Hi all! Imagine the situation. You have saved up money and are thinking about buying a car. Not the last question will be the choice of gearbox. And then the thought arises - buy yourself an automatic machine or opt for the good old mechanics. After all, it would seem that there could be more. But no. There is also a sequential gearbox.
I didn’t invent it and the device really exists. Although practice and communication even with your friends proves that not everyone knows such a name. And even more so, not everyone can immediately say what it is and how it works.
So that you don’t fall flat on your face and become a real expert in the field of gearboxes, I suggest you look into this topic in more detail. Maybe after this someone will want to buy a car with a sequential gearbox.
What is a sequential gearbox
This type of gearbox combines the features and advantages of manual and automatic gearboxes, so the resulting unit is characterized by ease of use and at the same time high precision of operation.
The gears in it are switched in a strict sequence - you cannot jump over one speed. At the same time, gears are changed 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 conventional automatic transmissions, is the absence of a clutch pedal. Moreover, there is only no pedal as a control element - the clutch itself is there, but its operation is ensured by automation. This makes it much easier for beginners to drive a car equipped with such a transmission.
To transmit rotation, sequential gearboxes use gears with straight teeth. Compared to helical elements, they have much higher efficiency due to the minimal friction forces that arise during their rotation.
Cam or sequential
By creating a sequential gearbox, the developers set a goal to reduce the interval between speed changes. Thanks to the design features of such a transmission, this is achieved by simplifying switching and eliminating operations with the clutch pedal. This is especially important for new and inexperienced drivers who have difficulty performing switching procedures correctly. But professionals will also appreciate the gearbox, thanks to its convenience and the ability to subtly sense and control the behavior of the car, using the maximum of its capabilities.
Operating principle of a sequential gearbox
According to the principle of operation, such a transmission is in many ways similar to conventional mechanics. However, it also has many individual characteristics:
- The automatic transmission does not have a clutch pedal - the clutch here is controlled by electronics, which monitors the force of pressing the accelerator pedal using special sensors;
- to change gears, you can use the usual lever or buttons or paddle keys located on the steering wheel;
- hydraulic servos compensate for possible inaccuracies in driving mode adjustments.
In general, the driver can only shift sequentially when accelerating or braking. This principle greatly simplifies driving.
A significant reduction in shifting time is achieved thanks to the modernized principle of using rods included in the gearbox design:
- on a conventional “mechanics”, when the driver changes the position of the lever, the rod is tightened, rotated and only then pressed to engage a new gear;
- in a sequential box, the thrust of the previous gear is tightened, and at the same time the thrust of the new speed is squeezed out.
As a result, this reduces switching time 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 - but this is a significant gap in the world of auto racing. This is why sequential gearboxes are now used on Formula 1 and other high-speed championship cars.
At the same time, controlling such a transmission is quite simple and does not require special skills or reaction speed from the driver. This distinguishes it from cam boxes, with which SKPP has many similarities.
Basic misconceptions and myths
There are many myths and misconceptions surrounding the sequential gearbox. It is worth dispelling them before anyone decides to purchase a car with this type of transmission.
Many drivers believe that an automatic transmission is the same mechanism as a robotic gearbox. Yes, they have a similar operating principle, but still have big differences. For example, the robot box contains electric servos.
Another myth is that there is an opinion that the sequential and mechanical gearboxes are inseparable. This is not true, since automatic transmission can exist separately from “automation”.
The third big misconception is that sequential gearboxes are only found on sports cars. The combination of these technologies gives a great advantage to racers on the track, but automatic transmission has been used on production cars for several years.
The sequential transmission base is a good option for racers and those who simply enjoy driving at high speeds. With the help of such a box you will practically not have to drive the car yourself. A fast and comfortable ride can be enjoyable and not require unnecessary movements.
Where is a 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, since the mid-90s of the last century, such boxes began to appear on public production vehicles - the Bavarian concern BMW became a pioneer in this direction.
However, for the first time, sequential gearboxes did not appear on vehicles at all - they have been used on motorcycles for more than 50 years. On most bikes, gear shifting occurs sequentially: pressing the lever forward increases the gear, and pressing the lever back decreases it. Moreover, this principle is used on motorcycles of a wide variety of classes - both on choppers and tourers, and on sportbikes and enduro.
Also today, sequential type transmissions are installed on various heavy vehicles:
- agricultural and construction equipment;
- trucks whose gearboxes often have more than a dozen speeds.
In all these cases, the principle of sequential gear shifting significantly simplifies vehicle control - the driver does not need to waste time choosing the moment to shift and finding the desired speed, which is especially important for trucks.
What vehicles are equipped with automatic transmission?
Sequential gearboxes can be found on production cars, and not just on sports cars. For example, the BMW company has been producing models with such a transmission for several years. It has an individual drive rod, which provides a change of speeds. On the BMW M5 E60, the unit increases driving dynamics. If we take into account Russian-made cars, then automatic transmission was found on the VAZ-2108. A simplified unit was installed here, but with its help the driver could make maneuvers, switching from one speed to another.
