Vvti Toyota - what kind of beast is this? V-TEC, Vanos and VVT-i: how do they all work? i phase vvt system.

20.08.2013

This system provides the optimum intake torque in each cylinder for given specific engine operating conditions. VVT-i virtually eliminates the traditional trade-off between big low-end torque and high-end power. VVT-i also provides greater fuel economy and reduces emissions of harmful combustion products so effectively that there is no need for an exhaust gas recirculation system.

VVT-i engines are installed on all modern Toyota vehicles. Similar systems are being developed and used by a number of other manufacturers (for example, the VTEC system from Honda Motors). Toyota's VVT-i system replaces the previous VVT (Hydraulically Actuated 2-Stage Control) system used since 1991 on 20-valve 4A-GE engines. VVT-i has been in use since 1996 and controls the opening and closing of the intake valves by changing the gear between the camshaft drive (belt, gear or chain) and the camshaft itself. The camshaft position is controlled hydraulically (pressurized engine oil).

In 1998, Dual (“double”) VVT-i appeared, controlling both intake and exhaust valves (first installed on the 3S-GE engine on the RS200 Altezza). Also, dual VVT-i is used on new Toyota V-engines, such as the 3.5-liter V6 2GR-FE. Such an engine is installed on Avalon, RAV4 and Camry in Europe and America, on Aurion in Australia and on various models in Japan, including Estima. Dual VVT-i will be used in future Toyota engines, including a new 4-cylinder engine for the next generation Corolla. In addition, dual VVT-i is used in the D-4S 2GR-FSE engine on the Lexus GS450h.

Due to the change in the moment of opening the valves, the start and stop of the engine are practically imperceptible, since the compression is minimal, and the catalyst heats up very quickly to the operating temperature, which dramatically reduces harmful emissions into the atmosphere. VVTL-i (stands for Variable Valve Timing and Lift with intelligence) Based on VVT-i, the VVTL-i system uses a camshaft that also controls how much each valve opens when the engine is running at high speeds. This allows not only higher engine speeds and more power, but also the optimal opening moment of each valve, which leads to fuel savings.

The system was developed in cooperation with Yamaha. VVTL-i engines are found in modern Toyota sports cars such as the Celica 190 (GTS). In 1998, Toyota began offering the new VVTL-i technology for the 2ZZ-GE twin camshaft 16 valve engine (one camshaft controls the intake and the other exhaust valves). Each camshaft has two lobes per cylinder, one for low RPM and one for high RPM (large opening). Each cylinder has two intake and two exhaust valves, and each pair of valves is driven by a single rocker arm, which is acted upon by a camshaft cam. Each lever has a spring-loaded sliding follower (the spring allows the follower to slide freely over the "high speed" cam without affecting the valves). When the engine speed is below 6000 rpm, the rocker arm is actuated by a "low speed cam" through a conventional roller follower (see illustration). When the frequency exceeds 6000 rpm, the engine control computer opens the valve, and oil pressure moves the pin under each sliding pushrod. The pin supports the sliding pusher, as a result of which it no longer moves freely on its spring, but begins to transfer the impact from the "high-speed" cam to the rocking lever, and the valves open more and for a longer time.

VVTi Toyota what is it and how does it work? VVT-i - this is how the designers of the Toyota auto concern called the valve timing control system, who came up with their own system for improving the efficiency of internal combustion engines.

This does not mean that only Toyota has such mechanisms, but we will consider this principle using its example.

Let's start with decryption.

This technology was first introduced to the market by Toyota ten years ago, in 1996. All automakers and brands have similar systems, which speaks of their benefits. They are called, however, all in different ways, confusing ordinary motorists.

What did VVT-i bring to engine building? First of all - an increase in power, uniform throughout the entire rev range. Motors have become more economical and therefore more efficient.

The control of the valve timing or the control of the moment of raising and lowering the valves occurs by turning to the desired angle.

How it is implemented technically, we will consider further.

Vvti toyota what is it or how does VVT-i valve timing work?

The Toyota VVT-i system is what it is and why, we understand. Time to delve into her insides.

The main elements of this engineering masterpiece:

• clutch VVT-i;
• solenoid valve (OCV - Oil Control Valve);
• Control block.

The algorithm of this whole construction is simple. The clutch, which is a pulley with cavities inside and a rotor mounted on the camshaft, is filled with pressurized oil.

There are several cavities, and the VVT-i valve (OCV), acting on commands from the control unit, is responsible for this filling.

Under the pressure of oil, the rotor together with the shaft can turn at a certain angle, and the shaft, in turn, determines when to raise and lower the valves.

