Valve adjustment as often. Determination of transient parameters. Determination of the dynamic characteristics of the control object without self-leveling on its transitional characterization

The trouble-convergence procedure is made to eliminate and prevent the occurrence of problems with the handling of the vehicle. If the wheel is incorrectly adjusting the wheel, the car will be weaker to the steering movement, it is hard to enter turns, the problem of rapid wear of the tires arises (in some cases, the wear threshold can be 500 km). Currently, the adjustment of the similarity-collapse is made only on specialized service stations. Contrary to the opinion of some car owners, such a procedure cannot be made at home.

What is the collapse of the wheels?

The collapse is the angle of deviation of the wheels along the vertical axis. A positive collapse happens if the angle formed by the upper parts of the wheels is greater than the lower. This collapse is used on trucks moving in a loaded state that compensates for the difference in corners. The negative collapse happens when the angle of the upper parts of the wheels is less than the lower. This collapse is used to stabilize the car when turning turns at high speeds. The most preferable zero collapse, in which the angles of the upper and lower parts of the wheels are the same. Such a collapse ensures the manageability of the city car and reduces tire wear. The wheel alignment is also positive and negative. With positive context, the front parts of the wheels are at a distance of less than the rear. With a negative - on the contrary, the rear parts of the wheels are closer. Proper adjustment The convergence is extremely important, since incorrectly exhibited convergence is capable of improving the wear of the tires several times.

Signs of incorrectly exhibited disorder:

Despite the fact that the gathering variation is regulated only on professional equipment In a hundred, you can independently digitate the correctness of its adjustment. Below we give a few signs that indicate the need to set the similarity-collapse:

• there is a screech with high-speed turning
• the car moves in direct only after the power deviation to the side
• without fixing the steering wheel car pulls to the side
• fast wear of the tires

When should the collapse adjustment be carried out?

There are a number repair workAfter which the adjustment of the score must necessarily be required:

• after installing a new ball support
• when replacing the steering rack or steering tip
• after replacing and installing a new scrus

To carry out the adjustment of the gathering-collapse, we recommend that you use only high-quality spare parts you can find in the store of Ixora. Qualified managers will help to make right choicewill answer all your questions. Contact, it is profitable and convenient.

5 years ago

Welcome!
Valve adjustment - most people of course know what kind of process is and for which it needs to be performed regularly on some cars for example on the "classic", but there are such people who do not know anything about it and want to understand this issue, therefore especially for such People were prepared this article from which you learn a lot. And if you become something incomprehensible, then write a commentary with your question at the very bottom of the site and we will answer it in the near future.

Note!
And in addition at the end of the article, you are waiting for an interesting video video, thanks to which you will understand a lot for yourself in adjustment of the valve drive!

What do you need to adjust the valve?

Their adjustment is needed so that the machine is stable working both on high and low engine speeds. Because as a rule, due to improper adjustment of the valves, the gaps that should be between the camshaft cam and the valve itself are violated, which leads to a too strong opening of the valve when the engine is operational and as a result of which depressurization will occur in the cylinder which in turn can adversely affect the engine resource .

Note!
In the event that the gap between the valve seat and the side particles of the cylinder became very large (see the photo below, there this gap is marked), then in this case, the valve can occur, as well as if the piston moves very large then can happen Meeting valves with the piston themselves when the engine is running. Therefore, the adjustment of the valves should be produced periodically and with special care, since incorrectly displayed gaps when adjusting can adversely affect the motor resource!

How will the valve work with the incorrect gap?

In this case, as mentioned earlier, the valves are broken, in connection with this, the valves begin to either open a little more than it should be, or begin in a constantly open position because of which sealing in the cylinder disappears, for clarity, see the photo below on which the valve adjustment is impaired And in connection with which the valve is in constantly open mode.

How to get rid of valve adjustment?

Once not asked: "Why for example on a 16-valve prior, do not regulate the valve?" And the thing is that in the engine the priors instead of the "pusher" due to which the camshaft camshaft pushes the valve, cost "hydro-compensators" which in turn due to high pressure Oils find the optimal clearance between the cam and the "hydro-compensator" of the valve and in connection with this valve always work with optimal gaps.

Note!
By the way, "hydro-compensators" can be installed almost any car in connection with which you can forget about the valve adjustment, but there is one thing! "Hydro-compensators" can be installed only on cars in which the "gas-distribution mechanism - it is the GDM" consists of camshaft, crankshaft, as well as valves and piston groups - in essence it is the main part of the car!

Engines internal combustionwhich are installed on modern carsThese are quite complex mechanisms with many details. Therefore, for normal operation for a long time, they require proper maintenance.

