Constant experimentation to improve the mechanical transmission led to the invention of various types of transmissions. All developments were aimed at simplifying the actions of the driver at the time of driving.
One of the important steps in the modernization of the manual transmission was the invention of the automatic gearbox. Car manufacturers have focused on the implementation of these particular boxes. Currently, it is an automatic transmission that is installed on most cars. The driver, making a trip in a car with an automatic transmission installed, does not think about shifting the gears to an up or down gear. Automation carries out this process without human intervention.
But the designer did not forget about the mechanical box. Various experiments for modernization and improvement were constantly carried out. After numerous experiments, the problem of creating a sequential gearbox was solved. The main difference from a conventional manual gearbox is the gearshift sequence.
Sequential - this word is not familiar to many Russian drivers and it is rather difficult for a Russian to pronounce it. The reason for this is the English origin of the word. Translated from English, it means "sequential". A sequential gearbox is most often an automated gearbox. It can change gears sequentially, for example, from first to second and higher, as well as in reverse order.
Principle of operation
This box was developed on the basis of a mechanical box. The main difference is the use of spur gears. Therefore, the presence of the clutch pedal has lost its necessity. The design has an electronic control unit that performs this function. Gear shifting due to hydraulic mechanism. The switching itself takes place in a time interval of up to 150 milliseconds.
This circumstance is especially true for sports cars. Cars participating in various races, including Formula 1, are equipped with sequential gearboxes. When developing racing cars, the designers came to the conclusion that this box is the most convenient for the pilots. With significant vibrations and overloads, it will be easier for pilots to get into gear using just such a gearbox.
It is worth noting that sequential gearboxes have been present on ordinary cars for several years. On cars with an automatic transmission there is a sequential mechanism, which has received the name "manual" mode among drivers.
Peculiarities
The shift lever on vehicles with sequential gearboxes is located on the steering wheel in the form of a button marked S. In these vehicles, both automatic and manual gear changes are provided. The sequential gearbox can operate in three modes:
- Standard mechanical.
- Mechanical sports.
- With automatic changeover without driver intervention.
pros
A sequential gearbox, like any other mechanism, has its own advantages and disadvantages. Among the advantages can be noted the absence of a clutch pedal, which is very pleasing to newbie drivers. The next plus can be considered the speed of gear shifting. And, of course, the undoubted plus is efficiency. Due to the quick changeover, there is a significant reduction in fuel consumption.
Another plus is the ability to choose between an automatic or manual transmission. Some vehicles have "paddles" under the steering wheel that allow the driver to change gear without taking their hands off the steering wheel.
Minuses
But this box also has its drawbacks. The hydraulic mechanism is subject to significant wear due to the heavy load during operation. On cars participating in races, mechanics repair the box after the second race. In production cars, a much greater durability resource is laid.
When used, they do not experience the same stress as sports cars. Therefore, with proper operation, the service life of a sequential box is no less than that of a mechanical or automatic box. But if you operate such a box without thinking about the consequences, then you are guaranteed a premature failure. It will be a hydraulic clutch drive, another unit or unit, it is not so important. The main thing to remember is that repairing a sequential box is very expensive.
Nowadays, sequential transmission is attracting more and more car owners. It is installed on many new models of cars and even motorcycles. The technology of this transmission is being improved and brought to ideals. The time is not far off when not only sports cars that are equipped with a sequential gearbox, and even a cam gearbox, will use a convenient transmission, but many car owners will also be able to appreciate the advantage of sequential gear shifting.
Most people interested in the automotive industry are accustomed to the fact that the car can be driven either with the help of a manual transmission, where all the changes are carried out directly by the driver from the car's interior, or with the help of its more comfortable analogue - an automatic transmission, which is independently responsible for changing gears. However, there is a proposal in the automotive market for those who want to combine the dynamism of a manual transmission and the convenience of an automatic when driving a car - this solution is called a sequential gearbox.
It is not difficult to understand what a sequential gearbox is by analyzing the meaning of the first word. The adjective "sequential" takes its roots from the English language and literally translates as "sequence" or "sequence". Accordingly, the presence of this type of gearbox in a car implies that the speeds can only be switched in a strict sequence. The choice of gear is carried out by moving the selector in only one direction, which is the difference from mechanics, where the gear can be selected in any order. Sequential gearboxes have been used by car manufacturers since the mid-90s. For example, BMW's famous motorsport division installed the first generation of these boxes in their 3 Series sports cars (M3 in the E36 body). Pre-sale tests have shown that the sequential gearbox helps the driver adapt the car to his driving style better than using an automatic transmission, while retaining the ability to independently influence gear changes with the same efficiency as a mechanic if a consistent change in speed is necessary.
