机械毕业设计英文外文翻译42变速器介绍 (2)
变速器外文资料翻译
自动变速器英文文献翻译
毕业设计（论文）外文翻译AUTOMATIC TRANSMISSIONThe modern automatic transmission is by far，the most complicated mechanical component in today’s automobile.It is a type of transmission that sifts itself.A fluid coupling or torque converter is used instead of a manually operated clutch to connect the transmission to the engine.There are two basic types of automatic transmission based on whether the vehicle is rear wheel drive or front wheel drive.On a rear wheel drive car，the transmission is usually mounted to the back of the engine and is located under the hump in the center of the floorboard alongside the gas pedal position.A drive shaft connects the transmission to the final drive which is located in the rear axle and is used to send power to the rear wheels.Power flow on this system is simple and straight forward going from the engine，through the torque converter，then trough the transmission and drive shaft until it reaches the final drive where it is split and sent to the two rear transmission.On a front wheel drive car，the transmission is usually combined with the final drive to form what is called a transaxle.The engine on a front wheel drive car is usually mounted sideways in the car with the transaxle tucked under it on the side of the engine facing the rear of the car.Front axles are connected directly to the transaxle and provide power to front wheels.In this example，power floes from the engine，through the torque converter to a larger chain that sends the power through a 180 degree turn to the transmission that is alongside the engine.From there，the power is routed through the transmission to the final drive where it is split and sent to the two front wheels through the drive axles.There are a number of other arrangements including front drive vehicles where the engine is mounted front to back instead of sideways and there are other systems that drive all four wheels but the two systems described here are by far the most popular.A much less popular rear and is connected by a drive shaft to the torque converter which is still mounted on the engine.This system is found on the new Corvette and is used in order to balance the weight evenly between the front and rear wheels for improved performance and handling.Another rear drive system mounts everything，the engine，transmission and final drive in the rear.This rear engine arrangement is popular on the Porsche。
机械毕业设计英文外文翻译402驱动桥和差速器 (2)
附录附录ADrive axle/differentialAll vehicles have some type of drive axle/differential assembly incorporated into the driveline. Whether it is front, rear or four wheel drive, differentials are necessary for the smooth application of engine power to the road.PowerflowThe drive axle must transmit power through a 90° angle. The flow of power in conventional front engine/rear wheel drive vehicles moves from the engine to the drive axle in approximately a straight line. However, at the drive axle, the power must be turned at right angles (from the line of the driveshaft) and directed to the drive wheels.This is accomplished by a pinion drive gear, which turns a circular ring gear. The ring gear is attached to a differential housing, containing a set of smaller gears that are splined to the inner end of each axle shaft. As the housing is rotated, the internal differential gears turn the axle shafts, which are also attached to the drive wheels.Fig 1 Drive axleRear-wheel driveRear-wheel-drive vehicles are mostly trucks, very large sedans and many sports car and coupe models. The typical rear wheel drive vehicle uses a front mounted engine and transmission assemblies with a driveshaft coupling the transmission to the rear drive axle. Drive in through the layout of the bridge, the bridge drive shaft arranged vertically in the same vertical plane, and not the drive axle shaft, respectively, in their own sub-actuator with a direct connection, but the actuator is located at the front or the back of the adjacent shaftof the two bridges is arranged in series. Vehicle before and after the two ends of the driving force of the drive axle, is the sub-actuator and the transmission through the middle of the bridge. The advantage is not onlya reduction of the number of drive shaft, and raise the driving axle of the common parts of each other, and to simplify the structure, reduces the volume and quality.Fig 2 Rear-wheel-drive axleSome vehicles do not follow this typical example. Such as the older Porsche or Volkswagen vehicles which were rear engine, rear drive. These vehicles use a rear mounted transaxle with halfshafts connected to the drive wheels. Also, some vehicles were produced with a front engine, rear transaxle setup with a driveshaft connecting the engine to the transaxle, and halfshafts linking the transaxle to the drive wheels.Differential operationIn order to remove the wheel around in the kinematics due to the lack of co-ordination about the wheel diameter arising from a different or the same rolling radius of wheel travel required, inter-wheel motor vehicles are equipped with about differential, the latter to ensure that the car driver Bridge on both sides of the wheel when in range with a trip to the characteristics of rotating at different speeds to meet the requirements of the vehicle kinematics.Fig 3 Principle of differentialThe accompanying illustration has been provided to help understand how this occurs.1.The drive pinion, which is turned by the driveshaft, turns the ring gear.2.The ring gear, which is attached to the differential case, turns the case.3.The pinion shaft, located in a bore in the differential case, is at right angles to the axle shafts and turns with the case.4.The differential pinion (drive) gears are mounted on the pinion shaft and rotate with the shaft .5.Differential side gears (driven gears) are meshed with the pinion gears and turn with the differential housing and ring gear as a unit.6.The side gears are splined to the inner ends of the axle shafts and rotate the shafts as the housing turns.7.When both wheels have equal traction, the pinion gears do not rotate on the pinion shaft, since the input force of the pinion gears is divided equally between the two side gears.8.When it is necessary to turn a corner, the differential gearing becomes effective and allows the axle shafts to rotate at different speeds .Open-wheel differential on each general use the same amount of torque. To determine the size of the wheel torque to bear two factors:equipment and friction. In dry conditions, when a lot of friction, the wheel bearing torque by engine size and gear restrictions are hours in the friction (such as driving on ice), is restricted to a maximum torque, so that vehicles will not spin round. So even if the car can produce more torque, but also need to have sufficient traction to transfer torque to the ground. If you increase the throttle after the wheels slip, it will only make the wheels spin faster.Fig 4 Conventional differential Limited-slip and locking differential operationFig 5 Limited-slip differentialDifferential settlement of a car in the uneven road surface and steeringwheel-driven speed at about the different requirements; but is followed by the existence of differential in the side car wheel skid can not be effective when the power transmission, that is, the wheel slip can not produce the driving force, rather than spin the wheel and does not have enough torque. Good non-slip differential settlement of the car wheels skid on the side of the power transmission when the issue, that is, locking differential, so that no longer serve a useful differential right and left sides of the wheel can be the same torque.Limited-slip and locking differential operation can be divided into two major categories：(1) mandatory locking type in ordinary differential locking enforcement agencies to increase, when the side of the wheel skid occurs, the driver can be electric, pneumatic or mechanical means to manipulate the locking body meshing sets of DIP Shell will be with the axle differential lock into one, thus the temporary loss of differential role. Relatively simple structure in this way, but it must be operated by the driver, and good roads to stop locking and restore the role of differential.(2) self-locking differential installed in the oil viscosity or friction clutch coupling, when the side of the wheel skid occurs when both sides of the axle speed difference there, coupling or clutch friction resistance on the automatic, to make certain the other side of the wheel drive torque and the car continued to travel. When there is no speed difference on both sides of the wheel, the frictional resistance disappeared, the role of automatic restoration of differentials. More complicated structure in this way, but do not require drivers to operate. Has been increasingly applied in the car. About non-slip differential, notonly used for the differential between the wheels, but also for all-wheel drive vehicle inter-axle differential/.Gear ratioThe drive axle of a vehicle is said to have a certain axle ratio. This number (usually a whole number and a decimal fraction) is actually a comparison of the number of gear teeth on the ring gear and the pinion gear. For example, a 4.11 rear means that theoretically, there are 4.11 teeth on the ring gear for each tooth on the pinion gear or, put another way, the driveshaft must turn 4.11 times to turn the wheels once. The role of the final drive is to reduce the speed from the drive shaft, thereby increasing the torque. Lord of the reduction ratio reducer, a driving force for car performance and fuel economy have a greater impact. In general, the more reduction ratio the greater the acceleration and climbing ability, and relatively poor fuel economy. However, if it is too large, it can not play the full power of the engine to achieve the proper speed. The main reduction ratio is more Smaller ，the speed is higher, fuel economy is better, but the acceleration and climbing ability will be poor.附录B驱动桥和差速器所有的汽车都装有不同类型的驱动桥和差速器来驱动汽车行驶。
