Where is the vvti valve and how to check it? MRM VVT-I Systems from Toyota Differences VVT Corporation from VVTi

VVT-I valve is a gas distribution phase displacement system car Engine internal combustion From the manufacturer of Toyota.

This article posted answers to such fairly common questions:

• What is the VVT-I valve?
• VVTI device;
• What is the principle of VVTI?
• How is the Cleaning VVTI?
• How to repair valve?
• How is the replacement?

VVT-I device

The main mechanism is placed in the camshaft pulley. The housing is connected along with a tooth pulley, and the rotor with the distribution room. Lubricating oil is delivered to the valve mechanism with any of the sides of each petal rotor. Thus, the valve and the distribution roller begins to rotate. At the moment when the car engine is in a muffled state, the maximum detention angle is installed. This means that the angle is determined that corresponds to the latest work and closing of the vacuum valves. Due to the fact that the rotor is connected to the housing using a locking pin immediately after launch when the pressure of the oily highway is not enough to make an efficient valve manual, there can not arise any blows in the valve mechanism. After that, the locking pin opens with the help of pressure that oil has on it.

What is the principle of action of VVT-I? VVT-I provides the possibility of a smooth change in gas distribution phases, corresponding to all the conditions of the operation of the automotive engine. This function is ensured by the product of the rotation of the camshaft of the vacuum valves with respect to the rollers of the producing valves, along the corner of the rotation of the crankshaft from forty to sixty degrees. As a result, it is changed by changing the moment of initial opening of the giving valve, as well as the amount of time when the producing valves is in a closed position, and released in open. The manual presented valve type occurs due to the signal that comes from the manual block. After the signal arrives, the electronic magnet on the plunger moves the main spool, flowing at the same time in any direction.

At that moment, when the car engine does not function, the spool moves with the springs so as to accommodate the maximum delay angle.

For the product of camshaft, the oil under defined pressure using an spool moves into one of the sides of the rotor. At the same time, the cavity is discovered on the other side of the petals to drain the oil. After determining the camshaft location control unit, all pulley channels are closed, so it is held in a fixed position. The operation of the mechanism of this valve is carried out by several conditions of operation of the automotive engine with various modes.

There are only seven modes of operation of the automotive engine and now their list:

1. Idle movement;
2. Low load movement;
3. Movement with the average load;
4. High load movement and low level Rotation frequency;
5. Movement with high load and high speed frequency;
6. Movement with low cooling fluid temperature;
7. During running and stopping the engine.

Independent purification procedure A VVT-I

Violation of functioning is usually accompanied by a variety of features, therefore it will be more logical to first consider these signs.

So, such: the main signs of violation of normal functioning are:

• The car sharply stalls;
• The vehicle cannot hold the turnover;
• The brake pedal is noticeably mounted;
• Does not pull the brake pedal.

Now you can go to the consideration of the VVTI cleansing process. WVTI cleansing, we will be step by step.

So, the algorithm for cleansing VVTI:

1. Remove the plastic cover of the automotive engine;
2. Unscrewing bolts and wrenches;
3. Remove the iron cover, the main task of which is fixing the machine generator;
4. Remove with vvti connector;
5. We unscrew the bolt for ten. Do not be afraid, you will not be able to make a mistake, as it is only one there.
6. Remove vvti. Only, in no case do not pull for the connector, because it fits sufficiently tightly to it and the sealing ring is placed on it.
7. Clean VVTI with any cleaner, which is designed to cleanse the carburetor;
8. To complete VVTI cleansing, remove the VVTI filter. The presented filter is located under the valve and has a type of stub with a hole for the hexagon, but this item is optional.
9. Clearing Completed You can only collect everything in the reverse order and pull the belt without resting in vvti.

DIY repair VVT-I

Quite often arises the need for the repair of the valve, since it is simply not always effective.

So, for starters, let's figure it out with the main signs of the need for repair:

• The car engine does not hold idle;
• Inhibits the engine;
• It is impossible to move the car on low revs;
• No brake amplifier;
• The gears are poorly switched.

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

• The coil broke. In this case, the valve will not be able to react to the transmission of the voltage. It is possible to determine this violation using the work of measuring the resistance of the winding.
• Sticks stock. The cause of the stem is caught by the accumulation of dirt in the rod channel or the strain of the gum, which is located inside the rod. Remove dirt from the channels can be twisted or wort off.

