Liu L.,Tianjin University |
Li Z.-J.,Tianjin University |
Yue D.-P.,Tianjin University of Technology and Education |
Zhang Y.,Tianjin University |
Ma X.-Q.,Tianjin Internal Combustion Engine Research Institute
Kung Cheng Je Wu Li Hsueh Pao/Journal of Engineering Thermophysics | Year: 2013
A comparative analysis of the effect of sole EGR, sole LNT and EGR-LNT coupling system on NOx emission control is conducted in a lean-burn gasoline engine. Results show that, in the case of sole EGR, unstable operation do not occur until EGR rate is higher than 30%, and there is a significant effect of NOx reduction when EGR rate ranges between 15% and 30%. In the case of sole LNT, its NOx conversion efficiency can be stably maintained at about 89.3%. In the case of EGR-LNT coupling system, the coupling of that two technologies can make the system achieve the best effect of NOx reduction when EGR ranges between 10% and 20%. Compared with sole EGR and sole LNT, EGR-LNT coupling system has the potential to achieve both low NOx emission and low cost.
Zhang J.,Tianjin University |
Gao H.,Tianjin University |
Gao H.,Tianjin Internal Combustion Engine Research Institute |
Ni G.,Tianjin University
Chinese Journal of Mechanical Engineering (English Edition) | Year: 2011
Currently the extruded effect, roughness to the lubricant shear thinning, temperature changes and other factors or some combination of a single factor mainly considered in the lubrication study of piston ring-cylinder. In the study of the energy equation, the oil viscosity-temperature properties, adsorption layer characteristics are usually not considered. So the theoretical research is different from the actual situation of engineering. The lubrication of piston ring-cylinder liner system in internal combustion (IC) engines is studied here based on the theory of thermal flow. An unsteady and compressible hydrodynamic lubrication model with an equivalent viscosity based on shear and extruded flow factor is derived by employing the viscosity-temperature relationship, meanwhile, characteristics such as lubricating oil's density varying with pressure and temperature, thickness of adsorbent layer and oil film's geometry are also considered in this model. While setting up the energy equation, the effect of lubricating oil's volume expansion and viscous dissipation on temperature, the heat conduction along oil film's thickness direction are considered. Finite difference equation is formed by using a first-order difference scheme in time scale and second-order difference scheme in space scale. A common diesel engine is introduced as an instance to predict the distribution of the minimum oil film thickness in the piston ring-cylinder liner system. The results of simulation calculation show that the minimum oil film thickness will decrease especially around the top dead center when the oil's volume expansion, viscous dissipation and heat conduction are considered, which implies that: it is essential to take the thermal flow idea into account during investigating piston ring-cylinder liner system's lubrication. A more complete piston ring-cylinder liner lubrication theory was established according to thermal fluids from the perspective of research. It is more helpful to guide the practical application of engineering to improve the accuracy of forecasting the minimum film thickness. On the other hand, distribution of the minimum oil film thickness shows a nonlinear property if the thickness of piston rings and cylinder liner adsorbent layer are involved in the analysis. It may be feasible to increase the minimum oil film thickness by varying surface roughness and material properties of piston rings and cylinder liner. © 2011 Chinese Journal of Mechanical Engineering.
Li X.,Tianjin University |
Shu G.,Tianjin University |
Tian H.,Tianjin University |
Wei H.,Tianjin University |
Huang H.,Tianjin Internal Combustion Engine Research Institute
Proceedings of the 26th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, ECOS 2013 | Year: 2013
The application of Organic Rankine Cycle (ORC) has been growing in the field of utilization of waste heat from engine exhaust gases. Feasibility study has been carried out on exhaust heat recovery from diesel engine using supercritical power cycle in present work. Supercritical power cycle has several significant advantages in the heat recovery of engine exhaust, including lower exergy destruction rate and higher thermal efficiency and enthalpy drop compared with subcritical process. Parameters optimization of ORC systems are performed with pentane as working fluid in terms of ten indicators. All optimum indicators appear at supercritical stage, showing great advantage of supercritical power cycle in waste heat recovery of engine exhaust gases. Maximum improvement of brake fuel consumption rate (BSFC) and maximum thermal efficiency of combined system of diesel engine with bottoming ORC (E-ORC) are 8.1 % and 45.5 % respectively, which exhibit significant improvement of E-ORC combined system compared with the original engine.
Sun C.,Tianjin University |
Du Q.,Tianjin University |
Yin Y.,Tianjin University |
Jia B.,Tianjin Internal Combustion Engine Research Institute
Advanced Materials Research | Year: 2013
The performance of proton exchange membrane fuel cell is greatly influenced by the presence, distribution and transport of liquid water in the gas diffusion layer (GDL). In this study, air-water flow in a 3D GDL microstructure along the in-plane direction is studied numerically by using the volume of fluid (VOF) method. The GDL microstructure is considered initially filled with water, air flows into the structure under the driving force of a set pressure drop and the flow is supported by the capillary pressure due to the hydrophobic nature of the GDL structure. It is found that water removal can be accelerated by improving pressure drop. Pressure drop has little influence on the state-steady water volume fraction when the pressure drop is over a critical value. © (2013) Trans Tech Publications, Switzerland.