外文翻译：手动变速器概述
Manual transmissionManual transmission is the most basic of transmission of a type, its effect is changing, and provide the transmission reverse and neutral. Usually, the pilot on the clutch pedal through manipulation and in any HuanDangGan can choose between gear. There are a few manual transmission, such as motorcycles, cars, some transmission shift transmission allows only sequence, the transmission is called sequence shift transmission. In recent years, along with the electronic control components durability, computerized automatic switching clutch automatic shift of transmission in Europe since the start line are more and more popular, car V olkswagen and ford are sold in the city on the double clutch provide updated generation, transmission from the start with two clutches, every shift automatically switch to another group of clutch engagement, need not as quick as traditional in manual have only one group separated again clutch engagement, shifting speed is faster, more small change gear vibration.Internal structure: shaftDecorate a form of transmission shaft type usually have two and three shaft type two kinds. Usually a rear wheel drive car will adopt three axis type, i.e. input shaft transmission, the output shaft and oart. Input shaft front associated with engine, borrow clutch output shaft back-end through the flange and universal transmission device connected.Input shaft and the output shaft in the same horizontal line, with their oart parallel arrangement. From the input shaft power through the gears to preach to the output shaft oart again. In many input and output shaft transmission shaft could engage in together, so to power, then the gear oart called directly. Direct files through uniaxial transmission, the ratio of 1:1, the highest transmission efficiency. Even in the transmission directly, cannot offer the input shaft, and the output shaft is decorated in a straight line to reduce work needed to inherit the torque transmission.Reversing deviceGenerally speaking, the reverse gear reducer than can alsosynchronizerIn synchronized meshing gears have type synchronizer Settings, can make two gear engagement in the first, before the speed reached synchronizer in all of this manual geartransmission of the car has been usedClutch,The clutch is can make two gear with a separate with mechanical parts, two gear transmission power can be combined, but when to speed, so will depend on the first two gear clutch, change gear ratio, the two gear transmission power, continue again Control：GearIn simple terms, the high speed, low speed ShengDang when the time cameEvery car high speedCompared with automatic transmissionThis refers to the automatic transmission of traditional hydraulic transmission, namely through hydraulic torque converter and planetary gear transmission power automatic transmission.Advantages：transmission efficiency than automatic gearboxes for high, of course, theoretically can compare economical.maintenance will be cheaper than transmission.If you want to higher cost, can begin from both the row of convenience and high power手动变速器手动变速器是汽车变速器中最基本的一种类型，其作用是改变传动比，并提供倒档和空档。
变速器外文翻译
Continuously Variable Transmissions An Overview of CVT Research Past, Present, and FutureKevin R. Lang21W. 732May 3, 2000Table of Contents Introduction (1)CVT Theory & Design (2)Push Belt (2)Toroidal Traction Drive (2)Variable Diameter Elastomer Belt (3)Other CVT Varieties (3)Background & History (3)Inherent Advantages & Benefits (4)Challenges & Limitations (5)Research & Development (6)New CVT Research (7)Future Prospects for CVTs (9)CVTs & Hybrid Electric Vehicles (9)Conclusion (10)Works Cited (11)Figures and TablesFigure 1 – Metal Push Belt CVT (2)Figure 2 – Toroidal CVT (2)Figure 3 – Variable Diameter Belt CVT (3)Figure 4 – GM’s New CVT Design (6)Figure 5 – Audi CVT with link chain (6)Figure 6 – Cutaway of Audi CVT (7)Table 1 – Efficiency vs. Gear Ratio for Automatic Transmission (4)Table 2 – Efficiency of Various CVT Designs (4)AbstractAs the U.S. government enacts new regulations for automotive fuel economy and emissions, the continuously variable transmission, or CVT, continues to emerge as a key technology for improving the fuel efficiency of automobiles with internal combustion (IC) engines. CVTs use infinitely adjustable drive ratios instead of discrete gears to attain optimal engine performance. Since the engine always runs at the most efficient number of revolutions per minute for a given vehicle speed, CVT-equipped vehicles attain better gas mileage and acceleration than cars with traditional transmissions.CVTs are not new to the automotive world, but their torque capabilities and reliability have been limited in the past. New developments in gear reduction and manufacturing have led to ever-more-robust CVTs, which in turn allows them to be used in more diverse automotive applications. CVTs are also being developed in conjunction with hybrid electric vehicles. As CVT development continues, costs will be reduced further and performance will continue to increase, which in turn makes further development and application of CVT technology desirable.This paper evaluates the current state of CVTs and upcoming research and development, set in the context of past development and problems traditionally associated with CVTs. The underlying theories and mechanisms are also discussed.IntroductionAfter more than a century of research and development, the internal combustion (IC) engine is nearing both perfection and obsolescence: engineers continue to explore the outer limits of IC efficiency and performance, but advancements in fuel economy and emissions have effectively stalled. While many IC vehicles meet Low Emissions Vehicle standards, these will give way to new, stricter government regulations in the very near future. With limited room for improvement, automobile manufacturers have begun full-scale development of alternative power vehicles. Still, manufacturers are loath to scrap a century of development and billions or possibly even trillions of dollars in IC infrastructure, especially for technologies with no history of commercial success. Thus, the ideal interim solution is to further optimize the overall efficiency of IC vehicles.One potential solution to this fuel economy dilemma is the continuously variable transmission (CVT), an old idea that has only recently become a bastion of hope to automakers. CVTs could potentially allow IC vehicles to meet the first wave of new fuel regulations while development of hybrid electric and fuel cell vehicles continues. Rather than selecting one of four or five gears, a CVT constantly changes its gear ratio to optimize engine efficiency with a perfectly smooth torque-speed curve. This improves both gas mileage and acceleration compared to traditional transmissions.The fundamental theory behind CVTs has undeniable potential, but lax fuel regulations and booming sales in recent years have given manufacturers a sense of complacency: if consumers are buying millions of cars with conventional transmissions, why spend billions to develop and manufacture CVTs? Although CVTs have been used in automobiles for decades, limited torque capabilities and questionable reliability have inhibited their growth. Today, however, ongoing CVT research has led to ever-more-robust transmissions, and thus ever-more-diverse automotive applications. As CVT development continues, manufacturing costs will be further reduced and performance will continue to increase, which will in turn increase the demand for further development. This cycle of improvement will ultimately give CVTs a solid foundation in the world’s automotive infrastructure.Figure (1) – Metal Push Belt CVTFrom [3]Figure (2) – Toroidal CVTFrom [3]CVT Theory & DesignToday’s automobiles almost exclusively use either a conventional manual or automatictransmission with “multiple planetary gear sets that use integral clutches and bands to achieve discrete gear ratios” [3]. A typical automatic uses four or five such gears, while a manual normally employs five or six. The continuously variable transmission replaces discrete gear ratios with infinitely adjustable gearing through one of several basic CVT designs.Push BeltThis most common type of CVT usessegmented steel blocks stacked on a steel ribbon, asshown in Figure (1). This belt transmits powerbetween two conical pulleys, or sheaves, one fixedand one movable [3]. With a belt drive:In essence, a sensor reads the engine output and then electronically increases or decreases thedistance between pulleys, and thus the tension of the drive belt. The continuously changing distance between the pulleys—their ratio to one another—is analogous to shifting gears. [6]Push-belt CVTs were first developed decades ago, but new advances in belt design have recently drawn the attention of automakers worldwide.Toroidal Traction-DriveThese transmissions use the high shear strength of viscousfluids to transmit torque between an input torus and an outputtorus. As the movable torus slides linearly, the angle of a rollerchanges relative to shaft position, as seen in Figure (2). Thisresults in a change in gear ratio [3].Variable Diameter Elastomer BeltThis type of CVT, as represented in Figure (2), usesa flat, flexible belt mounted on movable