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Analysis and Mathematical Description of the Ideal Thermotropic Cycle of Internal Combustion Engines
Issue:
Volume 3, Issue 4, August 2018
Pages:
97-102
Received:
25 July 2018
Accepted:
18 September 2018
Published:
29 October 2018
Abstract: A mathematical model of an ideal thermotropic cycle is proposed, which extends the idea of real working processes in the internal combustion engine (ICE). The thermotropic cycle the same for diesel, gasoline and gas ICE, and also provides significantly better correspondense to the real cycles than classical cycles. Heat supply to the cycle is carried out in the form of a combined process "compression-expansion". The combined process consists of two incomplete thermotropic processes and with a high degree of approximation reproduces the laws of real combustion processes in the ICE, from compression to expansion. The mathematical model of the basic thermotropic process is based on the laws of molecular kinetic theory and thermodynamics of ideal gases. The main thermotropic process is based on three fundamental equations of thermodynamics: differential equations of the first law of thermodynamics and the law of heat exchange of the external source of the working medium, as well as the equation of state (Clapeyron). The heat of the process in the thermotropic process, in contrast to the polytropic, is an independent value and takes into account fuel consumption. The equation of the main thermotropic process has additivity, which allows us to consider its parameters as the sum of the adiabatic and thermal components of the process occurring in the gas mixture. An important feature of the thermotropic process is also the variable heat capacity of the process. The gas laws of classical thermodynamics are special cases of a new process. The advantage of the new cycle model is mathematical simplicity. The initial system of equations made it possible to perform precise integration and express the equations of processes and cycles in elementary functions. Precise integration ensured high accuracy of estimation of influencing factors contained in the model and absolute convergence of thermal and material balances of the cycle. A number of elements of the theory of thermotropic processes and cycles can be used to replace isochoric-isobaric-polytropic combustion models in undergraduate and specialist studies. This is facilitated by the absence of the need for complex computer programs that significantly complicate the development of educational material. In General, models with more complex laws of heat supply can be useful for undergraduates and graduate students to pre-evaluate the effectiveness of the proposed project activities to improve the internal combustion engine.
Abstract: A mathematical model of an ideal thermotropic cycle is proposed, which extends the idea of real working processes in the internal combustion engine (ICE). The thermotropic cycle the same for diesel, gasoline and gas ICE, and also provides significantly better correspondense to the real cycles than classical cycles. Heat supply to the cycle is carri...
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High-speed BEV Reducer NVH Performance Optimization and Experimentation
Liu Xianghuan,
Liu Defu,
Sun Yincheng,
Li Chao
Issue:
Volume 3, Issue 4, August 2018
Pages:
103-112
Received:
8 August 2018
Accepted:
4 October 2018
Published:
29 October 2018
Abstract: To solve the common rattle and whine issues in high-speed BEV reducer, this article aims to calculate and analyze the NVH performance of the reducer by using MASTA. By optimizing gear macro geometry and micro geometry to reduce the transmission error of gear pair which plays a decisive role in the common rattle and whine. By using MASTA, import the macro and micro geometry parameters of the gear pairs of the reducer. And using ABAQUS/CAE to preprocessing reducer housing, differential housing etc. and import them to MASTA. And then, assembly those components together to simulate the reducer as precise as possible. The system stiffness matrix and mass matrix are calculated which is strongly concerned to the NVH performance of the reducer. This article analyzed the assembly vibration model by calculating the assembly stiffness matrix and mass matrix and optimized the gear pairs’ parameters to reduce the transmission error of the gear pairs. And compared the optimized reducer with the original reduce in the same conditions, to make sure that the optimization is work. And so get the experience to control the NVH performance from the research. And according to these experiences, instruct engineers to design reducers that meet the harshness requirements of NVH to optimize the performance of speed reducer assembly.
Abstract: To solve the common rattle and whine issues in high-speed BEV reducer, this article aims to calculate and analyze the NVH performance of the reducer by using MASTA. By optimizing gear macro geometry and micro geometry to reduce the transmission error of gear pair which plays a decisive role in the common rattle and whine. By using MASTA, import the...
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Experimental Study on Nail Joint Shearing Properties of Light Frame Wooden Shear Walls
Zhenhua Han,
Weibo Dong,
Boqi Song
Issue:
Volume 3, Issue 4, August 2018
Pages:
113-120
Received:
29 September 2018
Accepted:
22 October 2018
Published:
12 November 2018
Abstract: Shear walls in light wooden frame structure are major components to resist lateral loading. Nail joint is one of the most important factors that affects shear walls shearing properties. In this paper, different nail types, sheathing panel types and thickness and stud grain direction were set to study the influence factors of nail joint properties. Wooden shear walls made of studs with different cross size were monotonic and cyclic loaded to investigate the influence on lateral resistance properties. The failure of nail joint can be classified into three modes that nails bent and withdrawn from the studs, nail heads pulled off from the panels and nails split off along the stud grain. It is concluded from the nail joint loading and displacement results that twist nails get the largest bearing capacity compared with strip nails and coil nails due to the nail diameter and larger friction. Nail joints on China-produced structural plywood obtain the largest shearing resistance values among three different kinds of panels. And thicker panels can bear larger shearing loadings. The largest displacement of the nail joints load parallel to stud grain were larger than those perpendicular to stud grain. It can be derived from the shear wall lateral loading experiments that the lateral resistance of the shear wall could not be strengthened with the larger stud size, while the stiffness and energy capacity could be improved. In this way, the seismic resistance properties of shear walls can be enhanced by optimizing nail joint materials and studs parameters.
Abstract: Shear walls in light wooden frame structure are major components to resist lateral loading. Nail joint is one of the most important factors that affects shear walls shearing properties. In this paper, different nail types, sheathing panel types and thickness and stud grain direction were set to study the influence factors of nail joint properties. ...
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