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Li W.,Dalian University of Technology | Li W.,Dalian Jiaotong University | Xue D.-X.,Dalian University of Technology | Song X.-G.,Dalian University of Technology | And 2 more authors.
Neiranji Xuebao/Transactions of CSICE (Chinese Society for Internal Combustion Engines) | Year: 2013

By combination of combustion theories, acoustic theories and KIVA algorithm on the basis of the flow field, grid cells in the combustion chamber involving chemical reactions are served as acoustic sources that generate the combustion noise. These sources will produce the acoustic waves during the combustion. Areas around sources were divided into cells inside the acoustic wave and the others outside the acoustic wave according to the range of acoustic wave propagation. Thus, the pressure in combustion chamber can be calculated. The process of pressure oscillations in some positions can be captured. The characteristics of main acoustic sources leading to pressure oscillations were analyzed. Comparison on calculation and experiment shows that the hysteresis effect of acoustic wave propagation needs to be considered in the study of combustion process of IC engines. Source


Li W.,Dalian University of Technology | Li W.,Dalian Jiaotong University | Xue D.,Dalian University of Technology | Song X.,Dalian University of Technology | And 2 more authors.
Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering | Year: 2014

The heat release of a chemical reaction is a major source of combustion noise in internal-combustion engines. The simulation grid cells in the combustion chamber whose heat release changes as the crank angle changes serve as noise sources. These sources produce acoustic waves. By means of combining the acoustic theory and the KIVA program, the regions around the noise sources are divided into the cells inside the acoustic wave and the cells outside the acoustic wave respectively according to the range of acoustic wave propagation. Therefore the pressure of the cells are calculated on the basis of the cells lying in the different regions. The process of pressure oscillations in specific positions can be shown in the results. The characteristics of the main acoustic sources which caused the pressure oscillations can be analysed. On comparing the simulations and the experiments, the hysteresis effect of acoustic wave propagation can be taken into account when studying the combustion process in internal-combustion engines. © IMechE 2014. Source


Li W.,Dalian University of Technology | Li W.,Dalian Jiaotong University | Xue D.-X.,Dalian University of Technology | Song X.-G.,Dalian University of Technology | And 2 more authors.
Neiranji Xuebao/Transactions of CSICE (Chinese Society for Internal Combustion Engines) | Year: 2014

Volume of combustion chamber changes during the operation of an internal combustion engine. Meanwhile, the distribution of combustion sources also changes. High-frequency pressure oscillations are a very complex process. The model of pressure change caused by thermo-acoustic coupling was built by combining KIVA and SYSNOISE. Process of high-frequency pressure oscillations was analyzed quantitatively. Propagation of pressure waves was simulated under various combustion excitation conditions. The simulation results are consistent with the test measurement. The simulation results better demonstrate the process of pressure oscillations in some exact positions of combustion chamber. The characteristics of main acoustic sources were analyzed. Results show that there exists an interaction between heat release and acoustic field in the combustion chamber. Hysteresis effect should be considered during the propagation of pressure waves. Source


Huo J.,Dalian University of Technology | Li T.,Dalian University of Technology | Zhang X.,Dalian University of Technology | Yang J.,Dalian University of Technology | Lu L.,DEUTZ Dalian Engine Company Ltd
Harbin Gongcheng Daxue Xuebao/Journal of Harbin Engineering University | Year: 2014

The four-cylinder U-shaped transmission mechanism is the core component of the output power of the Stirling engine. The rationality of its design is closely related to its operational stability, efficiency and life of the Stirling engine system. Based on the characteristics of the four cylinder U-shaped drive mechanism, this paper built the theoretical model of the dynamic balance analysis of the transmission mechanism in order to get the quality and the phase of the balance weight on the rotation axis. Then the dynamics simulation model of the four-cylinder double-acting Stirling engine transmission mechanism was established through use of the multi-body dynamics simulation platform. In order to get a more realistic simulation of the crankshaft's actual operation conditions, this thesis established the crankshaft equivalent model with the dummy and universal hinge connection method, and the sliding bearing supported equivalent model with the virtual film method. The analysis results indicate that, compared with the original transmission mechanism model, the speed fluctuation coefficients of the output shaft and the crankshaft with the improved model are reduced by 11.5%, 36.8% and 34.4%, respectively; the vibration displacement of the center mass of the output shaft is decreased by 20.0%; the average dynamic load on the airframe is decreased by 23.4%. The feasibility and effectiveness of the improvement program in this thesis has been verified, and as a result it can provide useful information for the design and operation of the Stirling engine's transmission mechanism. Source


Zhang Z.-R.,China Automotive Technology and Research Center | Ji L.-M.,China National Accreditation Service for Conformity Assessment | Zhang Y.,DEUTZ Dalian Engine Company Ltd | Gao J.-H.,China Automotive Technology and Research Center | Wang F.-B.,China Automotive Technology and Research Center
Neiranji Gongcheng/Chinese Internal Combustion Engine Engineering | Year: 2015

Emission characteristics of a China State III diesel engine fueled with five diesel fuels of different AH contents, G5, D1, D2, D3 and D4, were analyzed in various load conditions. PAHs of gaseous phase and particle state were respectively trapped with serial foamed PUF and PTFE fiber filter, and analyzed by GC-MS, especially examining the PAHs emission. Results show that particulate matter (PM) emissions of all diesel fuels exhibit decrease-increase trend with load increase, finally reach max. values at full load. The PAHs emissions exist mainly in gaseous phase, more than 90% of the total. The rest in PM state is less than 10%. Majority of total PAHs is naphthalene and methylnaphthalene, and the PAHs emissions of each fuel depend on its PAHs content. The emitted gaseous phase PAHs are mainly of 2 and 3 benzene rings, and the PM state PAHs mainly of 3 and 4 benzene rings. ©, 2015, Chinese Society for Internal Combustion Engines. All right reserved. Source

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