The Vvt-i valve is a gas distribution phase displacement system car engine internal combustion from the manufacturer Toyota.

This article contains answers to these fairly common questions:

• What is a Vvt-i valve?
• vvti device;
• What is the operating principle of vvti?
• How to properly clean vvti?
• How to repair a valve?
• How is replacement carried out correctly?

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 ik starts to rotate. At the moment when the car engine is turned off, it is installed maximum angle detention. This means that the angle that corresponds to the most recent opening and closing of the intake valves is determined. Due to the fact that the rotor is connected to the housing using a locking pin immediately after starting, when the oil line pressure is insufficient to effectively operate the valve, no shock can occur in the valve mechanism. The locking pin is then opened by the pressure applied to it by the oil.

What is the principle Vvt-i actions? Vvt-i provides the ability to smoothly change the gas distribution phases, corresponding to all operating conditions of a car engine. This function is ensured by rotating the camshaft of the intake valves in relation to the rollers of the exhaust valves, according to 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 in the open position. The control of the presented type of valve occurs thanks to a signal that comes from the control unit. After receiving a signal, an electronic magnet moves the main spool along the plunger, allowing oil to flow in any direction.

At the moment when the car engine is not functioning, the spool moves with the help of a spring so as to position the maximum delay angle.

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

There are a total of seven modes of operation of a car engine and here is a list of them:

1. Driving at idle speed;
2. Movement at low load;
3. Movement with medium load;
4. Moving with high load And low level rotation speed;
5. Moving with heavy loads and high level rotation speed;
6. Driving with low coolant temperature;
7. When starting and stopping the engine.

Self-cleaning procedure for Vvt-i

There are usually many signs associated with dysfunction, so it makes sense to look at those signs first.

So, the main signs of disruption of normal functioning are:

• The car suddenly stalls;
• The vehicle cannot maintain speed;
• The brake pedal becomes noticeably stiff;
• The brake pedal does not pull.

Now we can move on to consider the Vvti purification process. We will carry out Vvti cleansing step by step.

So, the algorithm for Vvti cleansing is:

1. Remove the plastic cover of the car engine;
2. Unscrew the bolts and nuts;
3. We remove the iron cover, the main task of which is to fix the machine generator;
4. Remove the Vvti connector;
5. Unscrew the bolt by ten. Don't be afraid, you can't make a mistake, since there's only one there.
6. We remove Vvti. Just do not pull on the connector under any circumstances, because it fits quite tightly to it and there is a sealing ring on it.
7. We clean the Vvti using any cleaner that is designed to clean the carburetor;
8. To completely clean the Vvti, remove the filter of the Vvti system. The presented filter is located under the valve and looks like a plug with a hole for a hexagon, but this item is optional.
9. Cleaning is complete, all you have to do is put everything back in the reverse order and tighten the belt without resting on Vvti.

Self-repair Vvt-i

Quite often there is a need 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:

• Car engine won't hold idle speed;
• Engine brakes;
• It is impossible to move the car on low revs;
• No brake booster;
• Gear shifts poorly.

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

• The coil has broken. In this case, the valve will not be able to respond correctly to the voltage transfer. Define this violation can be done by measuring the winding resistance.
• The rod is stuck. The reason for the rod sticking may be the accumulation of dirt in the rod channel or deformation of the rubber band, which is located inside the rod. You can remove dirt from the channels by soaking or soaking.

