The engine is out of order. What should I do?.
Mention this kind of breakdown, some people can feel and the first kind of piston knock out a cylinder to have some contradictions, in fact, careful analysis is clear. We know that as the engine temperature increases, the rate of combustion of the mixture will increase accordingly. If the ignition time is too early, the maximum point of the cylinder combustion pressure will be ahead of time, and the force on the cylinder wall will be increased and the knock out noise will appear. The inspection contents and methods are as follows.
The reason for this phenomenon is due to excessive piston clearance or deformation of the piston. Because of the larger piston clearance cold, knock knock some serious natural, and when the engine temperature, the piston will expand, so that the piston clearance becomes small, abnormal sound of knocking naturally reduce. (stock tracking, black horse will take off from here... )
With the continuous development of automotive technology, in order to reduce engine noise and extend the engine maintenance cycle, the engine knock cylinder has undoubtedly become a problem that people must solve. Therefore, in order to reduce engine knocking chance, some engine uses the design center and the center line of the piston piston pin from a little, so that the piston thrust direction by changing the combustion pressure in the cylinder piston, piston slap to relieve pressure, so as to reduce the occurrence of the chance to knock. After understanding the causes of piston knocking, we will analyze the causes and detection methods of several common piston knock failures.
The so-called "piston knocking cylinder" abnormal sound, refers to the piston side tapping cylinder wall generated abnormal sound. Generally speaking, when the piston top produces the axial force direction, as the piston changes from the compression stroke to the power stroke, the piston knock out the cylinder. In other words, every time when the piston passes TDC moves downward, the piston will be forced to hit the wall, causing the piston knocking fault. The piston knocking the decisive factor is the clearance between the piston and cylinder wall, piston clearance is what we say normally (Figure 5). As for the specific effect of the clearance between the piston knock, the main show the following features: when the piston clearance is too large, prone to knock, the reason for this phenomenon, is decided by the material and working characteristics of the piston. Its intuitive performance is that when the engine is cold, the piston gap is large and the knocking is loud. But as the engine temperature increases, the piston clearance will become smaller and the knocking sound will be reduced accordingly.
