In the automotive world, there are many types of transmissions. The absolute majority are, of course, mechanics and automatic transmissions. But in third place was the variator. This box can be found on both European and Japanese cars. Often, the Chinese put the variator on their SUVs. What is this box? How to use a variator? Consider in our article today.
Characteristic
So, the variator is a continuously variable transmission of the car. Its main feature is the lack of specific steps - the gear ratio changes gradually, as the car picks up speed. This feature allows you to exclude jerks and jerks when switching, which are possible when driving on a mechanic, and also provides high acceleration dynamics. Indeed, when you press the gas, the car keeps constantly stable revolutions at which peak torque is achieved.
But due to power limitations, these boxes are placed mainly on cars and only on some crossovers (often these are representatives of Chinese brands). As for types, there can be two variators in total:
Device
Generally speaking, the design of this gearbox includes:
- CVT gear.
- The mechanism used to disconnect the gearbox from the engine and transmit torque.
- Control system.
- The mechanism for reversing.
To transmit torque from the engine to the box, the following can be used in the assembly:
- Automatic centrifugal clutch.
- Electromagnetic with electronic control.
- Torque converter
- Multi-plate wet clutch.
Now the most popular torque converter has received. It smoothly transmits torque, which is positively displayed on the resource box.
The variator design includes one or two belt drives. They are two pulleys that are interconnected by a V-belt. Conical disks are formed that can move and move apart. Due to this, the diameter of the pulley changes. To bring the cones together, the force of the springs or hydraulic pressure is used. The discs themselves have a certain angle (usually 20 degrees). This contributes to the least resistance when moving the belt along the pulley.
Note that the material of the belt may be different. The first models used rubber. Due to its high flexibility and elasticity, it did not have a large resource. Therefore, most variators come with a metal belt. It consists of ten steel strips. And the torque is transmitted due to friction between the pulley and the side surface of the belt.
The principle of operation of the device
The algorithm of action is to change the diameter of the pulley depending on the load and the operating mode of the engine. So, the diameter is changed by means of a special drive (most often hydraulic). At start, the drive pulley has a small diameter, and the driven pulley is maximized. As the speed increases, the sizes of the elements change. So, the leader increases in diameter, and the follower - on the contrary. When the machine slows down, the pulley sizes change back.
How to use the variator? The basics
First of all, you need to understand that a car with a CVT does not have a clutch pedal. Drivers who transfer to such cars with mechanics have the habit of using the left pedal. Using the variator, it is enough to work only with the right foot. The left always rests with the driver. This seemingly insignificant nuance needs to be remembered. As for the operating modes, everything here is similar to an automatic box:
- R. This is parking. It is used in situations when the car arrives at a place of long parking. In this case, it uses a special blocking element, which prevents further movement of the car.
- D - drive. This is the mode in which the car moves forward as usual, with sequential gear shifting.
- N is neutral. It is used in cases when the machine is standing for a long time on an inclined surface. To do this, apply the hand brake and move the lever to the appropriate position. In this case, we get rid of the need to constantly keep the brake pedal depressed. The mode is relevant in the case when the stop time is more than half a minute.
- R - reverse gear.
Additional modes
It is worth saying that many CVT boxes have several more modes of operation. Among them it is worth noting:
- L. In this case, the engine runs at high speeds with maximum braking effect. This mode is relevant for long descents in the mountains and when towing.
- S. This is a sport mode. In this case, the full potential of the engine is used. As a rule, the car accelerates 0.3-0.5 seconds earlier to one hundred. The mode is suitable for those who want to get a sharp start from a traffic light.
- E. Economy mode. The machine will use the minimum speed. In this case, the dynamics of acceleration worsens, but the flow rate drops. Usually this mode is used in a calm, measured manner of driving.
How to get started?
We continue to study the question of “how to use the variator”. At Toyota and other cars of foreign manufacture, the scheme for using the variator is the same. Therefore, this instruction can be applied to any brand. So, we get into the car and install the key in the ignition switch. We check whether the car is in the "parking" (mode P). If the lever is in the “neutral” position, the engine should be started after installing the car on the handbrake.
After that, you need to squeeze the brake with your right foot. Without releasing the foot from the pedal, we translate the key in the lock to the "start" position. We wait until the engine starts (as a rule, it takes no more than two seconds). Next, put the gear lever into drive mode. We don’t let go of the brake pedal. After the "drive" mode is turned on, you can start moving. We translate the right foot from the brake pedal to the accelerator. Here's how to use the CVT on the Qashqai and other cars. Do not forget about the handbrake (if it is turned on, remove it). Further switching the car will produce on its own.