Valve repair algorithm:

1. Remove the adjusting bar of the car generator;
2. We remove the fasteners of the car hood lock, thanks to this you can gain access to the axial bolt of the generator;
3. Remove the valve. Just do not pull on the connector under any circumstances, because it fits quite tightly to it and there is a sealing ring on it.
4. Remove the Vvti system filter. The presented filter is located under the valve and looks like a plug with a hole for a hexagon.
5. If the valve and filter are very dirty, then clean them using special liquid for cleaning the carburetor;
6. We check the functionality of the valve by briefly applying twelve volts to the contacts. If you are satisfied with how it functions, then you can stop at this stage, but if not, then follow these steps.
7. We put marks on the valve in order to prevent mistakes during reinstallation;
8. Using a small screwdriver, disassemble the valve on both sides;
9. We take out the rod;

1. We wash and clean the valve;
2. If the valve ring is deformed, then replace it with a new one;
3. Roll it up inner side valve This can be done using a cloth, 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 outside of the valve to press the outer ring;
7. The valve repair is complete and all you have to do is reassemble everything in reverse order.

Procedure self-replacement valve Vvt-i

Often, cleaning and repairing the valve does not give much results and then it becomes necessary to completely replace it. In addition, many car enthusiasts claim that after replacing the valve vehicle will work much better and fuel consumption will drop to approximately 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 vehicle alternator adjusting bar;
2. Remove the car hood lock fasteners, thanks to this you can gain access to the axial bolt of the generator;
3. 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 tighten the bolt securing the valve;
7. The valve replacement is complete and all you have to do is reassemble everything in reverse order.

Not really

· 08/20/2013

This system provides the optimal intake timing in each cylinder for given specific engine operating conditions. VVT-i virtually eliminates the traditional trade-off between more low-end torque and high power on high. Also VVT-i provides greater fuel economy and reduces emissions so effectively harmful products combustion, eliminating the need for an exhaust gas recirculation system.

VVT-i engines are installed on all modern cars Toyota. Similar systems are being developed and used by a number of other manufacturers (for example, VTEC system from Honda Motors). Toyota's VVT-i system replaces the previous VVT (2-stage hydraulically actuated control system) used since 1991 on 20-valve 4A-GE engines. VVT-i has been in use since 1996 and controls the timing of the opening and closing of intake valves by varying the transmission between the camshaft drive (belt, gear or chain) and the camshaft itself. To control the camshaft position it is used hydraulic drive(motor oil under pressure).

In 1998, Dual VVT-i appeared, controlling both intake and exhaust valves (first installed on the 3S-GE engine in the RS200 Altezza). Also dual VVT-i is used on new V-engines Toyota, for example, on a 3.5-liter V6 2GR-FE. This 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 new Corolla generations. Additionally, dual VVT-i is used in the D-4S 2GR-FSE engine in the Lexus GS450h.

By changing the opening moment of the valves, starting and stopping the engine is almost imperceptible, since compression is minimal, and the catalyst very quickly heats up to 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 the amount of opening of each valve when the engine is running at high speed. This allows you to provide not only higher speeds and more power engine, but also the optimal opening moment of each valve, which leads to fuel savings.

The system was developed in collaboration with by Yamaha. VVTL-i engines are installed on modern sports cars Toyota, such as the Celica 190 (GTS). In 1998 Toyota started suggest new technology VVTL-i for the 2ZZ-GE twin-camshaft 16-valve engine (one camshaft controls the intake valves and the other controls the exhaust valves). Each camshaft has two cams 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 operated by a camshaft cam. Each lever has a spring-loaded sliding tappet (the spring allows the tappet 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" via a conventional roller tappet (see illustration). When the speed exceeds 6000 rpm, the engine management computer opens the valve and oil pressure moves the pin under each sliding tappet. The pin supports the sliding pusher, as a result of which it no longer moves freely on its spring, but begins to transfer the force from the “high-speed” cam to the swinging lever, and the valves open more and for a longer time.

VVTI is a variable valve timing system developed by Toyota. If we translate this abbreviation from in English, then this system is responsible for intelligent phase shift. Now on modern Japanese engines The second generation of mechanisms has been installed. And for the first time VVTI began to be installed on cars in 1996. The system consists of a coupling and a special VVTI valve. The latter acts as a sensor.