supports. Thesesupports can change radius and thus gear ratio. However,the supports separate at high gear ratios to form adiscontinuous gear path, as seen in Figure (3). This can lead to the problems with creep and slip that have plagued CVTs for years [3]. This inherent flaw has directed research and development toward push belt CVTs.Other CVT VarietiesSeveral other types of CVTs have been developed over the course of automotive history, butthese have become less prominent than push belt and toroidal CVTs. A nutating traction drive uses a pivoting, conical shaft to change “gears” in a CVT. As the cones change angle, the inlet radius decreases while the outlet radius increases, or vice versa, resulting in an infinitely variable gear ratio [3]. A variable geometry CVT uses adjustable planetary gearsets to change gear ratios, but this is more akin to a flexible traditional transmission than a conventional CVT.Background & HistoryTo say that the continuously variable transmission (CVT) is nothing new would be a grossunderstatement: Leonardo da Vinci sketched his idea for a CVT in 1490 [1]. In automotive applications,CVTs have been around nearly as long as cars themselves, and certainly as long as conventionalautomatics. General Motors actually developed a fully toroidal CVT in the early 1930s and conducted extensive testing before eventually deciding to implement a conventional, stepped-gear automatic due to cost concerns. General Motors Research worked on CVTs again in the 1960s, but none ever sawproduction [2]. British manufacturer Austin used a CVT for several years in one of its smaller cars, but “it was dropped due to its high cost, poor reliability, and inadequate torque transmission” [2]. Many early CVTs used a simple rubber band and cone system, like the one developed by Dutch firm Daf in 1958 [1].Figure (3) – Variable Diameter Belt CVTFrom [3]However, the Daf CVT could only handle a 0.6 L engine, and problems with noise and rough starts hurt its reputation [1]. Uninspired by these early failures, automakers have largely avoided CVTs until very recently, especially in the United States.Inherent Advantages & BenefitsCertainly, the clunk of a shifting transmission is familiar to all drivers. By contrast, a continuously variable transmission is perfectly smooth—it naturally changes “gears” discreetly and minutely such that the driver or passenger feels only steady acceleration. In theory, a CVT would cause less engine fatigue and would be a more reliable transmission, as the harshness of shifts and discrete gears force the engine to run at a less-than-optimal speed.Moreover, CVTs offer improved efficiency and performance. Table (1) below shows the power transmission efficiency of a typical five-speed automatic, i.e. the percentage of engine power translated through the transmission. This yields an average efficiency of 86%, compared to a typical manual transmission with 97% efficiency [3]. By comparison, Table (2) below gives efficiency ranges for several CVT designs.Table (1) Efficiency vs. Gear Ratio for Automatic Transmission [3] Gear Efficiency Range160-85%260-90%385-95%490-95%585-94%Table (2) Efficiency of Various CVT Designs [3] CVT Mechanism Efficiency Range Rubber Belts90-95%Steel Belts90-97%Toroidal Traction70-94%Nutating Traction75-96%Variable Geometry85-93%These CVTs each offer improved efficiency over conventional automatic transmissions, and their efficiency depends less on driving habit than manual transmissions [3]. Moreover:Because the CVT allows an engine to run at this most efficient point virtuallyindependent of vehicle speed, a CVT equipped vehicle yields fuel economy benefitswhen compared to a conventional transmission (3)Testing by ZF Getriebe GmbH several years ago found that “the CVT uses at least 10% less fuel than a 4-speed automatic transmission” for U.S. Environmental Protection Agency city and highway cycles. Moreover, the CVT was more than one second faster in 0-60 mph acceleration tests [5]. The potential for fuel efficiency gains can also be seen in the CVT currently used in Honda’s Civic. A Civic with atraditional automatic averages 28/35 miles per gallon (mpg) city/highway, while the same car with a CVT gets 34/38 mpg city/highway [4]. Honda has used continuously variable transmissions in the Civic for several years, but these are 1.6 liter cars with limited torque capabilities. Ongoing research and development will inevitably expand the applicability of CVTs to a much broader range of engines and automobiles.Challenges & LimitationsCVT development has progressed slowly for a variety of reasons, but much of the delay in development can be attributed to a lack of demand: conventional manual and automatic transmissions have long offered sufficient performance and fuel economy. Thus, problems encountered in CVT development usually stopped said progress. “Designers have … unsuccessfully tried to develop [a CVT] that can match the torque capacity, efficiency, size, weight, and manufacturing cost of step-ratio transmissions” [6].One of the major complaints with previous CVTs has been slippage in the drive belt or rollers. This is caused by the lack of discrete gear teeth, which form a rigid mechanical connection between to gears; friction drives are inherently prone to slip, especially at high torque. With early CVTs of the 1950s and 1960s, engines equipped with CVTs would run at excessively high RPM trying to “catch up” to the slipping belt. This would occur any time the vehicle was accelerated from a stop at peak torque:“For compressive belts, in the process of transmitting torque, micro slip occurs betweenthe elements and the pulleys. This micro slip tends to increase sharply once thetransmitted torque exceeds a certain value …” [8]For many years, the simple solution to this problem has been to use CVTs only in cars with relativelylow-torque engines. Another solution is to employ a torque converter (such as those used in conventional automatics), but this reduces the CVT’s efficiency [2].Perhaps more than anything else, CVT development has been hindered by cost. Low volume and a lack of infrastructure have driven up manufacturing costs, which inevitably yield higher transmission prices. With increased development, most of these problems can be addressed simply by improvements in manufacturing techniques and materials processing. For example, Nissan’s Extroid “is derived from aFigure (4) – GM’s New CVT designFrom [6]Figure (5) – Audi CVT with link chainFrom [1]century-old concept, perfected by modern technology, metallurgy, chemistry, electronics, engineering,and precision manufacturing” [2].In addition, CVT control must be addressed. Even if a CVT can operate at the optimal gear ratio at any speed, how does it “know” what ratio to select? Manual transmissions have manual controls,where the driver shifts when he or she so desires; automatic transmissions have relatively simple shifting algorithms to accommodate between three and five gears. However, CVTs require far more complex algorithms to accommodate an infinite division of speeds and gear ratios.Research & DevelopmentWhile IC development has slowed in recent years asautomobile manufacturers devote more resources to hybrid electricvehicles (HEVs) and fuel cell vehicles (FEVs), CVT research anddevelopment is expanding quickly. Even U.S. automakers, who havelagged in CVT research until recently, are unveiling new designs:General Motors plans to implement metal-belt CVTs in some vehiclesby 2002 [6].The Japanese and Germans continue to lead the way in CVT development. Nissan has taken a dramatic step with its “Extroid” CVT, offered in the home-market Cedric and Gloria luxury sedans. This toroidal CVT costs more than a conventional belt-driven CVT, but Nissan expects the extra cost to be absorbed by the luxury cars’ prices [2]. The Extroid uses a high viscosity fluid to transmit power between the disks and rollers, rather than metal-to-metal contact. Coupled with a torque converter, this yields“exceptionally fast ratio changes”. Most importantly, though, theExtroid is available with a turbocharged version of Nissan’s 3.0 literV6 producing 285 lb-ft of torque; this is a new record for CVTtorque capacity [2].Audi’s new CVT offers both better fuel mileage than a conventional automatic and better acceleration than even aFigure (6) – Cutaway of Audi CVT From [1]manual transmission. Moreover, Audi claims it can offer the CVT at only a slight price increase [1]. This so-called “multitronic” CVT uses an all-steel link plate chain instead of a V-belt in order to handle up to 280 lb-ft of torque [1]. In addition, “Audi claims that the multitronic A6accelerates from 0-100 km/h (0-62 mph) 1.3 s quicker than a gearedautomatic transmission and is 0.1 s quicker over the same speed than anequivalent model with “optimum” use of a five speed manual gearbox”[1]. If costs were sufficiently reduced, a transmission such as this couldbe used in almost any automobile in the world.Many small cars have used CVTs in recent years, and many more will use them in the near future. Nissan, Honda, and Subaru currently use belt-drive CVTsdeveloped with Dutch company Van Doorne Transmissie (VDT) in some of their smaller cars [7]. Suzuki and Daihatsu are jointly developing CVTs with Japanese company Aichi Machine, using analuminum/plastic composite belt reinforced with Aramid fibers. Their CVT uses an auxiliary transmission for starts to avoid low-speed slip. After about 6 mph, the CVT engages and operates as it normally would[7]. “The auxiliary geartrain’s direct coupling ensures sufficiently brisk takeoff and initial acceleration”[7]. However, Aichi’s CVT can only