To set up the dynamic FEM model of a high-duty diesel's lower crankcase with sufficient precision, modal correlation research on tested and calculated modes have been fulfilled. MACs between each mode pairs, CoMAC...To set up the dynamic FEM model of a high-duty diesel's lower crankcase with sufficient precision, modal correlation research on tested and calculated modes have been fulfilled. MACs between each mode pairs, CoMACs and ECoMACs on each node of modal testing model have been calculated. On the assistant of modal shape comparison, MACs could afford information about correlating relations between tested and calculated mode groups. CoMACs and ECoMACs have pointed out the direction of structure modification to FEM model. The results of the study show that the analytic model built has a certain degree of accuracy.展开更多
The Positive Crankcase Ventilation (PCV) system in a car engine is designed to lower the pressure in the crankcase, which otherwise could lead to oil leaks and seal damage. The rotation of crankshaft in the crankcase ...The Positive Crankcase Ventilation (PCV) system in a car engine is designed to lower the pressure in the crankcase, which otherwise could lead to oil leaks and seal damage. The rotation of crankshaft in the crankcase causes the churn up of oil which conducts to occurrence of oil droplets which in turn may end in the PCV exhaust air intended to be re-injected in the engine admission. The oil catch can (OCC) is a device designed to trap these oil droplets, allowing the air to escape from the crankcase with the lowest content of oil as possible and thus, reducing the generation and emission of extra pollutants during the combustion of the air-fuel mixture. The main purpose of this paper is to optimize the design of a typical OCC used in many commercial cars by varying the length of its inner tube and the relative position of the outlet from radial to tangential fitting to the can body. For this purpose, CFD parametric analysis is performed to compute a one-way coupled Lagrangian-Eulerian two-phase flow simulation of the engine oil droplets driven by the air flow stream running through the device. The study was performed using the finite volume method with second-order spatial discretization scheme on governing equations in the Solid Works-EFD CFD platform. The turbulence was modelled using the k-? model with wall functions. Numerical results have proved that maximum efficiency is obtained for the longest inner tube and the tangential position of the outlet;however, it is recommended further investigation to assess the potential erosion on the bottom of the can under such a design configuration.展开更多
文摘To set up the dynamic FEM model of a high-duty diesel's lower crankcase with sufficient precision, modal correlation research on tested and calculated modes have been fulfilled. MACs between each mode pairs, CoMACs and ECoMACs on each node of modal testing model have been calculated. On the assistant of modal shape comparison, MACs could afford information about correlating relations between tested and calculated mode groups. CoMACs and ECoMACs have pointed out the direction of structure modification to FEM model. The results of the study show that the analytic model built has a certain degree of accuracy.
文摘The Positive Crankcase Ventilation (PCV) system in a car engine is designed to lower the pressure in the crankcase, which otherwise could lead to oil leaks and seal damage. The rotation of crankshaft in the crankcase causes the churn up of oil which conducts to occurrence of oil droplets which in turn may end in the PCV exhaust air intended to be re-injected in the engine admission. The oil catch can (OCC) is a device designed to trap these oil droplets, allowing the air to escape from the crankcase with the lowest content of oil as possible and thus, reducing the generation and emission of extra pollutants during the combustion of the air-fuel mixture. The main purpose of this paper is to optimize the design of a typical OCC used in many commercial cars by varying the length of its inner tube and the relative position of the outlet from radial to tangential fitting to the can body. For this purpose, CFD parametric analysis is performed to compute a one-way coupled Lagrangian-Eulerian two-phase flow simulation of the engine oil droplets driven by the air flow stream running through the device. The study was performed using the finite volume method with second-order spatial discretization scheme on governing equations in the Solid Works-EFD CFD platform. The turbulence was modelled using the k-? model with wall functions. Numerical results have proved that maximum efficiency is obtained for the longest inner tube and the tangential position of the outlet;however, it is recommended further investigation to assess the potential erosion on the bottom of the can under such a design configuration.