Valve structure of the VVTI system of Toyota cars

The element consists of a body. The control solenoid is located in the outer part. It is responsible for the movement of the valve. The device also has O-rings and a connector for connecting the sensor.

General operating principle of the system

The main control device in this variable valve timing system is the VVTI clutch. By default, engine developers designed the valve opening phases to obtain good thrust at low engine speeds. As the speed increases, the oil pressure also increases, due to which the VVTI valve opens. Toyota Camry and its 2.4 liter engine operate on the same principle.

Once this valve opens, the camshaft will rotate to a specific position relative to the pulley. The cams on the shaft are specially shaped, and as the element rotates, the intake valves will open a little earlier. Accordingly, it will close later. This should be the most in the best possible way affect the engine power and torque at high speeds.

Detailed job description

The main control mechanism of the system (this is the clutch) is installed on the engine camshaft pulley. Its body is connected to the sprocket or the rotor is connected directly to camshaft. Oil is supplied from one or both sides to each rotor lobe on the clutch, thereby causing the camshaft to turn. When the engine is not running, the system automatically sets the maximum retard angles. They correspond to the latest opening and closing of the intake valves. When the engine starts, the oil pressure is not strong enough to open the VVTI valve. To avoid any shocks in the system, the rotor is connected to the coupling body with a pin, which, as the lubricant pressure increases, will be pressed out by the oil itself.

The operation of the system is controlled by a special valve. Upon a signal from the ECU, an electric magnet using a plunger will begin to move the spool, thereby passing oil in one direction or the other. When the motor is stopped, this spool moves due to the spring so as to set the maximum delay angle. To rotate the camshaft to a certain angle, oil under high pressure through the spool it is supplied to one of the sides of the petals on the rotor. At the same time, a special cavity opens for drainage. It is located on the other side of the petal. After the ECU understands that the camshaft is turned to desired angle, the pulley channels overlap and it will continue to be held in this position.

Typical symptoms of VVTI system problems

So, the system must change the phases of operation. If any problems arise with it, then the car will not be able to function normally in one or more operating modes. There are several symptoms that indicate a malfunction.

So, the car does not keep idle speed at the same level. This indicates that the VVTI valve is not working as it should. Also, the “braking” of the engine will indicate various problems in the system. Often, if there are problems with this phase change mechanism, the motor is not able to operate at low speeds. Error P1349 may also indicate problems with the valve. If on warm power unit high idle speed, the car does not move at all.

Possible causes of valve failure

There are not many main causes of valve failure. There are two that are particularly common. So, the VVTI valve may fail due to breaks in the coil. IN in this case the element will not be able to respond correctly to voltage transfers. Diagnosis of the malfunction is easily carried out by checking the resistance measurement of the sensor coil winding.

The second reason why the VVTI (Toyota) valve does not work correctly or does not work at all is jamming in the stem. The cause of such jamming may be simple dirt that has accumulated in the channel over time. It is also possible that the sealing rubber inside the valve is deformed. In this case, restoring the mechanism is very simple - just clean the dirt from there. This can be done by soaking or soaking the element in special liquids.

How to clean the valve?

Many problems can be cured by cleaning the sensor. First you need to find the VVTI valve. Where this element is located can be seen in the photo below. It is circled in the picture.

Cleaning can be done using carburetor cleaning fluids. To completely clean the system, remove the filter. This element is located under the valve - it is a plug in which there is a hole for a hexagon. The filter also needs to be cleaned with this liquid. After all the operations, all that remains is to assemble everything in the reverse order, and then install it without resting against the valve itself.

How to check the VVTI valve?

Checking whether the valve is working is very simple. To do this, a voltage of 12 V is applied to the sensor contacts. It must be remembered that it is impossible to keep the element under voltage for a long time, since it cannot operate in such modes for so long. When voltage is applied, the rod will retract inward. And when the circuit opens, he will come back.

If the stem moves easily, then the valve is fully operational. It only needs to be washed, lubricated and can be used. If it does not work as it should, then repairing or replacing the VVTI valve will help.

