The fracture of a camshaft made of chilled cast iron, installed in a home-made Fukang car, happened only after running over a distance of 6,200 km. The fractured camshaft was received to conduct a series of failure an...The fracture of a camshaft made of chilled cast iron, installed in a home-made Fukang car, happened only after running over a distance of 6,200 km. The fractured camshaft was received to conduct a series of failure analyses using visual inspection, SEM observation of fracture section, microstructure analysis, chemical composition analysis and hardness examination and so on, while those of CKD camshaft made by Citroen Company in France was also simultaneously analyzed to compare the difference between them. The results showed that the fracture of the camshaft mainly results from white section in macrostructure and Ledeburite in microstructure; the crack in the fractured camshaft should be recognized to initiate at the boundary of coarser needle-like carbide and matrix, and then propagate through the transverse section. At the same tide, the casting defects such as dendritic shrinkage, accumulated inclusion and initiated crack and abnormal external force might stimulate the fracture of camshaft as well. Based on failure analysis, some measures have been employed, and as a result, the fracture of home-made camshafts has been effectively prevented.展开更多
Pressure-flow analytical formulas of lubrication film of slipper pairs on camshaft connecting rod type low speed high torque （LSHT） hydraulic motors are put forward. The bottom surface of slipper pairs is rectangle,...Pressure-flow analytical formulas of lubrication film of slipper pairs on camshaft connecting rod type low speed high torque （LSHT） hydraulic motors are put forward. The bottom surface of slipper pairs is rectangle, and the effect of squeeze flow and pressure differential flow is considered. The dynamic process of lubrication film formation through squeezing is numerically studied by computer simulation. Effects of supply pressure, initial lubrication film thickness, velocity damping coefficient, loading impact and gravity, etc are studied. Advantages of novel slipper pairs with large oil cavity area are pointed out.展开更多
A continuously variable displacement mechanism, which is composed of a hydraulic control valve with mechanical-positional feedback to camshaft, was designed for changing the displacement of traditional camshaft connec...A continuously variable displacement mechanism, which is composed of a hydraulic control valve with mechanical-positional feedback to camshaft, was designed for changing the displacement of traditional camshaft connecting-rod low speed high torque (LSHT) hydraulic motor continuously. The new type of continuously variable displacement mechanism is simple and easy to be made. The structure and principle of a continuously variable displacement mechanism was introduced. The mathematic model of the continuously variable displacement mechanism was set up and its static and dynamic characteristics were analyzed with the help of computer simulation. It can be seen that the cam ring on camshaft of the traditional LSHT hydraulic motor can stop at any position between minimum and maximum eccentricity, according to an input fluid pressure signal. And it can also stay anywhere stably through self-adjusting. Besides, it can work stabilized when load impact or oil leakage exists.展开更多
Inoculation can reduce the chill depth of a chilled iron,and therefore influence the microstructure and properties of the iron.In this paper,the effect of rare earth Lanthanun (La) on the microstructure and properties...Inoculation can reduce the chill depth of a chilled iron,and therefore influence the microstructure and properties of the iron.In this paper,the effect of rare earth Lanthanun (La) on the microstructure and properties of a chilled iron camshaft was studied.The results show that the La addition efficiently enhances the mechanical properties,yet with the unfavorable effect of decreasing the chilled depth and hardness.Moreover,La promotes graphite concentration and results in large graphite size,as well as A-type graphite.It is also found that excessive La destroys the interconnection and directivity of ledeburite.According to the experimental results,the optimum adding content of La should be no more than 0.02wt.%.展开更多
Based on the analysis of the piston engine camshatt common failure mode, combining the mechanical analysis and risk management means, the feasibility of its repair was much discussed, the repair technique are studied,...Based on the analysis of the piston engine camshatt common failure mode, combining the mechanical analysis and risk management means, the feasibility of its repair was much discussed, the repair technique are studied, and proved its correctness and effectiveness.展开更多
Automobiles evolved from primarily mechanical to electro-mechanical,or mechatronic,vehicles.For example,carburetors have been replaced by fuel injection and air-fuel ratio control,leading to order of magnitude improve...Automobiles evolved from primarily mechanical to electro-mechanical,or mechatronic,vehicles.For example,carburetors have been replaced by fuel injection and air-fuel ratio control,leading to order of magnitude improvements in fuel economy and emissions.Mechatronic systems are pervasive in modem automobiles and represent a synergistic integration of mechanics,electronics and computer science.They are smart systems,whose design is more challenging than the separate design of their mechanical,electronic and computer/control components.In this review paper,two recent methods for the design of mechatronic components are summarized and their applications to problems in automotive control are highlighted.First,the combined design,or co-design,of a smart artifact and its controller is considered.It is shown that the combined design of an artifact and its controller can lead to improved performance compared to sequential design.The coupling between the artifact and controller design problems is quantified,and methods for co-design are presented.The control proxy function method,which provides ease of design as in the sequential approach and approximates the performance of the co-design approach,is highlighted with application to the design of a passive/active automotive suspension.Second,the design for component swapping modularity(CSM)of a distributed controller for a smart product is discussed.CSM is realized by employing distributed controllers residing in networked smart components,with bidirectional communication over the network.Approaches to CSM design are presented,as well as applications of the method to a variable-cam-timing engine,and to enable battery swapping in a plug-in hybrid electric vehicle.展开更多
基金supported financially by the postdoctoral foundation from Yituo Group Co.,Ltd.,Chinathe doctoral foundation from Henan Polytechnic University,Henan,China.
