The vent valve crankcase gases: types, structure, working principle

During engine operation are not only exhaust gases. Few people know about the crankcase. At the bottom of the engine accumulate fuel vapors, oil, and water. Their accumulation impairs and destabilizie the operation of the engine. To remove these substances, the design of the car has a vent valve crankcase gases. Touareg is equipped with them too. What that element is and how it works? The answers to these and many other questions you will read in our today's article.

Characteristics

Note that the crankcase ventilation system is used for a very long time. Its idea is quite simple – the internal part of the engine connects to the exhaust manifold with a hose. Under the force of the vacuum accumulated in the engine water and oil vapors climb back into the intake tract.

The BMW valve ventilation crankcase gas is arranged so that the gases move only in one direction.

Types

There are two types of these systems:

• Open.
• Closed.

The First type was used on older motors. Here ventilation was made in the lid of the pushers through the discharge tube. All the gases out, in the hood space. The system was ineffective, so in the end of 70-s car manufacturers began to use a closed vent valve crankcase gases. "Opel" is no exception. The advantages of this system were the following:

• Decreased levels of emission of substances into the atmosphere.
• The Engine felt “fasting” and worked steadily throughout the rpm range, giving the desired thrust.
• Decreased pressure inside the case. This contributed to a greater resource of seals and gaskets (in an open system, they simply squeezed).

There are two types of valves type of exhaust gases into the intake manifold. There are in-line vent valve crankcase gases and forced type. Cars “Volga” with engines ZMZ-402 vapor of gasoline and oils was carried out using a thick pipe. It connected the valve cover to the carburetor. In the result, the gases went directly into the intake manifold without affecting the mixing portion of the fuel-air mixture.

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Device

Now the car is used a valve of ventilation system of crankcase gases diaphragm type. It consists of the following elements:

• Cap.
• Diaphragm.
• Return spring.
• The Case.

In the latter, there is 2 fitting. One is for supplying blow-by gas, the second – for their removal.

How it works?

The mechanism of Action depends on the mode of operation of the engine. So, on the damped motor, the valve under the force of the return spring overlap with the membrane. When the unit is idling, the diaphragm overcomes the spring force (because the vacuum is formed in the system), and part of the gas enters the intake manifold. Further, they along with the fuel-air mixture burnt with the chamber and are vented to the atmosphere. At speeds over a thousand channel fully released aperture. Thus, the crankcase gases into the intake at full volume. Thanks to the membrane they will not be able to get back into the crankcase.

How to test

As the operation of the valve of ventilation of crankcase gases begins to clog. However, this does not mean that the item has stopped working and requires replacement. To check whether the valve of ventilation of blow-by gas, its tube is disconnected from the engine and blown in one direction. On the proper mechanism for the air in the back should fall in a small volume.

There is another way to check the vent valve crankcase gases. To do this, start up the engine and disconnect the pipe from the inlet side, having loosened the clamp on it. Further applied to the fitting of the thumb. With intact valve it needs to stick. This suggests that the system has a vacuum.

Some diagnose the condition of the motor on this valve. So, between the hose and the intake manifold hits the transparent fuel filter (this is set on carbureted engines). After some time it will be oil and soot. If the filter is dirty for the first 100-150 miles, then the faulty motor of the cylinder-piston group. Though the system is designed for the circulation of harmful substances, through the valve should not be so much dirt in such a short period of time.

Possible fault

If you do not vacuum and gases do not fall into the intake manifold, the reason is one of two things:

• Out of order, the valve of ventilation of crankcase gases.
• There was a blockage of the hoses in the system.

In the latter case, the main cause of the problem is the wear of piston group. You should check compression in the cylinders. Also check the oil ring. If they are weakened or «lay», oil will get into the system in large quantity. Will be sakatsuka hoses. Along with this violated the very diaphragm of the valve. How dangerous is this phenomenon? If the system cannot pump the gases, they will accumulate in other places, and under great pressure. So, theysqueeze the gaskets and seals. The engine lost thrust, it is an unstable idling.

If the compression is good, and the hoses have no blockages, blame valve. In such a situation, it is enough to just replace with a new one.

Price

How much is a valve of ventilation of crankcase gases? “BMW” is equipped with a device for 2-2,5 thousand rubles. On the car "Ford Focus" this element is worth up to a thousand rubles. Domestic Vase valve is not more than a thousand.

How to replace with your own hands?

Let's look at how to change this element alone, for example, engine ‘BMW" M-54. So, first you need to find the valve of ventilation of crankcase gases. It is located in the front of the engine, under the intake manifold. Get to it, remove the IAC valve and electronic throttle. For convenience, you can disassemble the intake manifold (but not necessarily).

Now disconnect the hoses from vent valve and remove the element out. Install a new device in the reverse sequence. For reliability all hoses secured with clamps.

Conclusion

So we figured out how constructed and operates the vent valve crankcase gases. During vehicle operation, you should periodically check the status of this node. After all, a clogged valve can "get" on the replacement of seals and gaskets. This additional cost money and time. Also note that if there was a blockage hose, one cleaning it is not limited. If there is a problem with the piston, the carbon is formed after a couple of days. To drive with the malfunction is not recommended. Because the pressure in the crankcase exceeds the norm. You need to check the engine compression and condition of the oil ring.