A modern engine consists of many systems, including a lubrication system, a fuel system and an ignition system. All of them change over time, undergo changes, become more perfect. But there are other details that have remained unchanged throughout the entire time of its existence. For example, a crank mechanism. The fact is that from his very invention he remained in its original form.
Its application is quite widespread and it is not limited to internal combustion engines. It is used in such nodes where translational motion is required , since only it is able to provide not only the same period of such movements, but also a constant stroke, which is limited by the length of the crankshaft knee.
The crank mechanism was first used on a steam installation, after which, after the invention of ICE, it migrated to the latest development. There are two types of such installations: one transfers the force from the crankshaft to the part, which performs translational motion, the second receives this force from the piston, which is located at the other end of the connecting rod.
Consider the purpose of each part separately. The main part is the crankshaft. It can transmit force to the connecting rod or, conversely, receive it. It is made of high strength steels, most often of cast iron. It also houses a flywheel, which serves to preserve the energy received. Many motorists install a lightweight flywheel on their engine, which makes the crank mechanism more mobile. It is simply gaining momentum faster.
Now let's talk about the connecting rod. It is also made from hard grades of steel, because the pressure on it can be huge. In addition, its rod has the shape of an I-beam, since its deformation is fraught with serious consequences that will damage the cylinder.
The crank mechanism has a greater torque than rotary engines, since it uses the principle of lever action, that is, its strength is proportional to the length of the knee. Hence the conclusion: the larger the knee, the higher the torque. The next part is the piston. The piston can set the crankshaft in motion , as in an internal combustion engine, or receive force from it, as in compressors. It is usually made of aluminum, since soft metal is required here so as not to damage the cylinder walls if touched. Along the perimeter of the circle there are grooves into which the piston rings are inserted; they serve to seal and increase pressure.
In this case, the gases do a great job.
The crank mechanism of the engine is calculated to obtain average torque and revolutions, since shifting to one indicator results in a loss in another. The method of increasing the first is described above, but in this case the piston will have to go a greater distance, which affects the "ceiling" of revolutions.
The assembly of the VAZ engine does not differ from the above. It should be remembered that all the details of the crank must be carefully lubricated, since it rotates very quickly. From the very beginning of production, an oil film is created between the mating parts under pressure, which significantly reduces wear.