Valve repair algorithm:

1. Remove the regulatory bar of the car generator;
2. Remove the fastener of the hood of the car, thanks to this you can access the axial bolt of the generator;
3. Remove the valve. Only, in no case do not pull for the connector, because it fits sufficiently tightly to it and the sealing ring is placed on it.
4. Remove the vvti filter. The presented filter is located under the valve and has a type of stub with a hole for the hexagon.
5. If the valve and filter are strongly contaminated, then we clean them with special fluid To purify the carburetor;
6. Check the performance of the valve, with the help of a short-term supply of twelve volts to contacts. If you are satisfied, as it functions, you can stay at this stage, if not, then follow these steps.
7. Put the mark on the valve in order to prevent an error during the reverse installation;
8. Using a small screwdriver, we disassemble the valve on both sides;
9. Give rod;

1. Rinse and clean the valve;
2. If the valve ring is deformed, then replace it with a new one;
3. Rollytsey inner side valve. It is possible to do this with the help of a shelter, pressure on the rod, for pressing a new sealing ring;
4. Change the oil that is in the coil;
5. We replace the ring, which is located on the outside;
6. Rollytsey outside valve, for pressed the outer ring;
7. The valve repair is completed and you can only collect everything in the reverse order.

Procedure self-substitution VVT-I valve

Often, the cleansing and repair of the valve does not give the results and then there is a need to fully replace it. In addition, many motorists argue that after the replacement of the valve vehicle It will work much better and fuel costs will decrease approximately ten liters.

Consequently, the question arises: how to replace the valve?. Valve replacement we will step by step.

So, the valve replacement algorithm:

1. Remove the regulatory bar of the car generator;
2. Remove the fastener of the machine hood lock, thanks to this you can access the axial generator bolt;
3. Unscrew the bolt that fixes the valve;
4. Pull out the old valve;
5. Install a new valve to the place of the old;
6. Tighten the bolt, fixing the valve;
7. Replacing the valve is complete and you can only collect everything in the reverse order.

Well no

VVTI is a system for changing the phase values \u200b\u200bof gas distribution. If we translate this abbreviation with of English languageThis system is responsible for the intelligent phase displacement. Now on modern japanese engines The second generation of mechanisms has been established. And for the first time Vvti began to install on cars since 1996. The system is a coupling and a special vvti valve. The latter performs the role of the sensor.

VVTI VVTi VVTi Valve Device

The element consists of a housing. In the outer part there is a control solenoid. It is responsible for the movement of the valve. Also in the device there are sealing rings and a connector for connecting the sensor.

General principle of system operation

The main control device in this system of shift of the phase of gas distribution is the VVTI coupling. By default, the engine developers designed the valve opening phases so as to get a good traction on low motor turnover. As the rotation increases, the oil pressure is growing, due to which VVTI valve opens. Toyota-Camry and its 2.4 liter engine works on the same principle.

After this valve opens, the camshaft turn into a certain position relative to the pulley. The cams on the shaft have a special form, and in the process of rotation of the element, the inlet valves will be opened a little earlier. Accordingly, it is later closed. It should best affect the power and torque of the engine on high revolutions.

Detailed job description

The main control mechanism of the system (and this clutch) is installed on the motor camshaft pulley. The housing is connected to the asterisar or the rotor connects directly to the distribution shaft. Oil from is served from one or two sides to each rotor petal on the coupling, forcing the distribution shaft to rotate. When the engine is not running, the system automatically sets the maximum delay angles. They correspond to the very late opening and closing of the inlet valves. When the motor starts, the oil pressure is not strong enough to open the VVTI valve. To avoid any blows in the system, the rotor connects to the housing of the coupling with a pin, which, with the increase in pressure, the lubricant will be pressed by the oil itself.

The operation of the system is carried out by means of a special valve. By signal with the computer, an electric magnet with a plunger will begin to move the spool, thereby skipping the oil in one or in another direction. When the motor is stopped, this spool moves at the expense of the spring so as to set the maximum delay angle. To rotate the camshaft on a certain angle, the oil under high pressure by means of the spool is supplied to one of the sides of the petals on the rotor. Simultaneously with this, the special cavity opens. It is located on the other side of the petal. After the computer understands that the distribution shaft will be turned to the desired angle, pulley channels overlap and it will be left further in this position.