Unfortunately, many motorists do not pay due attention. For example, they do not understand very well, for which the valve adjustment is needed and often ignore this procedure, which leads to additional breakdowns and large costs for repairs. In this material, we will discuss what the valve adjustment is, which engines it is needed and how it is performed.

Before answering the question of what valve adjustment is, you must first find out what is the valves of internal combustion engines, where they are located, and the performance of what functions is assigned to them. Structurally, these important details modern engines Present "plates" of a cylindrical shape with sufficiently long rods. They are installed in the cylinder block, and in the amount of at least two for each of them. The valves in the closed state are adjacent to the saddles, which are made of steel and are compressed in the head of the cylinder block (GBC). Since these parts are experiencing significant mechanical and thermal loads in the process, they are made from special, resistant to these sodes steels.

Valves are component parts Gas distribution mechanisms of cars (MRM), which are often called valve. They are divided into intake and graduation. The function of the first is, as it is not difficult to guess through the very name, the inlet of the combustible mixture into the cylinders, and the second is the release of the exhaust gases. In the process of engine operation, the valves are expanded, their rods are lengthened, respectively, the size of the gaps, which should be between their ends and pushing cams (in the engines of old designs - rocker). During the operation of the FEA, the dimensions of these deviations increase, and precisely when they begin to exceed the maximum valid values, the valves should be adjusted. It is to bring the gaps to normal.

If the valves are not periodically adjusted, it can lead to very ugly consequences. In the case when the clearance is too small, "burning will inevitably happen. This means that a sufficiently dense layer of combustion products will be formed on the surfaces of the valves. fuel mixes. Because of it, the normal operation of the gas distribution system is disturbed, and, consequently, the engine as a whole. In addition, this tagar is quite difficult to remove.

In cases where the clearance is overly large, the valves are not fully open, and therefore the engine power drops significantly. In addition, they begin to "knock", and this knock has experienced drivers hearing, even being in the cabin, driving their cars. It goes without saying that increased valve gaps affect the operation of the internal combustion engine is no less negative than the excessively small.

What motors and when valve adjustment is needed?

It should be noted that not all internal combustion engines require periodic valve adjustments. The fact is that now in many modern DVSwhich are equipped carsIn the systems of their gas distribution mechanisms, the following types of hydrocomathers are established. These devices independently regulate the gaps in real time, and therefore their value is always optimal.

If there is no hydraulic components in the vehicle engine, then the valve control is necessary manually. It's time to come to deal with this case, it is quite easy to learn about some symptoms. One of them is the characteristic "Casting" of the valves, which has already been mentioned above, and the other is that the engine begins to "Troy", in its cylinders or significantly falls, or completely disappears compression. As soon as one of these symptoms manifests itself, it is necessary to check the size of the gaps in the valve mechanism.

It is also necessary to do this and without waiting for "disturbing bells", as part of activities on the current maintenance of the car. The frequency of checking valve gaps is indicated in technical documentation for each vehicleAnd, as a rule, is once every 25,000 - 30,000 mileage kilometers. It is usually carried out at stations maintenanceBut, possessing certain skills, checking valve gaps can be carried out independently.

Valve adjustment procedure

Valve adjustment is necessary only on a cold engine, and with strict observance of a certain sequence of actions. Otherwise, the gaps will be adjusted incorrectly with all the consequences of this.

The adjustment process begins with the fact that the cylinder piston is installed in the upper compression point. To bring it in this position, you need to turn crankshaft Or for the starting handle, or for the screw for the attachment of the pulley of the generator drive. It should be noted that the rotation must be performed only clockwise. After the piston is installed, it is necessary to check the size of the gap. This is done using a special probe.

If it turns out that the gap or is overly large, or too small, then it is necessary to change it. To do this, on the appropriate bolt or screw, you must first release the lock nut, and then set the gap to the limit required. It is determined by the thickness of the appropriate probe. As soon as the gap value is installed, you need to fix this position by tightening the locknut. It is necessary to do it carefully and carefully not to knock down the setting. After that, it is necessary to check the correctness of the valve adjustment using the probe: it should be included in the gap, but not free, but with some effort. If so, it means that adjusting the specific valve of a particular cylinder is made correctly, and you need to do all the procedure described above for all remaining valves and cylinders.

It should be noted that adjusting the valves of internal combustion engines - the procedure is very painstaking, requires accuracy, does not tolerate the rush. It is preferable not to produce it yourself, but to contact the service station and entrust this work to professionals with the appropriate experience and necessary skills.

