VVT-i泄漏量检测台结构设计【说明书+CAD】
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编号无锡太湖学院毕业设计（论文）相关资料题目： VVT-i泄漏量检测台结构设计 信机 系 机械工程及自动化专业学 号： 0923123学生姓名： 任晨曦 指导教师： 范圣耀 （职称：副教授 ） （职称： ）2013年5月25日目 录一、毕业设计（论文）开题报告二、毕业设计（论文）外文资料翻译及原文三、学生“毕业论文（论文）计划、进度、检查及落实表”四、实习鉴定表无锡太湖学院毕业设计（论文）开题报告题目： VVT-i泄漏量检测台结构设计 信机 系 机械工程及自动化 专业学 号： 0923123 学生姓名： 任晨曦 指导教师： 范圣耀 （职称：副教授 ） （职称： ）2012年11月25日 课题来源自拟科学依据（包括课题的科学意义；国内外研究概况、水平和发展趋势；应用前景等）（1） 课题科学意义随着我国汽车保有量的持续增加，汽车发动机泄露量检测作为影响发动机性能的一道重要工序，就显得越来越重要。发动机泄漏量检测台的运用减少了发动机故障的发生,为发动机正常工作提供了保障，提高产品的市场美誉度。本课题属工程设计类课题，要求完成VVT-i泄漏量检测台结构的设计。通过本设计，可以帮助学生加深对本专业的相关知识理解、加强学生对科学研究的基本功训练和提高综合运用专业知识独立分析问题、解决问题的能力。（2） 汽车自动清洗机研究概况VVT-i中文全名：可变气门正时系统。英文全名：Variable Valve Timing-Intelligent。VVT-i的前身，是一套名为VVT的配气相位技术，全称是VARIABLE VALVE TIMING：可变气门正时控制系统，虽然到了今时今日已经算不上什么新鲜玩意，或者已经有点跟不上技术潮流了，但在其推出的时候，的确引起过阵阵的轰动，让人们可以知道原来凸轮轴与凸轮轴皮带轮之间可以是活动连接的，并可以根据引擎的转速和工况对气门正时进行调整的！但VVT发动机并不能做到随时适应各种路况，它一般只有两套固定的控制模式，比如车速在70码以下都用模式A，70码以上则用都模式B。丰田的VVT-i则解决了这个问题，能够随路况的变化而不断改变控制模式 VVT-i和VVT的区别就像 无级变速器CVT 和 普通有极变速器一样VVT现在已经不算是先进的技术了，欧洲厂商现在已经很少提到它。奔驰和宝马的发动机都带有VVT，可是从来就没有在宣传资料里提到过。帕萨特也有，上海大众也没宣传过，奥迪也是。日系车和韩系车也只在我们国内宣传VVT技术，因为在国内这项技术依然是“尖端科技”（国内目前还没有自主的VVT技术）。和VVT类似的技术还有本田的VTEC，其实这项技术国外早在80年代就风靡过了。不过本田的i-VTEC和丰田的双VVT-i在世界上依然是先进技术，世界上掌握这类“连续可变”技术的厂家除了日本的“两田”外目前就只有德国大众和宝马了。汽车行业已发展近一百年，至今国内还没有完全拥有自主知识产权的汽车。汽车中最关键的部分是发动机，控制部分的ECU，国内依然空白。虽说国内的某些汽车厂家如：奇瑞。自称已经拥有完全自主知识产权的汽车，其实也是把别人落后几十年的技术弄回来稍微加工加工，完全没有自主知识产权可言。眼睁睁看着国内广大的市场而销售汽车的大部分钱落入外国账户。在这样的背景下，许多从国外留学回来的有志之士，运用国外的先进文化知识，利用国内的广阔空间，从事着汽车行业，为国内汽车行业的腾飞做出贡献。研究内容(1) 了解VVT-i泄漏量检测台的工作原理；(2) 熟练掌握机械设计的基本原则和有关计算机绘图软件，并绘制有关零件图，装配图等； (3) 熟练掌握液压系统的组成，控制部分及辅助元器件的选用；(4) 掌握油箱的构造，组成零件及造型；完成设计说明书的撰写，并翻译外文资料1篇。拟采取的研究方法、技术路线、实验方案及可行性分析通过对泄漏量检测台功能要求和运行过程的分析，确定检测台结构设计的总体设计方案，观察VVT-i的工况，确定实验台架的组成部分。确定各组成部分的元器件。根据台架的组成部分及元器件，给出台架初步构想图。确定台架部分的结构、详细尺寸、材料及加工方式。对液压部分进行重点分析计算，选择元器件。考虑安全问题，通过设计保护措施保护试验人员安全。研究计划及预期成果研究计划：2012年11月12日-2012年12月2日：按照任务书要求查阅论文相关参考资料，填写毕业设计开题报告书2012年12月3日-2013年1月20日：进入工厂实习，了解企业生产流程。2013年2月11日-2月23日：查找一篇关于泄漏量检测的英文资料，并完成翻译。2013年2月25日-3月2日：确定VVT-i泄漏量检测台结构设计的总体方案。2013年3月4日-3月30日：完成零件图的绘制。2013年4月1日-2013年4月13日：完成装配图绘制。2013年4月15日-2013年4月18日：设计计算。2013年4月20日-2013年5月18日：说明书的编写和修改2013年5月20日-2013年5月25日：完成论文，准备答辩。预期成果：按照计划完成本课题的设计，可以基本实现汽车自动清洗机的工作要求。所设计的控制程序，能够基本实现。特色或创新之处（1）主题明确，有针对性。（2）使用简易，功能完善。已具备的条件和尚需解决的问题条件：机械设计的基础知识，与课题相关的资料、期刊、文摘等问题：检测台的性能需在安装在实际设备中进一步的调试与多次记录数据对比之后进行完善。指导教师意见 指导教师签名：年 月 日教研室（学科组、研究所）意见 教研室主任签名： 年 月 日系意见 主管领导签名： 年 月 日英文原文Engine parts leak detection technology and applicationFirst, an overview of the voiceLeak detection techniques, sometimes referred to as the test technology or sealing leakage detection technology. In recent years has been widely used in automobile manufacturing industry, such as the cylinder block water jacket, water set of cylinder head, crankshaft oil holes, etc., in addition, there are clearance volume measurement and engine assembly testing, etc.With the application and development of leak detection technology, also has formed a professional manufacturers, more prestigious manufacturers such as Germany, French ATEQ JWFROEHLICH company, inc., United States of the U - SON company, COSM Intertech corporation, in addition to Japan, Tokyo Microctrol van type strains commune, Italy, etc.Leaking test machine is made up of leak detection instrument, mechanical sealing clamp, up-down material mechanical parts and electric control system composition and so on. Some manufacturers such as Germany, a Florida company, not only can provide all kinds of leak detection equipment, and can provide try leakage or leakage automatic line. In the leak detection technology, the first to point out is leaking and not leak is just a relative concept, is no leakage in theory, only when the leakage quantity does not exceed certain limits, we think that is not leak, or qualified.Second, fundamental knowledge of leakage1.1 the flow of the fluidA leak is content by a limited space to run to the external or other substances by space outside into the inside. Contents can be gas, liquid or solid. Limited space can make all kinds of explanation, such as engine cylinder body was sealed channel is a limited space. Leak, in short, is a kind of fluid flow phenomenon. In general, is fluid flows through the holes on the object or the. Fluid flow, like the flow of the electric, electronic mobile because a potential of high and low, as long as the potential difference between the conductors, there will be a flow of electric charge. Movement of material must have motive power, the electric potential difference is the driving force. Leakage, leakage amount depends on the size of the prime mover, available under type said: Q = f (delta), where Q said leakage, delta said impulsion, f is the function. F is a complex function normally, it is very difficult to determine the size of the, if we see it only as a kind of extremely pure proportional relationship, and also only to a pressure difference - delta, type on the Q = C (P1, P2), the proportionality constant C type, P1, P2, said the space