Typical symptoms of VVTI system problems

So, the system must change the phases of the work if any problems arise with it, then the car will not be able to function normally in one or several operating modes. You can select multiple symptoms that will affect faults.

So, the car does not keep idol at one level. This suggests that the vvti valve does not work as needed. Also about various malfunctions in the system will say "braking" of the engine. Often, when problems with this mechanism, the phase change lacks the possibility of working on low revs. More about problems with the valve can say error P1349. If on a heated force aggregate High idle speed, the car does not go at all.

Possible Causes Valve Fault

The main causes of valve faults is not so much. You can allocate two, which are especially common. So, the VVTI valve may fail due to the fact that there are cliffs in the coil. IN this case The element will not be able to react to the voltage transmission. Fault diagnostics is easily implemented using a measurement check for the resistance of the sensor coil.

The second reason why VVTI valve (Toyota) works incorrectly or does not work at all - it is jealous in stock. The reason for such jams can be a banal dirt that has accumulated in the channel over time. It is also possible that the sealing gum inside the valve is deformed. In this case, it is very easy to restore the mechanism - it is enough to clean the dirt from there. This can be done by wrinkling or dumping the element in special fluids.

How to clean the valve?

Many faults can be cured by cleaning the sensor. First you need to find VVTI valve. Where this element is located, you can see in the photo below. He is encountered in the picture.

Cleaning can be carried out using liquids for cleaning carburetors. To fully clean the system, remove the filter. This element is under the valve - it is a plug in which there is a hole under the hexagon. The filter also needs to be purified by this liquid. After all operations, it remains only to collect everything in the reverse order, and then install without resting at the same time in the valve itself.

How to check VVTI valve?

Check if the valve works, very simple. For this, the voltage in 12 V. is submitted to the sensor contacts, it is necessary to remember that it is impossible to keep the element under voltage for a long time, since it cannot work in such modes so much time. At the time of supplying the voltage, the rod will draw inside. And when the chain dispels, it will return back.

If the rod moves easily, the valve is fully working. It only needs to rinse, lubricate and can be operated. If it does not work as needed, then the repair or VVTI valve replacement will help.

DIY repair of the valve

First dismantle the regulating bar of the generator. Then remove the fastener of the hood lock. It will open access to the axial bolt of the generator. Next, we unscrew the bolt that holds the valve itself, and remove it. After filter is removed. If the last element and valve are dirty, then these parts are cleaned. Repair is an inspection and lubrication. You can also replace the sealing ring. More serious repairs are not possible. If the item does not work, easier and cheaper to replace it with a new one.

Self Replacement VVTI Valve

Often cleaning and lubrication does not provide required result, and then the question arises full replacement Details. In addition, many car owners after replacement argue that the car began to work much better and the fuel consumption decreased.

To begin with, they remove the regulatory bar of the generator. Then remove the fastener and get access to the generator bolt. Pubrip the bolt to which is held the desired valve. The old element can be pulled out and throw away, and the old one put a new one. Then twist the bolt, and the car can be operated.

Conclusion

Modern cars at the same time and good, and bad. The bad they are the fact that not every operation associated with repair and maintenance can be performed independently. But it is possible to replace this valve with your own hands, and this is a big plus to the Japanese manufacturer.

System of changing phases of gas distribution (generally accepted international name Variable Valve Timing, Vvt.) It is designed to regulate the parameters of the gas distribution mechanism, depending on the mode of operation of the engine. The use of this system provides an increase in engine power and torque, fuel efficiency and reduction of harmful emissions.

The adjustable parameters of the gas distribution mechanism include:

• the moment of opening (closing) of valves;
• the duration of the opening of the valves;
• valve lift height.

In the aggregate, these parameters are the phases of gas distribution - the duration of the intake and output clocks, a pronounced angle of rotation of the crankshaft relative to the "dead" points. The gas distribution phase is determined by the shape of the camshaft camshaft acting on the valve.

At different modes of engine operation, various phases of gas distribution are required. Thus, at low engine speeds, the gas distribution phase should have a minimum duration ("narrow" phases). In high speed, on the contrary, the gas distribution phases should be as wide as possible and at the same time ensure the overlap of the intake and output clocks (natural recycling of exhaust gases).

