Which means an inscription on the IWT engine 1. What is the VVT-I motor. Vvti Toyota What is it or how the VVT-I timing works

Vvti Toyota What is it and how is it arranged? VVT-I - the constructors of the Toyota autoota control system of gas distribution phases, which have come up with their system of increasing the efficiency of internal combustion engines.

This does not mean that such mechanisms are only at Toyota, but consider this principle on its example.

Let's start with the decryption.

For the first time on the market, this technology is represented by Toyota Ten years ago, in 1996. There are similar systems in all autocontracens and brands, which speaks of their benefits. They are called, however, everything is different, in full swing of ordinary motorists.

What brought VVT-I to the Motor Building? First of all, the increase in power is uniform in the entire range of revolutions. Motors have become more economical, and therefore more efficiently.

The gas distribution phase control or the moment of raising and lowering the valves occurs by turning to the desired angle.

How it is implemented technically, consider further.

Vvti Toyota What is this or how does the VVT-I gas distribution work?

The VVT-I Toyota system is what it is for what, we understood. Time to deepen in its inside.

The main elements of this engineering masterpiece:

• coupling VVT-I;
• solenoid valve (OCV - OIL CONTROL VALVE);
• control block.

The algorithm of all this design is simple. The coupling, which is a pulley with cavities inside and the rotor, fixed on the camshaft, is filled with oil under pressure.

The cavities are somewhat, and for this filling answers the VVT-I valve (OCV) acting by commands of the control unit.

Under the pressure of oil, the rotor together with the shaft can be rotated at a certain angle, and the shaft is already, in turn, determines when climbing and dropping valves.

In the start position, the position of the camshaft of the intake valves provides maximum cravings on low motor revolutions.

With an increase in the speed of rotation, the system turns the camshaft in such a way that the valves open earlier and closed later - it helps to increase the return on high revs.

As we see, the technology of VVT-I, the principle of which considered, is quite simple, but, nevertheless, effective.

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 manages work not only camshaft inlet valves, but also graduation.

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

Here, the Toyota engineers have completely abandoned the hydraulic method of controlling the camshaft position, which had a number of disadvantages, because for turning the shaft it was necessary that the oil pressure rose to a certain level.

To eliminate this lack, it was possible to eliminate the electric motors - now they turn shafts. That's how.

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

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The VVT-I system allows to smoothly change the phases of the gas distribution 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 starting the opening of intake valves and the magnitude of the "overlapping" time (that is, the time when the exhaust valve is not yet closed, and the intake is already open).

The main control device is the coupling VVT-I. "By default", the opening phases of the valves are exhibited for good traction at low revs. After the momentum increases significantly, the increased pressure of the oil opens the VVT-I valve, after which camshaft Turns to a certain angle relative to pulley. Cams have a certain shape and when turning crankshaft Open intake valves a little earlier, and close later, which increases the power and torque at high speed.

The functioning of the VVT-I system is determined by the operating conditions of the engine at various modes:

Mode (number in Figure)	Phase	Functions	Effect
Idling (1)		The angle of rotation of the camshaft, corresponding to the very late start of the opening of the ink valves (the maximum delay angle). "Overlapping" of valves minimally, the inverse flow of gases on the inlet is minimal	Engine works more stable on idling, fuel consumption is reduced
	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 the "pumping" losses are reduced and part of the exhaust gases enters the inlet	Fuel efficiency improves, NOX emission decreases
High Load, Rotation Frequency Below Middle (4)		Early closing of intake valves is ensured to improve cylinders	Torque increases on low and medium turns
High Load, High Rotation Frequency (5)		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

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Constructive generations VVT-I

Vvt (Generation 1, 1991-2001)

To uncover...

The conditional 1-generation represents the timing belt drive on both camshafts and the phase change mechanism with a piston with a screw cutting in the intake camshaft pulley. It was used on the 4a-ge engines type'91 and type'95 (Silvertop and Blacktop).

The System VVT (VARIABLE VALVE TIMING) of generation 1 allows step-to-change the phases of the gas distribution in accordance with the operating conditions of the engine by turning the camshaft of the intake valves relative to the pulley by 30 ° at the corner of the crankshaft rotation.