文摘The fracture of a camshaft made of chilled cast iron, installed in a home-made Fukang car, happened only after running over a distance of 6,200 km. The fractured camshaft was received to conduct a series of failure analyses using visual inspection, SEM observation of fracture section, microstructure analysis, chemical composition analysis and hardness examination and so on, while those of CKD camshaft made by Citroen Company in France was also simultaneously analyzed to compare the difference between them. The results showed that the fracture of the camshaft mainly results from white section in macrostructure and Ledeburite in microstructure; the crack in the fractured camshaft should be recognized to initiate at the boundary of coarser needle-like carbide and matrix, and then propagate through the transverse section. At the same tide, the casting defects such as dendritic shrinkage, accumulated inclusion and initiated crack and abnormal external force might stimulate the fracture of camshaft as well. Based on failure analysis, some measures have been employed, and as a result, the fracture of home-made camshafts has been effectively prevented.
文摘Pressure-flow analytical formulas of lubrication film of slipper pairs on camshaft connecting rod type low speed high torque （LSHT） hydraulic motors are put forward. The bottom surface of slipper pairs is rectangle, and the effect of squeeze flow and pressure differential flow is considered. The dynamic process of lubrication film formation through squeezing is numerically studied by computer simulation. Effects of supply pressure, initial lubrication film thickness, velocity damping coefficient, loading impact and gravity, etc are studied. Advantages of novel slipper pairs with large oil cavity area are pointed out.
文摘A continuously variable displacement mechanism, which is composed of a hydraulic control valve with mechanical-positional feedback to camshaft, was designed for changing the displacement of traditional camshaft connecting-rod low speed high torque (LSHT) hydraulic motor continuously. The new type of continuously variable displacement mechanism is simple and easy to be made. The structure and principle of a continuously variable displacement mechanism was introduced. The mathematic model of the continuously variable displacement mechanism was set up and its static and dynamic characteristics were analyzed with the help of computer simulation. It can be seen that the cam ring on camshaft of the traditional LSHT hydraulic motor can stop at any position between minimum and maximum eccentricity, according to an input fluid pressure signal. And it can also stay anywhere stably through self-adjusting. Besides, it can work stabilized when load impact or oil leakage exists.
基金supported by the Science and Technology Project of Xi’an,China (grant No.CXY1134WL18)
文摘Inoculation can reduce the chill depth of a chilled iron,and therefore influence the microstructure and properties of the iron.In this paper,the effect of rare earth Lanthanun (La) on the microstructure and properties of a chilled iron camshaft was studied.The results show that the La addition efficiently enhances the mechanical properties,yet with the unfavorable effect of decreasing the chilled depth and hardness.Moreover,La promotes graphite concentration and results in large graphite size,as well as A-type graphite.It is also found that excessive La destroys the interconnection and directivity of ledeburite.According to the experimental results,the optimum adding content of La should be no more than 0.02wt.%.
文摘Based on the analysis of the piston engine camshatt common failure mode, combining the mechanical analysis and risk management means, the feasibility of its repair was much discussed, the repair technique are studied, and proved its correctness and effectiveness.
基金the National Science Foundation,the U.S.A.Army Automotive Research Center,the Ford Motor Company,and United Technologies,Inc.
文摘Automobiles evolved from primarily mechanical to electro-mechanical,or mechatronic,vehicles.For example,carburetors have been replaced by fuel injection and air-fuel ratio control,leading to order of magnitude improvements in fuel economy and emissions.Mechatronic systems are pervasive in modem automobiles and represent a synergistic integration of mechanics,electronics and computer science.They are smart systems,whose design is more challenging than the separate design of their mechanical,electronic and computer/control components.In this review paper,two recent methods for the design of mechatronic components are summarized and their applications to problems in automotive control are highlighted.First,the combined design,or co-design,of a smart artifact and its controller is considered.It is shown that the combined design of an artifact and its controller can lead to improved performance compared to sequential design.The coupling between the artifact and controller design problems is quantified,and methods for co-design are presented.The control proxy function method,which provides ease of design as in the sequential approach and approximates the performance of the co-design approach,is highlighted with application to the design of a passive/active automotive suspension.Second,the design for component swapping modularity(CSM)of a distributed controller for a smart product is discussed.CSM is realized by employing distributed controllers residing in networked smart components,with bidirectional communication over the network.Approaches to CSM design are presented,as well as applications of the method to a variable-cam-timing engine,and to enable battery swapping in a plug-in hybrid electric vehicle.
