The gas tank of any car always contains vapors formed due to a decrease in atmospheric pressure or heating of the fuel. In order to prevent the leakage of fuel vapors into the vehicle, a special gasoline vapor recovery system (VPSU) is installed. Thanks to it, the vapors retained by the adsorber (essentially activated carbon) enter the intake manifold and burn in the engine cylinders. To regulate the amount of gasoline vapor coming from the adsorber to the manifold, a special solenoid valve is used.
Automotive gasoline vapor trap: adsorber and its purpose
You should immediately understand the question of what an adsorber is and why it is needed on a car. Initially, it is worth noting that the correct name of this device is an adsorber, that is, it is written with the letter “d,” although many call it an absorber, which is not entirely correct. The difference between an adsorber and an absorber is that the first one accumulates vapors (in this case, gasoline) and holds them, while the second one completely absorbs the substance (that is, with the impossibility of their subsequent release).
We will find out why cars use an adsorber and not an absorber after understanding the purpose of this device.
A gasoline vapor collector is a kind of filter that prevents direct contact of gasoline with the atmosphere, which reduces the level of pollution. Such devices were invented after the introduction of the Euro-2 environmental standard, which prohibits atmospheric pollution with gasoline vapors.
The main purpose of the device is to temporarily absorb the vapors that form in the gas tank and use them for selfish purposes, that is, not just suppress, but transport them to the engine, where they will be supplied to the cylinders for combustion along with the fuel assembly.
Returning to the name of the device, we can safely say that the Priora and other modern cars use an adsorber that only temporarily accumulates gasoline vapor (which occurs while the engine is not running). The use of absorbers would not allow vapors to be directed into the combustion chambers of the engine due to their complete absorption by the sorbent.
This is interesting! Activated carbon is used as a sorbent in automobile adsorbers.
Why do you need an adsorber?
The first development of a car adsorber appeared as an additional system that increased the environmental friendliness of the car. Thanks to this device and the modernization of the power unit, the car could comply with the Euro2 eco-standard. This system itself is not needed for better engine performance. If you correctly adjust the gasoline injection , set the ignition and equip the car with a catalyst , the vehicle will comply with more stringent environmental standards.
This system was not used in carburetor engines. For this reason, there is always the smell of gasoline near an old car. If the vehicle is stored outside, it is hardly noticeable. But it is no longer possible to stay in a garage next to such a car for a long time without signs of gasoline vapor poisoning.
With the advent of injection internal combustion engines, the adsorber is an integral element of any car. The fact is that the environment is polluted not only by the removal of exhaust gases through the exhaust pipe. Gasoline vapors also enter the air, and even the highest quality engine with a modern exhaust gas purification system without this system for purifying vapors generated in the gas tank will not meet the high requirements of environmental protocols.
On the one hand, it would be possible to close the gas tank hermetically, and the problem is solved - the fumes do not enter the environment. However, this would not mean that gasoline would stop evaporating. As a result, the pressure in a sealed tank (especially during the hot season) will increase. This process is undesirable for the fuel system. For this reason, the tank must have ventilation.
It turns out to be a vicious circle: the tank cannot be closed hermetically so that gasoline vapors do not increase the pressure in it, but if ventilation is provided in it, these same vapors inevitably enter the atmosphere. The very purpose of the adsorber is to maintain the pressure in the tank at atmospheric level, but at the same time the environment is not polluted with harmful fumes.
In addition to environmental concerns, automakers have improved the safety of the vehicles themselves. The fact is that when the car is stored in a garage, without an adsorber, the air near it will be saturated with toxic fumes. Inevitably, this air enters the vehicle interior. Even with the windows open while driving, it will take time for these volatile substances to dissipate. Because of this, the driver, as well as all passengers, partially inhale polluted air and are poisoned.
