4 speed manual transmission advantages
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4 speed manual transmission advantagesIt uses a driver-operated clutch, usually engaged and disengaged by a foot pedal or hand lever, for regulating torque transfer from the engine to the transmission; and a gear selector that can be operated by hands.Higher-end vehicles, such as sports cars and luxury cars are often usually equipped with a 6-speed transmission for the base model. Automatic transmissions are commonly used instead of manual transmissions; common types of automatic transmissions are the hydraulic automatic transmission, automated manual transmission, dual-clutch transmission and the continuously variable transmission (CVT). The number of forward gear ratios is often expressed for automatic transmissions as well (e.g., 9-speed automatic).Most manual transmissions for cars allow the driver to select any gear ratio at any time, for example shifting from 2nd to 4th gear, or 5th to 3rd gear. However, sequential manual transmissions, which are commonly used in motorcycles and racing cars, only allow the driver to select the next-higher or next-lower gear.A clutch sits between the flywheel and the transmission input shaft, controlling whether the transmission is connected to the engine ( clutch engaged - the clutch pedal is not being pressed) or not connected to the engine ( clutch disengaged - the clutch pedal is being pressed down). When the engine is running and the clutch is engaged (i.e., clutch pedal up), the flywheel spins the clutch plate and hence the transmission.This is a fundamental difference compared with a typical hydraulic automatic transmission, which uses an epicyclic (planetary) design. Some automatic transmissions are based on the mechanical build and internal design of a manual transmission, but have added components (such as servo-controlled actuators and sensors) which automatically control the gear shifts and clutch; this design is typically called an automated manual transmission (or a clutchless manual transmission ).http://polymer-consulting.com/pic/bosch-manuals.xml
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Operating such transmissions often uses the same pattern of shifter movement with a single or multiple switches to engage the next sequence of gears.The driver was therefore required to use careful timing and throttle manipulation when shifting, so the gears would be spinning at roughly the same speed when engaged; otherwise, the teeth would refuse to mesh.Five-speed transmissions became widespread during the 1980s, as did the use of synchromesh on all forward gears.This allows for a narrower transmission since the length of each countershaft is halved compared with one that contains four gears and two shifters.For example, a five-speed transmission might have the first-to-second selectors on the countershaft, but the third-to-fourth selector and the fifth selector on the main shaft. This means that when the vehicle is stopped and idling in neutral with the clutch engaged and the input shaft spinning, the third-, fourth-, and fifth-gear pairs do not rotate.For reverse gear, an idler gear is used to reverse the direction in which the output shaft rotates. In many transmissions, the input and output shafts can be directly locked together (bypassing the countershaft) to create a 1:1 gear ratio which is referred to as direct drive.The assembly consisting of both the input and output shafts is referred to as the main shaft (although sometimes this term refers to just the input shaft or output shaft). Independent rotation of the input and output shafts is made possibly by one shaft being located inside the hollow bore of the other shaft, with a bearing located between the two shafts.The input shaft runs the whole length of the gearbox, and there is no separate input pinion.When the dog clutches for all gears are disengaged (i.e. when the transmission is in neutral), all of the gears are able to spin freely around the output shaft.http://www.fotoanderson.com.br/edgas/uploads/bosch-maxx-1000-user-manual.xml When the driver selects a gear, the dog clutch for that gear is engaged (via the gear selector rods), locking the transmission's output shaft to a particular gear set.It has teeth to fit into the splines on the shaft, forcing that shaft to rotate at the same speed as the gear hub. However, the clutch can move back and forth on the shaft, to either engage or disengage the splines. This movement is controlled by a selector fork that is linked to the gear lever. The fork does not rotate, so it is attached to a collar bearing on the selector. The selector is typically symmetric: it slides between two gears and has a synchromesh and teeth on each side in order to lock either gear to the shaft. Unlike some other types of clutches (such as the foot-operated clutch of a manual-transmission car), a dog clutch provides non-slip coupling and is not suited to intentional slipping.These devices automatically match the speed of the input shaft with that of the gear being selected, thus removing the need for the driver to use techniques such as double clutching.Therefore, to speed up or slow down the input shaft as required, cone-shaped brass synchronizer rings are attached to each gear. In a modern gearbox, the action of all of these components is so smooth and fast it is hardly noticed. Many transmissions do not include synchromesh on the reverse gear (see Reverse gear section below).This is achieved through 'blocker rings' (also called 'baulk rings'). The synchro ring rotates slightly because of the frictional torque from the cone clutch. In this position, the dog clutch is prevented from engaging. Once the speeds are synchronized, friction on the blocker ring is relieved and the blocker ring twists