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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 | Year: 2011

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.

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 | Year: 2014

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.

Zhao R.,Tsinghua University | Zhuge W.,Tsinghua University | Zhang Y.,Tsinghua University | Yin Y.,Dongfeng Commercial Vehicle Technical Center | And 2 more authors.
Applied Thermal Engineering | Year: 2014

Turbocompounding is a promising technology to recover waste heat from the exhaust and reduce fuel consumption for internal combustion engine. The design of a power turbine plays a key role in turbocompound engine performance. This paper presents a set of parametric studies of power turbine performed on a turbocompound diesel engine by means of turbine through-flow model developed by the authors. This simulation model was verified and validated using engine performance test data and achieved reasonable accuracy. The paper first analyzed the influence of three key geometrical parameters (blade height, blade radius and nozzle exit blade angle) on turbine expansion ratio and engine fuel consumptions. After that, the impacts of the geometrical parameters on power distribution, air mass flow rate and exhaust temperature were analyzed. Results showed that these parameters had significant effects on engine BSFC and power. At high engine speeds, there existed an optimum value of geometry parameter to obtain the lowest BSFC. At low engine speeds, the engine BSFC kept increasing or decreasing continuously as the geometry parameters changed. Research also found that the engine BSFC was most sensitive to the nozzle exit blade angle, which should be considered carefully during the design process. This paper provides a useful method for matching and designing of a power turbine for turbocompound engine. © 2014 Elsevier Ltd. All rights reserved.

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 | Year: 2015

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.

Hua S.,Huazhong University of Science and Technology | Huang R.,Huazhong University of Science and Technology | Zhou P.,Huazhong University of Science and Technology | Cheng W.,Dongfeng Commercial Vehicle Technical Center | Jia L.,Dongfeng Commercial Vehicle Technical Center
ASME 2015 Internal Combustion Engine Division Fall Technical Conference, ICEF 2015 | Year: 2015

Generally, the turbulent-flame velocity of natural gas is significantly lower than diesel in the combustion process, which results in the thermal loads of natural gas engines being significantly higher than those of diesel engines under the same stoichiometric condition without EGR. In this study, a heavy-duty natural gas engine is taken as the research object, which is used to measure the temperatures to analyze the heat transfer characteristics in the cylinder head water jacket around the valve bridges, under different speeds and loads, as well as different coolant temperatures and pressures. Twelve thermocouples are inserted by drilling through the metal in the cylinder head with different heights to measure the metal temperatures at thermally critical areas such as the valvebridge regions. Therefore, the local heat flux and the extrapolation to coolant wall temperatures are obtained by Fourier's Law under different engine operating conditions. In addition, the thermal balance tests of the engine are also carried out, and the energy distributions are analyzed in different parts of the engine. The results of the research show that: a) the engine cooling condition has a direct impact on the engine cylinder head temperature. If the cooling temperature is low, the temperatures of the cylinder head's measuring points have the same increases as the increasing coolant temperature. When the coolant temperature is high, the measuring temperatures have hardly any difference from the increases in cooling temperature. With increasing cooling pressure, the temperature increase at all measuring points, and the temperature of the measuring points varies substantially under high load conditions compared with the low load condition. The results indirectly indicated that local nucleate boiling appeared in the water jacket. b) The heat transfer characteristic curve of the water jacket was obtained from the processing of experimental data. Wall heat flux increases with increasing load, and the relationship between wall heat flux and wall temperature is no longer linear. The heat transfer characteristic curve indicates that the convective heat transfer and boiling heat transfer both appeared in the cooling water jacket. c) With the decrease of engine load, the percentage of crankshaft power in the combustion heat gradually decreases, then the percentage of the heat taken away by the cooling water increases gradually. At the same time, the percentage of the heat taken away by exhaust has changed little. d) The engine cooling temperature has a substantial influence on the engine thermal balance, and the cooling pressure has little effect on the engine thermal balance. With increasing cooling temperature, the heat taken by the cooling water decreased, which lead to an increase in the proportion of crankshaft power. It can be concluded that properly increasing the coolant temperature of the engine can improve the fuel economy of the machine. Copyright © 2015 by ASME.

Xu X.,Dongfeng Commercial Vehicle Technical Center | Chen W.,Dongfeng Commercial Vehicle Technical Center | Cao Y.,Dongfeng Commercial Vehicle Technical Center | Zhang Y.,Dongfeng Commercial Vehicle Technical Center | Guo H.,Dongfeng Commercial Vehicle Technical Center
SAE Technical Papers | Year: 2016

The stiffness of the frame has a great influence on the ride comfort of the heavy truck. Reducing frame thickness was proved to be unacceptable in terms of ride comfort, which is verified by the testing results. The truck frame was reinforced in order to improve the ride comfort. The modal analysis showed that the pitch frequency of the vehicle has increased 0.5 Hz and the frequency response has decreased by 20%. In order to research the influence of frame stiffness on the heavy truck ride comfort, a detailed model including a flex frame, chassis suspension, cab suspension, driveline, etc., was built by MSC.ADAMS. The Simulation results showed that the ride comfort can be improved by reinforce the frame, and the ride comfort can be improved by 5%∼10%. The results of this study need to be further examined through field testing. © Copyright 2016 SAE International.

Chen W.,Dongfeng Commercial Vehicle Technical Center | Sun Z.,Dongfeng Commercial Vehicle Technical Center | Zheng J.,Dongfeng Commercial Vehicle Technical Center | Pan L.,Dongfeng Commercial Vehicle Technical Center | Yi X.,Dongfeng Commercial Vehicle Technical Center
SAE Technical Papers | Year: 2016

This paper presents the relationship between suspension and steering systems and wheels, and proposes the vehicle dynamics modeling method. A vehicle dynamics model combined with the suspension K&C test data of a concrete vehicle was built based on the method. The simulation results show that the method is correct and feasible, and the dynamics model performed characteristics of the suspension and steering systems with high precision can be used for the followup simulation and optimization. Copyright © 2016 SAE International.

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 | Year: 2015

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.

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 | Year: 2015

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.

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