The VVT \u200b\u200bdrive housing (with an inner screw cutting) is connected to the pulley, the inner gear with the screw cutting is connected to the inlet camshaft. Between them is a movable piston with inner and outer cutting. With the axial movement of the piston, the shaft rotates relative to the pulley.

1 - damper, 2 - screw cutting, 3 - piston, 4 - camshaft, 5 - return spring.

The control unit based on sensor signals monitors the oil supply in the pulley cavity (by means of an electromagnetic valve).

When you turn on the ECM signal, the solenoid valve shifts the gloss of the control valve. Motor oil Under pressure enters the piston and shifts it. Looking through the screw cutting, the piston turns the camshaft in the direction of ahead. When the solenoid valve is turned off, the piston moves back and the camshaft returns to its original position.

With high load and turnover below average, early closure of intake valves allows you to improve the filling of cylinders. Due to this, the torque increases on low and medium turnover. At high revs later, closing the intake valves (when the VVT \u200b\u200bis disconnected) contributes to an increase in maximum power.

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VVT-I (generation 2, 1995-2004)

To uncover...

The conditional 2nd generation is a belt drive timing on both camshafts and a phase change mechanism with a piston with a screw cutting in an intake camshaft pulley. It was used on the engines 1JZ-GE Type'96, 2JZ-GE type'95, 1JZ-GTE type'00, 3S-GE type'97. There was an option with the phase change mechanisms on both camshafts - the first Dual VVT Toyota (see below, 3S-GE type'98, Altezza).

The VVT-I system allows you to smoothly change the phases of the gas distribution in accordance with the operating conditions of the engine, which is achieved by turning the camshaft of the ink valves relative to the pulley in the range of 40-60 ° at the corner of the crankshaft rotation.

GRM drive (Series JZ). 1 - VVT, 2 - VVT valve, 3 - camshaft position sensor, 4 - crankshaft position sensor.

The VVT-i drive housing (with the inner screw cutting) is connected to the pulley, the inner gear with the screw cutting is connected to the inlet camshaft. Between them is a movable piston with inner and outer cutting. With the axial movement of the piston, a smooth rotation of the shaft relative to the pulley occurs.

JZ series. 1 - body (inner cutting), 2 - pulley, 3 - piston, 4 - outer cutting of the shaft, 5 - external piston cutting, 6 - inlet camshaft.

GRM drive (Series JZ). 1 - intake camshaft, 2 - spool, 3 - plunger, 4 - VVT valve, 5 - oil canal (from pump), 6 - cylinder head, 7 - external piston cutting, 8 - piston, 9 - VVT drive, 10 - Inner cutting piston, 11 - pulley.

The control unit based on sensor signals monitors the oil supply in the advance cavity and VVT drive delay by means of an electromagnetic valve. On the plugged engine, the spool moves the spring in such a way as to ensure the maximum delay angle.

a - Spring, B - sleeve, C - spool, D - to the drive (ahead of ahead), E - to the drive (delay cavity), F - Reset, G - oil pressure, H - winding, j - plunger.

ahead And shifts the spool of the control valve. Motor oil under pressure enters the left side of the piston and shifts it to the right. Looking through the screw cutting, the piston turns the camshaft in the direction of ahead.

The electromagnetic valve on the ECM signal switches to the position delay And shifts the spool of the control valve. Motor oil under pressure enters the right side of the piston and shifts it to the left. Looking through the screw cutting, the piston turns the camshaft in the delay direction.

After installing the specified ECM position switches the control valve in the neutral position (position hold), maintaining pressure on both sides of the piston.

This is what the valve looks like on the example of the engine 1JZ-GTE:

VVT-I gas distribution phases on the example of the JZ series:

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VVT-I (generation 3, 1997-2012)

To uncover...

The conditional 3rd generation is a timing belt drive with a gear transmission between the camshafts and the mechanism of changing phases with a blade rotor in the front of the exhaust camshaft or in the rear of the intake. Applied on 1MZ-FE engines Type'97, 3MZ-FE, 3S-FSE, 1JZ-FSE, 2JZ-FSE, 1G-FE type'98, 1UZ-FE type'97, 2UZ-Fe type'05, 3UZ-Fe . It allows you to smoothly change the phases of the gas distribution in accordance with the operating conditions of the engine by turning the camshaft of the intake valves relative to the pulley in the range of 40-60 ° (over the corner of the crankshaft rotation).

