首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
转速变化对配气机构相关参数的影响   总被引:1,自引:0,他引:1  
针对传统运动学计算不足以准确描述配气机构各零部件的运动规律的问题,阐述了对用复合形法优化了的FH-Ⅱ凸轮,利用单自由度模型对FB-Ⅱ型对称凸轮的下置凸轮轴式配气机构进行动力学计算计算结果表明,在工作状态下,配气机卡勾各个零部件会发生较大变形;当凸轮轴转速变化时,配气机构各相关参数会发生相应的变化.FB-Ⅱ凸轮配气机构具有较大的丰满系数.FB-Ⅱ型线凸轮对转速低于3000r/min的柴油机是一种比较理想的选择.  相似文献   

2.
本文提出了复合三型凸轮形线,并导出了计算方程式,以复摆三型凸轮形线为例,对内燃机配气凸轮形线设计参数的最佳组合进行了分析和比较。作者以这种方法选取三种凸轮(复摆三型凸轮、多项动力凸轮、组合直线凸轮),并进行了试制和试验。试验结果表明:新凸轮的充气系数有所提高,扭矩有所增大,油耗下降了5~10克/马力小时。  相似文献   

3.
配气凸轮优化设计综述   总被引:1,自引:0,他引:1  
探讨发发动机配气凸轮设计的近代技术发展,重点论述了凸轮型线的静态优化设计和动态优化设计及系统优化设计,阐述了这三种方法的特点以及用这些方法设计凸轮的优缺点,在此基础上讨论了凸轮型线优化设计方法的发展方向。  相似文献   

4.
探讨了发动机配气凸轮设计的近代技术发展,重点论述了凸轮型线的静态优化设计和动态优化设计及系统优化设计,阐述了这三种方法的特点以及用这些方法设计凸轮的优缺点,在此基础上讨论了凸轮型线优化设计方法的发展方向.  相似文献   

5.
结合实例系统地研究了单顶置凸轮轴式配气机构,详细地分析了其中的关键零件凸轮轴和摇臂,研究了凸轮型线设计和型线方程计算的具体方法,讨论了不对称凸轮顶点加速度连续性问题.将不对称凸轮型线作为整体来设计,以及考虑了保持缓冲段与工作段之间的连续性,对配气机构的关键零件摇臂进行了具体分析,提出了摇臂接触区圆弧方向角的概念,分析了摇臂接触区圆弧半径和方向角对配气机构性能的影响.配气系统优化中所研究的实例已取得良好的效果.  相似文献   

6.
使用概率法对内燃机配气凸轮进行设计和分析,计算平面挺拉升程、速度和加速度的公差变化规律,讨论加工精度对凸轮型线的影响.  相似文献   

7.
配气凸轮的概率设计初探   总被引:2,自引:0,他引:2  
使用概率法对内燃机配气凸轮进行设计和分析,计算平面挺柱升程,速度和加速度的公差变化规律,讨论加工精度对凸轮型线的影响。.  相似文献   

8.
针对某增压柴油机原机油耗高和配气机构存在的冲击、反跳问题,结合柴油机性能试验数据,建立了配气机构的运动学和动力学仿真模型以及工作过程仿真模型,计算优化了原机配气相位和凸轮型线。研究结果表明:通过优化配气相位和凸轮型线,在一定程度上提高了发动机在中高速下的动力性和经济性,改善了原机配气机构运动学与动力学特性,减缓了进、排气门开闭时的加速度冲击,消除了气门落座时的反跳现象。  相似文献   

9.
本文以高速柴油机顶置凸轮轴式配气机构为研究对象,在运动学、动力学计算的基础上,根据凸轮基圆半径及相应的推杆升程曲线,采用解析函数法与数值法相结合的方法对配气凸轮线型进行了优化设计。通过优化配气机构的凸轮线型,是凸轮的扭矩值在低速段提升了3.44%,高速段提升了1.40%,从而使整机性能得到提升;同时也为汽车凸轮型线的设计提供一定的理论参考。  相似文献   

10.
非对称N次谐波凸轮的优化设计   总被引:1,自引:0,他引:1  
讨论了非对称N次谐波凸轮的设计方法及其特点,并应用正交设计的方法初步确定凸轮型线的设计参数的变化区域,建立合理的优化模型进行求解,在国内首次应用非对称N次谐波理论设计凸轮。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

13.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

14.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

15.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

18.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

19.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号