Energy Science and Technology
Saeed Ahmadipour; Mohammad Hossein Aghkhani; Javad Zareei
Abstract
Start of fuel injection and fuel type are two important factors affecting engine performance and exhaust emissions in internal combustion engines. In the present study, a one-dimensional computational fluid dynamics solution with GT-Power software is used to simulate a six-cylinder diesel engine to study ...
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Start of fuel injection and fuel type are two important factors affecting engine performance and exhaust emissions in internal combustion engines. In the present study, a one-dimensional computational fluid dynamics solution with GT-Power software is used to simulate a six-cylinder diesel engine to study the performance and exhaust emissions with different injection timing and alternative fuels. Starting the fuel injection was from 10 °CA BTDC to the TDC with an interval between two units and from alternative fuel bases (diesel), including methanol, ethanol, diesel, and ethanol compounds, biodiesel and decane was used. To validate the model, a comparison is made between simulation data and experimental data (including torque and power) showing the validation error is less than 6.12% and indicating the software model validation. Also, the modeling results show that decane fuel has higher brake power and brake torque of more than 6.10 % while fuel is injected at 10 °CA BTDC compared to the base fuel, and illustrates a reduction of 5.75 % in specific fuel consumption due to producing higher power. In addition, with the advance of injection timing compared to baseline, the amount of CO and HC in biodiesel fuel reduces to 83.88% and 64.87%, respectively, and the lowest NOX emission with the retardation of starting injection, to decane fuel is awarded. In general, the results show that decane fuel could be a good alternative to diesel fuel in diesel engines when it starts fuel injection at 10 °CA BTDC.
Fluid Mechanics
H. Chamani; H. Karimaei; M. Bahrami; S. M. Agha Mirsalim
Abstract
Nowadays, due to the increasing power of diesel engines, especially heavy duty diesel engines, and increasing gas pressure inside the combustion chamber, the forces acting on the engine bearings have dramatically raised. On the other hand, becaus eof the competition in the market, it is necessary to ...
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Nowadays, due to the increasing power of diesel engines, especially heavy duty diesel engines, and increasing gas pressure inside the combustion chamber, the forces acting on the engine bearings have dramatically raised. On the other hand, becaus eof the competition in the market, it is necessary to increase the engine bearing life and reduce its failure as much as possible. The engine bearings analysis is a vital issue in engine design process as well as other related engineering tasks such as engine power upgrading, reverse designing, and bearing failure analysis. So, many attempts have been made to simulate accurate engine bearings. In this paper, results of a thermo-elasto-hydrodynamic (TEHD) analysis of a connecting rod big end (BE) bearing of a heavy duty diesel engine are presented. Here, the oil film viscosity is considered a function of oil's local temperature and pressure. Effects of flexibility of bearing shell and connecting rod structure are also considered. Therefore, the computed oil film pressure and temperature distributions are relatively precise. In the proposed analytical procedure, at first, elasto-hydrodynamic (EHD) analysis is carried out and the averaged fluid velocity in the bearing is obtained. Then, the averaged heat transfer coefficient between oil film and crank pin is calculated, which is used as an input in TEHD analysis. Results of EHD and TEHD analyses are compared with each other and the main characteristic parameters in bearing design are reported and interpreted.