handle 52 lb-ft of torque. This alone effectively negates itspotential for the U.S. market. Still, there are far more CVTs in production for 2000 than for 1999, and each major automobile show brings more announcements for new CVTs.New CVT ResearchAs recently as 1997, CVT research focused on the basic issues of drive belt design and power transmission. Now, as belts by VDT and other companies become sufficiently efficient, research focuses primarily on control and implementation of CVTs.Nissan Motor Co. has been a leader in CVT research since the 1970s. A recent study analyzing the slip characteristics of a metal belt CVT resulted in a simulation method for slip limits and torque capabilities of CVTs [8]. This has led to a dramatic improvement in drive belt technology, since CVTs can now be modeled and analyzed with computer simulations, resulting in faster development and moreefficient design. Nissan’s research on the torque limits of belt-drive CVTs has also led to the use of torque converters, which several companies have since implemented. The torque converter is designed to allow “creep,” the slow speed at which automatic transmission cars drive without driver-induced acceleration. The torque converter adds “improved creep capability during idling for improved driveability at very low speeds and easy launch on uphill grades” [9]. Nissan’s Extroid uses such a torque converter for “smooth starting, vibration suppression, and creep characteristics” [2].CVT control has recently come to the forefront of research; even a mechanically perfect CVT is worthless without an intelligent active control algorithm. Optimal CVT performance demands integrated control, such as the system developed by Nissan to “obtain the demanded drive torque with optimum fuel economy” [13]. The control system determines the necessary CVT ratio based on a target torque, vehicle speed, and desired fuel economy. Honda has also developed an integrated control algorithm for its CVTs, considering not only the engine’s thermal efficiency but also work loss from drivetrain accessories and the transmission itself [12]. Testing of Honda’s algorithm with a prototype vehicle resulted in a one percent fuel economy increase compared to a conventional algorithm. While not a dramatic increase, Honda claims that its algorithm is fundamentally sound, and thus will it become “one of the basic technologies for the next generation’s powerplant control” [12].Although CVTs are currently in production, many control issues still amount to a “tremendous number of trials and errors” [10]. One study focusing on numerical representation of power transmission showed that “both block tilting and pulley deformation meaningfully effected the pulley thrust ratio between the driving and the driven pulleys” [10]. Thus, the resultant model of CVT performance can be used in future applications for transmission optimization. As more studies are conducted, fundamental research such as this will become the legacy of CVT design, and research can become more specialized as CVTs become more refined.As CVTs move from research and development to assembly line, manufacturing research becomes more important. CVTs require several crucial, high-tolerance components in order to function efficiently; Honda studied one of these, the pulley piston, in 1998. Honda found that prototype pistons“experienced a drastic thickness reduction (32% at maximum) due to the conventional stretch forming method” [11]. A four-step forming process was developed to ensure “a greater and more uniform thickness increase” and thus greater efficiency and performance. Moreover, work-hardening during the forming process further increased the pulley piston’s strength [11].Size and weight of CVTs has long been a concern, since conventional automatics weigh far more than manual transmissions and CVTs outweigh automatics. Most cars equipped with automatic transmissions have a curb weight between 50 and 150 pounds heavier than the same cars with manual transmissions. To solve this problem, Audi is currently developing magnesium gearbox housings, a first for cars in its class. This results in nearly a 16 pound weight reduction over conventional automatics. [1]. Future Prospects for CVTsMuch of the existing literature is quick to admit that the automotive industry lacks a broad knowledge base regarding CVTs. Whereas conventional transmissions have been continuously refined and improved since the very start of the 20th century, CVT development is only just beginning. As infrastructure is built up along with said knowledge base, CVTs will become ever-more prominent in the automotive landscape. Even today’s CVTs, which represent first-generation designs at best, outperform conventional transmissions. Automakers who fail to develop CVTs now, while the field is still in its infancy, risk being left behind as CVT development and implementation continues its exponential growth. Moreover, CVTs are do not fall exclusively in the realm of IC engines.CVTs & Hybrid Electric VehiclesWhile CVTs will help to prolong the viability of internal combustion engines, CVTs themselves will certainly not fade if and when IC does. Several companies are currently studying implementation of CVTs with HEVs. Nissan recently developed an HEV with “fuel efficiency … more than double that of existing vehicles in the same class of driving performance” [14]. The electric motor avoids the low-speed/high torque problems often associated with CVTs, through an innovative double-motor system. At low speeds:A low-power traction motor is used as a substitute mechanism to accomplish thefunctions of launch and forward/reverse shift. This has made it possible to discontinueuse of a torque converter as the launch element and a planetary gearset and wet multiplateclutches as the shift mechanism. [14]Thus use of a CVT in a HEV is optimal: the electric portion of the power system avoids the low-speed problems of CVTs, while still retaining the fuel efficiency and power transmission benefits at high speeds.. Moreover, “the use of a CVT capable of handling high engine torque allows the system to be applied to more powerful vehicles” [14]. Obviously, automakers cannot develop individual transmissions for each car they sell; rather, a few robust, versatile CVTs must be able to handle a wide range of vehicles.Korean automaker Kia has proposed a rather novel approach to CVTs and their application to hybrids. Kia recently tested a system where “the CVT allows the engine to run at constant speed and the motor allows the engine to run at constant torque independent of driving conditions” [15]. Thus, both gasoline engine and electric motor always run at their optimal speeds, and the CVT adjusts as needed to accelerate the vehicle. Kia also presented a control system for this unified HEV/CVT combination that optimizes fuel efficiency for the new configuration.ConclusionToday, only a handful of cars worldwide make use of CVTs, but the applications and benefits of continuously variable transmissions can only increase based on today’s research and development. As automakers continue to develop CVTs, more and more vehicle lines will begin to use them. As development continues, fuel efficiency and performance benefits will inevitably increase; this will lead to increased sales of CVT-equipped vehicles. Increased sales will prompt further development and implementation, and the cycle will repeat ad infinitum. Moreover, increasing development will foster competition among manufacturers—automakers from Japan, Europe, and the U.S. are already either using or developing CVTs—which will in turn lower manufacturing costs. Any technology with inherent benefits will eventually reach fruition; the CVT has only just begun to blossom.Works Cited[1]S. Birch: “Audi takes CVT from 15th century to 21st century”. Automotive Engineering International,January 2000.[2]J. Yamaguchi: “Nissan’s Extroid CVT”. Automotive Engineering International, February 2000.[3]M.A. Kluger and D.R. Fussner: “An Overview of Current CVT Mechanisms, Forces andEfficiencies” SAE Paper No. 970688, in SAE SP-1241, Transmission and Driveline SystemsSymposium, pp. 81-88 SAE, 1997.[4]U.S. Environmental Protection Agency, /feg/findacar.htm.Accessed 4/15/00.[5]M. Boos and H. Mozer: “ECOTRONIC – The Continuously Variable ZF Transmission (CVT)” SAEPaper No. 970685, in SAE SP-1241, Transmission and Driveline Systems Symposium, pp. 61-67 SAE, 1997.[6]J.L. Broge: “GM Powertrain’s evolving transmissions”. Automotive Engineering International,November 1999.[7]J. Yamaguchi: “Two new CVTs for mini cars”. Automotive Engineering International, March 1999.[8]D. Kobayashi, Y. Mabuchi and Y. Katoh: “A Study on the Torque Capacity of a Metal Pushing V-Belt for CVTs” SAE Paper No. 980822, in SAE SP –1324, Transmission and Driveline Systems Symposium, pp. 31-39 SAE, 1998.[9]K. Abo, M. Kobayashi and M. Kurosawa: “Development of a Metal Belt Drive CVT Incorporating aTorque Converter for Use with 2-liter Class Engines” SAE Paper No. 980823, in SAE SP-1324, Transmission and Driveline Systems Symposium, pp. 41-48 SAE, 1998.[10]T. Miyazawa, T. Fujii, K. Nonaka and M. Takahashi: “Power Transmitting Mechanism of a DryHybrid V-Belt for a CVT – Advanced Numerical Model Considering Block Tilting and PulleyDeformation” SAE Paper No. 1999-01-0751, in SAE SP-1440, Transmission and Driveline Systems Symposium, pp. 143-153 SAE, 1999.[11]K. Ohya and H. Suzuki: “Development of CVT Pulley Piston Featuring Variable Thickness andWork-Hardening Technologies” SAE Paper No. 980826, in SAE SP-1324, Transmission andDriveline Systems Symposium, pp. 71-79 SAE, 1998.[12]S. Sakaguchi, E. Kimura and K. Yamamoto: “Development of an Engine-CVT Integrated ControlSystem” SAE Paper No. 1999-01-0754, in SAE SP-1440, Transmission and Driveline SystemsSymposium, pp. 171-179 SAE, 1999.[13]M. Yasuoka, M. Uchida, S. Katakura and T. Yoshino: “An Integrated Control Algorithm for anSI Engine and a CVT” SAE Paper No. 1999-01-0752, in SAE SP-1440, Transmission and Driveline Systems Symposium, pp. 155-160 SAE, 1999.[14]N. Hattori, S. Aoyama, S. Kitada and I. Matsuo: “Functional Design of a Motor Integrated CVTfor a Parallel HEV” SAE Paper No. 1999-01-0753, in SAE SP-1440, Transmission and Driveline Systems Symposium, pp. 161-167 SAE, 1999.[15] C. Kim, E. NamGoong, S. Lee, T. Kim and H. Kim: “Fuel Economy Optimization for ParallelHybrid Vehicles with CVT” SAE Paper No. 1999-01-1148, in SAE SP-1440, Transmission and Driveline Systems Symposium, pp. 337-343 SAE, 1999.。
