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Deng Y.,Huazhong University of Science and Technology | Deng Y.,Wuhan University of Technology | Huang R.,Huazhong University of Science and Technology | Cheng W.,Dongfeng Commercial Vehicle Technical Center
2011 International Conference on Electric Information and Control Engineering, ICEICE 2011 - Proceedings

Thermal balance of the LNG (liquefied natural gas) engine were tested on overall conditions at four different coolant temperatures, which were set at 60 °C, 70 °C, 80 °C and 90 °C in the tests. The testing results show that coolant temperatures have influence on the heat distribution of the LNG engine. As coolant temperature climbs, proportion of useful power increases and less proportion of heat are taken away by coolant, resulting better fuel economy but more NOx emission. The coolant temperature influences HC and CO emissions, although in unobvious ways. © 2011 IEEE. Source

Hua S.,Huazhong University of Science and Technology | Huang R.,Huazhong University of Science and Technology | Li Z.,Dongfeng Commercial Vehicle Technical Center | Zhou P.,Huazhong University of Science and Technology
Applied Thermal Engineering

Subcooled boiling is an effective heat transfer form for modern engine cooling systems. The significantly higher heat transfer rate achievable with boiling can keep the temperature in key thermal areas within an acceptable level and optimize thermal management strategies even at high engine loads. In this study, an experimental setup was designed using cast iron as heating block to simulate the flow boiling in engine cooling passage. The heat transfer characteristics were obtained under comprehensive cooling conditions for an engine, where the inlet temperature ranges from 75 to 95°C, the system pressure ranges from 100 to 300 kPa, and the flow velocity ranges from 0.2 to 2.0 m/s. The experimental results were used to verify the wall heat flux of subcooled flow boiling in the cooling system of diesel engine, which was predicted by three types of empirical boiling models with primitive parameters. The results indicate that the prediction models are not accurate. Based on the experimental results and Franz's correlation, a modified boiling model was developed to adapt to the cast iron heating surface status. © 2014 Elsevier Ltd. All rights reserved. Source

Wei S.-L.,Jiangsu University | Wang F.-H.,Jiangsu University | Chen H.,Dongfeng Commercial Vehicle Technical Center | Leng X.-Y.,Jiangsu University
Binggong Xuebao/Acta Armamentarii

A double ω-combustion chamber matched with a double-row nozzle hole combustion system is proposed to improve the spray spatial distribution and the mixture formation quality for diesel engines. The in-cylinder spray, mixture formation and combustion process of the new combustion system are simulated and investigated by using AVL FIRE software. The effects of nozzle hole distribution on the fuel/air equivalence ratio, temperature field and emission characteristics in the chamber are analyzed by changing the spatial distribution of nozzle hole. The results show that the mixture formation quality can be effectively improved by increasing the number of nozzle holes in the upper row, and moreover, the combustion process can be improved. With the spatial distribution of 5 nozzle holes in the upper row and 3 nozzle holes in the lower row, NOx and Soot emissions can be reduced. ©, 2015, China Ordnance Society. All right reserved. Source

Fang C.,Tsinghua University | Gao G.-J.,Tsinghua University | Yang F.-Y.,Tsinghua University | Xiang X.-S.,Dongfeng Commercial Vehicle Technical Center | Li J.,Changzhou ECTEK Automotive System Co.
Neiranji Gongcheng/Chinese Internal Combustion Engine Engineering

Based on MPC5644A microcontroller, a new in-cylinder combustion analysis unit was developed. The unit took cylinder pressure signal once every 0.2°CA, and calculate combustion indexes according to the pressure and its position information cycle by cycle. Verification test in a 4.75 L common rail diesel engine demonstrates that the unit successfully acquires the real-time information and provides the combustion indexes, such as instantaneous and integrated heat release rate, IMEP, CA50, etc., satisfying the control requirements of diesel engine. Source

Xu X.,Petrochina | Sun S.,Dongfeng Commercial Vehicle Technical Center | Wang P.,Petrochina | Lei A.,Petrochina | Peng G.,Dongfeng Commercial Vehicle Technical Center
Tribology Online

This paper investigates the friction and wear properties of the fresh and soot-contaminated API CF-4 and CI-4 diesel engine oil using the SRV4 tribometer. It was found that the comprehensive wear properties of CI-4 oil was better than those of the CF-4 oil. Tests of the fresh and contaminated CF-4 oil in combination with two types of rings of different surface treatment showed discriminations, and these discriminations also reflected on the CF-4 oil tests with test rings of different surface coatings. Copyright © 2015 Japanese Society of Tribologists. Source

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