What is the fuel adsorber and why does your car need it?

What you should know about fuel pressure cleaner

Three or four decades ago the problem of environmental pollution was far at the back of the world’s attention. But times have changed and today this aspect is receiving a great deal of attention. Especially when it comes to the car, which is considered one of the main sources of emission of a whole range of harmful volatile substances into the atmosphere. It has been experimentally established that air pollution occurs not only through the exhaust system as a result of combustion of FAM – gasoline itself, in contact with the air, releases vapors that cause irreparable damage to the environment. To reduce this effect the fuel adsorber, mounted in the venting system of the fuel tank of the absolute majority of modern cars, is designed. Application of this device is regulated by the European ecological standards, starting with Euro-2, that is quite a long time ago. But, as it often happens, a lot of car owners have no idea what this detail is, what it is for and how it works. We are trying to fill these gaps in automobile education.

What is the fuel adsorber and why does your car need it?

Fuel adsorber: what is it?

Adsorption is understood to be a physical process consisting in the absorption of a substance of higher density into a more rarefied substance. However, no chemical reactions occur, there is no transformation of substances, there is only the diffusion of particles without changing their properties. This phenomenon is widely used in a wide variety of activities, including the automotive industry. Although it is difficult to force a car manufacturer to do something that is not part of their plans, the inclusion of the requirement to equip cars with an adsorber to absorb diesel or gasoline vapors in the environmental standard has done its job. Today, all European automobile manufacturers have to strictly follow these standards for fear of severe penalties. Although automakers from other parts of the world are not concerned about European standards, they have to make concessions not to lose voluminous market of the Old World.

By the way, about the term. In the Russian-speaking segment of the World Wide Web circulates the word “absorber”, which is consonant with the correct, but is erroneous, though quite common. And in order not to be called illiterate, we recommend to use exactly the correct variant.

So, we have already superficially clarified, why the adsorber is necessary. Now let’s try to describe the advantages of its use in more detail:

  • This device makes its own, albeit insignificant, contribution to the fuel economy. Construction of the adsorber is such that part of the gasoline vapors, condensing, is separated into fuel itself and other substances. So, the gasoline goes back into the tank instead of evaporating, which allowed to get rid of its smell in the cabin of the car, which for older models is still a pressing problem;
  • The adsorber helps to normalize the pressure in the gas tank. Therefore, in cars equipped with this device, you do not have to exert excessive force when opening the tank lid. In older cars, especially in abnormal heat, because of which the pressure in the closed tank increases several times, this operation can turn into a real test of your physical capabilities;
  • The main factor explaining why a car needs an adsorber is undoubtedly the reduction of the environmental load on nature. Considering that the number of cars on the planet has now exceeded the two billion mark, the cumulative environmental effect is quite significant;
  • Finally, automobile manufacturers claim that thanks to the use of the adsorber it has been possible to reduce the explosion hazard of cars.
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Purpose of the adsorber

Construction of the adsorber

Modern devices that use the principle of adsorption use a variety of materials as an absorbent, from activated carbon to natural minerals. In the auto adsorber, it is activated carbon, a type of hydrocarbon with a porous internal structure, that pretends to play this role. Actually, the absorber is a plastic cylindrical container, which is located in the engine compartment near the power unit. In some models, the adsorber can be found near the fuel tank, but some of its parts are still located in the underhood space. Schematically, the fuel vapor absorber consists of the following elements:

  • gravity sensor;
  • separator with an emergency valve;
  • actual filter (as a rule it is crushed activated carbon);
  • electromagnetic purge valve;
  • connecting pipes.

The separator is a structure designed to collect condensed gasoline in order to send it back to the fuel tank. The task of the gravity gauge is to monitor the gasoline vapor pressure inside the tank, and if necessary, relieve it to reduce the chance of damage. The filter element is a rather large container, the lower part of which contains an adsorbent substance, which functions are to absorb petrol/salad vapors in order to condense them and then separate them. Separately we should mention the emergency valve. In normal situations it does not work, but in emergency cases, when there is a risk of fuel spillage (e.g. in an accident, if the car overturns), it activates, completely blocking the fuel line. The role of the connecting tubes is quite obvious – to connect all the assemblies of the adsorber. As for the solenoid valve, its purpose is to control the modes of the separator, we will tell you about how it works a little later.

Construction of the adsorber

The principle of operation of the fuel vapor absorber

The functioning of the absorber is based on a fairly simple scheme, but here there are subtleties that will be useful to all car owners. Therefore, let’s consider how the auto adsorber works, with the necessary degree of detail. Since gasoline vapors, partially consisting of light (volatile) hydrocarbons, are lighter than air, they accumulate at the top of the fuel tank, getting into the separator. This, in its turn, is connected with the gravity sensor. Directly in the separator a certain part of the fuel vapor condenses, flowing down the pipe back into the gas tank, but already as liquid fuel.