Do-it-yourself valve repair

First, remove the generator control bar. Then remove the hood lock fasteners. This will give access to the generator axle bolt. Next, unscrew the bolt that holds the valve itself and remove it. Then remove the filter. If the last element and valve are dirty, then these parts are cleaned. Repair consists of inspection and lubrication. You can also replace the O-ring. More serious repairs are not possible. If a part doesn't work, it's easier and cheaper to replace it with a new one.

Do-it-yourself VVTI valve replacement

Often cleaning and lubrication do not provide the desired result, and then the question arises complete replacement details. In addition, after replacement, many car owners claim that the car began to work much better and fuel consumption decreased.

First, remove the generator control bar. Then remove the fasteners and gain access to the generator bolt. Unscrew the bolt that holds it in place the right valve. The old element can be pulled out and thrown away, and a new one can be put in place of the old one. Then the bolt is tightened and the car can be driven.

Conclusion

Modern cars are both good and bad. They are bad because not every operation related to repair and maintenance can be performed independently. But you can replace this valve yourself, and this is a big plus for the Japanese manufacturer.

In this blog I will tell you in detail about the types of Toyota's internal combustion engine variable valve timing system.

VVT-i system.

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

The operating principle 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 speeds. After the speed rises significantly, and with it the oil pressure increases, which opens the VVT-i valve. After the valve is opened, the camshaft rotates at a certain angle relative to the pulley. The cams have a certain shape and, when turning the crankshaft, they open the intake valves a little earlier and close later, which has a beneficial effect on increasing power and torque at high speeds.

VVTL-i system.

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

Third generation VVT systems. Distinctive feature from the second generation VVT-i lies in English word Lift - lifting the valves. 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, 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 operate at once - one normal and the other enlarged. Under normal conditions, the enlarged cam works at idle, because in the rocker arm there is a so-called slipper underneath it, which fits freely inside the rocker arm, thereby preventing the large cam from transmitting the pressing force to the rocker arm. Underneath the slipper is a locking pin that is operated by oil pressure.

The principle of operation is as follows: under increased load at high speeds, the ECU sends a signal to an additional VVT valve - it is almost the same as on the clutch itself, with the exception of minor 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 it, now the slippers are blocked in the rocker and have no freewheel. The moment from the large cam begins to be transmitted to the rocker arm, thereby lowering the valve deeper into the cylinder.

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

System Dual VVT-i.

Dual VVT-i is TMC's proprietary valve timing system. The system has general principle work with the VVT-i system, but extended to the exhaust camshaft. In the cylinder head on each pulley of both camshafts VVT-i couplings are located. In fact, it is a conventional dual VVT-i system.

As a result, the engine ECU now controls the opening timing of the intake and exhaust valves, allowing 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. Considering the fact that Toyota decided to abandon the valve lift adjustment as in the VVTL-i system, the Dual VVT-i therefore does not have the disadvantage of being relatively low in environmental friendliness.

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 V10 LR series, V8 UR series, V6 GR series, AR and ZR series.

VVT-iE system.

VVT-iE is a proprietary valve timing system of Toyota Motor Corporation. From English Variable Valve Timing - intelligent by Electric motor, which translated means intelligent change of 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 at a certain angle to advance or retard the sprockets by an electric motor, rather than by oil pressure, as in previous models VVT. Now the operation of the system does not depend on the level of engine speed and operating temperature, unlike VVT-i systems, which is not capable of operating at low engine speeds and without reaching the 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 in any way on motor oil and its pressure. This system also has another plus - the ability to accurately position the camshaft offset depending on the operating conditions of the engine. The system begins its work from the start of the engine until it stops completely. Her work contributes to high environmental friendliness modern engines Toyota, maximum fuel efficiency and power.