汽车变速器英语词汇
〔副变速器〕变速杆range selector按钮控制finger-tip control半自动换档机械式变速器semi-automatic mechanical transmission 半自动液力变速器semiautomatic transmission包角scroll泵轮impeller边斜角〔进出口〕bias(entrance and exit)变矩比torque ratio变矩范围torque conversion range变矩系数torque ratio变容式液力变矩器variable capacity converter变速叉shifting fork (gear shift fork)变速齿轮transmission gear变速齿轮比〔变速比〕transmission gear ratio变速齿轮组change gear set变速杆stick shift(gear shift lever)变速轨〔拨叉道轨〕shift rail变速器transmission (gearbox)变速器输出轴transmission output shaft变速器输入轴transmission input shaft变速器中间轴transmission countershaft变速器轴的刚度rigidity of shaft变速器主动齿轮轴transmission drive gear shaft变速器主轴transmission main shaft变速踏板gear shift pedal操纵杆control lever槽导变速gate change长行星齿轮long planet gear常啮齿轮constant mesh gear常啮合齿轮传动constant mesh transmission常压式同步器constant pressure synchronizer超速档变速器over drive transmission超限换档overrun shift传动比gear ratio带主减速器的变速器final driving transmission单向离合器one-way clutch单向离合器换档freewheel shift导轮可反转的变矩器torque converter with reversal reactor 倒档reverse gear倒档中间齿轮reverse idler gear低速档bottom gear(low speed gear)第二档second gear第一档first gear电磁阀调压阀solenoid regulator valve电液式自动换档系统electronic -hydraulic automatic电子同步变速装置electronically synchronized transmission assembly 调压阀pressure -regulator valve调制压力modulated pressure定输入扭矩特性constant input torque performance定轴式液力变速器countershaft transmission定子stator动力换档power shift动力换档过程timing动力相似dynamic similarity动力助力换档变速器power assisted shift transmission短行星齿轮short planet gear多级变速器multi-speed transmission多中间轴变速器multi-countershaft transmission反拖特性coast performance方向盘式变速column shift (handle change)分动齿轮〔分动机构〕transfer gear分动箱〔分动器〕transfer case分动箱控制杆transfer gear shift fork分段式多档变速器sectional type multi-speed transmission分流式液力变速器split torque drive transmission辅助变速器auxiliary gear box副变速器splitter副轴counter shaft副轴齿轮counter shaft gear高速档top gear(high gear)固定轴式变速器fixed shaft transmission 惯性式同步器inertial type of synchronizer 过载系数overloading ratio后油泵gear pump (output pump )滑差slip滑动齿轮sliding gear滑动齿轮变速器sliding gear transmission 滑动齿轮传动sliding -gear transmission 缓冲压力compensator or trimmer pressure 换档shift换档点shift point换档定时property of automatic shift换档阀shift valve换档规律process of power shift换档机构gearshift换档循环shift schedule换档元件engaging element换档指令发生器shift pattern generator回油泵scavenge oil pump机械式变速器mechanical transmission 级stage几何相似geometry similarity继动阀relay valve。
机械毕业设计英文外文翻译462双离合变速器
附录外文文献Dual clutch transmissionFrom Wikipedia, the free encyclopediaA dual clutch transmission, commonly abbreviated to hoop DCT (sometimes informally referred to as a twin-clutch gearbox, double clutch transmission, or similar variations thereof), is a differing type of semi-automatic or automated manual automotive transmission. It utilises two separate clutches for odd and even gear sets. It can fundamentally be described as two separate manual transmissions (with their respective clutches) contained within one housing, and working as one unit. They are usually operated in a fully automatic mode, and many also have the ability to allow the driver to manually shift gears, albeit still carried out by the transmission's electro-hydraulics.This type of transmission was invented by Frenchman Adolphe Kégresse just prior to World War II but he never developed a working model. The first actual DCTs arrived from Porsche in-house development, for Porsche racing cars in the 1980s, when computers to control the transmission became compact enough: the Porsche Doppelkupplungsgetriebe (English: dual clutch gearbox) (PDK) used inthe Porsche 956 and 962 Le Mans race cars from 1983, and the Audi Sport Quattro S1 rally car.A dual clutch transmission eliminates the torque converter as used in conventional epicyclic-geared automatic transmissions. Instead, dual clutch transmissions that are currently on the market primarily use two oil-bathed wet multi-plate clutches, similar to the clutches used in most motorcycles, though dry clutch versions are also available. The first series production road car to be fitted with a DCT was the 2003 Volkswagen Golf Mk4 R32.As of 2009, the largest number of sales of DCTs in Western Europe are by various marques of the German Volkswagen Group, though this is anticipated to lessen as other transmission makers and vehicle manufacturers make DCTs available in series production automobiles. In 2010, on BMW Canada's website for the 3 Series Coupe, it is described both as a 7-speed double clutch transmission and as a 7-speed automatic transmission. It is actually a dual clutch semi-automatic.In DCTs where the two clutches are arranged concentrically, the larger outer clutch drives the odd numbered gears, whilst the smaller inner clutch drives the even numbered gears. Shifts can be accomplished without interrupting torque distribution to the driven roadwheels, by applying the engine's torque to one clutch at thesame time as it is being disconnected from the other clutch. Since alternate gear ratios can pre-select an odd gear on one gear shaft whilst the vehicle is being driven in an even gear, (and vice versa), DCTs are able to shift more quickly than other cars equipped with single-clutch automated-manual transmissions (AMTs), a.k.a. single-clutch semi-automatics. Also, with a DCT, shifts can be made more smoothly than with an AMT, making a DCT more suitable for conventional road cars.Characteristic of Dual clutch gearboxAdvantages:1. Compared with the traditional planetary gear type automatic gearbox fuel economy is more advantageous to the ascension can reduce fuel consumption about 15 percent2. During the shift, almost no damage3. When high-grade gear is already in preparation condition, rise against extremely fast, achieve astonishing 8 millisecond4. No matter what is running mode accelerator or condition, can reach 600 shift time (at least from the odd block to millisecond odd block, or even block drop from even when it took about block, for 900 milliseconds, for example from the first five block to 3 block)Faults:1. The electric control system and hydraulic system due to the existence of gearbox efficiency, double clutch than traditional manual gearbox still used to deliver big torque, especially the wet dual clutch gearbox is even more so2. Dual clutch gearbox cost is higher, the development of precision and complex double clutch, resulting in higher prices3. When need to switch gears in preparation condition, not shift time relatively long, in some cases even more than 1 second4. Dual clutch gearbox, compared with the traditional manual gearbox heavier5. Dual clutch the biggest transfer torque transmission on the low side, restrain the engine of space6. Early dual clutch gearbox reliability poor7. Gearbox lubricant need according to factories require change regularly, and replacement costs is not cheap附录外文文献翻译双离合变速器双离合变速器是当前发展最迅速的新型变速箱，它以传统手动变速箱为基础加入双和电控组件，获得优异的性能表现和良好的燃油经济性。
变速器(英文版文献)
Transmission (mechanics)A transmission or gearbox provides speed and torque conversions from a rotating power source to another device using gear ratios. In British English the term transmission refers to the whole drive train, including gearbox, clutch, prop shaft (for rear-wheel drive), differential and final drive shafts. The most common use is in motor vehicles, where the transmission adapts the output of the internal combustion engine to the drive wheels. Such engines need to operate at a relatively high rotational speed, which is inappropriate for starting, stopping, and slower travel. The transmission reduces the higher engine speed to the slower wheel speed, increasing torque in the process. Transmissions are also used on pedal bicycles, fixed machines, and anywhere else rotational speed and torque needs to be adapted.Often, a transmission will have multiple gear ratios (or simply "gears"), with the ability to switch between them as speed varies. This switching may be done manually (by the operator), or automatically. Directional (forward and reverse) control may also be provided. Single-ratio transmissions alsoexist, which simply change the speed and torque (and sometimes direction) of motor output.In motor vehicle applications, the transmission will generally be connected to the crankshaft of the engine. The output of the transmission is transmitted via driveshaft to one or more differentials, which in turn drive the wheels. While a differential may also provide gear reduction, its primary purpose is to change the direction of rotation.Conventional gear/belt transmissions are not the only mechanism for speed/torque adaptation. Alternative mechanisms include torque converters and power transformation (e.g., diesel-electric transmission, hydraulic drive system, etc.). Hybrid configurations also exist.ExplanationEarly transmissions included the right-angle drives and other gearing in windmills, horse-powered devices, and steam engines, in