Ventilation valve for crankcase gases: types, device, principle of operation

During engine operation, not only exhaust gases are released. Few people know about crankcase. At the bottom of the engine, fuel, oil and water are collected. Their accumulation worsens and destabilizes the motor. To remove these substances, the car's ventilation valve is provided with a crankcase ventilation valve. Tuareg is also equipped with them. What is this element and how is it arranged? The answers to these and many other questions you will read in our today's article.

Characteristic

Note that the crankcase ventilation system has been used for a long time. The essence of its work is very simple - the inner part of the engine is connected to the exhaust manifold with a hose. Under the influence of the rarefaction force, the water accumulated in the engine and the oil vapor are taken back into the intake path.

On BMW cars, the venting valve of the crankcase gases is arranged in such a way that the gases move only in one direction.

Types

There are two types of these systems:

• Open.
• Closed.

The first type was used on old motors. Here ventilation was carried out in the lid of the pushers through a branch pipe. All the gases went outside, into the engine compartment. The system was inefficient, so in the late 70's automotive manufacturers began to use a closed crankcase ventilation valve. Opel was no exception. The advantages of such a system were as follows:

• The level of release of substances into the atmosphere decreased.
• The engine did not experience "starvation" and worked steadily at any speed, giving out the right traction.
• Decreased pressure inside the crankcase. This contributed to a greater resource of seals and gaskets (in the open system they were simply squeezed out).

Also, the valves are distinguished by the type of gas discharge into the intake manifold. There is a direct-flow valve for ventilation of crankcase gases and a forced type. On cars "Volga" with engines ZMZ-402 removal of steams of gasoline and oils was carried out through a thick branch pipe. He connected the valve cover to the carburetor. As a result, gases were delivered directly to the intake manifold, without affecting the mixing of the portion of the fuel-air mixture.

Device

Now the cars use a valve of the ventilation system of crankcase gases of the membrane type. It consists of the following elements:

• Covers.
• Diaphragms.
• The return spring.
• Shells.

In the latter there are 2 chutes. One is for supply of crankcase gases, the second is for their discharge.

How does it work?

The operation of the mechanism depends on the operating mode of the engine. So, at the muffled motor the valve under force of a returnable spring is covered by a membrane. When the unit is idling, the diaphragm overcomes the force of the spring (since a vacuum is generated in the system), and some of the gases enter the intake manifold. Next, they, together with the fuel-air mixture, are burned in the chamber and discharged to the atmosphere. On the turns over one and a half thousand channels is completely released by the diaphragm. Thus, crankcase gases enter the inlet in full. Thanks to the membrane they can not get back into the crankcase.

How to check

As the operation begins, the venting valve of the crankcase gases starts to clog. However, this does not mean that the element has stopped working and requires replacement. To check if the crankcase vent valve is defective, its nozzle is disconnected from the engine and blown to one side. On a good mechanism, the air in the opposite direction should fall into a small volume.

There is one more way of how to check the venting valve for crankcase gases. To do this, start the engine and detach the branch pipe from the inlet side, first loosening the clamp on it. Then put a thumb to the nipple. With a good valve, it must suck. This indicates that there is a vacuum in the system.

Some diagnose also the condition of the engine on this valve. So, between the hose and the intake manifold a transparent fuel filter cuts in (this is installed on carburetor motors). After a while, oil and soot will appear on it. If the filter is contaminated for the first 100-150 kilometers, then the cylinder-piston group is faulty in the engine. Although the system is designed to circulate harmful substances, no amount of dirt should flow through the valve in such a short period of time.

Possible malfunctions

If there is no rarefaction in the system and the gases do not enter the intake manifold, the cause is one of two:

• The venting valve for crankcase gases has failed.
• Hose clogged system.

In the latter case, the main reason for the problem is the wear of the piston group. It is worth checking the compression in the cylinders. Also check the oil-removal rings. If they are weakened or "laid down", the oil will fall into the system in large quantities. There will be zakoskovka hoses. Along with this, the valve itself is broken. What is dangerous for this phenomenon? If the system can not normally pump gases, they will accumulate in other places, and under great pressure. So, they squeeze out seals and gaskets. In the engine, the thrust disappears, it is unstable running at idle.

If the compression corresponds to the norm, and the hoses do not have blockages, the valve itself is to blame. In such a situation it is enough to simply replace it with a new one.

Price

How much does the venting valve of the crankcase gases cost? "BMW" is completed with the device for 2-2,5 thousand rubles. On the car "Ford Focus" this element costs up to one and a half thousand rubles. The valve does not cost more than a thousand for domestic VAZ.

How to replace yourself?

Let's look at how to change this element yourself, using the example of the BMW engine M-54. So, first you need to find the venting valve itself crankcase gases. It is located in the front of the engine, under the intake manifold. Having reached it, we remove the idler and electronic throttle. For convenience, you can also dismantle the intake manifold (but not necessarily).

Now disconnect the hoses from the ventilation valve and remove the element itself outwards. Installation of the new device is in the reverse order. For reliability, all hoses are secured with clamps.

Conclusion

So, we found out how the venting valve for crankcase gases works and works. When operating the vehicle, you should periodically check the condition of this unit. After all, if the valve is clogged, you can "get" to replace the oil seals and gaskets. And this is an additional cost and money, and time. Also note that if there is a blockage of hoses, one cleaning operation is not limited to this. If there are problems with the piston, this deposit is formed after a couple of days. It's not recommended to ride with such a malfunction. After all, the pressure in the crankcase at times exceeds the norm. It is necessary to check the compression of the engine and, if possible, the condition of the oil-removal rings.