slightly, bringing into alignment certain grooves or notches that allow the dog clutch to fall into the engagement.The latter involves the stamping the piece out of a sheet metal strip and then machining to obtain the exact shape required.https://labroclub.ru/blog/02-kx-250-manualThese rings and sleeves have to overcome the momentum of the entire input shaft and clutch disk during each gearshift (and also the momentum and power of the engine, if the driver attempts a gearshift without fully disengaging the clutch). Larger differences in speed between the input shaft and the gear require higher friction forces from the synchromesh components, potentially increasing their wear rate.This means that moving the gearshift lever into reverse results in gears moving to mesh together. Another unique aspect of the reverse gear is that it consists of two gears— an idler gear on the countershaft and another gear on the output shaft— and both of these are directly fixed to the shaft (i.e. they are always rotating at the same speed as the shaft). These gears are usually spur gears with straight-cut teeth which— unlike the helical teeth used for forward gear— results in a whining sound as the vehicle moves in reverse.To avoid grinding as the gears begin to the mesh, they need to be stationary. Since the input shaft is often still spinning due to momentum (even after the car has stopped), a mechanism is needed to stop the input shaft, such as using the synchronizer rings for 5th gear.This can take the form of a collar underneath the gear knob which needs to be lifted or requiring extra force to push the gearshift lever into the plane of reverse gear.Without a clutch, the engine would stall any time the vehicle stopped and changing gears would be difficult (deselecting a gear while the transmission requires the driver to adjust the throttle so that the transmission is not under load, and selecting a gear requires the engine RPM to be at the exact speed that matches the road speed for the gear being selected).In most automobiles, the gear stick is often located on the floor between the driver and front passenger, however, some cars have a gear stick that is mounted to the steering column or center console.http://dhirarchitects.com/images/4-speed-manual-transmission-for-chevy-350.pdfGear selection is usually via the left foot pedal with a layout of 1 - N - 2 - 3 - 4 - 5 - 6. This was actuated either manually while in high gear by throwing a switch or pressing a button on the gearshift knob or on the steering column, or automatically by momentarily lifting the foot from the accelerator with the vehicle traveling above a certain road speed.When the crankshaft spins as a result of the energy generated by the rolling of the vehicle, the motor is cranked over. This simulates what the starter is intended for and operates in a similar way to crank handles on very old cars from the early 20th century, with the cranking motion being replaced by the pushing of the car.This was often due to the manual transmission having more gear ratios, and the lock-up speed of the torque converters in automatic transmissions of the time.The operation of the gearstick— another function that is not required on automatic transmission cars— means that the drive must use take one hand off the steering wheel while changing gears. Another challenge is that smooth driving requires co-ordinated timing of the clutch, accelerator, and gearshift inputs. Lastly, a car with an automatic transmission obviously does not require the driver to make any decisions about which gear to use at any given time.This means that the driver's right foot is not needed to operate the brake pedal, freeing it up to be used on the throttle pedal instead. Once the required engine RPM is obtained, the driver can release the clutch, also releasing the parking brake as the clutch engages.Please help improve it by rewriting it in an encyclopedic style. ( June 2020 ) ( Learn how and when to remove this template message ) Multi-control transmissions are built in much higher power ratings but rarely use synchromesh.Usual types are:The first through fourth gears are accessed when low range is selected. To access the fifth through eighth gears, the range selector is moved to high range, and the gear lever again shifted through the first through fourth gear positions. In high range, the first gear position becomes fifth, the second gear position becomes sixth, and so on. This allows even more gear ratios. Both a range selector and a splitter selector are provided. In older trucks using floor-mounted levers, a bigger problem is common gear shifts require the drivers to move their hands between shift levers in a single shift, and without synchromesh, shifts must be carefully timed or the transmission will not engage. Also, each can be split using the thumb-actuated under-overdrive lever on the left side of the knob while in high range. L cannot be split using the thumb lever in either the 13- or 18-speed. The 9-speed transmission is basically a 13-speed without the under-overdrive thumb lever.Transmissions may be in separate cases with a shaft in between; in separate cases bolted together; or all in one case, using the same lubricating oil. With a third transmission, gears are multiplied yet again, giving greater range or closer spacing. Some trucks thus have dozens of gear positions, although most are duplicates. Two-speed differentials are always splitters. In newer transmissions, there may be two countershafts, so each main shaft gear can be driven from one or the other countershaft; this allows construction with short and robust countershafts, while still allowing many gear combinations inside a single gear case.One argument is synchromesh adds weight that could be payload, is one more thing to fail, and drivers spend thousands