The car engine has a complex device. ICE includes many different systems, one of which is timing. This mechanism is responsible for the timely injection of the mixture and the release of its gases after a working cycle. A key component of the gas distribution mechanism is the engine camshaft. This element can have a different arrangement and different design, however, its function remains unchanged. What is a camshaft, where is it and how does it work? Consider in our article today.
Description
So what is a camshaft? This is one of the components of the timing, which performs the function of closing and opening the internal combustion engine valves at a certain point. This shaft consists of a metal rod on which "cams" are rigidly fixed - elements that interact with valve pushers. Cams rotate with the shaft. Their number may be different. However, it is always limited by the number of engine valves. The camshaft rotates strictly according to the pulley.
However, this is not the whole device of the shaft. Supporting necks can be found on its sides. They serve to hold the shaft in bearings on both sides. In addition, there are oil channels in the shaft. It is through them that grease passes, which is further distributed on the cams. The latter constantly interact with pushers, and therefore are heavily loaded. Oil is sprayed to reduce friction and wear. Lubrication also enters the bearings.
Features
What is a camshaft and why is this element so important? It depends on it the moment of opening and closing the valves, and accordingly the correct operation of the engine. Also, the duty cycle requires observing the exact moment of valve shutoff. Therefore, at the slightest malfunction of the camshaft, the engine starts to behave unstably.
Among the design features, it is worth noting the number of gear teeth of this element of the fuel system. Their number is always double that of a cranked one. Why is that? It's simple: the principle of the internal combustion engine is such that for the entire cycle of operation the crankshaft rotates twice, and the camshaft - one.
Number, location
How many camshafts can be in the engine? Earlier, automakers practiced installing only one. It's about classic four-cylinder engines. But in the early 2000s, many companies began to use engines with two camshafts. The number of valves has also increased. Previously, there were eight. But with the advent of two camshafts, the number of valves doubled.
Now about the location. Where is the camshaft located? VAZ, as well as many European automakers, practice installing an engine with an overhead shaft. This scheme is used in 90 percent of modern cars. But there are also engines with an average camshaft position. As a rule, these are classic American engines. This scheme is considered less practical, since it requires the presence of long rods that would drive the pushers. With an overhead shaft, rods are not required. In addition, it is much easier to repair or replace this item. It is enough to unscrew the valve cover, after which complete access to the timing element will be provided.
Principle of operation
The rotation of such an element is provided due to the pulley of the crankshaft, which is engaged with the camshaft gear between each other with a belt or chain. The latter option is outdated, although it is still used by some manufacturers. Most use a belt drive because it is more compact and less noisy. The camshaft is installed strictly according to the marks, since the accuracy of opening and closing the internal combustion engine valves is important. Also, with improper installation, the valve can simply be damaged.
And the camshaft works very simply. Rotating, the cams are driven. The latter, in turn, act on the pushers. Due to the special shape (similar to a drop of water), the cams during rotation move the valve to a certain height and close them in the same way. At this time, the mixture enters the cylinder, and then after combustion, exhaust gases come from the chamber.
Camshaft malfunctions
Typically, this mechanism has the same resource as the engine itself. However, there are exceptions, especially on older engines (classic “Lada” motors confirm this). The cams wear out, which creates a certain gap. Even slight wear can provoke improper gas distribution. You can also hear the characteristic clatter of the camshaft. All this suggests that the working surface of the cams has wear. In this case, the mechanism must be replaced with a new one or the valve must be restored and adjusted to new clearances.
Conclusion
So, we found out what a camshaft is. This element plays an important role in the gas distribution mechanism. Therefore, at the first signs of wear, you should seek the help of specialists.