GRM drive (MZ series). 1 - position sensor throttle valve, 2 - camshaft position sensor, 3 - VVT valve, 4 - cooling fluid temperature sensor, 5 - crankshaft position sensor.

GRM drive (1G-FE type'98). 1 - VVT valve, 2 - camshaft position sensor, 3 - coolant temperature sensor, 4 - crankshaft position sensor.

GRM drive (UZ series). 1 - VVT valve, 2 - camshaft position sensor, 3 - coolant temperature sensor, 4 - crankshaft position sensor.

The VVT \u200b\u200bdrive with a blade rotor is installed in the front or back of one of the camshafts. With a plugged engine, the retainer holds the camshaft in the maximum delay position to provide normal launch.

1MZ-FE, 3MZ-FE. 1 - exhaust camshaft, 2 - inlet camshaft, 3 - drive Vvt, 4 - Lock, 5 - body, 6 - driven gear, 7 - rotor.

1G-FE type'98. 1 - Case, 2 - rotor, 3 - Lock, 4 - exhaust camshaft, 5 - inlet camshaft. A - when stopping, b - in work, C is ahead, D - delay.

2UZ-FE type'05. 1 - Drive VVT, 2 - intake camshaft, 3 - exhaust camshaft, 4 - oil channels, 5 - rotor of the camshaft position sensor.

2UZ-FE type'05. 1 - Case, 2 - Rotor, 3 - Lock, 4 - Ahead of ahead, 5 - Delay Camera, 6 - inlet camshaft. A - when stopping, B - in work, C is the oil pressure.

The electromagnetic valve on the ECM signal switches to the position ahead

The electromagnetic valve on the ECM signal switches to the position delay

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VVT-I (generation 4, 1997- ...)

To uncover...

The conditional 4th generation of VVT-I is a chain drive of the timing to both camshafts and a phase change mechanism with a blade rotor on an inlet camshaft. It was used on the engines of the series NZ, AZ, ZZ, SZ, KR, 1GR-FE type'04. It allows you to smoothly change the gas distribution phases in accordance with the operating conditions of the engine by turning the camshaft of the inlet valves relative to the drive sprocket in the range of 40-60 ° at the corner of the crankshaft.

GRM drive (AZ series). 1 - control valve VVT-I, 2 - camshaft position sensor, 3 - coolant temperature sensor, 4 - Crankshaft position sensor, 5 - VVT drive.

A VVT drive is installed on the intake camshaft with a blade rotor. When the engine is shoved, the lock holds the camshaft in the maximum delay position to ensure normal startup. In some modifications, an auxiliary spring can be used, which applies the moment in the direction of ahead to return the rotor and the reliable triggering of the retainer after turning off the engine.

VVT-I drive. 1 - Case, 2 - Lock, 3 - rotor, 4 - camshaft. A - when stopping, b - in work.

The 4-petal rotor allows you to change the phases within 40 ° (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 working cavities are expanding. 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 completely exclude the overlap of the valves at idle, at a low temperature or launch.

The control unit by means of an electromagnetic valve controls the oil supply in the advance cavity and the VVT \u200b\u200bdrive delay based on the signals of the camshaft position sensors. On the plugged engine, the spool moves the spring in such a way as to ensure the maximum delay angle. The control signals from the VVT \u200b\u200bvalve unit are used by the pulse modulation (the larger ahead, the pulses are wider, when the delay is shorter, respectively).

1 - electromagnetic valve. A - Spring, B - sleeve, C - spool, D - to the drive (ahead of ahead), E - to the drive (delay cavity), F - Reset, G - oil pressure, H - winding, j - plunger.

The electromagnetic valve on the ECM signal switches to the position ahead And shifts the spool of the control valve. Motor oil under pressure enters the rotor on the side of the advance cavity, turning it together with the camshaft in the direction of the advance.

