我国汽车发动机发展现状及未来趋势(上)

中国汽车工业已有60余年的发展历史。初创阶段,国内汽车工业主要以发展商用车为主,因此商用车发动机在"中国制造"的大背景下,从20世纪五六十年代就已经形成了批量,涌现出了锡柴、上柴、玉柴等一批知名商用车发动机企业。但乘用车尤其是轿车的发展,则是从改革开放之后才开始起步的。20世纪90年代,国内的汽车市场主要被几家合资企业垄断,同时国内每年都要从国外进口大量轿车,直到2000年之后,大量的自主品牌轿车才开始出现。受其影响,我国自主品牌轿车发动机也基本是在10年前才开始发展起来的,尤以奇瑞、吉利、长城、华晨和江淮等企业为代表。尽管十年间,我国自主品牌轿车发动机在国家政策的大力支持下,取得了较快发展,年产量达到了200多万台,但产量与技术水平都与合资品牌存在着一定差距,尤其是发动机高压共轨、涡轮增压等关键技术,仍主要掌握在外资零部件企业手中,国内只有极少数自主品牌零部件企业掌握了这些技术。加快发动机关键零部件技术的开发,是业内十分关心的问题。     

汽车安全技术：自主品牌美中有不足

10年前,人们一说起汽车安全问题,首先提到的就是自主品牌,尤其是吉利牌轿车,不少人表示不能买吉利的原因是该车不安全。近几年这样的评价已近绝迹,反而吉利、长城、华晨、奇瑞、江淮及比亚迪等自主品牌因其安全可靠、价格便宜,在中国汽车市场已是有口皆碑。     

努力推进轿车刀具国产化工作

１－轿车刀具国产化是建立我国轿车工业自主开发体系的战略措施朱基总理访美后,我国加入世贸组织（ＷＴＯ）的进程已进入关键阶段。一旦我国加入ＷＴＯ,中国汽车市场将成为世界汽车业的重要目标市场,国际汽车巨头们早已虎视眈眈地瞄准了中国这块潜力巨大、尚未完全开发的“处女地”,他们挟资金雄厚、管理先进、生产规模大、产品性能好、价格低廉等诸多优势,力图大举进占中国汽车市场。这使正处于成长阶段的我国汽车工业面临严峻挑战,尤其是我国的轿车工业,无论在生产规模、劳动生产率、产品价格还是产品开发能力和质量水平上均与国…     

不以规矩，不能成方圆——中国汽车工业协会首次中国汽车出口企业等级颁证仪式亮相

目前,本土品牌汽车上的转向器对自主品牌生产的产品使用率很高。例如：商用车（主要是载货车）有95％以上配装自主品牌转向器,低档轿车几乎全部使用自主品牌转向器。而在出口方面,我国转向器生产企业国际竞争力明显不足。综合各方面表现主要有几点：开发能力不强,规模化程度不高,国际贸易渠道不宽,出口自律欠缺。其实,在我国汽车零部件行业,这种情况是普遍存在的。“散、乱、差”作为多年来国外市场对“中国制造”的直观认识严重影响了我国汽车零部件行业诚信体系建设和出口市场持续健康发展。     

不以规矩,不能成方圆——中国汽事工业协会首次中国汽车出口企业等级颁证仪式亮相

目前,本土品牌汽车上的转向器对自主品牌生产的产品使用率很高.例如:商用车(主要是载货车)有95％以上配装自主品牌转向器,低档轿车几乎全部使用自主品牌转向器.而在出口方面,我国转向器生产企业国际竞争力明显不足.综合各方面表现主要有几点:开发能力不强,规模化程度不高,国际贸易渠道不宽,出口自律欠缺.其实,在我国汽车零部件行业,这种情况是普遍存在的.“散、乱、差”作为多年来国外市场对“中国制造”的直观认识严重影响了我国汽车零部件行业诚信体系建设和出口市场持续健康发展.     

高压共轨柴油轿车电控系统设计

本文简要介绍了满足未来排放要求的柴油轿车的几种关键技术后,对基于高压共轨的柴油轿车电控系统进行了模块化设计,主要包括电控单元、传感器、执行器及多电控单元通信网络等.实验证明,所设计电控系统工作稳定、可靠,对于国内柴油轿车的自主开发具有一定参考价值.     

新闻

<正>工业和信息化部:中国汽车发展进入重要转型期我国连续三年成为世界第一汽车生产大国和第一大汽车市场,但是大而不强。工业和信息化部副部长苏波近日表示,我国汽车产业对外技术依存度较高,自主品牌竞争力还不强。随着我国汽车发展进入重要转型期,亟待实现由量到质的转变。苏波指出,我国汽车产业在快速发展的同时也暴露出不少问题。集中表现为自主品牌市场竞争力不强,尤其是对外技术和品牌的长期依赖削弱了自主品牌创新能力。占轿车产销四分之三的合资企业仍以引进     

覆盖件模具CAD／CAE／CAM一体化技术现状与发展

1.汽车及模具工业现状 当今世界各国都将汽车工业作为国民经济的支柱产业之一,竞争日趋激烈。衡量汽车特别是轿车工业发展水平的重要标志是车型的自主开发与设计能力。美国、日本和西欧许多国家依靠先进的技术手段,花大气力发展轿车工业。众所周知,轿车工业的发展将带动许多相关工业,如机械工业、电子工业的发展,因此,轿车工业的发展水平是一个国家经济和科技实力的象征。据报道,从新车型设计到投产整个周期来看,美国需4～5年,德国需4年,日本只需30个月左右的时间。日本的周期最     

我国轿车自主品牌市场占有率居第二

中国汽车工业协会常务副会长董扬近日说，我国汽车工业自主开发加速发展，截至2007年，我国轿车自主品牌数目达到47个，市场占有率位居第二。     

国内轿车轮胎均匀性试验机问世

青岛高校软控自主研发的国内轿车轮胎均匀性试验机,日前通过了青岛市经贸委和青岛市科技局组织的成果鉴定,主要指标性能达到了国际先进水平,这对提升国产轿车轮胎档次、企业突破轿车子午胎质量和安全等制约因素具有重大意义。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.