both inside and outside pressure, leakage of the prime mover is like current electromotive force, C is like conductance, so can be C said as conduction. A leakage is refers to the fluid through the holes through the phenomenon, through the quantity is related to pressure difference on both sides of the hole, also with the ease of flow through, namely, conduction.1.2 fluid motionAccording to fluid mechanics theory, the flow of the fluid are two kinds of state, the laminar flow and turbulent flow. When laminar viscous force plays a leading role, the particle is governed by viscous fluid, not voluntary movement, the inertial force plays a leading role when turbulent flow, fluid particle in high-speed motion viscosity no longer bind it. In the vacuum technology, can be divided into laminar (viscous flow) and molecular flow. According to the theory of gas molecular motion, for through the gas cylinder, when the gas when the mean free path is larger than the diameter of the cylinder, as molecular flow. On the other hand, the mean free path of gas hours, than the diameter of the cylinder is viscous flow.1. 3 the pipeline resistance and conductionWith the conduction of electricity needs a conductor, the conductor is the pipeline. For the leak itself, whether it is a small hole or crack, can be regarded as a kind of pipe. In the type, Q = C (P1, P2), conduction C as the reciprocal of resistance. Therefore, can be calculated in the pipeline transmission pipeline resistance. Fluid flow is far more complicated than the electric conduction, when calculating the C value, should be according to the size, shape, pressure pipe, fluid characteristics, such as specific conditions to calculate. If a container under a certain pressure leak, but it does not leak. Could get, from we have talked about the formulas of gas and liquid in the same pipeline transmission is not the same.2.1 leakage of formContainer leak phenomenon, such as water leakage of the engine cylinder, usually is mainly due to the local tissue loose on the blank casting quality, casting or machining error cause the hole wall is too thin and process caused by unequal sealant plugging place daub reason.In fact, for leakage technology, there is no need for accurate understanding of the leakage of various forms, but it is also impossible. Leak detection belongs to a kind of non-destructive testing, metallographic analysis of it is different from the material. Therefore, we can do is determine leakage.In order to better understand the leakage phenomenon, it is necessary to know some similar diffusion and through the phenomenon to leak phenomenon. These phenomena in the gas flow through solid this point, and the leakage of the result is the same.Diffusion phenomenon refers to both sides of the gas in a vehicle with a differential pressure, or pressure difference. Gas from high pressure or high pressure to low in the direction of the flow direction. This phenomenon is similar to leak. When the vehicle is solid, gas from medium flows through the holes, or spread to the vehicle (vehicle no leak hole) flow after the past. In both cases is belong to which kind of, sometimes it is difficult to judge.Through refers to gas from a solid passed dissolved the material first, increasing concentration, finally in the wee hours.2.2 the leakageThere are three kinds of leakage of representation:(1) in size, such as round and straight shape, inner diameter and length is how much for each please indicate as said. Actually this size measurement is very difficult to do it, even cant do. So, this method is not practical.(2) using leak, said to the difficulty of the transmission box. This way is not said leakage shape itself, but said the size of the gas pathway.(3) expressed in gas flow. This method has been widely used, because it is easy to use instrument to measure the flow of gas, or gas flow measurement with a collection of bubbles method.3.1 the classification of test methodTo one device to know the leaks, and will know how much its leakage, must exert a prime mover, i.e. let the device produces a pressure difference between inside and outside, so can the device compression or decompression two ways. In addition, can also be classified according to the leak detection process, one kind is placed, another for dynamic method. Also have according to the determination of object classification, can be divided into the amount of gas or liquid quantity measurement and pressure measurement directly or partial pressure measurement.In the above detection method, pressure method is used for the detection of commonly used methods. Pressure method is used for the detection of commonly used methods. Place pressure method and pressure method and pressure dynamic method. Decompression method is commonly referred to as vacuum method, this method is no compression method used widely, but it has high detection accuracy, and easy in the workpiece to be measured have to seal. Vacuum process, like pressure, vacuum and vacuum dynamic placement. Such as vacuum differential pressure method, liquid coating method, etc. And methods used in the vacuum conditions than the kinds of pressure under the condition of the kinds of detection methods.3.2 selection of leak testIn numerous detection methods, each method has its different features. Choices should consider who is suitable for, those who dont fit. According to the different features of various detection methods to choose from the following aspects into consideration:Principle: (1) irrespective of the approach, dont fully understand the principle of the method, will not get good result.