The concept of "compression ratio" refers to reciprocating piston engines that have a combustion chamber. This term refers to the ratio of the amount of space above the piston when it is at the bottom of the dead point to the amount of supranating space in the upper dead point. In other words, this is a mathematically different difference in the pressure inside the combustion chamber at the time of the blending of the mixture in the cylinder and at the time of its ignition. There are many misunderstandings and myths around this term. To understand that the truth is true, and that it is a lie, it is worth finding out why different engines have this parameter, and the advantages of low or high compression. Advantages of High Compression
Advantages of High Compression
The internal combustion engine shall be operated by the ignition of a mixture of air and fuel vapor. When a mixture ignites the mixture is expanded and the piston which rotates the shaft shall be pushed. With more compression, the pressure on the piston is increasing, and the zac alone is more useful.
The lack of detonation in diesel engines is simple: the combustion chamber first compresses the clean air and the fuel is charged later
It is understood that the quantity of petrol in the fuel-air mixture remains unchanged and higher than the amount of air it burns with higher efficiency.
At the present stage of the construction of passenger cars, the use of low-compression motors has practically stopped. Although they are allowed to use low-octane and low-octane gasoline A-80, their popularity is zero. The fact is that modern consumers are seeking to acquire automobiles with a large number of horses under the hood, and with engines intended for low-octane gasoline (for example, UAZ, 469, which is true, with a modified compression ratio and a number of modern-day modern-day upgrades), it is impossible to remove the high power for good reasons.
Can I change the compression ratio?
It is possible to increase the compression ratio by reducing the amount of combustion chamber, but with the modernization of the existing engine, engineers have to constantly seek compromise between efficiency and safety. The fact is that the increase in compression leads to a lowering of the detonation threshold. If you increase the compression ratio too much, you might find that there is no way to prevent detonation. In other words, it is sometimes easier to develop (or bet on another, more powerful car) a new engine is easier than upgrading the old one.
Modern engines are characterized by a high degree of compression. In the vast majority of cases, they use octane gasoline or 95 or even 98 octane number
One variation of the compression ratio available to private tuners is the milling of the cylinder head. The combustion chamber decreases after "coral". The compression ratio will increase. There is also the reverse side of this manipulation (by the way, officially called it by force), the total amount of combustible mixture, which is burned in the cylinder over one cycle, will be reduced.
Volumetric compression or compression?
The compression ratio is often confused with the notion of compression. It's not the same thing. The compression is referred to as the maximum cylinder pressure when the piston moves from the lower dead point to the top. The compression is measured in the atmosphere, and the compression ratio is mathematical terms, for example, 10: 1 (ten to one).
Premature ignition and detonation
The mixture entering the combustion chamber shall not be blown up, but shall burn uniformly and over the duration of the piston until the piston is moving downstream. Under this condition, the energy is spent as efficiently as possible and the piston groups shall be curated evenly and not overheated. The difficulty is that the burn rate of the mixture is usually much faster than the speed of the piston.
This creates a major challenge to those who have set the goal of increasing compression. When the pressure is increased, the mixture will spontaneously light. This is known as premature ignition. Furthermore, the ignition of the mixture occurs when the piston is still completing the compression phase. In this case, the energy of the burning fuel creates additional resistance and is squanderingly wasted.
The second problem is the allocation of excessive amounts of energy. It's just an explosion. The phenomenon is called a detonation in the theory of engine-building and has extremely negative consequences.
Thus, the increase in compression can play an evil joke with the engine's owner. In order to avoid unpleasant consequences, it is worth to know what the octane number is.
What is an octanoic number and what does it affect?
The petrol used for the operation of the DMF is resistant to detonation and self-ignition. The term "octane number" is being introduced to indicate the level of this persistence.
Detonation only occurs in the combustion chamber of the petrol engine. Combustion of diesel fuel requires more compression, and it is ignited by "itself" heated by pressure and in contact with hot metal parts. It seems that all conditions for the creation are created, but thanks to some features of diesel engine it is completely protected from this harmful phenomenon.
An important fact-octane number of gasoline does not affect the amount of energy that fuels the combustion fuel. In other words, to think that the engine of petrol with higher octane number, you increase its power by mistake. It is very simple: with a high compression ratio, it is necessary to use a fuel with a large octane number.
Effects of the use of fuel with inappropriate octane number
It is worth drawing attention that, if the fuel used is not in conformity with the manufacturer's requirements, the following problems may arise:
-If the fuel is used with a large octane number, the exhaust valves may be available. This is because the gasoline with a large octane number is burning with less temperature and slower. Accordingly, when used, a burning mixture is flying over the exhaust flow through the exhaust valve.
-A tan may be used for the use of high-octane fuel with high octane number. The reasons are the same: the burning rate may not coincide with the piston cycles.
-If a low-octane number is used, the engine control unit (or the octane adjuster) will not be able to determine the angle of advance without detonation.
Alternate Method of Change in Compression
In modern engine development practice, an alternative way to dynamically change the degree of compression is actively used-the installation of a turbocharger. It helps to increase the pressure in the combustion chamber without changing the volume of the combustion chamber. The principle of the injection timing is that the combustion chamber receives more air per unit of time.
As a result, the compression ratio changes continuously to respond to the increase and reduce the load on the engine. This process is controlled by electronics, which rapidly changes the conditions of ignition of the fuel-air mixture. As a result of all the above negative factors associated with the change of pressure in the combustion chamber, it is possible to avoid.
In the United Arab Emirates, the race on diesel SUVs is extremely popular. To increase compression and power, the maximum performance turbines are used
The fans of the tuning have taken the use of turbochargers as a more flexible and manageable way to increase engine power. It can be said that the acquisition of a turbo whale (a set of components intended for the installation of turbocharging for a particular engine) is much more common in comparison with the advance. Oppressors of different types have been successfully used and, if necessary, to increase the efficiency of the diesel engine.