Another part of the gasoline vapors manages to slip further. This is where the adsorber awaits them, where the vapors get stuck in carbon pellets and here they condense into a special cavity. A solenoid valve is responsible for emptying this cavity of accumulated fuel, directing it either to the throttle system or directly to the intake manifold. Thus, the gasoline captured by the adsorber becomes a full participant in the process of forming the fuel-air mixture, rather than evaporating outward, polluting the surrounding area. Although you can understand from the above that the adsorber works quite primitively, its efficiency is beyond doubt. True, much depends on both the specific implementation of the design and the absorbent used. Simply activated carbon is considered the most accessible material, so it is widespread.

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What the fuel absorber affects

With a functioning absorber, you probably will not even guess about the presence of this device. But since the adsorber in the car is responsible for relieving pressure in the tank, for the condensation of gasoline vapors and reuse of fuel, it is only natural that its presence allows you to reduce fuel consumption and increase the safety of the fuel system as a whole. But everything changes if any part of the adsorber begins to malfunction, or completely fails. The most common problem is with the solenoid valve, but it is not uncommon for the filter chamber cavity or piping to become clogged. It is clear that in this case the adsorber does not affect the operation of the engine in the most positive way, because the natural fuel flow is disturbed. The pressure in the tank may also be beyond the control of the device, and this is not good from a safety point of view either.

Consequences of removing the adsorber

A certain part of motorists believe that any measures aimed at improving the ecology of the car have a negative impact on the performance characteristics of the power unit. In particular, such criticism refers to the adsorber, which is really necessary due to the requirements of ecological standards. Pessimists argue that this device is not only useless, it is harmful, because instead of fuel savings it gives overconsumption, instead of improved dynamics – reduced intake of the motor, etc. As a result, simply dismantle the device (or solenoid valve). How justified such actions, is there any logic in them?

In terms of impact on the engine – if the adsorber is working, it is almost zero, because it almost does not affect the operation of the fuel system in terms of gasoline supply to the engine. Does it save any money? Theoretically, yes, though only slightly, because a part of petrol doesn’t evaporate but goes back to the petrol tank. In practice, it’s quite difficult to check, especially in quantitative terms. And if you believe the reviews of car owners, the positive material is much rarer than the negative, although the degree of confidence in them is much greater. In any case it is not necessary to expect from an adsorber some miracle, especially regarding fuel economy. Frankly speaking, the environmental contribution can hardly be called tangible, especially compared to the functioning of the catalytic converter.

As for the claims about the harm of the device, they look unfounded. You can remove the adsorber and in 99% of cases you will not feel any changes in the engine behavior. However, there is an opinion, that since gasoline vapors will not condense now, you thereby eliminate all artificial obstacles on the way of fuel to the combustion chamber (valves, sensors, separator, filter). The very procedure of switching off the adsorber consists in adding a fine filter (suitable from VAZ carburetor models) to the hose coming from the separator. In this case gasoline fumes will fly safely into the atmosphere. The hose coming from the electromagnetic valve is simply squeezed. But since the operation of the adsorber is controlled by the onboard computer, such a design change will be perceived as a breakdown, with the corresponding illumination of the Check Engine. To remove this error, you will need to re-flash the ECU.

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Among the undoubted disadvantages of such a step are the following:

  • you will make a “feasible” contribution to deterioration of ecological situation. Minimal, but still;
  • you might get a petrol/solar smell in the passenger compartment;
  • the same smell will be felt next to the car, but far from obvious.

Dismantling the Exchanger

There are also advantages, which are also noted by many users:

  • when the adsorber is located in the engine compartment, if you remove it, a lot of scarce space is freed up, because the can of activated charcoal itself has a solid size;
  • unstable operation of the power unit in idling mode usually disappears;
  • there is no need to replace the failed valve or other components of the device.

It is for you to decide whether to follow the recommendations of homebrew experts or car manufacturers, but if you really belong to the category of the population, which is not indifferent to global problems, including environmental problems, the fuel adsorber will be a useful and even necessary element of the car design.

Adsorber. What is it, what is it for, signs of malfunction

I decided to deal with this topic for myself and started googling, I read and understood) now I want to share with you, who are interested in this same question.

of the various topics I read, I liked the one that I copy here, simple and clear without water and unnecessary. the theme is copied from this post

It seems to be such an inconspicuous element, which at first sight is not important for a car, but without which it can’t work normally. Slows down, the engine “trots” can even destroy the gas tank! It is all because of a faulty adsorber valve. Many people don’t know what it is, how it works and most importantly, what it affects. Today I will try to explain everything in simple words and describe the main signs of malfunction. Definitely it will be useful, so read it and see… First of all let’s start with the definition.

The adsorber (from Latin sorbeo – to absorb) is a car system that serves to capture gasoline vapors that escape from the tank. When the engine is running, they are directed to the fuel injection system, namely to the intake manifold. When the engine is switched off, part of the vapors are collected by the separator (it sends them back to the tank), and the remaining vapors go to the adsorber, where they are neutralized.

Why the adsorber was created

This is actually a tribute to the environmental standard, namely EURO-2. In fact, it is a large filter that captures light hydrocarbons. According to the new standards, gasoline vapors are not allowed to enter the atmosphere, because it contributes to the pollution of the atmosphere. Also, the vapors should not pass into the passenger compartment of the car, because it is harmful to say the least! In the old carbureted cars, there was no filter and no valve, the system was different. But the carburetor was gone along with the old standards, now you only have the injector and a MUST filter system.