(2) the sensitivity (the minimum leakage can be measured) should consider which method is used to measure of the level to which the leakage.(3) detection time irrespective of the detection method, it takes a certain time. For placement testing, from Richard will extend the placed time will improve the sensitivity and the detection of an artifact of the leakage takes a long time, obviously cannot be used for on-line detection of engine parts.(4) test environment of various test methods is different to the requirement of test environment. If adopt the method of measuring pressure value, it is follow the ideal gas equation of state, so the temperature, humidity and other factors on the measuring results is larger, the influence of the choice is must be taken into account.(5) leakage position judgment in all kinds of detection methods, some can only give to the leakage, leakage can determine whether artifacts, but it cant leak, some can reflect the workpiece is leaking, and determine leak, but the specific leakage it is difficult to get, and can give leakage, can determine the specific leak again. If want to repair the leakage of the workpiece, the leak of the judgment is necessary.6 reliability leak detection belongs to a measuring technique, the measurement must be credible and reliable. All kinds of method is usually accompanied by human eye detection, due to the factors that, its consistency is poor, but is stable and reliable. And various instrument method, although better consistency, but its stability and reliability of the instrument, and many other factors influence.All landowners economy detection efficiency when choosing method of measurement is also a factor to consider. The above items is our starting point of how to choose what kind of test method. In specific choices, they should be and other factors, such as tests, the influence of work piece to seal the ease of combination of consideration, and choose the best method for leak detection.4 several major leak detector and the detection methodIn the leak detection technology, at present the main leakage detector and the detection method has a) absolute pressure type leakage detector b) differential pressure type leakage detector c) mass flow leak detector4.1 the absolute pressure type leak detector and the detection methodCommonly used is the step-down method, also can use booster and the vacuum is measured. The test procedure can be roughly divided into: pre inflatable, inflatable, voltage regulator, measurement - exhaust five stages; 1 open the valve, air inflated to the pressure P, filling stage and can be broken down into pre aeration and aeration step or two. Stable stage: 1 valve closed, this phase is to provide the stable gas and heat exchange of time, it is necessary for precise measurement, the stable phase over the instantaneous pressure value as a reference pressure storage.Phases: measurement system for measuring. To monitor the final pressure, and comparing with reference value, measure the P values, P values in excess of the prescribed threshold for unqualified, leak rate can be obtained by P value V; Exhaust phase: the artifacts in the gas from the atmosphere, usually adopts loose blocking artifacts to exhaust.4.2 the differential pressure type leak detector and the detection methodIn the absolute pressure type testing instrument, sensitive element USES the pressure sensor, differential pressure type leakage detector is used in the differential pressure sensor. Differential pressure type of leak detector measurement process basically is divided into five stages. The difference is inflatable stage 1, 2 valve are opened. By gas phase into the stable (balance), 1 off valve, the valve open 2, so the balance at the end of the stage, back pressure chamber H and L pressure equal to the pressure room, P = 0.When entered the measurement phase, valve shut off. If leaks artifacts have L cavity pressure is reduced, producing pressure differential P, in the same way, and can be determined from P V leak rate. Absolute pressure and differential pressure type leak detector detector is measured by using the pressure value to indirectly measure the change of the leak rate of V.4.3 the mass flow type leak detector and the detection methodMass flow type leak detector is directly measured workpiece