The camshaft camshal has a certain form and cannot simultaneously provide narrow and wide phases of gas distribution. In practice, the cam shape is a compromise between the high torque on low revolutions and high power at high speeds crankshaft. This is a contradiction, just allows the system of changing the phases of gas distribution.

Depending on the adjustable parameters of the gas distribution mechanism, the following methods of changing phases of gas distribution are distinguished:

• rotation of the camshaft;
• applying cams with different profile;
• changing the lifting height of the valve.

The most common systems of changing the phases of gas distribution, using the rotation of the camshaft:

• Vanos. (Double Vanos.) from bmw;
• VVT-I.(Dual VVT-I), Variable Valve Timing with Intelligence from Toyota;
• Vvt., Variable Valve Timing from Volkswage n.;
• VTC., VARIABLE TIMING CONTROL FROM HONDA;
• CVVT., Continuous Variable Valve Timing from Hyundai, Kia, Volvo, General Motors;
• VCP., Variable Cam Phases from Renault.

The principle of operation of these systems is based on the rotation of the camshaft along the rotation, which is achieved by the early opening of the valves compared to the initial position.

The design of the changing system of the phase timing of this type includes a hydraulic coupling and a system of controlling this clutch.

Hydro-controlled coupling (source name phasemator) directly performs a rotation of the camshaft. The coupling consists of a rotor connected to a camshaft, and the housing, which is the role of the camshaft actuator. Between the rotor and the case there are cavities to which the channels are supplied motor oil. The filling of one or another cavity oil provides rotation of the rotor relative to the housing and, accordingly, rotate the camshaft to a certain angle.

For the most part, the water-controlled coupling is installed on the camshaft of the intake valves. To expand control parameters in separate structures, the couplings are installed on inlet and exhaust camshafts.

The control system provides automatic control of the work of the hydraulic controlled coupling. Structurally, it includes input sensors, the electronic unit Controls and executive devices. The management system uses the Hall sensors that assess the provisions are used. distributional shafts, as well as other sensors of the engine control system: the frequency of rotation of the crankshaft, the temperature of the coolant, air flow meter. The engine control unit receives signals from the sensors and forms the control effects on the actuator - the electro-hydraulic distributor. The distributor is solenoid valve and provides an oil supply to the hydraulic airborne coupling and the removal from it depending on the engine operation modes.

The gas distribution phase change system provides for work, as a rule, in the following modes:

• idling (minimum crankshaft turnover);
• maximum power;
• maximum torque.

Another type of system of changing the phases of gas distribution is built on the use of cams of various shapes, which reaches a stepwise change in the duration of the opening and lifting height of the valve. Famous systems are:

• Vtec., VARIABLE VALVE TIMING AND LIFT Electronic Control from Honda;
• VVTL-I., Variable Valve Timing and Lift with Intelligence from Toyota;
• MiveC., Mitsubishi Innovative Valve Timing Electronic Control from Mitsubishi;
• Valvelift System from Audi.

These systems have, mostly similar design and principle of operation, with the exception of ValveLift System. For example, one of the most famous VTEC systems includes a set of cams of various profiles and a control system.

The camshaft has two small and one large cam. Small cams through the corresponding rockers (rockers) are connected to a pair of inlet valves. Big cam moves free rocker.

The control system ensures switching from one mode of operation to another by the triggering of the blocking mechanism. The blocking mechanism has a hydraulic drive. With low engine speed (low load), the operation of the intake valves is made from small cams, while the phases of gas distribution are characterized by a small duration. When the engine is reached, the control system activates a blocking mechanism. The rockers of small and large cams are connected using a locking pin into one whole, while the force on the inlet valves is transmitted from a large couch.

Another modification of the VTEC system has three modes of regulation, determined by the work of one small cam (opening one intake valve, low engine speed), two small cams (opening two inlet valves, medium speed), as well as a large cam (high revs).

The modern system for changing the phases of the Honda gas distribution is the i-VTEC system, uniting VTEC and VTC systems. This combination is significantly expanding the engine control parameters.

The most committed from a constructive point of view, a variation of the system of changing phases of gas distribution is based on the adjustment of the lifting height of the valves. This system allows you to abandon throttle on most engine operation modes. Pioneer in this area is the company BMW and its system Valvetronic. Similar principle used in other systems:

• Valvematic. from Toyota;
• Vel, VARIABLE VALVE EVENT AND LIFT SYSTEM from Nissan;
• Multiair. from Fiat;
• Vti, VARIABLE VALVE AND TIMING INJECTION FROM PEUGEOT.