CVT neutral
Can I reset the lever to the neutral position on this box? Everything here is similar to an automaton. There are cases when this can be done, but there are times when it is unacceptable. So, it is strictly forbidden to use the neutral mode, trying to move "coast". When you try to re-enable the "drive" at speed, there is a significant blow to the clutch, and the box is subjected to load. Therefore, you should switch to neutral only when the car is in traffic and the downtime is more than 30 seconds.
Warming up
Many questions arise about how to use the CVT on the Nissan in the winter. It is worth mentioning that in this gearbox there is also oil that acts as a working fluid. However, if the machine contains about ten liters, then the variator only seven. That is, you need to warm up the box, but less time is spent on it. So, how to use the variator in the winter? Warming up can be done both in parking mode and in neutral. These modes are practically the same, except that the "parking" blocks the wheels. Therefore, we just start the car and wait five minutes until the engine and gearbox warm up. It is worth saying that the lower the temperature, the more time should be given to warming up (and vice versa).
If snow / ice
How to use a variator on this type of coating? Here you need to know that when the wheels slip on a slippery surface, it is possible to engage them with a harder coating. So, the driver mechanically presses on the gas when the car "grabbed" and was about to ride in the snow. But here on the way comes the asphalt, and the wheels meet him at high speed. As a result - a significant impact on the clutch. Hydraulic clutch wear occurs. For a couple of such tricks, she can even wear out. The same goes for riding with chains. Do not sharply press on the gas when the car is about to start. All this is significantly displayed on the clutch of the box, especially if it is a chain-bracelets. Therefore, on a slippery road we move as smoothly and accurately as possible, even if the car has already started to drive after it has stalled. And of course, you need to monitor the temperature of the oil in the box. The box will not withstand prolonged slippage.
About heavy loads
Many have heard that sudden loads on the box led to its soon failure. This is really true. Due to their design, these transmissions are not able to "digest" large torque. However, how to prevent this? How to use a variator? Everything is simple. It is necessary to abandon the frequent aggressive driving and warm up the box in the winter. Also note that on many boxes, electronics can signal overheating. So, if the oil temperature is above normal, the corresponding lamp will light up on the instrument panel. And on some cars, electronics will not let you budge at all until the box cools down.
CVT and off-road
This is also worth talking separately. Many are wondering how to use the CVT on the Mitsubishi Outlander and other SUVs. The variator is not intended for operation on a primer or off-road. Just a few slip is enough to overheat the transmission. Therefore, if you often travel in this area, it is better to choose a car on the mechanics. But how to use the variator on the Outlander in such a situation?
If the car got on the "belly", do not make desperate attempts to move it from its place. Otherwise, the gearbox will overheat. Only evacuation is relevant. Also, do not often switch from R mode to "drive", trying to rock the car. Because of this, the splined connections of the box wear out significantly.
Towing
Considering the question of how to use the variator, it must be said that this box is afraid of towing. So, a car with a CVT cannot be transported in tow - only a tow truck. As in the previous case, splined joints are strongly broken here.
Trailers
How to use the CVT on the Nissan X-Trail, if it is equipped with a hitch and you need to transport the goods on a trailer? In this case, you should adhere to the rule that the weight of the trailer with the load should not exceed one ton. As for cars, they should be discarded from transportation (meaning in tow).
Service
You need to know the nuances of service, and not just how to use the variator. At Mitsubishi, like other cars with this gearbox, regular oil changes should be made. The regulation is 60 thousand kilometers. It is important to know that the oil must comply with all tolerances and specifications. Only original products are recommended. The fact is that the variator is more demanding on the quality and properties of oil than an automatic machine and mechanics. Therefore, only liquid from a trusted manufacturer is poured here. As for the repair, for any signs of slipping or other incorrect operation of the gearbox, you need to go for detailed diagnostics to the service station. The device of the variator is quite complex, so the box should be repaired only by professionals.
Also note that even with regular maintenance, the resource of such a transmission does not exceed 200 thousand kilometers. This must be considered when acquiring a used car.
Causes and signs of damage
Consider the most common of them:
- Inability to turn on any gear. This indicates a failure of the gearbox selector. There may also be problems with the wiring (oxidation of the contacts, connectors or mechanical damage to the wires).
- Beats when switching from “neutral” to “drive”. There is a faulty pressure solenoid valve. Also, kicks occur due to a faulty control unit.
- The drop in acceleration dynamics. The machine cannot move when you press the accelerator. In this situation, there may be problems with the torque converter, control unit or forward clutch.
Conclusion
So, we found out how the CVT gearbox is arranged and working, as well as how to use the CVT. In order not to “sentence” this box ahead of schedule, you need to avoid increased loads and serve it on time. This is the only way to save the resource of this complex automatic transmission.