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Viewing 1 to 30 of 11517
2018-05-15
Event
2018-01-16
Event
2017-10-08
Technical Paper
2017-01-2229
Byeongsoek Lee, Heechang Oh, SeungKook Han, SooHyung Woo, JinWook Son
There are two way to improve engine thermal efficiency. One is to improve the theoretical thermal efficiency by increasing the compression ratio and specific heat ratio. The other is to reduce various engine losses like friction, pumping, heat loss. For the development of Ultra High Efficiency, We designed the new 2.0L NA GDI engine based on HMC's Nu 2.0L GDI engine. We conducted various parameter studies related to gasoline combustion characteristic, such as compression ratio, ignition system, intake port design, cam duration, Cooled EGR, etc. As a result, we achieved the maximum thermal efficiency up to 42%(~200g/kWh) in stoichiometric AFR. This paper described the ways and possibilities to improve the maximum thermal efficiency.
2017-10-08
Technical Paper
2017-01-2204
Hoon Lee, Kwangwoo Jeong, Sanghoon Yoo, Byungho Lee, Sejun Kim
Hyundai Motor Company recently developed a multi-way, electrical coolant valve for engine thermal management module. The main purposes of the system that replaces a mechanical thermostat are to boost fuel economy by accelerating warm-up and to enhance thermal efficiency by actively controlling engine operating temperature. The electrical valve controls the amount of coolant flow to components such as oil heat exchanger, heater core, and radiator, while providing separate cooling for engine block and head. The coolant flow is modulated by varying the valve angle actuated with an electric motor. The system operates under a thermal management strategy that consists of multiple phases including zero coolant flow mode, and for those phases that require coolant temperature control, a feedback algorithm is designed for the flow control.
2017-10-08
Technical Paper
2017-01-2196
Giuseppe Cicalese, Fabio Berni, Stefano Fontanesi, Alessandro D'Adamo, Enrico Andreoli
High performance Diesel engines are characterized by remarkable thermo-mechanical loads. Therefore, compared to spark ignition engines, designers are forced to increase component strength in order to avoid failures. By the way, 3D-CFD simulations represent a powerful tool for the evaluation of the engine thermal field and may be used by designers, along with FEM analysis, to prevent thermo-mechanical failures. The current work aims at providing an integrated in-cylinder/CHT methodology for the estimation of a Diesel engine thermal field. On one hand, in-cylinder simulations are fundamental to evaluate not only the global heat transfer at the combustion chamber walls, but also its point-wise distribution. In particular, thanks to an improved heat transfer model based on a modified thermal wall function, wall heat fluxes due to combustion are correctly estimated.
2017-10-08
Technical Paper
2017-01-2222
ZhenYang Liu, Xihui Wang
The ever increasing popularity of electric vehicles and demand in passengers comfort and safe requirements of vehicle have led more efficient heat pump air conditioning system to an indispensable device in electric vehicle. Many studies have shown that the addition of nano particles contributes to improving the thermal conductivity of nano fluids more than that of conventional refrigerants. Therefore, the appliance of the magnetic nano-refrigerant in heat pump air conditioning system has great potential to improve the heat transfer efficiency. This paper aims at studying the magnetic nano-refrigerant comprised of the magnetic nano powder Fe3O4 and refrigerant R134a.According to the relevant theoretical analysis and different empirical formula, the heat transfer coefficient, density, viscosity, and other physical parameters are calculated approximately.
2017-10-08
Technical Paper
2017-01-2381
Kristian Hentelä, Ossi Kaario, Vikram Garaniya, Laurie Goldsworthy, Martti Larmi
In the present study, a new approach for modelling emissions of coke particles or cenospheres from large diesel engines using HFO (Heavy fuel oil) was studied. The used model is based on a multicomponent droplet mass transfer and properties model that uses a continuous thermodynamics approach to model the complex composition of the HFO fuel and the resulting evaporation behavior of the fuel droplets. Cenospheres are modelled as the residue left in the fuel droplets towards the end of the simulation. The mass-transfer and fuel properties models were implemented into a cylinder section model based on the Wärtsilä W20 engine in the CFD-code Star CD v.4.24. Different submodels and corresponding parameters were tuned to match experimental data of cylinder pressures available from Wärtsilä for the studied cases. The results obtained from the present model were compared to experimental results found in the literature.
2017-10-08
Technical Paper
2017-01-2408
Lei Zhou, Hongxing Zhang, Zhenfeng Zhao, Fujun Zhang
The Opposed Piston Two-Stroke (OPTS) engine has several advantages for power density, fuel tolerance, fuel efficiency and package space. A new type of balanced opposed-piston folded-crank train two-stroke engine for Unmanned Aerial Vehicle (UAV) was studied in this paper. The effects of high altitude environment on engine performance and emissions are investigated by thermodynamic simulation. Moreover, the matching between the engine and turbocharger was designed and optimized for different altitude levels. The results indicate that a suitable turbocharger for OPTS engine can achieve the purpose of improving the quality of scavenging, lowering the fuel consumption and recovering power at high altitude environment. Finally, an optimized OPTS engine model especially for UAV is proposed in this research.
2017-10-08
Technical Paper
2017-01-2442
Bingqing Xiao, Wei Wu, Jibin Hu, Shihua Yuan, Chenhui Hu
The prediction of temperature distribution and variation of oil-cooled sliding disk pair is essential for the design of wet clutches and brakes in vehicle transmission system. A heat transfer model is established in the study and some fluid-solid coupled heat transfer simulations are performed to investigate the thermal behaviors of wet clutch during sliding. Both cooling liquid and grooved solid disks are contained in the heat transfer model and the heat convection due to the cooling liquid in the radial grooves is also considered by fluid-solid coupled transient heat transfer simulations. The temperature distribution and variation of the grooved disk are discussed and analyzed in detail. The results indicate that the temperature distribution on the grooved disk is nonuniform. The temperature within the middle radius area is higher than that in the inner and outer radius area. The outer radius temperature is higher than the inner radius temperature at the contact face.
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