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It is a large plastic jar with activated carbon inside, because this compound is perfectly fights gasoline vapors.

The main parts can be described as follows: – Separator + gravity valve – Pressure sensor – Filter part (usually made of charcoal) – Connecting tubes – Solenoid valve – As you can see absolutely nothing complicated. Separator – serves to trap some of the gasoline, then sends them back into the tank. Gravity valve – Almost never used, but it is needed in emergency situations, like accidents, it prevents fuel overflowing from the tank (e.g. when the car is overturned). Pressure sensor, a very necessary thing – it controls the pressure of gasoline vapors inside the tank, if necessary opens and discharges it, not allowing the structure to be damaged. The filtering part is, as I wrote above, a big jar in which is poured carbon powder, in fairly large granules. This is done so that the vapors can pass through and condense unhindered. Connecting tubes – needed to connect all the main parts, filters, sensors and valves, I think it is clear. Electromagnetic valve – serves for switching modes of collecting gasoline vapors, we will talk about it in more detail below. How the system works – principle of work

Why do I focus attention on the electromagnetic valve, because it is almost the key in this system. For better understanding, I lay out the scheme of the injector car, and in this case is the VAZ 10 – го family.

So, fuel vapors go up the tank and stop at the separator, which is combined with a gravity sensor (as I wrote above – it prevents the flow of fuel in accidents – rollovers from the tank). In it they partially condense and return back (as liquid fuel). But another part of the evaporation, bypassing the gravity valve, goes to the adsorber, where they actually accumulate. Accumulation occurs when the engine is not running! THIS IS IMPORTANT. After starting the engine, the solenoid valve, opens – thereby connects the cavity of the adsorber (where the gases are as if in a conclusion) with the intake manifold or throttle assembly (in different cars differently). THE PROCESS CALLED PURGING BEGINS! The vapors mix with air (from the street), which is fed through the throttle assembly, then enter the intake manifold and then into the engine cylinders, where they are afterburning with the air-fuel mixture. The system is very simple if you understand how it works.

What affects the adsorber valve Many problems are related specifically to the adsorber valve. It is essentially a very simple device that opens or closes under certain conditions (engine running or shut off). If the valve works well, there is no problem at all, you may not even know about its presence in your system. However, when there is a breakdown, for example – the adsorber cavity itself is clogged, or the valve does not work. Then your car can have serious damages. Because there is no purging of the cavity, as well as not discharged pressure from the tank.

Signs of the malfunction of the adsorber valve As it becomes clear, there are problems with the power system: – RPMs are floating. But not immediately, but after about 5 – 10 minutes on the warmed up engine – At idle, if the engine is running, you press the gas pedal – almost throttles. Feels like running out of fuel – On the run the car does not develop the necessary power, it feels like they took away 10 – 15% of the engine power – Can go crazy fuel tank sensor. Shows then – “full”, then – “empty”, etc. – If you open the tank to refuel. You hear a strong whistling sound, as if a vacuum is created inside. – Increases fuel consumption – When the sensor of absorber is cold it can make a big noise, they are often mistaken with engine valves It’s also worth noting that the reason is not always in the valve, often the can with activated carbon (that is, the cavity of the adsorber itself) can get clogged. If necessary, it must be replaced or disassembled and cleaned – to dry, that is, to restore the filtration of gases so that they pass unobstructed. If you have these faults, it is necessary to look – to check the valve and if necessary to change it, blessing it costs a penny. As well as the cavity itself with activated carbon. Is it possible to remove Some motorists disregard environmental standards and remove the adsorber valve. The words are basically such – “what for do I need it, the car became slower, the consumption became more, in general I will throw it away”. But really, is it possible to do it? Will not it make the car worse?

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It should be understood that the system, in general, does not affect the operation of the engine, and even saves a little fuel, because the vapors that remained in the main body then afterburning in the engine, of course wait that the savings will be huge is not worth it, but a few kilometers of mileage turns out. You can remove it, of course, the car simply does not care about it! Even better, because the evaporation from the tank will not condense (purified), and go directly into the atmosphere. That is, you kind of remove all the cans – valves and give, an open flow of air to the tank. Physically they do it this way – on the hose from the separator hangs a fine filter from the carburetor VAZ, gasoline vapor goes into the atmosphere. The hose from the adsorber valve, cut off, flash the engine (chip tuning), otherwise there will be an error, that’s all!

However, this has disadvantages: – For example, the cabin will often smell of gasoline, the fumes will go (often) is in it. – Atmosphere will be polluted with light hydrocarbons – There will be a persistent smell of gasoline near auto (though it is disputable) Pros of disconnection: – Freeing up space in the under-hood, the can takes up quite a lot of space – Unstable idling – No need to pay a lot of money for a new adsorber and its valve I think the system is quite useful, personally I was often annoyed – when the carbureted car stank of gasoline, from wherever you can. You could get a headache because of this system, it avoids that, it saves a little bit of fuel and it doesn’t pollute the atmosphere.

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