(Note) ¹ Saving the filling volume LPG car fuel tanks (85%)

To store the fuel supplied to the engine, a special reservoir is provided in the design of each car - a fuel tank. It is a sealed container and, depending on the features of the machine model, may differ in shape, material of manufacture and volume. In automotive practice, the fuel tank is used for liquid fuels (gasoline, diesel) and gas.

Features of the location of the tank in the car

For each category of vehicles, optimal configurations of fuel tanks are developed, and the most rational location of the tank in the overall design is selected. So, for example, in passenger cars the tank is located at the rear under the seat (in front of rear axle), since this zone is the most protected in a collision.

IN trucks fuel tanks (one or more) are most often installed between the front and rear axles on the sides of the frame. This is due to the fact that for this category of cars the most common accidents with a frontal collision. If the car has been “tuned”, its fuel tank can be moved to an arbitrary location, but in some cases this may threaten the owner with a fine.

Since the fuel tank is often located near the exhaust system, special heat shields are used to prevent it from heating up.

Types of fuel tanks and materials of manufacture

The main requirement for fuel tanks is the high tightness of the container, which prevents the leakage of fuel (or its vapors) into the environment. This ensures the safety of operation and the economy of fuel consumption in general.

For the manufacture of gas tanks, the following types of materials are used:

• Steel - used mainly in trucks, as well as in gas systems;
• Aluminum - used in gasoline-powered vehicles;
• Plastic is the most popular material because it is suitable for all types of fuel.

A sufficient amount of fuel reserve ensures uninterrupted engine operation and a longer interval of autonomous driving. Modern automotive industry standards provide for such a volume of capacity that would allow moving at least 400 km without refueling. On the other hand, if the tank is too large, this increases the weight of the machine and complicates its design.

The volume of the fuel tank can be conditionally divided into nominal (indicated in the vehicle documentation) and real (when filling under the neck). The actual capacity of the fuel tanks, depending on the model, may exceed the nominal capacity by 2 to 17 liters. The volume of a gas tank for passenger cars, on average, ranges from 50 to 70 liters. Some very powerful models have a tank volume of up to 80 liters, while small cars are equipped with tanks of only 30 liters. Trucks can have a fuel reserve of 170 to 500 liters.

Design of modern fuel tanks

There is no single form for the fuel tank of a car. To achieve the maximum volume of fuel tanks without sacrificing their compactness, they are given a complex geometry, which can vary not only depending on the make and model of the car, but also on the configuration of a particular car.

In metal containers, a complex shape is achieved through stamping sheet metal and sealed welded joints. Plastic tanks are molded under high temperature and pressure.

The main components of the gas tank

In spite of different shape, the design of most modern gas tanks has common details:

• Filler neck - has access to the outer part of the body and is designed for filling fuel. Most often located on the driver's side (above the rear wing of the body). In most vehicles, the fuel filler has a special sealed screw cap to prevent fuel from escaping and dust from entering. However, some modern cars do not have such a cover. It has been replaced by the Easy Fuel system, a small electrically operated sunroof that opens and closes the gas tank.
• Body or walls (directly container).
• Fuel intake pipe - equipped with a filter to prevent the ingress of contaminants. On modern passenger cars, this function is performed by a submersible module. It is equipped with an additional removable filter (mesh).
• Drain hole (normally closed with a plug) - used when it is necessary to urgently drain the fuel.
• Fuel level sensor with a float - designed to measure the amount of fuel.
• Ventilation tube.

The device and principle of operation of the ventilation system

Special attention when considering design features and devices of the automobile fuel tank should be given to the ventilation system. It allows you to solve several important tasks at once:

• Removal of excess air that gets inside when refueling.
• Maintaining the pressure inside the tank at atmospheric level, which is necessary for normal operation in general. Since the tank is as tight as possible, a vacuum is created during fuel exhaustion, which can lead to deformation and rupture of the hull.
• Cooling the tank and maintaining a safe temperature.

Modern cars, as a rule, are equipped with closed ventilation systems. This design does not have a direct exit from the fuel tank to the atmosphere and is equipped with a number of devices designed for air intake and vapor extraction. Air intake is carried out using check valve fuel tank ventilation. As soon as the vacuum builds up, under the action of internal pressure, the valve spring is pressed out and air enters. This happens until atmospheric pressure is established inside the tank.