leak flow instrument, the sensitive element is the flow sensor (usually using the module component). In flow sensor with a constant temperature heating system, when the air flow (flow) change, take away the heat change make temperature t, so that the temperature of the closed-loop system heating current (or voltage) changes, which can measure the flow changes, due to the zero method is used to measure, so it can obtain higher precision. This kind of flow sensor can detect very small flow not only, also can measure the larger flow leakage rate, but also can measure the direction of airflow.Due to flow was measured under constant temperature, so the measured mass flow rate is, the relatively small effect on the temperature, can be used for leak detection of large flow, large volume.In order to improve the accuracy of measurement, the mass flow type testing, also often use standard artifacts and gas circuit composed of workpiece to be measured. When the workpiece to be tested for leaks, the pressure is reduced, while the standard artifacts the pressure inside the container remains constant. Sensors pick up between the two artifacts, compressed air pressure is P from the standard workpiece to be measured by sensor artifacts.Despite the above three kinds of measurement methods can meet the requirements of the vast majority of leak detection, but from practice situation and price level, first recommended the use of leak detector is absolute pressure type, because it is simple, reliable, does not need to balance the reference artifacts. Under the condition of the high accuracy requirement, it is recommended to use differential pressure type leak detector. Under the big leakage flow, is recommended to use mass flow type leak detector, such as leak detection of inlet and exhaust valve seat.5 engine parts, leakage try leakage process analysis and commonly used methodSealing is a relative concept, based on the theory of leakage of theory and practice, the flat parts dont leak, how to determine the leakage of engine parts and do not leak? Common practice is to give the maximum allowable leakage, and time needed for testing should be regulations, working temperature and working pressure, etc.In engine parts try leakage process, first problem is how to determine the process parameters. Largely because of the traditional hydraulic leak test method is carried out under the working condition of simulated parts, determine the process parameters of issues are covered up. In the pressure test, either wet or dry, will be involved in the problem. At present, some manufacturers for the determination of process parameters is not perfect, some is not reasonable, and even some have no this aspect of the indicators.According to the workpiece the allowed minimum leakage, should adopt different methods of leak detection. In engine parts try leakage process, some use wet, some use dry. Wet with water pressure test method and pressure leakage in immersion test leakage; There is absolute pressure method in dry method, differential pressure method and flow method, etc.At present, our country to the water pressure test leakage and leakage air pressure immersion test method. In recent years, with the introduction of foreign new technology and improve the quality of our products, some manufacturers have adopted the dry method.(1) the pressure leak test methodThis method has been widely used, should be reasonably determined in the use of leakage of water pressure and the time the two process parameters. Engine parts leak test pressure is usually based on the maximum working pressure on the fluid. Hydraulic leak test method within the scope of placement method, to extend the time of leakage test, the sensitivity of the measurement will be improved. In mass production engine parts, however, because of the limitation of production beats long try leakage time is impossible. Some use increase leakage test pressure for this way. Hydraulic fracturing only when the measured parts is serious defect and spray leaking or dripping, to determine the apparent leaks. For slight leakage, (that is, sweating or infiltration), it is difficult to determine, if parts of the internal and external complex structure, its internal leakage. Also can not be measured(2) immersion test method of leakage air pressureAlso known as bubble leak test method. Its principle is to seal the workpiece after pressurized water, observe the surface within the time stipulated in the presence of air bubbles escape, in order to determine whether artifacts leaks. By looking at the size or the number of air bubbles, it can estimate the size of the leakage, and parts from air bubbles. This method both at home and abroad try leakage technology is widely used in parts.In actual production, the leakage air pressure immersion test method is used to the workpiece must be submerged in the water tank, and the place such as work piece at the bottom of the vesicles will be dependent