Sales of copies equipped with a sequential gearbox showed that many drivers liked this alternative to their more familiar counterparts, however, one could hear feedback from some buyers about the relatively long gearshift interval. The situation was corrected by the release of the second generation of the sequential gearbox and integration into the company's new sports model with the M3 E46 index.
The BMW engineers did not stop there, and the third generation of sequential gearboxes has become a distinctive feature of their legendary M5 E60. With each new stage of development, the sequential gearbox was more and more adjusted by the designers to the needs of the consumer: the time spent on changing gears was significantly reduced, while the dynamics of the car increased noticeably with each change.
OPERATING PRINCIPLE OF SEQUENTIAL GEARBOX
The main task of a sequential gearbox, the principle of its operation when accelerating a car, is to reduce the interval between gear changes. The use of a sequential gearbox as a transmission allows this to be achieved not only by making the shifting process as simple as possible, but also by eliminating the need for the driver to operate the clutch independently. The lack of a clutch as an additional pedal gives an advantage to both novice drivers, for whom getting used to all the intricacies of the driving process presents some difficulties, as well as professionals who operate the car to the limit of its capabilities and for whom every fraction of a second is a lot of time wasted during acceleration. In fact, the sequential gearbox also has clutch, but it is controlled by a separate electronic unit, which independently calculates, based on the current vehicle speed and the driver's force on the accelerator pedal, which gear is currently the most optimal.
From this unit, a signal is sent to the transmission, to the location of the speed detection sensors. The next and final point of sending the signal after processing by the sensors is a progressive block - the unit responsible for correcting the data on the operation of the internal combustion engine. In addition to data on the vehicle speed, the progressive block also processes information about the operation of all elements of the comfort unit and, based on the totality of the received data, makes calculations to optimize the movement.
CONSTRUCTION FEATURES OF SEQUENTAL GEARBOX
The sequential gearbox differs from its competitors in the following unique features:
- the structure of a sequential gearbox is based on gears with straight teeth, and this is its main distinguishing feature from a mechanical gearbox, where helical gears are taken as a basis. This difference is the advantage of a sequential gearbox, since spur gears, unlike analogs, during the operation of the gearbox almost do not create friction;
- also, the diameter of each gear is slightly increased in comparison with those used for manual transmissions, which allows a greater amount of torque to be transmitted to the wheels;
- Another characteristic feature of the sequential transmission is the use of a hydraulic servo drive. Unknowing drivers sometimes confuse hydraulic servos with automatic transmissions, thereby misleading, as design, operating principle, and efficiency are significantly different as a result.
SEQUENTIAL GEARBOX ADVANTAGES
Undoubtedly, the transmission used in sports cars of the world's most famous manufacturers cannot but have a number of strengths that distinguish it favorably from other proposals. The advantages of a sequential gearbox are:
- high speed of gear shifting is the main plus of the gearbox on a sequential basis. The gear change really happens instantly - just 150 m / s. The reason for such a high indicator was the previously listed design features of the transmission: spur gears with an increased diameter and a servo drive based on hydraulics;
- complete absence of loss of speed when switching - gears do not just switch at lightning speed, their change to each other does not in any way affect the dynamics of the car's movement;
- rapid achievement of the maximum number of revolutions - the sequential gearbox interacts better with the car engine, due to which the gearshift occurs in the optimal engine speed range for acceleration;
- lack of recoil in the driver's hand in the form of vibrations and vibrations - again, thanks to the well-established gearbox mechanism on a sequential basis, this kind of discomfort will not bother the owner of a car with such a gearbox;
- reduced fuel consumption due to the design features of the gearbox.
IMPORTANT: in cars with sequential gearboxes, even shifting with paddle shifters is significantly faster than in models with competing transmissions. This advantage can be decisive, for example, when competing for the best result in a straight line.