of hours driving so can take the time to learn to drive efficiently with a non-synchromesh transmission. Since the clutch is not used, it is easy to mismatch speeds of gears, and the driver can quickly cause major (and expensive) damage to the gears and the transmission.Since few heavy-duty transmissions have synchromesh, automatic transmissions are commonly used instead, despite their increased weight, cost, and loss of efficiency.Diesel truck engines from the 1970s and earlier tend to have a narrow power band, so they need many close-spaced gears. Starting with the 1968 Maxidyne, diesel truck engines have increasingly used turbochargers and electronic controls that widen the power band, allowing fewer and fewer gear ratios. A transmission with fewer ratios is lighter and may be more efficient because there are fewer transmissions in series. Fewer shifts also make the truck more drivable.Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( June 2020 ) ( Learn how and when to remove this template message ) Gear oil has a characteristic aroma because it contains added sulfur-bearing anti-wear compounds. These compounds are used to reduce the high sliding friction by the helical gear cut of the teeth (this cut eliminates the characteristic whine of straight cut spur gears ).Retrieved 10 March 2020. By using this site, you agree to the Terms of Use and Privacy Policy. The transmission allows the vehicle to change gears, thereby transferring power from the engine to the drive axle in the most efficient way possible. In lower gears, this increases available power while reducing speed. Higher gears, on the other hand, reduce power and increase speed. This enables cars to distribute power and speed in the most efficient way for any given situation. After all, both transmissions have their own unique advantages and disadvantages, and where one may be perfect in one situation, it may end up being absolute rubbish in another situation. Yet, despite their apparent popularity, automatic transmissions are not necessarily a better choice for many drivers. However, they do offer advantages over manual transmissions in several key areas.This is possible when driving an automatic transmission vehicle, but is not possible with a manual transmission. Automatic transmissions take care of this issue, enabling your car to operate efficiently no matter how steep the hill might be. This isn’t a common problem for those driving automatic transmission, where stalling will only occur if there’s a mechanical problem in the vehicle. This isn’t normally a problem, but in heavy traffic where a car isn’t able to get up to speed, drivers may notice that the constant starting and stopping becomes a difficult chore. Automatic transmissions allow the driver to move through heavy traffic without having to do more than push a single pedal. Manual transmission cars require very little maintenance, and generally maintenance and repairs end up being significantly less costly. Be warned, however, because one thing that a manual has that the automatic doesn’t have to worry about is the clutch, and if that thing quits on you, then you could be in trouble. The end result is that you’ll end up getting more kilometres out of the petrol you pump in than you would with an automatic. Manual transmissions have been known to save drivers between 5 and 15 on their fuel costs. This means that should a car-thief decide to give your car a closer inspection in preparation for stealing it, there’s a fairly good chance that simply having a manual transmission will be enough to deter the criminal. At the same time, they are built to respond to conditions as they are encountered, which doesn’t allow for drivers to either anticipate an oncoming condition, or to purposely select a lower gear for an added boost of power. Manual transmissions give drivers greater control over the vehicle. After all, you may need to get from point A to point B, but it’s completely up to you how you make the journey! Please consider your needs, the Financial Services Guide and the Product Disclosure Statement when deciding to buy insurance. Subject to meeting underwriting criteria. Discounts are applied before government charges, taxes, levies and fees, including instalment processing fees (as applicable). The full extent of discounts may therefore be impacted. There are several reasons why this trend toward increased automation in the power train is to be expected in Europe. The automobile is becoming more and more just a means to an end - it is used to get from Point A to Point B comfortably and little operating effort possible. Stringent exhaust and noise regulations require that vehicles be run at the optimum operating point - for instance during the warm-up phase. Without automatic gear selection, driver action could very well negate pollution control features. Modern automatic transmission designs can compete with manual transmissions in fuel consumption and driving performance. The added cost is in the price range of a good car radio. The advantages of more relaxed driving and the world-wide statistics indicating fewer accidents with automatic transmissions should not be underrated. This presentation will focus on several options for automating the power train, starting with the manual shift transmission equipped with an automated clutch and concluding with a look at continuously variable transmissions. For purposes of comparison, these examples are all based on a vehicle with a 3 L engine because either production or prototype models of all the various automatic systems exist for this vehicle class. Weight: 48 kg Length: 470 mm Figure 1: 5-speed manual transmission (MT) The transmission is very compact and weighs only 48 kg, including the dual mass flywheel and the shift linkage. Losses that are incurred as the result of electronic clutch management and slip strategies will be explained later when fuel consumption is compared. 