Nowadays, few people will be surprised by such an invention as an internal combustion engine. Millions of diverse devices use them for their operation. An invention of this type appeared in the 19th century, and it was due to the need to create a modern and effective mechanism that could set in motion technical devices. Initially, it had many shortcomings, and the efficiency was extremely low. Subsequently, it underwent various changes, was improved and now we have the opportunity to use this invention. Including it is used in the construction of a motorcycle.
A two-stroke engine, as well as any other engine, is the heart of technology. Regardless of the type, its primary task is to ensure the movement of the mechanisms connected to it. Almost everyone knows how it looks and where it is installed, but not everyone understands how it works. Let's try to figure this out now.
The engines of modern motorcycles have a number of differences and the main ones are:
- The way to implement the work cycle
There are four and two stroke engines. The latter differ almost twice as much power with the same volume of cylinders with a four-stroke counterpart. But such an advantage is considered very conditional. Firstly, they have a relatively low efficiency. Therefore, they are used in conditions where light weight, size are required and the issue of fuel economy is not important . This makes such units ideal for use in motorcycles, light motor boats, chainsaws, chainsaws, etc.
The engine can be air or liquid cooled. In view of the small size, the two-stroke engine is most often supplied with air cooling. In his device, everything is aimed at minimizing its weight.
A large volume provides a larger power reserve.
Four-stroke engines are popular, economical, efficient, but two-stroke engines are most often used in motorcycles. This preference is caused, first of all, by the simplicity of the motor design, its low weight, low fuel consumption. The negative point is that the filling of the combustible mixture is insufficient. This nuance is associated with poor cleaning of the cylinders from the exhaust gas mixture.
The principle of operation of a two-stroke engine is based on a short duty cycle, which occurs in one revolution of the crankshaft.
During the upward movement from the bottom dead center (BDC) to the top dead center (TDC), the piston creates a vacuum that allows the fuel-air mixture to enter the crankcase. At this point, compression of the fuel (working mixture) is provided in the combustion chamber. Then, at the top dead center, the working mixture lights up and, expanding, moves the piston down into the BDC.
A modern two-stroke engine is not much different from its predecessors, in this regard, the scheme for supplying fresh fuel mixture and the output of working out in these units are approximately the same.
Now consider another option - an engine with a poppet type valve.
As the piston moves down, pressure increases in the crankcase, which helps to close the poppet valve. At this time, the piston provides the opening of the exhaust windows, and the spent working mixture in the form of exhaust gases rushes into the receiver. The next action of the movement of the piston towards the BDC is the opening of the purge windows, from which the charge of the fresh working mixture flows. The two-stroke engine continues to operate. The cycle repeats, ensuring the movement of the motorcycle.
The principle of the two-stroke engine ensures a long life of the motorcycle, as the system is simple and does not contain a large number of parts. It is resistant to many factors (whether it is low-quality fuel or oil) and powerful enough to cope with the functions assigned to it.