In the starting position, the position of the intake camshaft provides maximum traction at low engine speeds.

As the engine speed increases, the system rotates the camshaft so that the valves open earlier and close later - this helps to increase output at high speeds.

As you can see, the VVT-i technology, the principle of operation of which was considered, is quite simple, but, nevertheless, effective.

The development of VVT-i technology: what else did the Japanese come up with?

There are other varieties of this technology. So, for example, Dual VVT-i controls the operation of not only the intake camshaft, but also the exhaust ones.

This made it possible to achieve even higher engine parameters. Further development of the idea was called VVT-iE.

Here, Toyota engineers completely abandoned the hydraulic method of controlling the camshaft position, which had a number of disadvantages, because in order to rotate the shaft, it was necessary that the oil pressure rise to a certain level.

It was possible to eliminate this drawback thanks to electric motors - now they turn the shafts. That's it.

Thank you for your attention, now you yourself can answer the question "VVT-i Toyota what is it and how does it work" to anyone.

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The Vvt-i valve is a variable valve timing system for an automotive internal combustion engine manufactured by Toyota.

This article contains answers to such fairly common questions:

• What is a Vvt-i valve?
• vvti device;
• What is the principle of operation of vvti?
• How to properly clean vvti?
• How to repair a valve?
• How is the replacement done?

Vvt-i device

The main mechanism is located in the camshaft pulley. The housing is connected together with a toothed pulley, and the rotor with a camshaft. Lubricating oil is delivered to the valve mechanism from either side of each petal rotor. Thus the valve and camshaft starts to rotate. At that moment, when the car engine is in a muffled state, the maximum angle of detention is set. This means that an angle is determined that corresponds to the most recent product of the opening and closing of the intake valves. Due to the fact that the rotor is connected to the housing by a locking pin immediately after start-up, when the pressure of the oil line is insufficient to effectively control the valve, no shocks can occur in the valve mechanism. After that, the locking pin opens with the help of the pressure that the oil exerts on it.

What is the principle of operation of Vvt-i? Vvt-i provides the ability to smoothly change the gas distribution phases, corresponding to all conditions for the functioning of an automobile engine. This function is ensured by rotating the inlet camshaft relative to the outlet valve shafts, along the angle of rotation of the crankshaft from forty to sixty degrees. As a result, there is a change in the moment of initial opening of the intake valve, as well as the amount of time when the exhaust valves are in the closed position, and the exhaust valves are open. The control of the presented type of valve is due to the signal that comes from the control unit. After a signal is received, an electronic magnet moves the main spool along the plunger, while passing oil in any direction.

At the moment when the car engine is not working, the spool moves with the help of a spring so that the maximum delay angle is located.

To produce a camshaft, oil under a certain pressure is moved to one side of the rotor with the help of a spool. At the same moment, a cavity opens on the other side of the petals to drain the oil. After the control unit determines the location of the camshaft, all the channels of the pulley are closed, thus, it is held in a fixed position. The operation of the mechanism of this valve is carried out by several conditions for the functioning of an automobile engine with different modes.

In total, there are seven modes of operation of an automobile engine, and here is a list of them:

1. Idling movement;
2. Movement at low load;
3. Movement with an average load;
4. Driving with high load and low speed;
5. Traveling with a high load and a high level of rotational speed;
6. Traveling with low coolant temperature;
7. During engine start and stop.

Self cleansing procedure a Vvt-i

Dysfunction is usually accompanied by many signs, so it is most logical to look at these signs first.

So, the main signs of a violation of normal functioning are as follows:

• The car abruptly stalls;
• The vehicle cannot maintain momentum;
• The brake pedal noticeably stiffens;
• Does not pull the brake pedal.

Now we can proceed to consider the process of purification of Vvti. We will carry out the purification of Vvti step by step.

So, the algorithm for cleaning Vvti:

1. Remove the plastic cover of the car engine;
2. We unscrew the bolts and nuts;
3. We remove the iron cover, the main task of which is to fix the generator of the machine;
4. We remove the connector from the Vvti;
5. We unscrew the bolt by ten. Don't be afraid, you won't be able to make a mistake, as there is only one of them.
6. We remove Vvti. Just in no case do not pull on the connector, because it fits snugly enough to it and a sealing ring is placed on it.
7. We clean Vvti with any cleaner that is designed to clean the carburetor;
8. For complete purification of Vvti, remove the filter of the Vvti system. The presented filter is located under the valve and has the form of a plug with a hole for the hexagon, but this item is optional.
9. Cleansing is complete, you just have to assemble everything in reverse order and tighten the belt without resting on Vvti.