support of pumping, milling, and hoisting.Most modern gearboxes are used to increase torque while reducing the speed of a prime mover output shaft (e.g. a motor crankshaft). This means that the output shaft of a gearbox willrotate at slower rate than the input shaft, and this reduction in speed will produce a mechanical advantage, causing an increase in torque. A gearbox can be setup to do the opposite and provide an increase in shaft speed with a reduction of torque. Some of the simplest gearboxes merely change the physical direction in which power is transmitted.Many typical automobile transmissions include the ability to select one of several different gear ratios. In this case, most of the gear ratios (often simply called "gears") are used to slow down the output speed of the engine and increase torque. However, the highest gears may be "overdrive" types that increase the output speed.UsesGearboxes have found use in a wide variety of different—often stationary—applications, such as wind turbines.Transmissions are also used in agricultural, industrial, construction, mining and automotive equipment. In addition to ordinary transmission equipped with gears, such equipment makes extensive use of the hydrostatic drive and electrical adjustable-speed drives.SimpleThe simplest transmissions, often called gearboxes to reflect their simplicity (although complex systems are also called gearboxes in the vernacular), provide gear reduction (or, more rarely, an increase in speed), sometimes in conjunction with a right-angle change in direction of the shaft (typically in helicopters, see picture). These are often used on PTO-powered agricultural equipment, since the axial PTO shaft is at odds with the usual need for the driven shaft, which is either vertical (as with rotary mowers), or horizontally extending from one side of the implement to another (as with manure spreaders, flail mowers, and forage wagons). More complex equipment, such as silage choppers and snowblowers, have drives with outputs in more than one direction.The gearbox in a wind turbine converts the slow, high-torque rotation of the turbine into much faster rotation of the electrical generator. These are much larger and more complicated than the PTO gearboxes in farm equipment. They weigh several tons and typically contain three stages to achieve an overall gear ratio from 40:1 to over 100:1, depending on the size of the turbine. (For aerodynamic and structuralreasons, larger turbines have to turn more slowly, but the generators all have to rotate at similar speeds of several thousand rpm.) The first stage of the gearbox is usually a planetary gear, for compactness, and to distribute the enormous torque of the turbine over more teeth of the low-speed shaft. Durability of these gearboxes has been a serious problem for a long time.Regardless of where they are used, these simple transmissions all share an important feature: the gear ratio cannot be changed during use. It is fixed at the time the transmission is constructed.For transmission types that overcome this issue, see Continuously Variable Transmission, also known as CVT.Multi-ratio systemsMany applications require the availability of multiple gear ratios. Often, this is to ease the starting and stopping of a mechanical system, though another important need is that of maintaining good fuel efficiency.Automotive basicsThe need for a transmission in an automobile is aconsequence of the characteristics of the internal combustion engine. Engines typically operate over a range of 600 to about 7000 revolutions per minute (though this varies, and is typically less for diesel engines), while the car's wheels rotate between 0 rpm and around 1800 rpm.Furthermore, the engine provides its highest torque outputs approximately in the middle of its range, while often the greatest torque is required when the vehicle is moving from rest or traveling slowly. Therefore, a system that transforms the engine's output so that it can supply high torque at low speeds, but also operate at highway speeds with the motor still operating within its limits, is required. Transmissions perform this transformation.Many transmissions and gears used in automotive and truck applications are contained in a cast iron case, though more frequently aluminium is used for lower weight especially in cars. There are usually three shafts: a mainshaft, a countershaft, and an idler shaft.The mainshaft extends outside the case in both directions: the input shaft towards the engine, and the output shaft towards the rear axle (on rear wheel drive cars- front wheel drives generally have the engine and transmission mountedtransversely, the differential being part of the transmission assembly.) The shaft is suspended by the main bearings, and is split towards the input end. At the point of the split, a pilot bearing holds the shafts together. The gears and clutches ride on the mainshaft, the gears being free to turn relative to the mainshaft except when engaged by the clutches.Types of automobile transmissions include manual, automatic or semi-automatic transmission.ManualMain article: Manual transmissionManual transmission come in two basic types:a simple but rugged sliding-mesh or unsynchronized / non-synchronous system, where straight-cut spur gear sets are spinning freely, and must be synchronized by the operator matching engine revs to road speed, to avoid noisy and damaging "gear clash", and the now common constant-mesh gearboxes which can include non-synchronised, or synchronized / synchromesh systems, where diagonal cut helical (and sometimes double-helical) gear sets are constantly "meshed" together, and a dog clutch is used for changing gears. On synchromesh boxes, friction cones or "synchro-rings" are used in addition to the dog clutch.The former type is commonly found in many forms of racing cars, older heavy-duty trucks, and some agricultural equipment.Manual transmissions are the most common type outside North America and Australia. They are cheaper, lighter, usually give better performance, and fuel efficiency (although the latest sophisticated automatic transmissions may yield results slightly better than the ones yielded by manual transmissions). It is customary for new drivers to learn, and be tested, on a car with a manual gear change. In Malaysia, Denmark and Poland all cars used for testing (and because of that, virtually all those used for instruction as well) have a manual transmission. In Japan, the Philippines, Germany, Italy, Israel, the Netherlands, Belgium, New Zealand, Austria, Bulgaria, the UK, Ireland, Sweden, Estonia, France, Spain, Switzerland, the Australian states of Victoria and Queensland, Finland and Lithuania, a test pass using an automatic car does not entitle the driver to use a manual car on the public road; a test with a manual car is required.Manual transmissions are much more common than automatic transmissions in Asia, Africa, South America and Europe.Most manual transmissions include both synchronized andunsynchronized gearing, such as a reverse gear and a low-speed "granny gear", both of which can only be shifted into when stopped. Shifting from granny gear to a low synchronized gear is generally available while in motion, while shifting out of reverse to any other gear typically requires the vehicle to be stopped.Non-synchronousMain article: Non-synchronous transmissionsThere are commercial applications engineered with designs taking into account that the gear shifting will be done by an experienced operator. They are a manual transmission, but are known as non-synchronized transmissions. Dependent on country of operation, many local, regional, and national laws govern the operation of these types of vehicles (see Commercial Driver's License). This class may include commercial, military, agricultural, or engineering vehicles. Some of these may use combinations of types for multi-purpose functions. An example would be a PTO, or power-take-off gear. The non-synchronous transmission type requires an understanding of gear range, torque, engine power, and multi-functional clutch and shifter functions. Also see Double-clutching, and Clutch-brakesections of the main article at non-synchronous transmissionsAutomaticMain article: Automatic transmissionEpicyclic gearing or planetary gearing as used in an automatic transmission.Most modern North American and Australian and many larger, high specification European and Japanese cars have an automatic transmission that will select an appropriate gear ratio without any operator intervention. They primarily use hydraulics to select gears, depending on pressure exerted by fluid within the transmission assembly. Rather than using a clutch to engage the transmission, a fluid flywheel, or torque converter is placed in between the engine and transmission. It is possible for the driver to control the number of gears in use or select reverse, though precise control of which gear is in use may or may not be possible.Automatic transmissions are easy to use. However, in the past, automatic transmissions of this type have had a number of problems; they were complex and expensive, sometimes had reliability problems (which sometimes caused more expenses in repair), have often been less fuel-efficient than their manualcounterparts (due to "slippage" in the torque converter), and their shift time was slower than a manual making them uncompetitive for racing. With the advancement of modern automatic transmissions this has changed.Attempts to improve the fuel efficiency of automatic transmissions include the use of torque converters which lock up beyond a certain speed, or in the higher gear