DISADVANTAGES OF SEQUENTIAL GEARBOX
Like other types of transmissions, sequential gearboxes have negative aspects in operation:
- relatively fast wear - since cars with installed sequential gearboxes drive, as a rule, very quickly, and this driving mode and aggressive driving style are constantly maintained, this leads to frequent breakdowns and subsequent calls to the service station. The electronic load distribution unit in the sequential gearbox acts as an advantage during acceleration, but it can also cause a malfunction, since any untimely speed change completely violates the necessary algorithm and leads to the destabilization of the entire system;
- the cost of consumables and work on their replacement / installation - just as in the case of the electronic unit, the constituent elements of the sequential box are an advantage when it comes to speed characteristics, but the cost of repairing these mechanisms cannot be attributed to the advantages of this type of transmission ... Fixing something in it yourself is also a dubious prospect for the owner of a car with a box on a sequential basis.
IMPORTANT: when repairing the transmission on a sequential basis, only original spare parts must be used. Since such a box is significantly different in design from mechanics and an automatic machine, it will not work to replace most of the consumables with similar ones used in other boxes.
SEQUENTIAL GEARBOX MISUSE
For laymen, the most common are two false stereotypes about sequential checkpoints. Explaining:
- Is not another name for a robotic box. Basically, the first uses a hydraulic servo, and the second is electric;
- sequential gearbox- this is not an automaton any more. Do not confuse the automatic transmission with the ability to switch to manual mode with the sequential analogue.
CONCLUSIONS ABOUT SEQUENTAL GEARBOX
A sequential-based transmission will be an excellent solution for lovers of dynamic driving and fast acceleration, who do not want to completely give control of the car to the bail of modern electronic assistants, but at the same time want to get not only maximum drive and adrenaline, but also combine this with comfortable operation, without the need unnecessary movements and operations.
Reading 5 min.
Here it turns out that one rod is pulled up at the moment of switching, and the other is pressed. That is, at the moment of tightening the first gear shift thrust, the second gear thrust is pressed. This made it possible to significantly reduce the time interval for switching in comparison with a conventional gearbox.
Translated from English, sequential is translated as a sequence. Therefore, a sequential gearbox only means sequential gear changes. This principle of operation consists in influencing the control of the foot (an example is a motorcycle), for quick switching - a sports car; in the case of a large number of gears, the selection of which using the lever shift is not very convenient - this is a tractor, trucks. Most often, shifting occurs due to the displacement of the control from the neutral position. While the principle of operation of a classic gearbox is an independent choice of gear.
Sequential box development
So many transmission boxes have not been created in the entire history of the automotive industry. So the creation of a sequential transmission did not pass by. Most often we hear, manual transmission or automatic, but it is worth understanding that this is not the end of the matter, as there are many more options for shifting gears.
There is a difference between these checkpoints that is worth understanding. Take, for example, a conventional car with a manual transmission. In this case, the driver independently chooses the speed transmission. That is, having accelerated, he has the opportunity to switch from third speed to fifth, or, on the contrary, when braking, go from fifth to third. This mechanism can also be called a search mechanism, since the inclusion of a gear transmission is completely dependent on the driver. Once again, I would like to note that the gear can be any, the most important thing is to match the driving mode and the loads on the car.
But as for the owners of a sequential gearbox, they are deprived of such a possibility of free switching. This action can be performed only one value, either up or down. That is, the switch will look like this: two-three-four or seven-six-five, which is typical for BMW motorcycles and M1-M motorcycles. It is impossible to achieve another switch on such a box.
Sports type M
More recently, a seven-speed sequential gearbox has been developed. This is the first model of the 7-speed SMG transmission in the global automotive industry. Thanks to its ultra-short shift times, combined with the power of the powertrain, it allows its owner to make their own choice of sporty or comfortable riding style.
Historical background
Such a box has already managed to become traditional for BMW cars. Already in 1996, SMG 1 began to be installed on the E36 M3 model. In 2001, the E46 M3 models were equipped with SMG 2. And already in 2005, the SMG 3 gearbox was installed on the E60 M5 model. What distinguishes this gearbox from previous models is a noticeable reduction in the time spent on gear shifting.
This third-generation transmission model is equipped with individual shift rods, which allows for a noticeable reduction in thrust at the time of shifting. How could this have happened?
How the switching process works
Comparing a conventional gearbox with a sequential SMG 3, you notice that in a conventional gearbox, at the moment of shifting, the gearshift rod is pulled up, then turned and pressed. In the compared device, everything happens differently. Here it turns out that one rod is pulled up at the moment of switching, and the other is pressed. That is, at the moment of tightening the first gear shift thrust, the second gear thrust is pressed. This made it possible to significantly reduce the time interval for switching in comparison with a conventional gearbox.