on workpiece, so that in a short period of time without air bubbles escape out of the water. For some manufacturers design and manufacture with flip agencies and swing into the water tightness test machine, is advantageous for the observation of each part of the workpiece, put into use effect is good. The method with the naked eye observation, due to the detection of different observation skills, so that there will be a shadow especially when the result of the test artifacts just immersed in the water, and produces some of the leakage caused by bubbles and water solution of the gas, for example, is affected by the condition such as temperature and become bubbles escape, thus affecting the observer of the observations.Anyhow, leakage pressure immersion test method has high sensitivity, can satisfy the general engine parts leak test process requirements, and has the advantages of intuitive judgment. Its disadvantage is need measured parts of the human eye observation and cause corrosion, etc.(3) differential pressure leak test methodBy the workpiece to be measured by the differential gauge compared with standard containers are linked together to form a system. Detection when open the valve 1, 2, first, to the standard container and the measured workpiece measurement chamber aeration at the same time, reach the measuring pressure, close the valve 1. After a certain time after balance, make the pressure differential gauge on both sides is equal, and then close the valve, 2 into the measurement phase. The leak test of the stipulated time, the standard container without leakage, if measured workpiece no leak, differential pressure gauge is still in balance; If there is a leak, artifacts will cause the workpiece measuring chamber air pressure drop, overbalance the differential pressure gauge. Usually caused by leakage of workpiece measurement chamber pressure drop is small, general pressure gauges and pressure sensors simply reflect not to come out, and the differential pressure gauge is to accurately reflect the pressure difference.In the process of detection, gas, the gas is compressed within the system, make the temperature curve rapidly increase; After entered the stage of balance temperature first drop very quickly, and then gradually decreased; In measuring temperature stage is still in change, finally gradually close to the final value. At the same time, the pressure curve (excluding changes caused by the leakage) as well as temperature curve changes with temperature. Through the analysis of the process, it can be seen that some articles about gas differential pressure test method can measure the pressure of caused by leakage of specimen is lower compared with the test pressure before and the pressure difference of the formulation, tight in practice is not enough.Through the study of differential pressure test method of leakage detection process can be concluded, that is measured by differential pressure leak test method must be in the same temperature conditions, the measured workpiece measuring cavity gas temperature is the same as the standard gas temperature of the container. To do this, have to make the workpiece to be measured with standard containers have the same temperature, and energy exchange with the gas properties are the same. At present the most economical and most reliable way is being measured workpiece as standard containers, and USES the same as the measured workpiece way of sealing materials and sealing to seal, and make them reach room temperature, but in some of the production line now, because cleaning workpiece by high temperature, etc, so that it is difficult to reach room temperature, and other compensation measures must be taken.Test apparatus of gas pipe line. If possible can use volume shrinking plug to reduce the volume measured workpiece, thus improve the accuracy of measurement.Seal material selection should be considered in addition to the temperature, the volume problem mentioned above, also should consider to choose as far as possible for smaller air diffusion coefficient and transmission coefficient of material. Such as volume reduction should choose metal material, and should not choose loose material, easy breathable material.