In the ValveTronic system, the change in the lifting height of the valve provides a complex kinematic scheme, in which the traditional communication cam-fishing valve is supplemented with an eccentric shaft and an intermediate lever. The eccentric shaft receives rotation from the electric motor through the worm gear. The rotation of the eccentric shaft changes the position of the intermediate lever, which, in turn, sets a certain movement of the rocker and the corresponding movement of the valve. Changing the lifting height is continuously depending on the engine operation modes.

The ValveTronic system is installed only on intake valves.

10.07.2006

Consider here the principle of functioning of the system of the VVT-I second generation, which is now applied on most Toyotov engines.

VVT-I system (VARIABLE VALVE TIMING INTELLIGENT - changing phases of gas distribution) allows you to smoothly change the gas distribution phases in accordance with the operating conditions of the engine. This is achieved by turning the camshaft of the intake valves relative to the graft shaft in the range of 40-60 ° (at the corner of the rotation of the crankshaft). As a result, the moment of the opening of the inlet valves and the time of the "overlapping" (that is, the time when the exhaust valve is not yet closed, and the intake is already open).

1. Design

The VVT-I actuator is placed in the camshaft pulley - the drive body is connected to an asterisk or gear pulley, rotor - with camshaft.
The oil is supplied from one or another side of each of the rod petals, forcing it and the shaft itself is turned. If the engine is muled, then the maximum delay angle is set (that is, an angle corresponding to the latest opening and closing of the inlet valves). To immediately after launch, when the pressure in the oil line is still not enough to effectively control the VVT-I, there were no shocks in the mechanism, the rotor is connected to the housing of the locking pin (then the pin is pressed by the oil pressure).

2. Functioning

For the turning of the camshaft, the oil under pressure using an spool is sent to one of the sides of the rotor petals, simultaneously opens to the plums of the cavity on the other side of the petal. After the control unit determines that the camshaft occupied the desired position, both channels to the pulley overlap and it is held in a fixed position.

Mode	№	Phase	Functions	Effect
Idling			The angle of rotation of the camshaft, corresponding to the very late start of the opening of the ink valves (the maximum delay angle). The "overlap" of the valves is minimal, the inverse flow of gases on the inlet is minimal.	Engine works more stable at idle, fuel consumption decreases
		The overlap of the valves decreases to minimize the return flow of gases to the inlet.	Increases engine stability
		The overlap of the valves increases, while decreasing "pumping" losses and part of the exhaust gases enters the inlet	Fuel efficiency improves, NOX emission decreases
High Load, Rotation Frequency below average			Early closing of intake valves is ensured to improve cylinders	Torque increases on low and medium turns
		It is also provided to the closure of intake valves to improve filling on high revs.	Maximum power increases
With low cooling fluid temperature	-		Mounted minimum overlap to prevent fuel loss	Stabilizes the increased speed of the idle rotation, improves efficiency
When starting and stopping	-		Mounted minimum overlap to prevent exhaust gas from entering the intake	Improves engine launch

3. Variations

The above 4-petal rotor allows you to change the phases within 40 ° (as, for example, on the engines of the ZZ and AZ series), but if you want to increase the angle of rotation (up to 60 ° in SZ) - 3-petal or workers cavities are applied.

The principle of operation and modes of operation of these mechanisms are absolutely similar, except due to the extended adjustment range it becomes possible to exclude overlapping valves at idle, at a low temperature or start.

The efficiency of the internal combustion engine often depends on the gas exchange process, that is, filling the air-fuel mixture and removal of exhaust gases. As we already know with you, it is engaged in timing (gas distribution mechanism), if correctly and "finely" configure it under certain revs, you can achieve very bad results in the efficiency. Engineers have long been fighting over this problem, you can solve it different ways, for example, the impact on the valve themselves or the rotation of the camshafts ...

In order for the DVS valve, they always work correctly and were not susceptible to wear, first appeared simply "pushers", then, but it turned out to be little, so manufacturers began the introduction of so-called "phase students" on camshafts.

Why do you need phaserators?

To understand what the phase studies are and why they are needed, read useful information. The thing is that the engine is not the same in various revs. For idle and not high revolutions, the "narrow phases" will be ideal, and for high - "wide".