Sequential gearbox operation
So, the familiar manual transmission has evolved and made it possible to come to a new type of transmission, which should make it easier for the driver to control the car. And such an important invention was the automatic transmission, which was modernized and improved. And today, it enables the driver not to think at all about what and when to change the speed. But no one threw away the mechanical equipment either. She also continued to develop and now the result of this research was the sequential gearbox. The result of this transmission was the inclusion of speed in a strict sequence.
Principle of operation
This type of gearbox was developed on the basis of mechanics. The main difference between this transmission is that instead of helical gears, gears with straight teeth are installed here, and there is also no clutch pedal (this role was taken over by the electronic control unit). Gear shifting in the box is carried out using a hydraulic mechanism, which leads to a significant reduction in gear shifting.
The installation of a gearbox with a sequential mechanism is especially common in racing cars. Realizing that such a sequential gearbox would be especially convenient for racing drivers, it means that it was necessary to perform such an installation on racing cars. This is due to the fact that high speed contributes to strong vibration of the car and in this case it is difficult for the driver to get into the required gear, while the sequential gearbox is able to cope with this task.
Advantages and disadvantages
This sequential transmission has its own characteristics. The advantages of this unit are the absence of a clutch pedal, which is especially convenient for novice drivers. The next positive quality that characterizes this model of the device is the speed of gear shifting, which exceeds the classic automatic and manual transmissions. Another advantage is economy, which occurs due to the reduced gear shifting. It also offers the possibility of choosing a mode - mechanic or automatic.
The disadvantage of this device can be called its design. That is, this mechanism is not resistant to wear and tear and quickly breaks down under heavy load. An example is racing cars. After each ride, the sequential gearbox is most often subject to a mandatory bulkhead. In principle, if the operating rules are not followed, then the sequential gearbox can fail on serial cars, which means that it will entail expensive repairs.
The traditional division of gearboxes used in cars into "automatic" and "mechanics" has long ceased to be relevant. In recent years, many other types of transmissions have appeared, the main purpose of which is to simplify the process of controlling a machine while improving its technical performance.
An example of this development is the sequential gearbox, which today is equipped with many sports cars, especially supercars. Its main feature is that the speeds in it are switched only sequentially - in other words, you cannot immediately jump from the first to the third, bypassing the second. The same rule applies when downshifting.
This principle has many features, including positive ones, which make it possible to use a sequential box on the fastest cars of our time. For a better understanding of them, you should first understand what a transmission of this type is and how it works.
This type of gearbox combines the features and advantages of mechanical and automatic gearboxes, due to which the resulting unit is characterized by ease of use and, at the same time, high precision of work. It switches gears in a strict sequence - you cannot jump over one speed. At the same time, transmissions change here in record time - the box takes about 120 milliseconds to do this. This high switching speed is ensured by the use of hydraulic servo drives.
An important feature of sequential gearboxes, which brings them closer to more familiar "automatic machines", is the absence of a clutch pedal. Moreover, there is only a pedal as a control element - the clutch itself is there, but its operation is provided by automatic equipment. This makes it much easier for beginners to drive a car equipped with such a transmission.
To transmit rotation in sequential gearboxes, gears with straight teeth are used. In comparison with helical elements, they have a much higher efficiency due to the minimal frictional forces arising during their rotation.
The principle of operation of the sequential gearbox
In principle, such a transmission is in many ways similar to conventional mechanics. However, she also has many individual characteristics:
- The SKPP does not have a clutch pedal - the clutch is controlled by electronics, which monitors the force of pressing the accelerator pedal with the help of special sensors;
- the usual lever or buttons or petal keys located on the steering wheel can be used to shift gears;
- hydraulic servos compensate for possible inaccuracies in the adjustment of the driving mode.
In general, the driver only has to switch sequentially when accelerating or decelerating. This principle greatly simplifies driving.
A significant reduction in shift times is achieved thanks to the modernized principle of the use of rods, included in the design of the gearbox:
- on conventional "mechanics", when the driver changes the position of the lever, the rod is pulled up, turned and only then pressed to engage a new gear;
- in the sequential box, the thrust of the previous gear is pulled up, and at the same time the thrust of the new speed is squeezed out.
As a result, the switching time can be reduced to 120 milliseconds. For comparison: a modern manual transmission takes about 1 second to change gears. During normal driving, such a time difference may not be felt - however, this is a significant gap in the world of auto racing. That is why sequential gearboxes are used today in Formula 1 and other high-speed championships.