The electromagnetic valve on the ECM signal switches to the position delay And shifts the spool of the control valve. Motor oil under pressure enters the rotor on the side of the delay cavity, turning it together with the camshaft in the delay direction.

When holding an ECM calculates the desired advance angle in accordance with the conditions of movement, and after setting the specified position, switches the control valve to a neutral position until the next change in external conditions.

Thase distribution phases (2AZ-FE):

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VVTL-I (subspecies of the 4th generation, 1999-2005)

To uncover...

VVTL-I, VARIABLE VALVE TIMING AND LIFT INTELLIGENT SYSTEM - subspecies of VVT-I technology, which also knows how to control the height and duration of the valve lifting (stepped - with the use of two cams of different profiles). It was first introduced on a 2zz-GE engine. Traditional VVT-I is responsible for improving traction at low revs, and the additional part is for maximum power and maximum moment, "throwing coal" at a speed of more than 6000 rpm (valve lifting height increases from 7.6 mm to 10.0 / 11.2 mm).

By itself, the mechanism of VVTL-I is simple enough. For each pair of valves on the camshaft there are two cams with different profiles ("calm" and "aggressive"), and on rocker - two different pushers (respectively, roller and sliding). In normal mode, the rocker (and the valve) is driven by a cam with a calm profile through a roller pusher, and the spring-loaded sliding pusher works in a frightened, moving in rocker. When moving to the forced mode, the oil pin is moved by a lock pin, which supports the rod of the sliding pusher, having rigidly connecting it with a rocker. When the fluid pressure is removed, the spring presses the pin and the sliding pusher is again released.

The sophisticated scheme with different pushers is explained by the fact that the roller (on the needle bearing) gives smaller friction losses, but, with an equal height of the cam profile, provides less filling (mm * hail), and on high turns of friction loss are almost aligned, so From the point of view of obtaining the maximum return, it becomes more profitable sliding. The roller pusher is made of hardened steel, and sliding, although it uses ferroalloys with elevated anti-semi-facing properties, still demanded the use of a special irrigation scheme with an oil installed in the block head.

The most unreliable part of the circuit is a lock pin. He cannot in one turn camshaft in the working position, so the collision of the rod with the pin inevitably occurs with their partial overlap, from which the wear of both parts only progresses. In the end, it reaches such a magnitude that the pin will constantly push the rod to its original position and will not be able to fix it, therefore only the fist of low revolutions will constantly work. With this feature fought a thorough treatment of surfaces, a decrease in the weight of the pin, an increase in pressure in the highway, but they could not be able to defeat it. In practice, there are still breakdowns of the axis and pins of this cunning rocker.

The second common defect - the bolt fastening the axis of the rumor axis is cut, after which she begins to rotate freely, the oil supply to the rockers stop, and VVTL-I in principle does not enter the forced regime, not to mention the violation of the lubricant of the entire node. Thus, the VVTL-I scheme remained technologically unaffected for mass production.

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Dual VVT-I

It is the development of the VVT-I of the conditional 4th generation.

DVVT-I (2004- ...)

To uncover...

The DVVT-I (Dual Variable Valve Timing Intelligent) system is a timing chain drive on both camshafts and a phase change mechanism with paddle rotors on an inlet and outskillers. For the first time was applied on the engine 3S-GE in 1998. It was used on the engines of the series AR, ZR, NR, GR, UR, LR.

It allows you to smoothly change the gas distribution phases on both camshafts in accordance with the operating conditions of the engine by turning the camshafts of intake and exhaust valves relative to the drive springs in the range of 40-60 ° (at the corner of the crankshaft rotation). In fact, the usual VVT-I system "in a double set".

Provides:

• greater fuel efficiency both at low and high speed;
• the best elasticity - torque is distributed evenly throughout the engine revolutions.

GRM drive (series Zr). 1 - VVT valve (release), 2 - VVT valve (inlet), 3 - camshaft position sensor (release), 4 - camshaft position sensor (inlet), 5 - coolant temperature sensor, 6 is the crankshaft position sensor.

Since Dual VVT-I does not use the control of the lifting height of the valves, as in VVTL-I, then the disadvantages of the VVTL-I are also absent.

