The inspection of engine lubricating oil can give an indication of the internal condition of an engine. By means of the Object-Oriented Programming (OOP), an expert system is developed in this paper to computerize the...The inspection of engine lubricating oil can give an indication of the internal condition of an engine. By means of the Object-Oriented Programming (OOP), an expert system is developed in this paper to computerize the inspection. The traditional components of an expert system, such us knowledge base, inference engine and user interface are reconstructed and integrated, based on the Microsoft Foundation Class (MFC) library. To testify the expert system, an inspection example is given at the end of this paper.展开更多
The friction coefficients between the surfaces of a ball and a disc lubricated by a space lubricating oil No.4129 were measured at various operating conditions on a ball-disc friction test rig. Friction characteristic...The friction coefficients between the surfaces of a ball and a disc lubricated by a space lubricating oil No.4129 were measured at various operating conditions on a ball-disc friction test rig. Friction characteristic curves were obtained under sliding and rolling movements at point contact. A new model for calculation of the friction coefficient was presented. The results show that the bigger the load is, the larger the friction coefficient becomes. The rolling speed ranging from 1 m/s to10 m/s has an important effect on the friction coefficient. The friction coefficient increases with the increase in sliding speed and the decrease in rolling speed. The linear variation region of the friction coefficient versus the sliding speed at high rolling speed is wider than that at low rolling speed. The model for calculation of the friction coefficient is accurate for engineering use.展开更多
The thermal elasto-hydrodynamic lubrication characteristics of the internal meshing gears in a planetary gear train under vibrations were examined considering the influence of the modification coefficient and time-var...The thermal elasto-hydrodynamic lubrication characteristics of the internal meshing gears in a planetary gear train under vibrations were examined considering the influence of the modification coefficient and time-varying meshing stiffness.Based on dynamic theory of the gear system,a dynamic model of the planetary gear train was established.The lubrication performances of modified gear systems under vibrations and static loads were analyzed.Compared with other transmission types,the best lubrication effect could be produced by the positive transmission.A thicker lubricating oil film could be formed,and the friction coefficient and oil film flash temperature are the smallest.Increasing modification coefficient improves the lubrication performance continuously but intensifies the engage-in and tooth-change impact.For the planetary and inner gears,the increase in the modification coefficient also leads a decrease in the oil film stiffness.展开更多
The paper described experimental investigation of heat transfer and single-phase pressure drop through tubes with different rotor-assembled strands inserted in the Reynolds number range of 800-9000 with lubricant as w...The paper described experimental investigation of heat transfer and single-phase pressure drop through tubes with different rotor-assembled strands inserted in the Reynolds number range of 800-9000 with lubricant as working fluid. In the experiment, fixed mounts were employed to eliminate the entrance effect. The experimental results showed that the employment of fixed mounts led to a visible bias of friction factor in the laminar regime while it could not affect the Nusselt numbers significantly. Experiment for the tube inserted with rotors-assembled strand showed remarkable improvement for heat transfer with the Nusselt number increased by 200%-225% in the laminar regime and 125%-160% in the transitional regime. Meanwhile, the friction factor increased inevitably by 200%-300% within the same range of Reynolds number. The comparison of different rotor-assembled strands in-serted tubes and plain tube showed that the heat transfer benefited from the increase of the diameter of rotor-assembled strand with the same lead and the decrease of the lead of rotor-assembled strand, so does the friction factor. Based on experimental data and thorough multivariant linear normal regression method, the correlations of average Nusselt number and friction factor are established.展开更多
The thermal elastohydrodynamic lubrication characteristics of a modified gear system under a dynamic load were investigated,including the influence of the modification coefficient and vibrations.Based on the dynamic t...The thermal elastohydrodynamic lubrication characteristics of a modified gear system under a dynamic load were investigated,including the influence of the modification coefficient and vibrations.Based on the dynamic theory of gear systems,a six-degree-of-freedom tribo-dynamics model was established.Thermal elastohydrodynamic lubrication characteristics of a modified gear system under vibrations and a static load were analyzed.The results showed that the positive transmission gear system exhibited the better lubrication effect compared with other transmission types.A thick lubricating oil film could be formed,and the friction coefficient between the teeth and the oil film flash temperature were the smallest.As the modification coefficient increased,the lubrication condition was continuously improved,and the scuffing load capacity was enhanced.The increment of the modification coefficient increased the meshing stiffness of the gear system but reduced the stiffness of the oil film.展开更多