(4) the absolute pressure leak test methodAfter the first to open the valve of inflatable, inflatable shutoff valves, balance of gas inside the system. And then turn to measure, by absolute pressure sensors to measure pressure values at the beginning of the deposit to the central processing unit (CPU). After a certain measuring time in measurement is measured at the end of the pressure value is input to the CPU, we compare the two pressure value, if the jobs have leak inevitably produce pressure drop. As well as the differential method, is also follows the ideal gas equation of state. Such factors such as temperature and humidity will have an impact on the measured results, the solution is similar to the differential method.Pressure drop method, can be said to be the real is caused by leakage of specimens decrease measurement compared to before the test pressure and differential pressure.Test pressure of the actual size influence on measurement accuracy is not big, as long as the absolute pressure sensor of high repeat precision, can satisfy the use requirement, of course, due to the range of absolute pressure sensor to contrast far wider range of pressure sensor, and absolute pressure leak test method to measure there would be no differential pressure method of high sensitivity, but also enough to meet general try leakage process requirement of engine parts. Pressure drop method has simple structure, less components needed, high reliability, which is widely used at home and abroad.(5) leakage flow test methodLeak detection belongs to the category of the flowmeter measurement, and, of course, also can use flow method for leak detection, flow meter can directly measure the leakage of artifacts. Obviously this method needs a constant pressure air supply is very stable, although usually adopt high precision differential pressure flowmeter, but because of its low measuring precision, and applies only to some of the wide range of leakage detection. Flow method can improve the accuracy of measurement. The method with differential pressure method is used as the standard sample, the measurement process is the same as the differential pressure method. This kind of method for flow measurement provides a relatively stable source, to improve the accuracy of measurement. In recent years, abroad for manufacturers to develop high-precision quality flow meter is used to replace differential pressure flowmeter, so as to make the measurement precision is improved further.(6) of dry leak test temperature compensationLeakage from the basic theory, as long as the pipeline with pressure difference on both sides, can produce fluid flow. Flow method with differential pressure method, if the balancing stage, gas did not reach the perfect balance to balance phase due to the influence of temperature, the meter will produce pressure difference on both sides, even the workpiece without leakage, flow meter will also measure the flow of gas. So either dry try leak detection, should consider the effect of temperature.Usually temperature from two aspects: one is the environment temperature, the second is the workpiece temperature. For the environment temperature, make the whole detection system should be in the same environment temperature and in the process of test should also avoid the change of environmental temperature. In addition, the pressure measurement method using differential pressure method, the workpiece to be measured with standard parts in the same environment temperature, can have compensation effect. For the workpiece temperature, on the production line is very difficult to realize the parts reach room temperature. Usually before the test, in particular, the workpiece must be clean, dry, in this case should be how to solve the workpiece temperature effect on the measurement result? Can adopt the following methods:(1) the secondary measurement method, to be on probation after sealing, first of all for less than the required test pressure pneumatic measurement, and then secondary air according to the required test pressure measurement, this method will speed up obviously artifacts and test gas temperature uniformity. This method because of its low accuracy of measurement, and the limitation of production beats, so less application.(2) statistics, in the actual test on the basis of the statistics obtained, find out the regularity, and appropriately modified waste threshold to meet the measurement requirements. This method is of simple structure, low cost is widely used now. If the temperature difference is bigger between workpiece and detection accuracy is higher, the statistics will not meet the requirements.(3) the two temperature sensors, one for the test inspection of gas temperature, one for measuring the temperature of the workpiece to be measured. Its way is according to the leak standard artifacts, measured with the test gas at various temperature difference and the corresponding pressure drop values, according to waste point, make the curve of temperature compensation, and the curve in the programming to the leak test instrument. In the actual production conditions, the measured again test the difference in temperature between gas and workpiece to be measured and the corresponding pressure drop value input to the instrument, and deposited in the curve, the temperature compensation to compensate after test results. This method can also be used to compensate the influence of environment temperature on the measurement results, the method is to use the above measurement is be on probation a temperature sensor measuring the temperature of the sealing clamp. The temperature compensation technology is a Florida west Germany patent