The camshafts are installed VVT drives with blade rotors. When the engine is shoved, the lock holds the camshaft in the maximum advance position to ensure normal start.

In some modifications, an auxiliary spring can be used, which applies the moment in the direction of ahead to return the rotor and the reliable triggering of the retainer after turning off the engine.

VVT drive (inlet). 1 - Case, 2 - Rotor, 3 - Lock, 4 - asterisk, 5 - camshaft. A - when stopping, b - in work.

VVT drive. 1 - Case, 2 - Rotor, 3 - Lock, 4 - asterisk, 5 - camshaft, 6 - Returning spring. A - when stopping, b - in work.

The control unit by means of an electromagnetic valve controls the oil supply in the advance cavity and the VVT \u200b\u200bdrive delay based on the signals of the camshaft position sensors. On the plugged engine, the spool moves the spring in such a way as to ensure the maximum delay angle for the intake and the maximum advance angle for release. Control signals use pulse modulation (similarly).

VVT valve (inlet). A - Spring, B - sleeve, C - spool, D - to the drive (ahead of ahead), E - to the drive (delay cavity), F - reset, G is the oil pressure.

VVT valve. A - Spring, B - sleeve, C - spool, D - to the drive (ahead of ahead), E - to the drive (delay cavity), F - reset, G is the oil pressure.

The electromagnetic valve on the ECM signal switches to the position ahead And shifts the spool of the control valve. Motor oil under pressure enters the rotor from the side of the advance cavity, turning it along with the camshaft in the direction of the advance (top picture - the inlet, the bottom - release):

The electromagnetic valve on the ECM signal switches to the position delay And shifts the spool of the control valve. Motor oil under pressure goes to the rotor on the side of the delay cavity, turning it along with the camshaft in the delay direction (top picture - the inlet, the bottom - release):

When holding an ECM calculates the desired advance angle in accordance with the conditions of movement, and after setting the specified position, switches the control valve to a neutral position until the next change in external conditions.

Dual-Vvt timing phases (2ZR-FE):

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VVT-IE (2006- ...)

To uncover...

VVT-IE, Variable Valve Timing - Intelligent by Electric Motor is an intellectual change in the phases of gas distribution using an electric motor. Differs from base technology VVT-I by the fact that the control of gas distribution phases on the inlet is carried out not by hydraulic pressure of the oil, but a special electric motor (the release is still controlled by hydraulics). For the first time was applied in 2007 on the engine 1ur-FSE.

Principle of operation: The VVT-IE electric motor rotates along with the distribution shaft on the same revs. If necessary, the electric motor is either slowed down, or accelerates relative to the camshaft sprocket, shifting the camshaft to the desired angle and thereby driving the gas distribution phases. The advantage of such a solution is the possibility of high-precision control of gas distribution phases, regardless of engine speed and operating temperature Oils (in the conventional VVT-I system on low revs and on an impenetrable oil pressure in the oil system is not enough to shift the VVT-I blades).

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VVT-IW (2015- ...)

To uncover...

VVT-IW (VARIABLE VALVE TIMING INTELLIGENT WIDE) is a chain drive of the TGM on both camshafts and a phase change mechanism with bladed rotors on an inlet and outskillers, and an extended inlet adjustment range. It was used on 6A-FSE engines, 8R-FTS, 8NR-FTS, 2GR-FKS. It allows you to smoothly change the gas distribution phases in accordance with the operating conditions by turning the camshaft of the intake valves relative to the drive asterisk in the range of 75-80 ° at the corner of the crankshaft.

Advanced, compared to the usual VVT, the range is mainly at the delay angle. On the second camshaft in this scheme, the VVT-I drive is installed.

The VVT-I system (VARIABLE VALVE TIMING Intelligent) allows you to smoothly change the phases of the gas distribution in accordance with the operating conditions of the engine. This is achieved by turning the camshaft of the exhaust valves relative to the drive asterisk in the range of 50-55 ° (over the corner of the crankshaft).

