehicles using on-board diagnostic (OBD) systems

Xuan Zheng, Sheng Lu, Liuhanzi Yang, Min Yan, Guangyi Xu, Xiaomeng Wu, Lixin Fu, Ye Wu

《环境科学与工程前沿(英文)》 2020年 第14卷 第2期 doi: 10.1007/s11783-019-1212-6

摘要: • Fuel consumption (FC) from LDPVs is measured using on-board diagnostic method (OBD). • The FC of the OBD is 7.1% lower than that of the carbon balance results. • The discrepancy between the approved FC and real-world FC is 13%±18%. • There is a strong relationship (R2=0.984) between the average speed and relative FC. An increasing discrepancy between real-world and type-approval fuel consumption for light-duty passenger vehicles (LDPVs) has been reported by several studies. Normally, real-world fuel consumption is measured primarily by a portable emission measurement system. The on-board diagnostic (OBD) approach, which is flexible and offers high-resolution data collection, is a promising fuel consumption monitoring method. Three LDPVs were tested with a laboratory dynamometer based on a type-approval cycle, the New European Driving Cycle (NEDC). Fuel consumption was measured by the OBD and constant-volume sampling system (CVS, a regulatory method) to verify the accuracy of the OBD values. The results of the OBD method and the regulatory carbon balance method exhibited a strong linear correlation (e.g., R2 = 0.906-0.977). Compared with the carbon balance results, the fuel consumption results using the OBD were 7.1%±4.3% lower on average. Furthermore, the real-world fuel consumption of six LDPVs was tested in Beijing using the OBD. The results showed that the normalized NEDC real-world fuel consumption of the tested vehicles was 13%±17% higher than the type-approval-based fuel consumption. Because the OBD values are lower than the actual fuel consumption, using a carbon balance method may result in a larger discrepancy between real-word and type-approval fuel consumption. By means of the operating mode binning and micro trip methods, a strong relationship (R2 = 0.984) was established between the average speed and relative fuel consumption. For congested roads (average vehicle speed less than 25 km/h), the fuel consumption of LDPVs is highly sensitive to changes in average speed.

关键词: Fuel consumption     Light-duty passenger vehicles     On-board diagnostic systems    

density measurement for plastic injection molding via ultrasonic technology

《机械工程前沿(英文)》 2022年 第17卷 第4期 doi: 10.1007/s11465-022-0714-2

摘要: Density variation during the injection molding process directly reflects the state of plastic melt and contains valuable information for process monitoring and optimization. Therefore, in-situ density measurement is of great interest and has significant application value. The existing methods, such as pressure−volume−temperature (PVT) method, have the shortages of time-delay and high cost of sensors. This study is the first to propose an in-situ density measurement method using ultrasonic technology. The analyses of the time-domain and frequency-domain signals are combined in the proposed method. The ultrasonic velocity is obtained from the time-domain signals, and the acoustic impedance is computed through a full-spectral analysis of the frequency-domain signals. Experiments with different process conditions are conducted, including different melt temperature, injection speed, material, and mold structure. Results show that the proposed method has good agreement with the PVT method. The proposed method has the advantages of in-situ measurement, non-destructive, high accuracy, low cost, and is of great application value for the injection molding industry.

关键词: ultrasonic measurement     melt density     in-situ measurement     injection molding    

凝析气藏的经济开采模式

刘廷元

《中国工程科学》 2001年 第3卷 第3期   页码 85-91

摘要:

液态凝析油是凝析气藏的重要产品,它的开采应该是有效而经济的。介绍了国外近20 a来在凝析气藏开采技术领域的各种经济模式,包括回注φd=75%干气、自流回注、注N2、注水、水气交替注和注CO2等开采模式。研究结果表明,这些开采模式同传统的降压开采方法相比,能够有效地适应地面-地下的各种复杂情况。

关键词: 凝析气藏     开采模式     注气     注氮     注水     注二氧化碳     经济    

Trend prediction technology of condition maintenance for large water injection units

Xiaoli XU, Sanpeng DENG

《机械工程前沿(英文)》 2010年 第5卷 第2期   页码 171-175 doi: 10.1007/s11465-009-0091-0

摘要: Trend prediction technology is the key technology to achieve condition-based maintenance of mechanical equipment. Large-sized water injection units are key equipment in oilfields. The traditional preventive maintenance is not economical and cannot completely avoid vicious accidents. To ensure the normal operation of units and save maintenance costs, trend prediction technology is studied to achieve condition-based maintenance for water injection units. The main methods of the technology are given, the trend prediction method based on neural network is put forward, and the expert system based on the knowledge is developed. The industrial site verification shows that the proposed trend prediction technology can reflect the operating condition trend change of the water injection units and provide technical means to achieve condition-based predictive maintenance.

关键词: water injection units     condition-based maintenance     trend prediction    

标题 作者 时间 类型 操作

A methodology for regulating fuel stratification and improving fuel economy of GCI mode via double main-injection

期刊论文

Emission components characteristics of a bi-fuel vehicle at idling condition

Sameh M. METWALLEY, Shawki A. ABOUEL-SEOUD, Abdelfattah M. FARAHAT

期刊论文

Numerical simulation of biodiesel fuel combustion and emission characteristics in a direct injection

Yi REN, Ehab ABU-RAMADAN, Xianguo LI,

期刊论文

A new approach for fuel injection into a solar receiver/reactor: Numerical and experimental investigation

M Helal Uddin, Nesrin Ozalp, Jens Heylen, Cedric Ophoff

期刊论文

Effects of Fischer-Tropsch diesel fuel on combustion and emissions of direct injection diesel engine

HUANG Yongcheng, WANG Shangxue, ZHOU Longbao

期刊论文

Effect of distributions of fuel concentration and temperature on ignition processes in a diesel PCCI

Yang YU, Wanhua SU,

期刊论文

Dimethyl ether as alternative fuel for CI engine and vehicle

Zhen HUANG , Xinqi QIAO , Wugao ZHANG , Junhua WU , Junjun ZHANG ,

期刊论文

Significant potential of Solid Oxide Fuel Cell systems for distributed power generation and carbon neutrality

期刊论文

Fuel poverty and low carbon emissions: a comparative study of the feasibility of the hybrid renewableenergy systems incorporating combined heat and power technology

期刊论文

喷射策略对低负荷下天然气——柴油双燃料预混压燃燃烧的影响研究

Hyunwook Park, Euijoon Shim, Choongsik Bae

期刊论文

Three-dimensional numerical simulation for plastic injection-compression molding

Yun ZHANG, Wenjie YU, Junjie LIANG, Jianlin LANG, Dequn LI

期刊论文

Real-world fuel consumption of light-duty passenger vehicles using on-board diagnostic (OBD) systems

Xuan Zheng, Sheng Lu, Liuhanzi Yang, Min Yan, Guangyi Xu, Xiaomeng Wu, Lixin Fu, Ye Wu

期刊论文

density measurement for plastic injection molding via ultrasonic technology

期刊论文

凝析气藏的经济开采模式

刘廷元

期刊论文

Trend prediction technology of condition maintenance for large water injection units

Xiaoli XU, Sanpeng DENG

期刊论文