At the same time, the control of such a transmission is quite simple and does not require special skills and reaction speed from the driver. This compares favorably with the cam boxes, with which the SKPP has many similarities.
Where is the sequential gearbox used?
Initially, this type of transmission was developed for the needs of motor sports - this is where it is very important to be able to quickly change gears without losing engine speed. However, from the mid-90s of the last century, such boxes began to appear on serial public cars - the Bavarian concern BMW became a pioneer in this direction.
However, for the first time, sequential gearboxes did not appear on vehicles at all - for more than 50 years they have been used on motor vehicles. On most bikes, the gear changes are sequential: pushing the lever forward increases the gear, and backward decreases it. Moreover, this principle is used on motorcycles of a very different class - both on choppers and tourers, as well as on sportbikes and enduros.
Also today, sequential type transmissions are installed on various heavy machines:
- agricultural and construction equipment;
- trucks, boxes of which often have more than a dozen speeds.
In all these cases, the principle of sequential gear shifting greatly facilitates the control of equipment - the driver does not need to spend time choosing the moment to switch and find the right speed, which is especially important for trucks.
Pros and cons of sequential gearbox
Of course, units that have such serious differences from the usual types of transmissions have their pros and cons. In particular, the advantages of sequential boxes include the following features:
- Clutch pedal missing... This is useful not only for novice drivers who often find it difficult to master the nuances of controlling three pedals at once, but also for experienced drivers.
- Switching speed... According to this indicator, the SKPP significantly surpasses the "mechanics", and she, in turn, works much faster than the brooding "machine". Thus, sequential boxes have no competitors in terms of response speed.
- Easy to switch... It doesn't matter which gear is on at the moment - you just have to move the lever in the right direction or press the corresponding button.
- Modes of operation... Many boxes of this type support several modes of operation. It can be an analogue of the usual "mechanics", a sport mode, which provides even higher speed and accuracy of switching, as well as an automatic mode in which the electronics will do everything by itself. Moreover, in this case, the same efficiency of work remains.
However, sequential transmissions are not ideal - along with significant advantages, they also have certain disadvantages. Moreover, in some situations, they can turn out to be more significant than the advantages. Here are the basic notes on these boxes:
- Fragility... They do not tolerate high loads that inevitably arise during the ride. A particularly sensitive element of such a box is the hydraulic servo drives. On average, the gearboxes are several times smaller in comparison with traditional types of gearboxes.
- Complexity of maintenance and repair... Maintenance and even more repair of a sequential transmission is costly due to the design features. It is almost impossible to eliminate any problem that has arisen here on your own. But even contacting a service station can not always solve your problem - sequential boxes are still quite rare in Russia, so finding a master who has experience with them can be very difficult.
In general, the sequential gearbox is undoubtedly one of the most promising types of transmissions, the use of which is important for powerful and high-speed cars. And the improvement of their design, elimination of weak points in the work will provide such gearboxes with the opportunity to become more widespread on production cars.
Video on the topic
The manual transmission can be either a simple robot with one clutch, or a preselective gearbox with two clutches of the DSG type. In this article we will talk about what a sequential gearbox is.
Read in this article
SMG Box: Sequential Transmission
As you know, at the initial stage in the automotive industry, only a manual transmission was used.
However, in the future, engineers have developed other types of transmissions, with the main task being to make driving as easy as possible.
A real breakthrough was the appearance of an automatic transmission, automatic transmission, which made it possible to realize the possibility of choosing and changing gears automatically, that is, without the participation of the driver.
At the same time, the hydromechanical "automatic" did not supplant the traditional mechanics for a number of reasons, the manual transmission continued to be refined, the design was constantly improved. As a result, a sequential gearbox became one of the types of manual transmissions.
In a nutshell, such a transmission differs from analogs in that the up and down gears are included only in a certain sequence. To put it simply, the driver of a car with a so-called sequential dial switches strictly in order "up" to turn on an increased, or "down" to turn on a lower gear.
At the same time, on conventional mechanics, the driver can change gears according to the "search" principle, that is, arbitrarily. The main thing is that the gear matches the speed of movement, etc. In practice, for example, you can start off from the second and immediately switch to the fourth. The sequential checkpoint will not allow this.
The device and principle of operation of the sequential gearbox
As already mentioned, a sequential gearbox (sometimes called a selective gearbox) is based on a simple manual transmission. However, there are differences from the manual transmission.
DSG gearbox (DSG): design, principle of operation, distinctive features. Reliability, DSG resource, types of robotic DSG boxes, tips.