Sun Y.,Tianjin Internal Combustion Engine Research Institute |
Sun Y.,Tianjin University |
Lu H.,Tianjin University |
Yang W.,Shijiazhuang Bearing Equipment Company Ltd |
Li G.,Shijiazhuang Bearing Equipment Company Ltd
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2011
TI worm gearing consists of involute helical gear and its enveloping hourglass worm. According to the previous research result of the parameter choice method of the worm gearing design, the design parameters for TI worm gearing are given. By utilizing a grinding wheel dresser and a special grinding head, the grinding process for TI worm tooth surface is realized on gear-hobbing machine. The hardened TI worm gearbox reducer is made with steel wheel teeth. Experimental research for testing transmission performance is carried out with two kinds of industrial lubricating oil. The input and output torques, box oil temperature, driving time and box vibration are measured. The worm transmission efficiency and its effect factors are analyzed. Test results show that the TI worm gearing reducer with hardened teeth has good transmission performance while the load is in low condition, the tooth friction wear becomes severe and transmission stability declines with the increase of load, and the lubricating oil with extreme pressure additive has good lubricating effect on the hardened TI worm gearing. © 2011 Journal of Mechanical Engineering.
Sun B.,Tianjin University |
He L.,Peiyang Chemical Equipment Co. |
Liu B.T.,Tianjin University |
Gu F.,Tianjin Internal Combustion Engine Research Institute |
Liu C.J.,Tianjin University
AIChE Journal | Year: 2013
A multi-scale approach with the combination of computational fluid dynamic (CFD) and macroscopic calculation methods has been proposed to predict the hydrodynamics behavior in the corrugated structured packing column. On the basis of the concept of the representative unit, the three-dimensional (3-D) volume of fluid (VOF) model of the structured packing is applied in the small scale simulation, and the stream split fraction coefficients and effective wetted area ratio are calculated. The unit network model, which is a mechanistic model, is applied in large scale calculation basing on the small scale results. The liquid holdup distribution in the entire column can be available by this multi-scale method. A comparison between the simulation results and the experimental data of our previous work is given to validate the present model. The multi-scale model is proved to be prospective to assist the analysis and design of structure packing columns in chemical engineering. © 2013 American Institute of Chemical Engineers.
Chen X.,Tianjin University |
Jia B.,Tianjin University |
Jia B.,Tianjin Internal Combustion Engine Research Institute |
Yin Y.,Tianjin University |
Du Q.,Tianjin University
Advanced Materials Research | Year: 2013
High temperature proton exchange membrane fuel cells (HT-PEMFCs) have been drawing much attention due to their easy water management and other advantages. A three-dimensional non-isothermal transient model of HT-PEMFCs with phosphoric acid doped polybenzimidazole (PBI) membrane is developed in this study. The inlet relative humidity (RH) is considered for the membrane conductivity in the model. The effect of inlet RH on the transient response of the cell is discussed and the results show that the increase of inlet RH had positive effect on cell performance but negative effect on transient response. © (2013) Trans Tech Publications, Switzerland.
Ling L.,Tianjin Internal Combustion Engine Research Institute |
Wang C.-Y.,China Automotive Technology and Research Center |
Gao J.-H.,China Automotive Technology and Research Center
Neiranji Gongcheng/Chinese Internal Combustion Engine Engineering | Year: 2014
A China-Vdiesel engine was tested in the CVS bench according to ESC and ETC to measure its load characteristics and full load speed characteristics fueled with State III, IV and V diesel oil respectively. Results show that on the full load speed characteristics, max. power of State V is less than other fuels. With fuel quality drop, NOx and PM emissions under ESC and ETC increase. Through extracting and chemical analysis for PM emissioms in the ESC and ETC, it is concluded that the latter PAHs value is 2~3 times for the former and the PAHs emissions of State III diesel is far more than state IV and V diesels in any conditions. ©, 2014, Chinese Society for Internal Combustion Engines. All right reserved.
Wang X.,Tianjin Internal Combustion Engine Research Institute |
Xia S.,Tianjin Internal Combustion Engine Research Institute
Xitong Fangzhen Xuebao / Journal of System Simulation | Year: 2014
In the concept confirmation phase, the performance of 1. 6L engine was evaluated by means of thermodynamic simulation using the GT-power and Optimus software. The multi_objective analysis with regard to torque targets was done at different engine speed about full load with four parameters, the tube length of intake manifold, intake cam profile, exhaust cam profile, exhaust cam installation timing. At the same time the valve timing of intake VVT was calculated by optimizer tool. The best performances were obtained fast, which gave the base of the development target and gave the theoretic function for the next work of performance development test and mechanical development test. Multi_objective optimization software used for engine development is fast and cost saving. ©, 2014, Chinese Association for System Simulation. All right reserved.
Ni H.,Nankai University |
Sun L.X.,Tianjin Internal Combustion Engine Research Institute |
Zhang Z.X.,Tianjin Internal Combustion Engine Research Institute
Applied Mechanics and Materials | Year: 2013
Based on 3D digital model of motorcycle constructed in UGNX, motorcycle multi-body model was established for dynamic behavior analysis under inbuilt assembling of coefficient matrix of dynamical equation in computation code of ADAMS. Through the comparison of simulation analysis for dynamics of different models in accelerations in time and frequency domains, it is concluded that realistic multi-body model better represents the dynamic behavior of motorcycle while simplified one with less physical parameters only provides qualitative analysis for the dynamic behavior. The simulation results shows that model IV with accurate parameters of components influences the dynamic response of frame, simplified models could not represent the influence of mass and inertia moment of subsystems on dynamic behavior, which means advanced motorcycle multi-body improves simulation effectiveness and approximates the dynamic behavior of motorcycle well so that the simulation developed to replace experiments in bad working conditions will promote the advancement of engineering. © (2013) Trans Tech Publications, Switzerland.