140 These discussions will also account for the efficiency of the electrical drive and the battery. The overall space required (including the clutch actuation system) is considerably less than for the automatic transmissions discussed later. Only the actuator - with the electonics incorporated - requires space in addition to the normally very compact manual transmission. The transmission has a total drive ratio range of 4.82. This value is typical for the Power-to-weight ratio of the vehicle class treated in this study. It is not necessary to increase the transmission ratio for 1st gear (underdrive) because of the need to avoid exceeding the tire adhesion limit, and the ratio in 5th gear (overdrive) must not be too low because of acceptance problems with respect to acceleration capability in top gear. Even most 6-gear manual transmissions have drive ratio ranges of between 4 and 5. Additional costs for automated clutch systems, including the flywheel and the gear-shift mechanism, currently lie in the range of 25 to 30 of base transmission costs. The acceleration curve is a good indication of comfort. High acceleration peaks with resonant decay phases decrease comfort with non-automated clutches. With automated clutch management, even inexperienced drivers shifting gears in the partial load range can achieve the same shift quality as with a modern multi-ratio automatic transmission. This solution is already in production for commercial vehicles, which often have more than 10 gears. Because conventional automatic transmissions with planetary gears would be very expensive and complex to build, designers have equipped the shift linkage in these systems with either semi- or fully automatic servo system operation. The additional expense of these systems, even for transmissions with up to 16 gears, is within an acceptable range when compared to what it would cost for a conventional fully automatic transmission. Shifting gears is, however, not fully automatic; the driver decides based on his own judgement or a shift indicator whether to up or downshift. The driver pushes a shift level in the desired direction to shift up or down; it isn't necessary to select the appropriate gear slot. The interruption of tractive force - resulting from the clutch disengagement required to shift gears - occurs when the driver initiates the shift command and is prevented from occuring at an unwanted moment, which could occur with a fully automated system. Although the additional expense for fully automatic as opposed to semiautomatic, demand-activated transmissions is quite minimal, the interruption of tractive force could, however, be one reason why no automated power-shift transmission has ever been introduced for production commercial vehicles. Regardless of whether gear shifting is achieved using a servo cylinder or a stepped shifting mechanism, strategies need to be developed for engaging any gear under any circumstances. Because torque transfer in the synchromesh gearset is achieved using gear teeth, i.e. via positive contact, it is possible for the gear teeth to be touching at the moment the driver decides to engage gears. Under these conditions, it is impossible to complete the shifting operation without an additional adjustment to the system. This occurs sometimes with manual transmissions - particularly in first gear and reverse - and can, for instance, make it necessary to circumvent this problem by rotating the shafts another turn by reengaging the clutch in the neutral slot. When only a few gears are involved, it costs almost as much to add an automatic gear selection feature as it does to introduce a fully automatic transmission, so this option has very little chance of establishing a market position. Although this design offers some slight fuel savings, in comparison to a fully automatic transmission, these savings are outweighed by the decreased shifting ease due to the interruption of tractive force. 143 Dual Clutch Transmission Some of the problems cited above, such as the interruption of tractive force, can be circumvented with dual clutch transmissions. The main feature of these transmissions is that they actually consist of two intermeshed transmissions linked to a single output shaft. Each transmission has its own clutch. The desired transmission ratio is selected by engaging the usual synchronizer in either sub-transmission 1 or subtransmission 2. It is possible to shift from one transmission to the other without interrupting the tractive force. If handled skillfully, controlled shift selection can be introduced virtually without disadvantages. For more than 5 gears, this transmission principle is equal to a planetary gear transmission. One of the two power shift clutches or perhaps an upstream torque converter with or without a bypass clutch can be used as the start-up component. For purposes of simplicity, one sub-transmission is represented as a shaft with a single drive ratio and a second drive ratio is obtained by pairing with a spur gear. Despite the speed differentials involved, torque can be transmitted via both clutches, but the sum of the torque values from both clutches must be accounted for. For instance, if one clutch transmits the full engine torque, the 2nd partially activated clutch only generates losses as a result of its slip. If the transmittable torque from 144 clutch 1 is reduced the torque from clutch 2 synchronously increases, the engine will be accelerated or decelerated to the speed of the other transmission train. Fine-tuning these procedures is easy with a fully electronic control system. Both theoretical and practical experience indicate that this design can be used to achieve the same shifting ease as with a planetary gear system.Losses can be lower than for a planetary gear system. Depending on the number of gears involved, Dual clutch transmissions - as the name would indicate - operate with two friction clutches and, depending on the number of gears, several positive clutches, which are usually combined with synchromesh elements. 