Performance Car Reviews, News and Parts for the Car Enthusiast

The modern internal combustion engine we are so used to today would never had become a practical invention without its means of controlling the intake and exhaust the air-fuel mixture: the cylinder valves. Most of us take these little parts for granted, but without these, the piston-based engines powering our cars would not operate efficiently. There is just no other practical means of opening and closing the combustion chamber of a gasoline engine.

The operation of valves are simple. On most engine designs, there is a camshaft that controls the timing of opening and closing of the cylinder valves. This is usually connected to the crankshaft by a series of gears or by a belt. The cams have lobes which push their corresponding valves. When the cam’s lobe pushes on the valve, it creates an opening inside the combustion chamber of engine. This allows the air or fuel mixture or exhaust gases to move in or out of the cylinder. When the cam rotates more, the valve is restored to its original position by a spring, effectively sealing the combustion chamber.

To illustrate further on how these valves operate, let’s take a look on how a four stroke gasoline engine works. The four strokes that the engine makes are as follows: the intake stroke, compression stroke, combustion power stroke, and exhaust stroke. Valves on each cylinder usually have the same position for the same stroke.

The intake stroke, as its name implies, is where the engine takes in its fuel and air mixture into the combustion chamber with the cylinder valves closed. The cams operate it on the intake port of the cylinder. The piston on this stage moves downwards, bringing the mixture into the cylinder.

After this, the intake cylinder valves spring back to closed. The piston moves upward again, squishing the mixture to high pressure. This is now the compression stroke.

As the compression stroke nears its end, a spark plug kicks in and burns the fuel and air mixture. This ignition pushes the piston back down, generating power. Hence, this stage is called the combustion or power stroke. This is the part of the cycle where an engine produces its power. After the fuel has been consumed, waste gases are still usually present in the cylinder. As engine rotates more, the camshaft opens the cylinder valve covering the exhaust port. The piston moves up, expelling the spent gases. Then the cycle repeats.

Some engines may have variable valve timing in which the valves have different rates of operation with different engine speeds. But the cylinder valves simple principles of operation remain unchanged. They are still used to open or close the cylinders. If even one of these valves fail in an engine, this could render the whole engine totaled. Surely, the modern internal combustion engine is nothing without the valves that control it.

The cylinder valve operates on a simple set of principles. But without these simple parts, the gasoline engine could not have conquered the roads. With no other practical substitute for it in reciprocating engines, saying that the valve is an important part is an understatement.

Learn more about chlorine cylinder valves.