technology of the company. But it should be noted that this compensation method is also follow certain statistical law, not according to ideal gas state equation only measure test gas can compensate the temperature changes, because it is impossible for inspection in the whole measurement process gas balance.With its measurement precision is bound to decrease after temperature compensation, and the temperature sensor, and easily damaged, the temperature compensation is adopted to increase the cost. In practice, also should according to the actual production condition make a number of artifacts of the experimental data, it selected a suitable curve programming into the instrument. Due to the temperature compensation is very complicated, should try to avoid using temperature compensation.6 the type of leak test machineUsually can be divided into dry type and wet type two kinds. Common dry leakage test machine is in sealing clamp to the capacity of the artifacts under test chamber aeration to certain pressure, leakage tester is used to inspect whether the leakage in the allowed range, if allowed in the scope of the term for qualified. The benefits of dry leak test machine is not to wet the workpiece, high efficiency, automation management, but not easy to find leak of artifacts.Wet leakage test machine is usually in the sealing clamp to the capacity of the artifacts under test cavity filling and sink water test to check. Its shortcomings are wet workpiece, the efficiency is low, not easy to realize automation, but the wet method has the advantage that you can find the leak position of the workpiece, easy to repair. Sometimes the leaking test machine designed to dry and wet dual-purpose way, using two kinds of program, which in most cases using dry check whether leakage of the workpiece in the allowed range, when the workpiece is unqualified, as measured by using the wet process check leak (leak detection instrument generally can provide multiple test procedure). This kind of compound leak test machine combines the advantages of two ways. Because, in fact, most of the workpiece is qualified, so you can meet the requirements of the production efficiency. Wet programs available for a small number of defective parts found leak and repair. For example in the cylinder block and cylinder head water jacket will often found in the test of leakage area, mainly in wall cover parts, in this case, as long as the back cover, can achieve qualified.Dry test leakage, can lead to positive pressure gas, can also be a negative pressure (vacuum), usually use air pressure gas. However, in some cases can be other gases, like helium leak test, it is the use of helium leak detection method of helium gas sensitive sensor, the precision of the leak test is higher. When a try leakage mechanism basically completed into the commissioning phase, must check the machine itself (including road and fixture system) whether there is leakage. Can be divided into two steps:Dew.Can consider after completion of the above two steps, in accordance with the original placement process parameters as a whole, an official of the leak detection automatically.Attention should be paid to the problems of leak detection(1) the leak tester is a precision instrument, must pay attention to maintenance and maintenance. In the process of measurement, avoid many times of stress. Air supply must pass a good water and dust filtering.(2) the leaking test machine installation location is not allowed to have direct sunlight to the artifact or jig, also are not allowed to have a fan blowing straight, in order to avoid temperature changes caused by measurement error.(3) measuring system of the pipeline must use a hard nylon tube, and the measuring line will try to short, best can fixed up, avoid the mobile. Sealing system must have the positioning device, lest produce elastic deformation produced the change of volume, affect the measurement result., filter element (4) the water to drain and clean regularly. Use unleaded gasoline or other corrosive solvents to clean. Fixture of exhaust fumes after each job, and then turning off the power of the air. Leakage test machine calibration leaking test machine using a differential pressure type leak detecting instrument need a standard container, usually use has good sealing, and confirmed in the submerged air container dont leak artifact as a reference. Absolute pressure detector does not need to standard containers. At present, in the process of engine parts manufacturing, the widespread adoption of dry leak test, adopt what kind of test method, should according to the actual situation, find out all kinds of relations, so as to choose the best way to test.Leak detection technology has reached mature stage at present. Most of the instruments realized modularity, digitalization and computerization, but its basic principle is the same. Various derived is a great variety of leak detecting instrument, the user can according to your requirement with related manufacturers to negotiate. For example, the measurement volume; Ask to order on a leak detector measure multiple different workpiece parameters (pressure, volume, leakage rate); Or require a visual function and so on, these are all achievable.