Self Repair Vvt-i

Quite often, it becomes necessary to repair the valve, since simply cleaning it is not always effective.

So, first, let's look at the main signs of the need for repairs:

• The car engine does not hold idle;
• Brakes the engine;
• It is impossible to move the car at low speeds;
• No brake booster;
• Poor gear changes.

Let's look at the main causes of valve failure:

• The coil broke. In this case, the valve will not be able to respond correctly to the voltage transfer. This violation can be determined by measuring the resistance of the winding.
• Seizes the stock. The cause of stem sticking can be the accumulation of dirt in the stem bore or deformation of the rubber that is located inside the stem. Dirt can be removed from the channels by soaking or soaking.

Valve repair algorithm:

1. We remove the regulating bar of the car generator;
2. We remove the fasteners of the lock of the hood of the car, thanks to this you can get access to the axial bolt of the generator;
3. We remove the valve. Just in no case do not pull on the connector, because it fits snugly enough to it and a sealing ring is placed on it.
4. We remove the filter of the Vvti system. The presented filter is located under the valve and has the form of a plug with a hole for the hexagon.
5. If the valve and filter are very dirty, then we clean them with a special liquid for cleaning the carburetor;
6. We check the operability of the valve, using a short supply of twelve volts to the contacts. If you are satisfied with how it functions, then you can stop at this stage, if not, then follow these steps.
7. We put marks on the valve in order to prevent mistakes during re-installation;
8. Using a small screwdriver, disassemble the valve from two sides;
9. We take out the stock;

1. We wash and clean the valve;
2. If the valve ring is deformed, then replace it with a new one;
3. Roll up the inside of the valve. This can be done with the help of a cloth, by pressing on the rod, to press the new sealing ring;
4. Change the oil that is in the coil;
5. We replace the ring, which is located on the outside;
6. Roll the outer side of the valve to press the outer ring;
7. The valve repair is completed and you just have to assemble everything in the reverse order.

Vvt-i valve self-replacement procedure

Often, cleaning and repairing the valve does not give much results, and then it becomes necessary to completely replace it. In addition, many motorists claim that after replacing the valve, the vehicle will work much better and fuel costs will drop to about ten liters.

Therefore, the question arises: How should the valve be replaced correctly? We will replace the valve step by step.

So, the valve replacement algorithm:

1. Remove the car alternator control bar;
2. Remove the fasteners of the lock of the hood of the car, thanks to this you will be able to gain access to the axial bolt of the generator;
3. We unscrew the bolt that secures the valve;
4. We take out the old valve;
5. We install a new valve in place of the old one;
6. We twist the bolt securing the valve;
7. The valve replacement is complete and you just have to assemble everything in the reverse order.

Not really

In this blog, I will tell you in detail about the varieties of the Toyota ICE valve timing system.

VVT system.

VVT-i is a proprietary timing system from Toyota Corporation. From the English Variable Valve Timing with intelligence, which means intelligent change in valve timing. This is the second generation of Toyota's variable valve timing system. Installed on cars since 1996.

The principle of operation is quite simple: the main control device is the VVT-i clutch. Initially, the valve opening phases are designed so that good traction is present at low revs. After the speed rises significantly, and with them the oil pressure increases, which opens the VVT-i valve. After the valve is open, the camshaft rotates at a certain angle relative to the pulley. The cams have a certain shape and when the crankshaft is turned, the intake valves open a little earlier and close later, which favorably affects the increase in power and torque at high speeds.

VVTL-i system.

VVTL-i is TMC's proprietary timing system. From the English Variable Valve Timing and Lift with intelligence, which means an intelligent change in the valve timing and valve lift.

The third generation of the VVT ​​system. A distinctive feature from the second generation VVT-i lies in the English word Lift - valve lift. In this system, the camshaft not only rotates in the VVT ​​clutch relative to the pulley, smoothly adjusting the opening time of the intake valves, but also, under certain engine operating conditions, lowers the valves deeper into the cylinders. Moreover, the valve lift is implemented on both camshafts, i.e. for intake and exhaust valves.

If you look closely at the camshaft, you can see that for each cylinder and for each pair of valves there is one rocker arm, along which two cams are worked out at once - one ordinary and the other enlarged. Under normal conditions, the enlarged cam works out at idle, because. in the rocker under it, a so-called slipper is provided, which freely enters the rocker, thereby preventing the large cam from transmitting the pressing force on the rocker. Under the slipper is a locking pin that is actuated by oil pressure.

