Pcv system how does it work

The PCV valve controls the flow and circulation in the system. The PCV valve, is effective as both a crankcase ventilation system and as a pollution control device. PCV systems have been standard equipment on all new cars, since the early sixties. The open system, draws fresh air though a vented oil filler cap. This presents no problem, as long as the vapor volume is minimal. However, when the crankcase vapor becomes excessive; it is forced back through the vented oil cap and into the atmosphere.

As a result, the open PCV system, is not completely effective, as a pollution control device. So, there is no vent in the oil filler cap. The closed system prevents vapor, whether normal or excessive, from reaching the open atmosphere. The closed system is, very effective as an air pollution control device. Commonly referred to as the PCV system, the flow control valve is the most important part. The purpose of the PCV valve is; to meter the flow of vapor from the crankcase to the intake manifold.

Blow-by gases and vapor should be removed, at about the same rate they enter. Blow-by is minimal at idle and increases, during high speed operation. The PCV valve, compensates for the engine ventilation needs. Consequently, changing at varying engine speeds. Manifold vacuum controls the PCV valve. And if you have the necessary DIY skills, you can even make one yourself.

There are actually a number of different ways in which these oil and air separators can work. Probably the most common kind blows the oily air through a mesh filter.

The oil droplets are trapped in the mesh while the air passes through. The most effective such filters are made up of microfibers, which can trap very small particles of oil. Alternatively, the air and oil filter may require the recycled gases to go down a tube with holes in its side. The lighter air molecules escape through the holes, while the heavier oil droplets fall all the way to the bottom, where they can be removed.

And some advanced systems use a centrifuge to drive the heavier oil droplets out of the air. The oil coalesces on the sides of the centrifuge and can be channeled back into the crankcase. It sometimes amazes me how much thought has gone over the years into the ways that cars work and how some of our ideas about automobile construction have changed over time. Today, emission control is an extremely important part of automobile design, because it minimizes the amount of pollutants that escape into the atmosphere and degrade the environment.

While researching this article I was impressed to learn that the idea of emission control began almost exactly half a century ago, with the invention of positive crankcase ventilation and the PCV valve.

Of course, there are much more advanced emissions control systems available today and cars with zero emissions are already possible -- electric cars have no emissions at the tailpipe, though emissions may be produced when the electricity is initially generated -- and within a few decades, when internal combustion engines in cars have become obsolete, automotive emissions may be a thing of the past. When that happens, we can thank the inventors of positive crankcase ventilation for leading the way.

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Mobile Newsletter chat subscribe. Under the Hood. Other Systems. A certain amount of air and fuel mix is pulled down by the piston and slips through the piston rings into the crankcase.

This escaping gas is called blow-by -- and it's unavoidable. See more pictures of engines. PCV System Oil and Air Separator The crankcase in a car is used as a storage place for oil, usually in a pan located below the crankshaft. Additionally, if your vehicle is idling roughly, your PCV valve could be to blame. Rough idling due to a damaged PCV valve, unfortunately, is often misdiagnosed as more expensive issues.

Save yourself time and frustration and contact Kennedy Transmission to get help from the experts. Prevent more expensive engine repairs by taking care of your PCV valve. Stop by one of our shops today for the excellent customer service and vehicle care that you deserve.

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