中文译文发动机零件泄漏检测技术及应用一、概述泄漏检测技术，有时也称为试漏技术或密封性检测技术。近年来已广泛地应用于汽车制造业，如缸体水套、缸盖水套、曲轴油道孔等，此外，还有燃烧室容积测定和发动机总成检测等。 随着泄漏检测技术的应用和发展，专业厂商也已形成，比较有名望的厂商如德国的 JWFROEHLICH 公司、法国的 ATEQ 公司、美国的 U-SON 公司、Intertech公司、此外还有日本的COSM，东京测范株式公社、意大利的Microctrol等。试漏机是由泄漏检测仪器、机械密封夹具、上下料机构等机械部件和电控系统组成。有些厂商如德国佛罗里西公司，不仅可以提供各类泄漏检测仪器，并可以提供试漏机或试漏自动线。 在泄漏检测技术中，首先要指出的是泄漏和不泄漏只是一个相对的概念，从理论上讲是没有不泄漏的，只是当泄漏的量值不超过一定的允许范围时，我们就认为是不泄漏的，或者说是合格的。二、泄漏的基础知识 1.1、流体的流动 所谓泄漏就是内容物由一个有限的空间跑到外部或者是其它物质由空间外部进入内部。内容物可以是气体、液体或固体。有限空间可以作各种解释，如发动机缸体上被密封的水道就是一个有限空间。 简而言之，泄漏就是一种流体的流动现象。在一般情况下，流体是通过物体上的小孔流出或流入的。 流体的流动就象电的流动一样，电子的移动是因为有电势的高低，只要导体之间存在电势差，就会有电荷的流动。物质的运动必须要有原动力，这里的电势差就是原动力。泄漏也是如此，泄漏量的大小取决于原动力，可用下式表示：Q=f() ，这里 Q 表示泄漏量，表示原动力，f 就是函数。通常 f是一个复杂函数，它的大小很难确定，如果我们将它只看作是一种极单纯的比例关系，而且也仅以压力差 来表示，则上式可Q =C（P1P2），C式比例常数，P1、P2 表示空间内外的压力，泄漏中的原动力就好比电流中的电动势，C好比电导，因此可以将 C 称作为传导。所谓泄漏就是指流体通过小孔的透过现象，透过量与孔的两侧的压力差有关，也与流体通过的难易程度，即传导有关。1.2、流体的运动状态 根据流体力学理论，流体的流动存在着两种状态，即层流和紊流。层流时粘性力起主导作用，流体的质点受粘性约束，不能随意运动，紊流时惯性力起主导作用，流体的质点在高速运动时粘性不再约束它。在真空技术中，可以分为层流（粘性流）和分子流。根据气体分子运动的理论，对于通过圆筒的气体来说，当气体的平均自由程比圆筒的直径大时，为分子流。反之，气体的平均自由程比圆筒的直径小时，则为粘性流。 1. 3、管道的阻力与传导 同电的传导需要有导体一样，这里的导体便是管道。对泄漏本身来说，不论是很小的孔还是裂纹，都可以看作是一种管道。在上式中，Q=C（P1P2），传导 C为阻力的倒数。因此，可从管道传导中求出管道阻力。流体的流动远比电的传导复杂，在计算 C值时，应根据管道的尺寸、形状、压力、流体的特点等具体条件进行计算。一个容器若在某一压力下漏气，但却不一定漏水。从我们已谈到的公式可以得之，气体和液体在同一管道的传导是不一样的。 2.1、泄漏的形式 容器出现泄漏现象，如发动机缸体的水道等出现泄漏，通常主要是由于毛坯铸造质量上存在局部组织疏松、铸造或机械加工误差引起孔道壁过薄以及工艺堵处密封胶涂抹不均等原因所致。 实际上，对于泄漏技术而言，没有必要准确地了解泄漏的各种形式，而且也是不可能的。泄漏的检测属于一种非破坏性的检测，它不同于材料的金相分析。因此，我们力所能及的是测定泄漏量。 为了更好地理解泄漏现象，有必要了解一些与泄漏现象相类似的扩散和透过现象。这些现象在气体通过固体流动这一点上，与泄漏的结果是相同的。 扩散现象是指气体在某媒介物的两侧有一个压力差，或者说是分压差。气体从压力高或分压高的方向向低的方向流动。这一现象与泄漏很类似。当媒介物为固体时，气体是从媒介物的小孔流过的，还是扩散到媒介物（媒介物无泄漏孔）之后流过去的。这两种情况究竟是属于哪一种，有时是很难判断的。 透过是指气体从固体中通过时，先溶解于那种物质，浓度不断增大，最后在相反侧表现出来。 2.2、 泄漏量的表示 泄漏量的表示方法有三种： (1) 用尺寸表示，例如对圆直管形，表示时要注明内径和长度各为多少。实际上这种尺寸的测量很难做到，甚至根本做不到。所以，这种方法并不实用。 (2) 用泄漏的难易程度表示，即用传导表示。这种方式不是表示泄漏形状本身，而是表示气体通路的大小。 (3) 用气体流量表示。这种方法目前被普遍采用，因为很容易用仪器测出气体的流量，或用采集气泡的方法测定气体流量。 3.1、检测方法的分类 对于某装置，要知道其有无泄漏，并且还要知道其泄漏量有多大，就必须施加一个原动力，即让装置内外产生一个压力差，因此就可以对该装置加压或减压两种办法。另外，还可以根据泄漏检测的过程进行分类，其中一类为放置法，另一类为动态法。也有按测定对象来分类的，可分为气体量或液体量的测定法、压力直接测定法或分压测定法。 在上述检测方法中，加压法为目前常用的检测方法。加压法为目前常用的检测方法。加压法又有加压放置法和加压动态法。减压法通常称为真空法，该方法虽没有加压法用得普遍，但却具有检测精度高、对被测工件得密封容易等优点。真空法同加压法一样，也有真空放置法和真空动态法。如真空差压法、液体涂敷法等。而且在真空条件下的检测方法的种类比加压条件下的检测方法的种类还要多。 3.2、泄漏检测法的选择 在众多的检测方法中，每种方法都有其不同的特点。选择的时候应考虑那些适合，那些不适合。按照各种检测方法的不同特点选择时应从以下几个方面加以考虑： 原理：不论采用哪种方法，不完全理解该方法的原理，就不会收到好的效果。 灵敏度（即可测出的最小泄漏量）应考虑采用哪种方法可测出哪一级的泄漏。 检测时间 不论采用哪种检测方法，都要花一定的时。如采用放置试验法时，从理上将讲延长放置时间会提高灵敏度，但检测一个工件的泄漏需要很长的时间，显然就不能用于对发动机零件的在线检测。 检测环境 各种检测方法对检测环境的要求是不同的。如采用测定压力值的方法，都是遵循理想气体状态方程的，因此温度、湿度等因素对测量结果的影响较大，在选择是必须加以考虑。 泄漏部位的判断 在各种检测方法中，有的仅能给出泄漏量，可判断工件是否泄漏，但不能判断泄漏部位，有的能反映工件是否泄漏，并判断泄漏部位，但具体的泄漏量很难给出，还有的即能给出泄漏量，又能判断出具体的泄漏部位。若要对泄漏的工件进行修理，则泄漏部位的判断就是必要的。 可靠性 泄漏检测属于一种计测技术，其测量结果必须可信、可靠。通常需人工肉眼检测的各类方法，由于认为因素的影响，其一致性差，但比较稳定，可靠。而各类仪表法，虽然一致性较好，但其稳定性、可靠性要受到仪表等诸多因素的影响。 经济性 检测的经济性在选择测量方法时也是一个需要考虑的因素。 上述几项便是我们如何选择何种检测方法的出发点。在具体选择时，应将它们及其它因素，如对被检测工件的影响、密封的难易程度等综合起来进行考虑，从而选择最佳的泄漏检测方法。 4、几种主要泄漏检测仪及检测方法 在泄漏检测技术中，目前采用的主要泄漏检测仪和检测方法有a)绝对压力式泄漏检测仪b)差压式泄漏检测仪c)质量流量泄漏检测仪4.1、绝对压力式泄漏检测仪及检测方法 通常使用的是降压法，也可以使用升压法和真空法进行测量。其试验程序大致可以分为：预充气充气稳压测量排气 五个阶段； 阀门1打开，气源充气至规定的压力P，充气阶段又可细分为预充气和充气两步。 稳定阶段：阀门1关闭，此阶段是提供气体稳定和热交换的时间，它是精确测量的必要条件，把稳定阶段结束瞬时的压力值做为参考压力值存贮起来。 测量阶段：测量系统进行测量。对最后的压力进行监控，并与参考值进行比较，测量出P值，P值超过规定的门槛就为不合格，由P值可以求得泄露率V；排气阶段：把工件中的气体排出大气，通常采用松堵工件来排气。 4.2、差压式泄漏检测仪及检测方法 在绝对压力式检测仪器中，敏感元件使用的是压力传感器，在差压式泄漏检测仪中是使用差压传感器。 差压式泄漏检测仪的测量过程基本上也分为五个阶段。所不同的是充气阶段阀门1、2都打开。由充气阶段进入稳定（平衡）阶段时，阀门1关闭，阀门2打开，所以平衡阶段末，背压室H和测压室L的压力相等，P=0。 当进入测量阶段时，阀2关闭。如果工件有泄漏，则L腔的压力降低，产生压差P，用同样的方法，可从P求出泄露率V。 差压式泄漏检测仪和绝对压力式检测仪都是利用测量压力的变化值来间接测出泄露率V。4.3、质量流量式泄漏检测仪及检测方法 质量流量式泄漏检测仪是直接测量工件泄露流量的仪器，其敏感元件是流量传感器（通常使用的是模块组件）。在流量传感器中有一个恒温的加热系统，当气流（流量）变化时，带走的热量使温度t发生变化，从而使恒温闭环系统的加热电流（或电压）产生变化，因而可测量出流量的变化，由于采用对零法测量，所以可获得较高的精度。这种流量传感器不仅可以测出很小的流量，也可以测出较大的流量泄漏率，同时也可测出气流的方向。 由于是在恒温下测得的流量，所以测得的是质量流量，对温度的影响比较小，可用于大流量、大容积的泄漏检测。 为提高测量精度，质量流量式检测，也常使用标准工件和被测工件组成的气路。当被测工件有泄漏时，其压力降低，而标准工件容器内的压力保持不变。传感器接在这两个工件之间，压力为P的压缩空气从标准工件经传感器至被测工件。 尽管上述三种测量方式都可以满足绝大多数的泄露检测的要求，但从实践情况及价格情况来看，首先推荐使用的是绝对压力式泄露检测仪，因为其比较简单可靠，不需要平衡参考工件。 在精度要求较高的情况下，推荐使用差压式泄露检测仪。 在大泄露流量下，推荐使用质量流量式泄露检测仪，例如对进、排气阀座的泄露检测。 5、发动机零件试漏工艺分析及常用的试漏方法 密封性是相对的概念，依据泄漏的理论和实践理论，漏气的零件不一定漏水，对发动机的零件如何确定漏与不漏呢？ 通常的做法是给出允许的最大泄漏量，并应规定检测所需时间、工作温度和工作压力等。 在发动机零件的试漏工艺中，首先遇到的问题是如何确定有关的工艺参数。由于传统的水压试漏法基本上是模拟零件的工作状态下进行的，因而确定工艺参数的问题被掩盖了。而在气压试验中，不论是湿式的还是干式的，都将涉及到这个问题。目前，一些厂家对该工艺参数的确定不够完善，有的不够合理，甚至有的根本没有这方面的指标。 根据工件所允许的最小泄漏量，应采用不同的泄漏检测方法。在发动机零件的试漏工艺中，有的采用湿式，有的采用干式。湿式中有水压试漏法和气压浸水试漏；干式法中有绝对压力法，差压法和流量法等。目前，我国以水压试漏法和气压浸水试漏法为主。近年来，随着国外新技术的引进和产品质量的提高，一些厂家也相继采用了干式法。 (1) 水压试漏法 这种方法已被普遍采用，在使用种中应合理地确定试漏的水压和时间这两个工艺参数。通常发动机零件的试漏压力是根据其所承受的流体的最大工作压力来确定的。 水压试漏法属于放置法的范围，延长试漏时间，测量的灵敏度会有提高。然而，在发动机零件的大批量生产中，由于生产节拍的限制，过长的试漏时间是不可能的。为此有的采用提高试漏压力的办法。 水压
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