The properties of lubricant filters in diesel engines directly affect operation of the lubricant system, and lubricant filters are apt to be impacted by many factors. Therefore, scientific and sensible methods evaluat...The properties of lubricant filters in diesel engines directly affect operation of the lubricant system, and lubricant filters are apt to be impacted by many factors. Therefore, scientific and sensible methods evaluating the properties for lubricant filter diesel engines are necessary to monitor filter properties on line and dynamically. This paper applies ferrographic techniques and adopts sampling methods that oil specimens are synchronously obtained in front of and behind filter elements to monitor the filters of ISUZU DA-220 diesel engine in two FD50 forklifts. Results show that the combination of ferrographic techniques and above sampling methods is effective in analyzing the whole operating process of filters used in diesel engines. The service life and ruined type of filter can be estimated through the relationship between ferrographic readings in front and behind of filter and operation time. Furthermore, through a great deal of tests, a series of experimental curves of readings and time and characteristic parameters for filters used in different machines can be gained, which has guiding significance to the selection and maintenance of the filters. But because of the limitation of the ferrographic technique, the debris on the substrate prevents determination of sizes. It is difficult to judge accurately the size of debris that a filter can filter.展开更多
Available model of 3D-quantitative structure-activity relationship (3D-QSAR, the method of TopomerCoMFA) has been used to establish relationship between antioxidant performances of lubricating oil (trimethylolpropane ...Available model of 3D-quantitative structure-activity relationship (3D-QSAR, the method of TopomerCoMFA) has been used to establish relationship between antioxidant performances of lubricating oil (trimethylolpropane trioleate, TMPTO) with 15 kinds of amine additives and its molecular structure. Correlation coefficient of the cross-validation (include internal q2 and external qpred 2 ) and conventional correlation coefficient showed the model to be both stable and good predictive. The electron-donating group and larger steric effects group are adopted at the para-position or meta-position of amido on the benzene ring, and suitably decreasing the branch chain near the para-position, these indicate that the antioxidant performance of amine additives can be enhanced. The results not only can help us understanding the rule of antioxidant performance, but also providing guidance(s) to predict antioxidant performance of existing amine additives and to design or modify new amine additives in lubricating oil.展开更多
文摘The inspection of engine lubricating oil can give an indication of the internal condition of an engine. By means of the Object-Oriented Programming (OOP), an expert system is developed in this paper to computerize the inspection. The traditional components of an expert system, such us knowledge base, inference engine and user interface are reconstructed and integrated, based on the Microsoft Foundation Class (MFC) library. To testify the expert system, an inspection example is given at the end of this paper.
基金supported by the National Science Foundation of China (51105131)the Excellent Youth Foundation of Henan Scientific Committee (12410050002)the Creative Talent Foundation at Universities of Henan Province (2011HASTIT1016)
文摘The friction coefficients between the surfaces of a ball and a disc lubricated by a space lubricating oil No.4129 were measured at various operating conditions on a ball-disc friction test rig. Friction characteristic curves were obtained under sliding and rolling movements at point contact. A new model for calculation of the friction coefficient was presented. The results show that the bigger the load is, the larger the friction coefficient becomes. The rolling speed ranging from 1 m/s to10 m/s has an important effect on the friction coefficient. The friction coefficient increases with the increase in sliding speed and the decrease in rolling speed. The linear variation region of the friction coefficient versus the sliding speed at high rolling speed is wider than that at low rolling speed. The model for calculation of the friction coefficient is accurate for engineering use.
基金Projects(51575289,51705270)supported by the National Natural Science Foundation of China。
文摘The thermal elasto-hydrodynamic lubrication characteristics of the internal meshing gears in a planetary gear train under vibrations were examined considering the influence of the modification coefficient and time-varying meshing stiffness.Based on dynamic theory of the gear system,a dynamic model of the planetary gear train was established.The lubrication performances of modified gear systems under vibrations and static loads were analyzed.Compared with other transmission types,the best lubrication effect could be produced by the positive transmission.A thicker lubricating oil film could be formed,and the friction coefficient and oil film flash temperature are the smallest.Increasing modification coefficient improves the lubrication performance continuously but intensifies the engage-in and tooth-change impact.For the planetary and inner gears,the increase in the modification coefficient also leads a decrease in the oil film stiffness.