The operating principle is as follows: the electric motor rotates together with the camshaft at its rotation speed. If necessary, the electric motor either slows down or, on the contrary, accelerates relative to the camshaft sprocket, thereby shifting the camshaft to the required angle, advancing or delaying the valve timing.

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

Valvematic system.

Valvematic is an innovative gas distribution system Toyota company, which allows you to smoothly change the valve lift height depending on engine operating conditions. This system applies to gasoline engines. If you look at it, the Valvematic system is nothing more than an improved VVT technology. At the same time, the new mechanism works in conjunction with the already familiar system of changing the valve opening time.

With help new system Valvematic engine becomes up to 10 percent more economical, as this system controls the amount of air admitted into the cylinder, and provides more output low content carbon dioxide, thereby increasing engine power. VVT-i mechanisms that perform main function, placed inside the camshafts. The drive housings are connected to toothed pulleys, and the rotor has camshafts. Oil envelops either one side of the rotor petals or the other, thereby causing the rotor and shaft to rotate. To prevent shocks from occurring when starting the engine, the rotor is connected with a locking pin to the housing, 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... There is a constant adjustment of the valve lift when 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 extraneous sound V internal combustion engine operation. This sound resembles the clicking sound of poorly adjusted valve clearances. But it goes away after 10-15 thousand. km.

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

Variable valve timing systems were a revolution for internal combustion engines, and they became popular thanks to Japanese models 90s. But how do the most famous systems differ in their operation from each other?

Since their inception, internal combustion engines have not been as efficient as possible. The average efficiency of such engines is 33 percent - all the remaining energy created by the burning fuel-air mixture is wasted. Therefore, any way to make the internal combustion engine more energy efficient was in demand, and the variable valve timing system became one of the most successful solutions.

The system varies valve timing (the point at which each valve opens and closes during the operating cycle), timing (the point at which the valve is open) and lift (how far the valve can open).

As you know, inlet valve in the engine it launches into the cylinder fuel-air mixture, which is then compressed, burned and pushed into the opening Exhaust valve. These valves are driven by pushrods controlled by the camshaft using a set of cams to ideal ratio closing and opening.

Unfortunately, conventional camshafts are made in such a way that only the opening of the valves can be controlled. This is where the problem lies, as the valves must close and open differently at different engine speeds for maximum efficiency.

For example, on high speed operation of the engine, the intake valve must be opened a little earlier due to the fact that the piston moves so quickly that it does not allow entry sufficient number air. If the valve is opened a little earlier, more air will enter the cylinder, which will increase combustion efficiency.

Therefore, instead of a compromise between camshafts for high and low speeds, a variable valve timing system appeared, recognized as one of the most effective in this area. Different companies have interpreted this technology in different ways, so let's look at the most popular ones.

Vanos (or Variable Nockenwellensteuerung) is BMW's attempt to create a variable valve timing system, and it was first used on the M50 engine installed on the 5-series in the 90s of the last century. It also uses the principle of retarding or advancing the interaction of timing mechanisms, but using a gear train inside the camshaft pulley, which moves with or against the camshaft, changing the operating phases. This process is controlled electronic unit control, which uses oil pressure to move the gear train forward or backward.

As is the case with other systems, gear moves forward to open the valves a little earlier, increasing the amount of air entering the cylinders and increasing the engine's power output. In fact, BMW first introduced a single Vanos that only ran on intake camshaft in certain modes at different engine speeds. German company later developed a system with two Vanos, which is considered more advanced, since it affects both camshafts and also adjusts the position throttle valve. The double Vanos was created for the S50B32, which was installed on the E36 BMW M3.

Now almost everyone major manufacturer has its own name for the valve timing system - Rover has VVC, Nissan has VVL, and Ford developed VCT. And this is not surprising, given that this is one of the most successful discoveries for internal combustion engines. Thanks to it, manufacturers were able to reduce consumption and increase the power of their engines.

But with the advent of pneumatic valve control, these systems will go away. However, now is just their time.