Video on the topic

Many motorists faced the process of adjusting the VAZ-2114 valves on the car service or conducted this operation with their own hands. But, not everyone knows, after what period of time it is necessary to carry out this operation.

The video below will tell about the adjustment of the valves on the VAZ-2114:

Circuit-device valve and elements for adjustment

Valve clearance process

According to the regulatory and technical documentation and the practice of motorists, the valve must be regulated every 15,000-20,000 km or if necessary.

Adjusting washer. With its help and the valve clearance is adjusted

Special adjusting washers are used to adjust the valves. There are 125 sizes there are, but the use of only a small amount.

Consider which: 3.30, 3.35, 3.40, 3.45, 3.50, 3.55, 3.60, 3.65, 3.70, 3.75, 3.80, 3.85, 3.90, 3.95, 4.00, 4.05, 4.10, 4.15, 4.20, 4.25, 4.30, 4.35, 4.40, 4.45, 4.50;

The consequences of untimely adjustment

It is known that untimely carrying out any car repair and maintenance operation, pulls certain consequences that can be lungs in one case, and in the other - fatal for power aggregate. So, consider the main of them:

1. The wear of parts and nodes of the head of the cylinder block, namely the gas distribution mechanism.
2. Wear distribution shafts.
3. Partial or complete destruction of pushers.
4. In a certain case, leads to the cliff of the timing belt and the corresponding consequences, such as. !

conclusions

Valve on VAZ-2114 worth adjusting no later than after 20,000 km run. Incompretable adjustment works can lead to unexpected and destructive consequences. Therefore, the car enthusiast must comply with the manufacturer's recommendation.

To determine the dynamic properties of the object in practice, the method of removal is most often used. And the definition of an object according to it () to the input is fed or a step test signal or a rectangular pulse - see "Section 2.3.The in the second case (the response curve) should be completed to the appropriate. The process of obtaining an object, based on the transition data, is called an object identification.

When removing the transition characteristic, you must perform a number of conditions,
presented in Table1:

Table1 - Transitional Removal Conditions

Note to Table1:

Initial transmission conditions for transitional characteristics:
At the initial moment, it is necessary that the control system is at rest, i.e. Adjustable value X. (for example, the temperature in the furnace) and the control effect of the regulator Y. (The output of the regulator to the actuator) did not change, and the external perturbations were absent. For example, the temperature in the furnace remained a constant and the actuator does not change its position. Then a stepped effect is applied to the actuator input, for example, a heater is turned on. As a result, the state of the object begins to change.

Determination of the dynamic characteristics of the control object with self-leveling of its transitional characterization

By self-leveling regulatory process The property of the adjustable object is called after the equilibrium disorders between the inflow and the flow rate to this state itself, the fruitlessness of the person or the regulator. Self-leveling contributes to a faster stabilization of the adjustable value and, therefore, facilitates the operation of the regulator. Parameter changes X (t) and its transitional characteristic h (T) Depicted in Fig.1. After, and evaluating the character of the control object (with or without self-leveling or without), you can define the parameters of the corresponding one.

it is recommended to apply for objects of control with a pronounced prevailing time constant. Before processing, the transitional characteristic (acceleration curve) is recommended to crimate (the range of changes in the normalized curve from 0 to 1) and allocate from its initial portion the magnitude of pure temporary delay.

When submitting to the entrance of some inclusion of stepped impact was obtained
transitional characteristic (see example in Fig. 1). It is required to determine the parameters of the transition
characteristics.

Defining objects on the acceleration curve is made method
tangent to point The transitional characteristic (acceleration curve). In this case, the point corresponds to the transition of the curve from the acceleration mode to the mode of deceleration of the rate of increasing output signal.

Figure 1 - Transitional characteristic (acceleration curve) Object with self-leveling

According to the type of transitional characteristics, you can determine the dynamic properties of the object: K, Hust,? D, T, R.

R \u003d Xust / t

Determination of the dynamic characteristics of the control object without self-leveling on its transitional characterization

Figure 2 - Transient characteristics (acceleration curve) Object without self-leveling

For objects without self-leveling, the sustainable functioning of the system without a regulator is impossible. For the object without self-leveling gain As defined as the ratio of the established rate of change of the output value x to the magnitude of the input jump U:

The value of dynamic delay in the object is determined as shown in Fig. 2 for regulators with relay output to the object, 100% of power is supplied. In some cases, the prolonged effect of such power is unacceptable. In this case, the heating element is allowed after determining and R.. At the same time, the rate of temperature change is fairly definitely possible after reaching the value H.values? 0.3hust. Then the speed of temperature change R. and time constant T. Defined by formulas.