The principle of operation is as follows: with an increased load at high speeds, the ECU sends a signal to the additional VVT valve - it is almost the same as on the clutch itself, with the exception of slight differences in shape. As soon as the valve opens, oil pressure is created in the line, which mechanically acts on the locking pin and moves it towards the base of the slipper. That's all, now the slippers are locked in the rocker and have no free play. The moment from the large cam begins to be transmitted to the rocker, thereby lowering the valve deeper into the cylinder.

The main advantages of the VVTL-i system are that the engine pulls well on the bottom and shoots on the top, fuel efficiency improves. The disadvantages are reduced environmental friendliness, which is why the system in this configuration did not last long.

Dual VVT-i system.

Dual VVT-i is TMC's proprietary timing system. The system shares the same principle of operation with the VVT-i system, but extended to the exhaust camshaft. VVT-i clutches are located in the cylinder head on each pulley of both camshafts. In fact, this is a conventional dual VVT-i system.

As a result, the engine ECU now controls the opening times of the intake and exhaust valves, allowing you to achieve greater fuel efficiency both at low speeds and at high speeds. The engines turned out to be more elastic - the torque is distributed evenly over the entire engine speed range. Given the fact that Toyota decided to abandon the valve lift adjustment as in the VVTL-i system, therefore, Dual VVT-i is devoid of its relatively low environmental friendliness disadvantage.

The system was first installed on the 3S-GE engine of the RS200 Altezza in 1998. Currently installed on almost all modern Toyota engines, such as the V10 LR series, V8 UR series, V6 GR series, AR and ZR series.

VVT-iE system.

VVT-iE is Toyota Motor Corporation's proprietary timing system. From English Variable Valve Timing - intelligent by Electric motor, which means an intelligent change in valve timing using an electric motor.

Its meaning is exactly the same as that of the VVTL-i system. The difference lies in the implementation of the system itself. The camshafts are deflected to a specific angle to advance or retard the sprockets by the electric motor rather than by oil pressure as on previous VVT models. The system is now independent of engine speed and operating temperature, unlike the VVT-i system, which is unable to operate at low engine speeds before reaching engine operating temperature. At low speeds, the oil pressure is low and it is not able to move the VVT ​​clutch blade.

VVT-iE does not have the disadvantages of previous versions, because. does not depend on engine oil and its pressure. Also, this system has another plus - the ability to accurately position the displacement of the camshafts depending on the operating conditions of the engine. The system starts its work from the start of the motor to its complete stop. Its work contributes to the high environmental friendliness of modern Toyota engines, maximum fuel efficiency and power.

The principle of operation is as follows: the electric motor rotates with the camshaft in the mode of its rotation speed. If necessary, the electric motor either slows down or, on the contrary, accelerates relative to the camshaft sprocket, thereby making the camshaft shift by the required angle, advancing or delaying the valve timing.

The VVT-iE system debuted for the first time in 2007 on the Lexus LS 460, installed in the 1UR-FSE engine.

Valvematic system.

Valvematic is Toyota's innovative valve timing system that allows you to smoothly change the valve lift depending on engine operating conditions. This system is used on gasoline engines. If you look, the Valvematic system is nothing more than an advanced VVTi technology. At the same time, the new mechanism works in conjunction with the already familiar system for changing the valve opening time.

With the help of the new Valvematic system, the engine becomes more economical by up to 10 percent, since this system controls the amount of air entering the cylinder, and provides a lower carbon dioxide content at the outlet, thereby increasing engine power. The VVT-i mechanisms that perform the main function are placed inside the camshafts. The drive housings are connected to the toothed pulleys, and the rotor is connected to the camshafts. Oil envelops either one side of the rotor petals or the other, thereby causing the rotor and shaft to turn. In order to prevent shocks when starting the engine, the rotor is connected by a locking pin to the body, then the pin moves away under oil pressure.

Now about the advantages of this system. The most significant of these is fuel economy. And also thanks to the Valvematic system, engine power increases, because. valve lift is continuously adjusted as the intake valves open and close. And of course, let's not forget about the environment... The Valvematic system significantly reduces carbon dioxide emissions into the atmosphere, up to 10-15%, depending on the engine model. Like any technological innovation, the Valvematic system also has negative reviews. One of the reasons for such reviews is an extraneous sound in the operation of the internal combustion engine. This sound resembles the clatter of poorly adjusted valve clearances. But it passes after 10-15 thousand. km.

Currently, the Valvematic system is installed on Toyota vehicles with engine sizes of 1.6, 1.8 and 2.0 liters. The system was first tested on Toyota Noah vehicles. And then it was installed on the ZR series engines.