基金Supported by the National Natural Science Foundation of Beijing （3102023） and the National Science and Technology Support Plan Project （2011BAA04B02）.
文摘The paper described experimental investigation of heat transfer and single-phase pressure drop through tubes with different rotor-assembled strands inserted in the Reynolds number range of 800-9000 with lubricant as working fluid. In the experiment, fixed mounts were employed to eliminate the entrance effect. The experimental results showed that the employment of fixed mounts led to a visible bias of friction factor in the laminar regime while it could not affect the Nusselt numbers significantly. Experiment for the tube inserted with rotors-assembled strand showed remarkable improvement for heat transfer with the Nusselt number increased by 200%-225% in the laminar regime and 125%-160% in the transitional regime. Meanwhile, the friction factor increased inevitably by 200%-300% within the same range of Reynolds number. The comparison of different rotor-assembled strands in-serted tubes and plain tube showed that the heat transfer benefited from the increase of the diameter of rotor-assembled strand with the same lead and the decrease of the lead of rotor-assembled strand, so does the friction factor. Based on experimental data and thorough multivariant linear normal regression method, the correlations of average Nusselt number and friction factor are established.
基金Projects(51575289,51705270)supported by the National Natural Science Foundation of China。
文摘The thermal elastohydrodynamic lubrication characteristics of a modified gear system under a dynamic load were investigated,including the influence of the modification coefficient and vibrations.Based on the dynamic theory of gear systems,a six-degree-of-freedom tribo-dynamics model was established.Thermal elastohydrodynamic lubrication characteristics of a modified gear system under vibrations and a static load were analyzed.The results showed that the positive transmission gear system exhibited the better lubrication effect compared with other transmission types.A thick lubricating oil film could be formed,and the friction coefficient between the teeth and the oil film flash temperature were the smallest.As the modification coefficient increased,the lubrication condition was continuously improved,and the scuffing load capacity was enhanced.The increment of the modification coefficient increased the meshing stiffness of the gear system but reduced the stiffness of the oil film.
文摘The properties of lubricant filters in diesel engines directly affect operation of the lubricant system, and lubricant filters are apt to be impacted by many factors. Therefore, scientific and sensible methods evaluating the properties for lubricant filter diesel engines are necessary to monitor filter properties on line and dynamically. This paper applies ferrographic techniques and adopts sampling methods that oil specimens are synchronously obtained in front of and behind filter elements to monitor the filters of ISUZU DA-220 diesel engine in two FD50 forklifts. Results show that the combination of ferrographic techniques and above sampling methods is effective in analyzing the whole operating process of filters used in diesel engines. The service life and ruined type of filter can be estimated through the relationship between ferrographic readings in front and behind of filter and operation time. Furthermore, through a great deal of tests, a series of experimental curves of readings and time and characteristic parameters for filters used in different machines can be gained, which has guiding significance to the selection and maintenance of the filters. But because of the limitation of the ferrographic technique, the debris on the substrate prevents determination of sizes. It is difficult to judge accurately the size of debris that a filter can filter.
基金supported by the National Basic Research Program of China(Grant No.2013CB632303)the National Natural Science Foundation of China(Grant No.51505341)
文摘Available model of 3D-quantitative structure-activity relationship (3D-QSAR, the method of TopomerCoMFA) has been used to establish relationship between antioxidant performances of lubricating oil (trimethylolpropane trioleate, TMPTO) with 15 kinds of amine additives and its molecular structure. Correlation coefficient of the cross-validation (include internal q2 and external qpred 2 ) and conventional correlation coefficient showed the model to be both stable and good predictive. The electron-donating group and larger steric effects group are adopted at the para-position or meta-position of amido on the benzene ring, and suitably decreasing the branch chain near the para-position, these indicate that the antioxidant performance of amine additives can be enhanced. The results not only can help us understanding the rule of antioxidant performance, but also providing guidance(s) to predict antioxidant performance of existing amine additives and to design or modify new amine additives in lubricating oil.