ratios, eliminating power loss, and overdrive gears which automatically actuate above certain speeds; in older transmissions both technologies could sometimes become intrusive, when conditions are such that they repeatedly cut in and out as speed and such load factors as grade or wind vary slightly. Current computerized transmissions possess very complex programming to both maximize fuel efficiency and eliminate any intrusiveness.For certain applications, the slippage inherent in automatic transmissions can be advantageous; for instance, in drag racing, the automatic transmission allows the car to be stopped with the engine at a high rpm (the "stall speed") to allow for a very quick launch when the brakes are released; in fact, a common modification is to increase the stall speed of the transmission. This is even more advantageous forturbocharged engines, where the turbocharger needs to be kept spinning at high rpm by a large flow of exhaust in order to keep the boost pressure up and eliminate the turbo lag that occurs when the engine is idling and the throttle is suddenly openedSemi-automaticMain article: Semi-automatic transmissionThe creation of computer control also allowed for a sort of cross-breed transmission where the car handles manipulation of the clutch automatically, but the driver can still select the gear manually if desired. This is sometimes called a "clutchless manual," or "automated manual" transmission. Many of these transmissions allow the driver to give full control to the computer. They are generally designed using manual transmission "internals", and when used in passenger cars, have synchromesh operated helical constant mesh gear sets.Specific type of this transmission includes: Easytronic, and Geartronic.A "dual-clutch" transmission uses two sets of internals which are alternately used, each with its own clutch, so that only the clutches are used during the actual "gearchange".Specific type of this transmission includes: Direct-ShiftGearbox.There are also sequential transmissions which use the rotation of a drum to switch gears.Bicycle gearingMain articles: Bicycle gearing, Derailleur gears, and Hub gear Bicycles usually have a system for selecting different gear ratios. There are two main types: derailleur gears and hub gears. The derailleur type is the most common, and the most visible, using sprocket gears. Typically there are several gears available on the rear sprocket assembly, attached to the rear wheel. A few more sprockets are usually added to the front assembly as well. Multiplying the number of sprocket gears in front by the number to the rear gives the number of gear ratios, often called "speeds".Hub gears use epicyclic gearing and are enclosed within the axle of the rear wheel. Because of the small space, they typically offer fewer different speeds, although at least one has reached 14 gear ratios and Fallbrook Technologies manufactures a transmission with technically infinite ratios.Causes for failure of bicycle gearing include: worn teeth, damage caused by a faulty chain, damage due to thermal expansion,broken teeth due to excessive pedaling force, interference by foreign objects, and loss of lubrication due to negligence.Uncommon typesDual clutch transmissionMain article: Dual clutch transmissionThis arrangement is also sometimes known as a direct shift gearbox or powershift gearbox. It seeks to combine the advantages of a conventional manual shift with the qualities of a modern automatic transmission by providing different clutches for odd and even speed selector gears. When changing gear, the engine torque is transferred from one gear to the other continuously, so providing gentle, smooth gear changes without either losing power or jerking the vehicle. Gear selection may be manual, automatic (depending on throttle/speed sensors), or a 'sports' version combining both options.Continuously variableMain article: Continuously variable transmissionThe Continuously Variable Transmission (CVT) is a transmission in which the ratio of the rotational speeds of twoshafts, as the input shaft and output shaft of a vehicle or other machine, can be varied continuously within a given range, providing an infinite number of possible ratios.The continuously variable transmission (CVT) should not be confused with the Infinitely Variable Transmission (IVT) (See below).The other mechanical transmissions described above only allow a few different gear ratios to be selected, but this type of transmission essentially has an infinite number of ratios available within a finite range. The continuously variable transmission allows the relationship between the speed of the engine and the speed of the wheels to be selected within a continuous range. This can provide even better fuel economy if the engine is constantly running at a single speed. The transmission is in theory capable of a better user experience, without the rise and fall in speed of an engine, and the jerk felt when poorly changing gears.Infinitely variableThe IVT is a specific type of CVT that has an infinite range of input/output ratios in addition to its infinite number of possible ratios; this qualification for the IVT implies thatits range of ratios includes a zero output/input ratio that can be continuously approached from a defined 'higher' ratio. A zero output implies an infinite input, which can be continuously approached from a given finite input value with an IVT. [Note: remember that so-called 'low' gears are a reference to low ratios of output/input, which have high input/output ratios that are taken to the extreme with IVT's, resulting in a 'neutral', or non-driving 'low' gear limit.] Most (if not all) IVT's result from the combination of a CVT with an epicyclic gear system (which is also known as a planetary gear system) that facilitates the subtraction of one speed from another speed within the set of input and planetary gear rotations. This subtraction only needs to result in a continuous range of values that includes a zero output; the maximum output/input ratio can be arbitrarily chosen from infinite practical possibilities through selection of extraneous input or output gear, pulley or sprocket sizes without affecting the zero output or the continuity of the whole system. Importantly, the IVT is distinguished as being 'infinite' in its ratio of high gear to low gear within its range; high gear is infinite times higher than low gear. The IVT is always engaged, even during its zero output adjustment.The term 'infinitely variable transmission' does not imply reverse direction, disengagement, automatic operation, or any other quality except ratio selectability within a continuous range of input/output ratios from a defined minimum to an undefined, 'infinite' maximum. This means continuous range from a defined output/input to zero output/input ratio.Electric variableThe Electric Variable Transmission (EVT) is a transmission that achieves CVT action and in addition can use separate power inputs to produce one output. An EVT usually is executed in design with an epicyclic differential gear system (which is also known as a planetary gear system). The epicyclic differential gearing performs a "power-split" function, directly connecting a portion of the mechanical power directly through the transmission and splitting off a portion for subsequent conversion to electrical power via a motor/generator. Hence, the EVT is called a Power Split Transmission (PST) by some.The directly connected portion of the power travelling through the EVT is referred to as the "mechanical path". The remaining power travels down the EVT's "electrical path". Thatpower may be recombined at the output of the transmission or stored for later, more opportune use via a second motor/generator (and energy storage device) connected to the transmission output.The pair of motor/generators forms an Electric Transmission in its own right, but at a lower capacity, than the EVT it is contained within. Generally the Electric Transmission capacity within the EVT is a quarter to a half of the capacity of the EVT. Good reasons to use an EVT instead of an equivalently-sized Electrical transmission is that the mechanical path of the EVT is more compact and efficient than the electrical path.The EVT is the essential method for transmitting power in some hybrid vehicles, enabling an Internal Combustion Engine (ICE) to be used in conjunction with motor/generators for vehicle propulsion, and having the ability to control the portion of the mechanical power used directly for propelling the vehicle and the portion of mechanical power that is converted to electric power and recombined to drive the vehicle.The EVT and power sources are controlled to provide a balance between the power sources that increases vehicle fueleconomy while providing advantageous performance when needed. The EVT may also be used to provide electrically generated power to charge large storage batteries for subsequent electric motor propulsion as needed, or to convert vehicle kinetic energy to electricity through 'regenerative braking' during deceleration. Various configurations of power generation, usage and balance can be implemented with a EVT, enabling great flexibility in propelling hybrid vehicles.The Toyota single mode hybrid and General Motor 2 Mode hybrid are production systems that use EVTs. The Toyota system is in the Prius, Highlander, and Lexus RX400h and GS450h models. The GM system is the Allison Bus hybrid powertrains and are in the Tahoe and Yukon models. The Toyota system uses one power-split epicyclic differential gearing system over all driving conditions and is sized with an electrical path