The collaboration of the VVT-IW on the inlet and VVT-I on the release provides the following effect:

1. Start mode (EX - advance, in - intermediate position). To ensure reliable startup, two independent retainers retaining the rotor are used in an intermediate position.
2. Partial load mode (EX - delay, in - delay). It is possible to operate the engine along the Miller / Atkinson cycle, while the pump losses decrease and efficiency improves.
3. Mode between medium and high load (EX - delay, in - ahead). It is ensured by the TN mode. Internal recycling of exhaust gases and improves the conditions of issue.

A VVT-IW drive is installed on the intake camshaft with a blade rotor. Two retainers hold the rotor in an intermediate position. The auxiliary spring applies the moment in the direction of ahead for returning the rotor to the intermediate position and reliable triggering of the clamps. This provides a normal engine launch dried in the delay position.

VVT-IW drive. 1 - Central Bolt, 2 - Auxiliary Spring, 3 - Front Cover, 4 - Rotor, 5 - Lock, 6 - Housing (asterisk), 7 - Rear cover, 8 - inlet camshaft. A - locking groove.

The control valve is built into the central drive bolt (sprocket) to the camshaft. In this case, the control oil channel has a minimal length, providing maximum speed response and triggering when low temperatures. The control valve is driven by the VVT-IW valve plunger.

a - Reset, b - to ahead of ahead, C - to the delay cavity, D - motor oil, E - to the retainer.

The design of the valve allows you to independently control the two locks, separately for the lifting and delay circuits. This is a challenge to fix the rotor in the intermediate position of the VVT-IW control.

1 - external pin, 2 - internal pin. A - The retainer is involved, B - the lock is free, C is oil, D is a locking groove.

The VVT-IW solenoid valve is mounted in the cap circuit lid and is connected directly to the actuator of the inlet camshaft phases.

1 - VVT-IW solenoid valve. A - Winding, B - Plunger, C - stock.

For ahead

For delay

1 - rotor, 2 - from ECM, 3 - electromagnetic valve VVT-IW. a - direction of rotation, b - the delay cavity, C is a guaard of ahead, D - to the advance cavity, E - from the delay cavity, F - reset, G is the oil pressure.

For hold ECM calculates the desired advance angle in accordance with the conditions of movement. After installation of the specified ECM position switches the control valve to the neutral position until the next change is to change external conditions.

On the graduation camshaft The VVT-I drive is installed with a vane rotor (traditional or new sample with a control valve built into the central bolt). When the engine is shoved, the lock holds the camshaft in the maximum advance position to ensure normal start.

The auxiliary spring applies the moment in the direction of ahead to return the rotor and reliable triggering of the lock after turning off the engine.

Drive VVT-I (AR). 1 - Auxiliary Spring, 2 - Case, 3 - Rotor, 4 - Lock, 5 - asterisk, 6 - camshaft. A - when stopping, b - in work.

VVT-I (GR) drive. 1 - central bolt, 2 - front cover, 3- housing, 4 - rotor, 5 - rear cover, 6 - inlet camshaft.

The control unit by means of an electromagnetic valve controls the oil supply in the advance cavity and the VVT \u200b\u200bdrive delay based on the signals of the camshaft position sensors. On the shredded engine, the spool moves the spring in such a way as to ensure the maximum advance angle.

VVT valve (AR). 1 - electromagnetic valve. A - Spring, B - sleeve, C - spool, D - to the drive (ahead of ahead), E - to the drive (delay cavity), F - reset, G is the oil pressure.

VVT valve (GR). 1 - electromagnetic valve. A - plum, b - to the drive (ahead of ahead), C - to the drive (the delay cavity), D is the oil pressure.

For ahead The electromagnetic valve over the ECM signal switches to the advance position and shifts the spool of the control valve. Motor oil under pressure enters the rotor on the side of the advance cavity, turning it together with the camshaft in the direction of the advance.

1 - rotor, 2 - from ECM, 3 - electromagnetic valve VVT-I. A - the direction of rotation, B is the delay cavity, C is a guaardment of ahead, D - to the advance cavity, E - from the delay cavity, F - draining, G is the oil pressure.

For delay The electromagnetic valve on the ECM signal switches to the delay position and shifts the gloss of the control valve. Motor oil under pressure enters the rotor on the side of the delay cavity, turning it together with the camshaft in the delay direction.