145 4-Speed automatic with hydraulic torque converter Automatic transmissions with a friction clutch for virtually each gear have been around for a long time. Whether this transmission is designed with a layshaft or as a planetary gear transmission, at least each of the forward gears is switched by means of a friction clutch. 4-Speed automatic transmission with layshaft Figure 7 shows an example of a 4-speed automatic transmission like those that have been built in the USA and Japan for many years. Weight: 91 kg Length: 620 mm Figure 7: Automatic transmission with layshaft The advantage of this transmission design is that it provides a relatively free ratio selection because each transmission ratio uses its own set of gears. A disadvantage is that the clutch diameter is limited by the distance between the shafts. State-of-the-art gear design and manufacturing procedures make it possible to suppress gear noise to the same level achieved by a planetary gear transmission - in other words, these transmissions are virtually noiseless. With or without one-way-clutches, they provide the same shift quality as planetary gear transmissions both in theory and in practice. 146 Planetary gear transmissions The first automatic transmissions were manufactured in the United States for high-torque engines. Planetary gear transmissions were used at the time because of the power density involved and remain the standard. As was the case with the dual clutch transmission, two power-shift clutches are used to shift gears without interrupting the flow of tractive force. If the torque converter has been retained as a start-up element, the total costs for this system are comparable to the cost for planetary gear transmissions with 5 shift elements, for layshaft transmissions with the same number of elements or for dual clutch transmissions (Figure 8). Weight: 72 kg Length: 590 mm Figure 8: 4-speed automatic All these transmissions require an oil pump for the transmission fluid supply to the torque converter and for the hydraulic control system. Even when equipped with an electronic control unit, some of the control functions are still assigned to the hydraulic control system. Because oil is used as the operating medium and because wet clutches - in contrast to the clutch used in manual transmissions - cannot transmit torque without any pressure or load, the pump must run constantly. Figure 9 shows the total resulting efficiency rating for a 5-speed automatic transmission with a hard locked torque converter under street load. Efficiency ratings can vary depending on the design. If the oil cooling system is added, then a transmission for this vehicle performance class has a total weight of between 80 and 90 kg, depending on the design used. The design volume of the torque transmitting components (shift elements, planetary gear sets and shafts) can be about the same as for the corresponding components of a manual transmission, but the hydraulic control system and the oil sump provide additional volume. In addition to the cost, this is the main reason why, although 5-speed manual transmissions are used in all front-wheel drive vehicles, generally only 4speed automatic transmissions are used in these vehicles. In comparison to manual transmissions, the total costs (including the flywheel and the clutch, etc.) are considerably higher. The additional cost can vary considerably depending on the design. For instance, if one-wayclutches are used to simplify gear shift control, they have to be bypassed with additional clutches in coast. 5-speed automatic transmission with hydraulic torque converter If one wants to retain start-up gradeability with an automatic transmission and at the same time achieve an overdrive ratio similar to that of a 5-speed manual transmission, it is usually necessary to add a gear. Until now it has been impossible for the torque converter to completely make up for the required gear ratio spread because power losses, for instance on a steep grade with a trailer, have been too great. In order to continue to take advantage of current investments in 4-speed transmissions, a supplemental planetary set gear with its shifting elements is frequently added in order to end up with a 5-speed transmission with a wider total drive ratio range. In terms of total range, these transmissions are comparable to 5-speed manual transmissions. In fact, with the start-up assist provided by the torque converter, they even operate with a more pronounced overdrive effect. The lower tractive force in the overdrive range can be made acceptable by shifting into the second highest gear. Unfortunately it has been very difficult to come up with a successful schedule. Several test reports criticize high shifting frequency in the top two gears. Adding the extra planetary gear ratio with two shift elements increases costs by about 25 compared to the basic design. The weight situation is significantly worsened as well - this type of 5-speed transmission can weigh up to 100 kg. In terms of design volume, this concept is only feasible for standard drive trains because the additional length required for the additional set of gears makes the system too long to install in a front-wheel drive vehicle. Figure 11 shows such a transmission. Weight: 90 kg Length: 680 mm Figure 11: 5-speed automatic 150 Modified 4-Speed Automatic with the LuK TorCon System The first automatic transmissions had only two, at most three, mechanical gears.