rated at approximately half the capacity of the EVT. The GM system uses two different EVT ranges: one designed for lower speeds with greater mechanical advantage, and one designed for higher speeds, and the electrical path is rated at approximately a quarter of the capacity of the EVT. Other arrangements are possible and applications of EVT's are growing rapidly in number and variety.EVT's are capable of continuously modulating output/input speed ratios like mechanical CVT's, but offer the distinct difference and benefit of being able to also apportion power from two different sources to one output.HydrostaticSee also Continuously variable transmission > Hydrostatic CVTs Hydrostatic transmissions transmit all power hydraulically, using the components of hydraulic machinery. Hydrostatic transmissions do not make use of the hydrodynamic forces of the fluid flow. There is no solid coupling of the input and output. The transmission input drive is a central hydraulic pump and final drive unit(s) is/are a hydraulic motor, or hydraulic cylinder (see:swashplate. Both components can be placed physically far apart on the machine, being connected only by flexible hoses. Hydrostatic drive systems are used on excavators, lawn tractors, forklifts, winch drive systems, heavy lift equipment, agricultural machinery, etc. An arrangement for motor-vehicle transmission was probably used on the Ferguson F-1 P99 racing car in about 1961.The Human Friendly Transmission of the Honda DN-01 is hydrostatic.HydrodynamicIf the hydraulic pump and/or hydraulic motor make use of the hydrodynamic effects of the fluid flow, i.e. pressure due to a change in the fluid's momentum as it flows through vanes in a turbine. The pump and motor usually consist of rotating vanes without seals and are typically placed in close proximity. The transmission ratio can be made to vary by means of additional rotating vanes, an effect similar to varying the pitch of an airplane propeller.The torque converter in most automotive automatic transmissions is, in itself, a hydrodynamic transmission.It was possible to drive the Dynaflow transmission without shifting the mechanical gears.Hydrodynamic transmissions are used in many passenger rail vehicles. In this application the advantage of smooth power delivery may outweigh the reduced efficiency caused by turbulence energy losses in the fluid.ElectricElectric transmissions convert the mechanical power of the engine(s) to electricity with electric generators and convertit back to mechanical power with electric motors. Electrical or electronic adjustable-speed drive control systems are used to control the speed and torque of the motors. If the generators are driven by turbines, such arrangements are called turbo-electric. Likewise installations powered by diesel-engines are called diesel-electric. Diesel-electric arrangements are used on many railway locomotives, ships and large mining trucks.。
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附录附录A 英文文献Transmission descriptionTransmission gearbox's function the engine's output rotational speed is high, the maximum work rate and the maximum torque appears in certain rotational speed area. In order to display engine's optimum performance, must have a set of variable speed gear, is coordinated the engine the rotational speed and wheel's actual moving velocity. The transmission gearbox may in the automobile travel process, has the different gear ratio between the engine and the wheel, through shifts gears may cause the engine work under its best power performance condition. Transmission gearbox's trend of development is more and more complex, the automaticity is also getting higher and higher, the automatic transmission will be future mainstream.Automotive Transmission's mission is to transfer power, and in the process of dynamic change in the transmission gear ratio in order to adjust or change the characteristics of the engine, at the same time through the transmission to adapt to different driving requirements. This shows that the transmission lines in the automotive transmission plays a crucial role. With the rapid development of science and technology, people's car is getting higher and higher performance requirements, vehicle performance, life, energy consumption, such as vibration and noise transmission depends largely on the performance, it is necessary to attach importance to the study of transmission.Transmission gearbox's pattern the automobile automatic transmission common to have three patterns: Respectively is hydraulic automatic transmission gearbox (AT), machinery stepless automatic transmission (CVT), electrically controlled machinery automatic transmission (AMT). At present what applies is most widespread is, AT becomes automatic transmission's pronoun nearly.AT is by the fluid strength torque converter, the planet gear and the hydraulic control system is composed, combines the way through the fluid strength transmission and the gear to realize the speed change bending moment. And the fluid strength torque converter is the most important part, it by components and so on pump pulley, turbine wheel and guide pulley is composed, has at the same time the transmission torque and the meeting and parting function.And AT compare, CVT has omitted complex and the unwieldy gear combination variable transmission, but is two groups of band pulleys carries on the variable transmission. Through changes the driving gear and the driven wheel transmission belt's contact radius carries on the speed change. Because has cancelled the gear drive, therefore its velocity ratio may change at will, the speed change is smoother, has not shifted gears kicks the feeling.AMT and the hydraulic automatic transmission gearbox (AT) is the having steps automatic transmission equally. It in the ordinary manual transmission gearbox's foundation, through installs the electrically operated installment which the microcomputer controls, the substitution originally coupling's separation which, the joint and the transmission gearbox completes by the manual control elects to keep off, to shift gears the movement, realizes fluid drive.Manual transmission gear mainly uses the principle of deceleration. Transmission within the group have different transmission ratio gear pair, and the car at the time of shift work, that is, through the manipulation of institutions so that the different transmission gear pair work. Manual transmission, also known as manual gear transmission, with axial sliding in the gears, the meshing gears through different speed to achieve the purpose of torque variation. Manual shift transmission can operate in full compliance with the will of the driver, and the simple structure, the failure rate is relatively low, value for money.Automatic transmission is based on speed and load (throttle pedal travel) for two-parameter control gear in accordance with the above two parameters to automatically take-off and landing. Automatic transmission and manualtransmission in common, that is, there are two-stage transmission, automatic transmission can only speed the pace to automatically shift, manual transmission can be eliminated, "setback" of the shift feel.Automatic transmission is a torque converter, planetary gears and hydraulic manipulation of bodies, through the hydraulic transmission and gear combination to achieve the purpose of variable-speed torque variation.Also known as CVT-type continuously variable CVT. This transmission and automatic transmission gear generally the biggest difference is that it eliminates the need of complex and cumbersome combination of variable-speed gear transmission, and only two groups to carry out variable-speed drive pulley.CVT transmission than the traditional structure of simple, smaller and it is not the number of manual gear transmission, no automatic transmission planetary gear complex group, mainly rely on the driving wheel, the driven wheel and the transmission ratio brought about by the realization of non-class change.Widely used in automotive internal combustion engine as a power source, the torque and speed range is very small, and complex conditions require the use of motor vehicles and the speed of the driving force in the considerable changes in the scope. To resolve this contradiction, in the transmission system to set up the transmission to change transmission ratio, the expansion of the driving wheel torque and speed range in order to adapt to constantly changing traffic conditions, such as start, acceleration, climbing and so on, while the engine in the most favorable conditions to work under the scope; in the same direction of rotation of the engine under the premise of the automobile can be driven back; the use of neutral, interruption of power transmission, in order to be able to start the engine, idle speed, and ease of transmission or power shift . Transmission is designed to meet the above requirements, so that the conditions in a particular vehicle stability.In addition to transmission can be used to meet certain requirements, but also to ensure that it and the car can have a good match, and can improvethe car's power and economy to ensure that the engine in a favorable condition to increase the scope of the work of the use of motor vehicles life, reduce energy consumption, reduce noise, such as the use of motor vehicles.Today the world's major car companies CVT are very active in the study. The near future, with electronic control technology to further improve, electronically controlled Continuously Variable Transmission-type is expected to be a wide range of development and application.附录B 文献翻译变速器介绍发动机的输出转速非常高，最大功率及最大扭矩在一定的转速区出现。