1 - rotor, 2 - Solenoid valve VVT-I, 3 - from ECM. a - direction of rotation, B - oil pressure, C - reset.

1 - rotor, 2 - from ECM, 3 - electromagnetic valve VVT-I. a - direction of rotation, b - the delay cavity, C is a guaard of ahead, D - from a lifting cavity, E - to the delay cavity, F - draining, G is the oil pressure.

For hold ECM calculates the desired advance angle in accordance with the conditions of movement and after setting the specified position switches the control valve into a neutral position until the next change in external conditions.

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.

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.

· 08/20/2013

This system provides an optimal intake moment in each cylinder for the data of the specific operating conditions of the engine. VVT-I almost eliminates the traditional compromise between the large torque on low revs and high high power. Also, VVT-I provides greater fuel economy and so effectively reduces emissions of harmful combustion products, which disappears the need for exhaust recycling system.

VVT-I engines are installed on all modern cars Toyota. Similar systems are developed and applied by a number of other manufacturers (for example, the VTEC system from Honda Motors). The Toyota VVT-I system replaces the previous VVT system (2-speed hydraulic drive control system) used since 1991 on 20-valve 4A-GE engines. VVT-I has been used since 1996 and manages the moment of opening and closing the inlet valves by changing the transmission between the camshaft drive (belt, gear or chain) and actually camshaft. To control the camshaft position used hydraulic drive (motor oil under pressure).

In 1998, Dual ("Dual") VVT-I, controlling and intake, and exhaust valves appeared (first installed on the 3S-GE engine on the RS200 Altezza). Also dual VVT-I is used on new V-shaped toyota engines, for example, on a 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. Double VVT-I will be used in future Toyota engines, including a new 4-cylinder engine for a new generation Corolla. In addition, dual VVT-I is used in the D-4S 2GR-FSE engine on Lexus GS450H.

Due to the change in the opening of the launch valves and the engine stop, the compression is minimal, and the catalyst is very quickly heated to the operating temperature, which dramatically reduces harmful emissions in atmosphere. VVTL-I (decoded as Variable Valve Timing and Lift with Intelligence) Based on VVT-I, the VVTL-I system uses camshaft, which also controls the value of the opening of each valve when the engine is operating at high revs. This allows you to ensure not only more high revs and greater engine power, but also the optimal point of opening of each valve, which leads to fuel economy.

The system is developed in collaboration with Yamaha. VVTL-I engines are installed on modern sports cars Toyota, such as Celica 190 (GTS). In 1998, Toyota began to offer new technology VVTL-I for a two-string 16-valve engine 2zz-GE (one camshaft controls intake, and the other outlet valves). On each camshaft there are two cams per cylinder: one for low revolutions, and the other for high (with a great opening). On each cylinder - two inlets and two exhaust valve, Each pair of valves is driven by one swing lever to which camshaft cam is affected. On each lever there is a spring-loaded sliding pusher (the spring allows the pusher to slide freely on a "high-shortest" cam, without affecting the valves). When the engine shaft rotation speed is below 6000 v / m, the "low-speed cam" is affected by the swing lever through a normal roller pusher (see Fig.). When the frequency exceeds 6000 rpm / m, the engine control computer opens the valve, and the oil pressure shifts the heel under each sliding pusher. The stud pushing the sliding pusher, as a result of which it is no longer moving freely on its spring, but begins to transmit a swing lever from the "high-turn" cam, and the valves open more and for more.

Long chose a car for my wife. I drove on Toyota for a long time. Corolla approached almost perfect. But honestly, it is nice to call it, the language did not turn. She resembled the face of unfortunate beauties after a plastic surgery, when the bandages just removed. When I saw the pictures of the updated - the desire was significantly increased. I put 5+ designers. It became at least clear what I meant that surgeon. Well, yes, not the essence. Taste and color, as you know ..

Honest 11.9% of the loan from Toyota Bank have tried to defeat doubts.

Now to the question of marketers.