Narrow phases - If the crankshaft rotates "slowly" (idling), the volume and speed of removal of exhaust gases is also small. It is here that the "narrow" phases are perfectly used, as well as the minimum "overlap" (time of the simultaneous opening of intake and exhaust valves) - the new mixture is not pushed into the exhaust manifold, through the open exhaust valve, but also the exhaust gases (almost) do not pass in the intake . This is the perfect combination. If you make a "phasing" - wider, it is with low rotations of the crankshaft, then "testing" can be mixed with incoming new gases, thereby reducing its qualitative indicators, which will definitely reduce the power (the motor will not work unambiguously or even stalls).

Wide phases - When the turns grow, the volume and speed of pumped gases grow accordingly. It is already important here to quickly blow cylinders (from working out) and to drive the incoming mixture into them faster, the phases must be "wide".

Of course, the usual distributional shaft leads the discoveries, namely, his "cams" (peculiar eccentrics), he has two ends - one as if sharp, it stands out, the other is simply made by a semicircle. If the end is sharp - then the maximum opening occurs if the rounded (on the other side) is the maximum closure.

But the full-time distributional shafts - there is no phase adjustment, that is, they cannot expand them or do already, yet engineers set the averaged indicators - something mean between capacity and efficiency. If you fill the shafts into one of the parties, then efficiency, or the engine efficiency will fall. "Narrow" phases will not give the engine to develop maximum power, but "wide" - not work normally to work on small revs.

To regulate depending on the revolutions! This was invented - in fact, it is a phase regulatory system, a simple - phasemators.

Principle of operation

Now we will not climb deep, our task is to understand how they work. Actually, the usual camshaft at the end has a distribution gear, which in turn connects to.

Camshaft with a phase displayer at the end has a slightly different, modified design. Here are two "hydro" or electrofiled couplings, which, on the one hand, also engage in the GRM drive, and on the other hand with shafts. Under the influence of hydraulics or electronics (there are special mechanisms), shifts can occur inside this clutch, thus, it can rotate a little, thereby changing the opening or closing of the valves.

It should be noted that the phase inspector is not always installed on two camshafts immediately, it happens that one is in the inlet or on the graduation, and on the second is just an ordinary gear.

As usual, the process manages, which collects data from various, such as crankshaft positions, hall, engine speed, speed, etc.

Now I suggest you to consider the main designs, such mechanisms (I think you will become more clarified in my head more).

Vvt (VARIABLE VALVE TIMING), KIA-HYUNDAI (CVVT), Toyota (VVT-I), Honda (VTC)

Among the first were offered to rotate the crankshaft (relative to the initial position), volkswagen., with mine vVT system (on the basis of her systems built many other manufacturers)

That it includes:

Phase pazers (hydraulic) are installed on inlet and graft shaft. They are connected to the motor lubrication system (actually it is oil and pumps them into them).

If you disassemble the coupling, then inside there is a special asterisk of an outdoor case, which is still connected to the rotor shaft. The housing and the rotor when pumping oil can be shifted relative to each other.

The mechanism is fixed in the block head, it has channels for lining oil to both couplings, the streams are controlled by two electro-hydraulic distributors. By the way, they are also fixed on the body of the block head.

In addition to these distributors in the system, there are many sensors - the frequency of the crankshaft, the load on the engine, the temperature of the coolant, the position of the distribution and knees of the shafts. When you need to rotate correct the phases (for example, high or low speed), the computer reading data gives orders to feed oils into the coupling, they open and oil pressure begins to pump the phase beams (thus they turn to the desired direction).

Idling - Turning occurs in such a way that the "intake" camshaft provided a later discovery and later closing of the valves, and the "graduation" unfolds so that the valve closes much earlier before the piston approach in the upper dead point.

It turns out that the amount of waste mixture is reduced almost to a minimum, and it practically does not interfere with the intake tact, it favorably affects the operation of the motor on idling, its stability and uniformity.

Middle and high speed - Here is the task to give maximum power, therefore "turning" occurs in such a way as to delay the opening of the exhaust valves. Thus, it remains the pressure of the gases on the workstop tact. Ink, in turn, open after reaching the piston of the upper dead point (NTC), and closes after NMT. Thus, we, as it were, we obtain the dynamic effect of "recovery" of the engine cylinders, which carries an increase in power.