Pros and cons of a sequential gearbox
Of course, units that have such significant differences from conventional types of transmissions have their pros and cons. In particular, the advantages of sequential boxes include the following features:
- There is no clutch pedal . 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 . In this indicator, automatic transmission is significantly superior to manual transmission, and it, in turn, works much faster than a thoughtful automatic transmission. Thus, sequential boxes have no competitors in terms of response speed.
- Easy to switch . It doesn’t matter which gear is currently engaged - you just need to move the lever in the desired direction or press the corresponding button.
- Operating modes . Many boxes of this type support multiple operating modes. This can be an analogue of a conventional “mechanics”, a sports mode that provides even higher speed and accuracy of switching, as well as an automatic mode in which the electronics will do everything itself. Moreover, in this case, the same efficiency of work is maintained.
However, sequential transmissions cannot be called ideal - along with significant advantages, they also have certain disadvantages. Moreover, in some situations they may turn out to be more significant than the advantages. Here are the main notes on such boxes:
- Fragility . They do not withstand high loads that inevitably arise during driving. Hydraulic servos are a particularly sensitive element of such a box. On average, manual transmissions last several times less compared to traditional types of transmissions.
- Difficulty in maintenance and repair . Maintenance and, especially, repair of a sequential transmission costs large sums, which is due to the design features. It is almost impossible to fix any problem that arises here on your own. But even going to a service station cannot always solve your problem - sequential boxes are still quite rare in Russia, so finding a technician who has experience working 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 relevant for powerful and high-speed cars. And improving their design and eliminating weak points in their operation will provide such gearboxes with the opportunity to become more widely used in production vehicles.
Advantages and disadvantages
Having learned what a sequential gearbox is on a car, owners become interested in what advantages and disadvantages it has. Some car enthusiasts want to buy a car with such a box, but they doubt their choice. To make a decision, they should study the pros and cons.
The benefits include:
Instant switching. The UPC switches gears almost instantly. This occurs due to the presence of an electronic control unit and servo drive in the system.
Economical. The sequential gearbox consumes fuel more economically than other gearboxes. This is achieved thanks to a very thoughtful design.
Comfort. At the SKP, everything happens the opposite of what needs to be done when controlling the “mechanics”. The driver can drive in comfort and enjoy the ride.
Paddle shifters. They are an additional feature that will make a person feel like a Formula 1 racer.
Weak resistance to loads and the high cost of a car with automatic transmission are the disadvantages that the gearbox has. Increased loads cause the transmission to fail in a short period of operation. The system is quite sensitive to untimely switching. But if a person manages to change gears and does not allow loads, then the transmission will work for a single year.
In addition to the fact that cars with manual transmission are quite expensive, they are correspondingly expensive to maintain. The high cost of maintenance is caused by the fact that the system has a large number of counters and analyzer units.
Features of installing a sequential gearbox on VAZ cars
Many car enthusiasts purchase sequential gearboxes with a cam mechanism as an upgrade to their VAZ. Their appearance is approximately this.
As for a significant effect, one cannot count on this, since the dynamics of the car, judging by the reviews of the owners, increases slightly, although these boxes are called “sports”. In addition, the weight of such boxes is usually higher than traditional ones. Wide, massive gears with perpendicular teeth are used there to compensate for their low load capacity.
In addition, straight teeth increase the noise level of the gearbox. The actual service life of a homemade sequential gearbox is short. Such a gearbox can be installed if the car is expected to participate in sports competitions, but not for everyday driving around the city.
Traditional box
On traditional gearboxes installed on most domestic cars, the neutral position of the gear lever is set in the middle. In order to get going, we depress the clutch and engage first gear. In the future, as the speed increases, it is recommended to switch them sequentially.
However, nothing prevents us from starting to move immediately in second speed if the road condition is normal and the engine is designed for such action. Trying to start the engine with a dead battery, we push the car and, to make it easier, we can immediately turn on the third, and even the fourth. Nothing prevents this. Reducing the speed to perform a maneuver, we slow down and go straight from fourth gear to second or first. If you mix it up, you can turn on the wrong speed while driving, which is far from harmless for a car.
Let's sum it up
An automatic transmission is a unit that combines the functions of a manual transmission and an automatic transmission. However, this transmission has a number of features not inherent in any other. The advantages of the box include high gear shift speeds and support for several operating modes. However, the disadvantages of CP include a short service life and high maintenance costs. Many drivers do not have a complete picture of this gearbox. Most consider it similar to a robot box, others think that it is only installed on sports cars.
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Automatic transmission
To simplify driving, an automatic transmission was invented, which freed the driver from having to choose a driving mode on a particular section of the road. The automatic switches itself, while the driver, working with one foot, either increases speed or slows down. Driving a car with an automatic transmission requires less qualifications, and it is not for nothing that the permit to operate such a vehicle is now allocated to a separate category.
But work on improving the mechanical transmission did not stop. The result is a sequential transmission, which also does not include a clutch pedal, but operates on different principles. And its main feature is strictly sequential gear shifting.