The logic of these people apparently never can be understood. I can forgive the "oars" in rear doors, cheap full-time magnetol, etc. But the lack of a stabilization system in any sets to put it mildly angry. Of course, I understand that you need to disseminate cars in different segments, so that there is no internal competition from the manufacturer, etc. But Bossh sells it for $ 200 !!! And by the way she saves life. There is nothing worse than the frontal accident on the highway. And they often occur precisely because of the loss of clutch with the road. I personally do not blinking the eye to surcharge for it 10-15 tons. I am sure that I'm not alone.

And more about sad.

I mean boxes. They were never strong side Toyota. Not in terms of reliability. There is just the same full order. And in terms of advancement. Toyota in this matter is hopelessly conservative. It is generally recognized that the "robot" was originally equipped with this car failed. Of course, I am very glad that he was replaced by a classic machine.

But why a four-stage ?? All have long been five, or even six gears! Yes, hell with her with Corolo. How did your hand rose to equip a 4-mortar RAV4?

Well, finally the last spoon of tar.

Heated seats. Why only two positions on / off ?? Of course, I do not pretend to smooth adjustment as at Lexus. But Hi / Lo is that the doctor prescribed. Hi - heated, Lo - Ride all day. And then ON and in a couple of minutes - your omelet is ready, Seda! And to turn on / off all the way, these tiny buttons are inconvenient, and unsafe, since both of them are located on the right of the Koch gearbox and find them uncooked rarely. And on the left of this place the plug. But why ???

Here is probably all of the unpleasant.

Put the hand on the heart, I say - the car is excellent! What is not surprising. This is the "meat" of Toyota sales. Engineers are not entitled to an error in this model.

1.6 DUAL VVTI engine - above all praise! Applauding motorists standing. Beautifully pulls both from below. It must be, to a large extent, smoothes long boxes. By the way, despite 4 steps, the box, oddly enough, still deserves at least 4+ marks. The lack of fifth transfer on the track and not a very big desire to jump down under overtakers, most likely only my fictional soldiers. Everything is quite expected to the automaton of the 20th century. But in the city, the box behaves unequivocally on firm 5! There are inadvertent unnecessary kikdaunov, when it's too late to squeeze the engine, the window in the neighboring row has already occupied.

Finish with the alliance engine the box would like on positive fuel consumption figures. On the highway comp. Showed 6.4, and judging by gas stations, it is not far from the truth. I will not write about the city consumption of fuel. All it will be different. Relying on their own experience, I can safely declare that it depends on two important factors: From the temperament of the driver and from its honesty. Besides the city city, the city is mounted. Someone has interpretations with traffic lights after 3 km. And someone in life stands in traffic jams

Now about the suspension.

In my opinion, almost the perfect balance of comfort and manageability. Traveled to Camry - too soft. Very roller in turns. But it is understandable. She was done under the fat rear of the darkens of hamburgers with Koloy. In fact, Russia is the only country, except the states where Camry is sold. Apparently no one tried to remake her under us.

Traveled to the test drive of the new Avensis. Very hard. Especially from behind. It's a pity. The previous "broom" was very pleasant.

So the Corolla is golden mean. In the measure of energy-intensive. Great ruling. Of course not BMW. But for its segment, manageability is very pleasant

In terms of ergonomics - everything is for me. Maybe because I have long been driving on Toyota. Or maybe just "Eurobill - 1 piece". In the cabin, nothing creaks, does not rattle. The plastic of course could be softer, but looking at the price tag you understand - ok. Seats are very comfortable. Pleasant side support. Behind, of course, three adults are closed. But gentlemen! Have a conscience. This is "C" class! The trunk deserves estimates 4. It is quite spacious, but the loop of the cover of course spoil the impression.

A little frustrating a budget option Restyling rear Lights. Of course, I understand that to redo the iron lid of the trunk is expensive. But this inserts from white "dashboats down on dark cars - like Belmo in the eye. That is why she is tritely silver. By the way restyling the American Corolla, all the same touched this very lid of the trunk. Lanterns there already. Again, the question for marketers - do you really cheaper to stamp different metal parts, for different markets ???

Managers claim that ground clearance One of the largest in class. We believe them for word. Of course, in comparison with my kruzak, believe it with difficulty. therefore next cars For my wife - without parckarter options. I am convinced that overlapping two wheels about the road - it is wrong :)

Good luck on the roads!