The car engine has a complex structure. The internal combustion engine includes many different systems, one of which is the timing. This mechanism is responsible for the timely injection of the mixture and the release of its gases after the working cycle. A key component of the gas distribution mechanism is the engine camshaft. This element may have a different location and a different design, but its function remains unchanged. What is a camshaft, where is it located and how does it work? Consider in our today's article.
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 moment. This shaft consists of a metal rod, on which "cams" are rigidly fixed - elements that interact with the valve lifters. The cams rotate with the shaft. Their number may be different. However, it is always limited by the number of valvesengine. The camshaft rotates strictly in accordance with the pulley.
However, this is not the whole shaft device. On the sides of it you can find support necks. They serve to hold the shaft in bearings on both sides. In addition, there are oil channels in the rod. It is through them that the lubricant passes, which is then distributed on the cams. The latter constantly interact with the pushers, and therefore are heavily loaded. Oil is sprayed to reduce friction and wear. Grease also gets on the bearings.
Features
What is a camshaft and why is this element so important? It depends on him 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 overlap. Therefore, at the slightest malfunction of the camshaft, the engine begins to behave unstable.
Among the design features, it is worth noting the number of gear teeth of this element of the fuel system. Their number is always twice as large as that of the crankshaft. Why is that? It's simple: the principle of operation of the internal combustion engine is such that for the entire cycle of operation the crankshaft rotates twice, and the camshaft rotates once.
Number, location
How many camshafts can an engine have? Previously, automakers practiced installing only one. These are 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 they wereeight. But with the advent of two camshafts, the number of valves has doubled.
Now about the location. Where is the distributor located? VAZ, as well as many European automakers, practice installing an engine with an overhead shaft. This scheme is used on 90 percent of modern cars. But there are also motors with an average camshaft position. As a rule, these are classic American engines. This scheme is considered less practical, since it requires long rods to actuate the pushers. With a top shaft arrangement, the presence of rods is not required. In addition, it is much easier to repair or replace this element. It is enough to unscrew the valve cover, after which complete access to the timing element will be provided.
Working principle
The rotation of such an element is provided by the crankshaft pulley, which is engaged with the camshaft gear between a belt or chain. The latter option is obsolete, 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, if the valve is installed incorrectly, they can simply be damaged.
And the camshaft works very simply. Rotating, the cams are also activated. The latter, in turn, act on pushers. Due to the special shape (similar to a drop of water), the camswhen rotating, they move the valves 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 out of the chamber.
Camshaft malfunctions
Usually this mechanism has the same resource as the engine itself. However, there are exceptions, especially on old engines (the engines of the classic Zhiguli are proof of this). The cams wear out, due to which a certain gap is formed. Even slight wear can cause incorrect gas distribution. You can also hear the characteristic knock 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 valves must be restored and adjusted to new clearances.
Conclusion
So we figured out what a camshaft is. This element plays an important role in the gas distribution mechanism. Therefore, at the first sign of wear and tear, you should seek help from specialists.
