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Construction vehicles own some inherent characteristics, such as low velocity, high power and following heavy heat flux et al. Aiming at decreasing flow resistance and managing airflow, a 39 ton single drum road roller from one of the biggest manufactures in China was employed as a research target to seek out the effect of air flow resistance on the performance of its heat dissipation system. For a start, a simplified 3D model of the road roller in a virtual wind tunnel was established with a commercial software, which was pre-processed in Gambit later. The radiators were set with heat exchanger boundary condition based on the analysis on the air-side elementary unit, as for the cooling fan, the experimental results in the wind tunnel were transformed into the corresponding boundary condition.

In this work, a XD132 Road Roller from XCMG in China was employed as a research basis to study the heat exchange performance of the heat dissipation module under varied working conditions. The module in the XD132 consists of a cooling fan and three radiators. At first, the numerical investigation on the elementary units of radiators was performed to obtain Colburn j factor and Fanning friction f factor, which were used for the ε-NTU method to predict the radiator performance. The fan was numerically tested in a wind test tunnel to acquire the performance curve. The performance data from both investigations were transformed into the boundary conditions of the numerical vehicle model in a virtual tunnel. A field experiment was carried out to validate the simulation accuracy, and an entrance coefficient was proposed to discuss the performance regularity under four working conditions.

A transient gas-solid heat transfer model for the 3-D (three-dimensional) coupling components in internal combustion chamber was built. In order to implement this model, a transient heat transfer program based on FEM (finite-element method) was developed, the KIVA3V code was improved, and a KIVA-FEM interface program was developed. A special treatment for the grid generation were designed and utilized. The 3-D transient non-uniform gas temperature field and convective heat transfer coefficient distribution near the combustion chamber wall can be obtained using this heat transfer model. In addition, both steady and transient temperature fields of the 3-D coupling component system of a gasoline engine were calculated and analyzed. The results show that the temporal and spatial non-uniformity of thermal boundary conditions has an important influence on the steady temperature field, transient temperature field and heat flux of the combustion chamber wall.

In this paper, an Electronic Control System (ECS) is designed to manage a 125 cc single-cylinder air-cooled motorcycle engine. The aim of this study was to accomplish low cost, high reliability and mainly meet the motorcycle engine emission standard of China Stage III. The intake port fuel injection mode was chosen with a redesigned part of intake pipe. Gathering information of speed, throttle position (TP), inlet temperature and pressure, cylinder temperature, switch-type exhaust gas oxygen sensor and the battery voltage, an Engine Control Unit (ECU) was devised to calculate fuel injecting pulse width, advance ignition angle and control the working conditions of the fuel pump and the exhaust gas oxygen sensor. Additionally, a three-way catalytic converter (TWC) was used to reduce exhaust gas emissions.

A 3-D numerical analysis model of transient heat transfer among the multi-component coupling system in combustion chamber of internal combustion engine has been developed successfully in the paper. The model includes almost all solid components in combustion chamber, such as piston assembly, cylinder liner, cylinder head gasket, cylinder head, intake valves and exhaust valves, etc. With two different coupling heat transfer modes, one is the lubricant film heat conduction between two moving components, another is the contact heat conduction between two immovable solid components, and with the direct coupled-field analysis method of FEM, the heat transfer relation among the components is established. The simulation result dedicates the transient heat transfer process among the components such as moving piston assembly and cylinder liner, moving valves and cylinder head. The effect of cylinder head gasket on heat transfer among the components is also studied.