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The components of an engine are many and it is difficult to know the operation and typology of all of them. Today we want to deepen the explanation of one of the key elements of the engine, we will discover what a camshaft is, what is its function within the engine and what types of it exist .
What is a camshaft?
The camshaft is an element generally made of cast iron or forged steel , this is so given the importance of having a great capacity for resistance to wear and torsion. It is located just below the engine and has a very important function: the opening and closing of the engine valves .
It is a vitally important element in the proper functioning of the engine, since if it fails, the inefficiency of the engine will be immediately detected. The camshaft is concerned with ensuring that the opening of the exhaust and intake valves take the shortest possible time interval and that they occur during similar intervals .
The camshaft is made up of a bar or axis of rotation that, together with some cams or blades, is capable of making the engine valves open and close. The shaft mounts onto the engine cylinder head or engine block , it is possible that in some cases there are two instead of just one: one for the exhaust valve and one for the intake valve. The camshaft is attached to the crankshaft by the timing chain, belt, or gears .
How does a camshaft work?
Once we understand what a camshaft is and what its main function is, the time has come to explain how it works .
It all starts with a turn of the contact of the equipment. When this occurs, an electrical impulse is generated that drives the movement of the crankshaft . All of the above causes the connecting rods to press and contract the pistons towards the cylinders. The result is a spark that ignites the spark plugs in the combustion chamber thanks to the compression of the fuel-air mixture that occurs in the process.
Thanks to the fact that the camshaft is attached to the crankshaft, it manages to start rotating, thus allowing the valves to open and close, allowing the mixture to pass through, or on the contrary, discharging the gases resulting from the procedure.
In addition to its fundamental function with the valves, the camshaft is also responsible for helping the proper functioning of the fuel pump and cooperates in the distribution of oil throughout the engine.
What types of camshaft are there?
In a general way we talk about two types of camshaft: SOHC and DOHC . The first case has a single camshaft for all its valves, while in the second case the camshafts are separated by exhaust and intake valves.
However, depending on its placement, three types of camshaft are known:
SV: It is known by the name of side valves since, as can be guessed, it is the position that they occupy in the cylinder, inside the engine.
In the case of this type of camshaft, the fact that the compression chamber must be of a larger size must be taken into account and that problems often occur since the size of the valve heads is limited by the space they have.
OHV: In this case, the camshaft is placed in the lower part of the engine block , with the cylinder head valves that we have previously mentioned. The crankshaft transmits the movement through the sprockets or a short chain directly.
Through this process there is a limitation in the number of revolutions that the engine can achieve. We must also take into account that due to the engine temperature, the amplitude of the tappets must be higher than usual.
OHC: This type of camshaft is located in the cylinder head, next to the valves . It is by far the most popular system since it uses fewer parts than other types. This results in a greater opening and faster closing of the valves, as well as a higher rpm.
If it is true that it makes movement from the crankshaft difficult and makes longer chains necessary, which brings with it greater wear and maintenance . It is an expensive and complicated system, but it is also very efficient .