Maximum torque - How it becomes clear, we need to fill cylinders as much as possible. To do this, it is necessary to open much earlier and, accordingly, much later to close the inlet valves, save the mixture inside and prevent it from the output back to the intake manifold. "Graduation", in turn, closes with some advance to VTC to leave a small pressure in the cylinder. I think it is understandable.

Thus, there are now many similar systems, of which are the most common Renault (VCP), BMW (Vanos / Double Vanos), KIA-HYUNDAI (CVVT), Toyota (VVT-I), Honda (VTC).

But these are not perfect, they can only shift the phases in one or the other side, but cannot really "narrow" or "expand" them. Therefore, more advanced systems are beginning to appear.

Honda (VTEC), Toyota (VVTL-i), Mitsubishi (Mivec), Kia (CVVL)

To additionally adjust the valve raising, even more advanced systems were created, but the genericant was company Honda., with your motor Vtec.(VARIABLE VALVE TIMING AND LIFT ELECTRONIC CONTROL). The essence is that in addition to changing the phases, this system can more lift the valve, thereby improving the filling of cylinders or removal of exhaust gases. Honda now has a third generation of such engines that absorbed both VTC systems (phase studies) and VTEC (valve raising) immediately, and now it is called - Dohc. i- Vtec. .

The system is even more complicated, it has advanced camshafts in which there are combined cams. Two ordinary on the edges, which are pressed on the rocker in the usual mode and the average more advanced cam (high-profile), which turns on and presses the valve to say after 5,500 revolutions. This design is available on each pair of valves and rocker.

How does it work Vtec? Approximately 5500 rpm The motor operates in normal mode, using only the VTC system (that is, the phase beams). The medium cam is not closed with two others around the edges, it simply rotates empty. And when achieving high revolutions, the ECU gives an orders to turn on the VTEC system, the oil starts to pump and the special pin is ejected forward, it allows you to close all three "cam" immediately, starts working the most high profile - Now it is he who gives a couple of valves, which the group is calculated. Thus, the valve is lowered much more, which makes it possible to additionally fill the cylinders with a new working mixture and take the larger amount of "testing".

It is worth noting that VTEC stands on intake and graduation shalads, this gives a real advantage and increase in power at high revs. The increase in approximately 5 - 7% is a very good indicator.

It is worth noting, although Honda was first, now similar systems are used on many cars, such as Toyota (VVTL-i), Mitsubishi (Mivec), Kia (CVVL). Sometimes, for example, in KIA G4NA engines, the valve elevator is used only on one camshaft (here only in the inlet).

But this design has its drawbacks, and the most important thing is a stepped inclusion in the work, that is, eat up to 5000 - 5500 and then you feel (fifth point) inclusion, sometimes like push, that is, there is no smoothness, but I would like it!

Smooth inclusion or Fiat (Multiair), BMW (Valvetronic), Nissan (VVEL), Toyota (Valvematic)

You want smoothness please, and here the first in the development was the company (drum fraction) - Fiat. Who would have thought, they first created the Multiair system, it is even more complicated, but more accurate.

"Smooth work" here is applied here on intake valves, and there is no camshaft here at all. It was preserved only at the prom, but it has an impact on the inlet (probably launched, but I will try to explain).

Principle of operation. As I said, there is one shaft here, and it is headed and intake and exhaust valves. However, if it is mechanically exposed to "graduation" (that is, it is trite through the cams), then it is transmitted to inlet exposure through a special electro-hydraulic system. On the shaft (for intake) there is something like "cams", which are pressed not on the valve themselves, but on the pistons, but they transmit orders through the electromagnetic valve on working hydraulic cylinders to open or close. Thus, it is possible to achieve the desired opening at a certain period of time and revolutions. With small circulation, narrow phases, with high - wide, and the valve is extended to the desired height, because everything is controlled by hydraulics or electrical signals.

This allows you to make smooth inclusion depending on the engine speed. Now there are also many manufacturers such as many manufacturers, such as - BMW (Valvetronic), Nissan (VVEL), Toyota (Valvematic). But these systems are not perfect until the end, what is wrong again? Actually, here again there is a GRM drive (which takes about 5% of power), there is a camshaft and throttle valve, It takes a lot of energy again, respectively steals the efficiency, here it would be possible to refuse them.