To remove fuel vapors from the tank, a ventilation pipeline (steam pipeline) is provided through which the vapors enter. In it they condense and accumulate. When the canister fills, the purge system is activated, supplying condensed fuel to intake manifold for further processing.

The service life of the fuel tank largely depends on the operating conditions and the quality of the fuel. Like any vehicle component, it requires appropriate after-sales service. First of all, this includes flushing the tank and removing contaminants. When flushing, do not use special cleaning additives that can adversely affect the main elements fuel system, and in some cases lead to the destruction and depressurization of the housing.

Limits the maximum volume of fuel tanks transport units. If the capacity of the fuel tanks Vehicle exceeds the maximum values ​​specified in ADR, these fuel tanks are considered dangerous goods. In this case, the amount of fuel in the fuel tanks does not play any role.

The capacity of fuel tanks is limited by subparagraph 1.1.3.3 a) of ADR. According to the requirements of this paragraph, the total capacity of built-in fuel tanks must not exceed 1500 liters per transport unit, and the capacity of the tank mounted on a trailer must not exceed 500 liters. At the same time, the capacity of both fuel tanks directly connected to the vehicle engine and fuel tanks connected to auxiliary equipment are taken into account.

Note . Transport unit - a combination consisting of a motor vehicle and a trailer coupled to it, or only a motor vehicle to which a trailer is not coupled.

Vehicle manufacturers often do not install such large tanks.

In practice, there are cases when a tractor with a fuel tank of 1500 liters tows a refrigerated semi-trailer with a tank of 200 liters. In this case, the total capacity of the fuel tanks installed on the transport unit is 1700 liters and the liquid fuel tanks are considered dangerous goods.

When transporting dangerous goods, the requirements of ADR must be met. However, in the considered case, it is unlikely that it will be possible to fulfill the requirements of ADR. There are two possible evaluations for road control.

1. Since the capacity of one of the fuel tanks exceeds 1000 liters, the carriage can be regarded as the carriage of dangerous goods in an integral tank. Consequently:

• the driver must undergo special training in the transport of dangerous goods in tanks;
• written instructions, transport document and certificate of approval of vehicles for the carriage of certain dangerous goods;
• all additional equipment, vehicles carrying dangerous goods, etc.

In this case, the regulatory authorities may prohibit the further movement of the vehicle.

2. It may be considered that the requirements of ADR do not apply to fuel contained in a fuel tank with a capacity of 1500 liters. Then only the fuel in the 200 liter refrigerated fuel tank will be considered as a case of transport of dangerous goods in packagings that have not passed the test and are not approved for the transport of dangerous goods. Such transportation must be carried out in compliance with the requirements of subsection 1.1.3.6 of ADR.

In this case, the regulatory authorities may also prohibit the further movement of the vehicle.

Thus, the carriage of any cargo on such a transport unit and its movement on public roads will constantly be associated with the risk of fines. Pay attention to volume of fuel tanks when buying vehicles.

It would seem that there can be nothing tricky inside the fuel tank - after all, it is just a container for gasoline or diesel fuel, perhaps especially durable and resistant to hydrocarbons. But it seems so only at first glance

The fuel tank has a shape determined by the design of the vehicle. Often it, being a single volume, is, in fact, two connected containers. For what? The fuel supply is a significant load for a car, approximately equal to the weight of one passenger, which is a lot. Of course, this "passenger" is modest in urban minicars: their tanks have a volume of 35-40 liters. For mid-size sedans and hatchbacks, the tank capacity is 45-60 liters, for heavy SUVs - 75-90 liters, for commercial vans- 90-120 liters, and for mainline tractors - already 300-600 liters.

Half full or empty?

Tank placement is a challenging task for engineers. After all, you have to take into account the load on the car, which, when refueling under a traffic jam, can fall on one side. You have to somehow divide the tank, turning it into a kind of butterfly in shape. Well, or positioned so that even when fully refueled, other devices compensate for the load on one of the sides. When choosing the location of the tank, the risk of damage in a collision is also taken into account.

The capacity of the tank is a conditional value, it is impossible to fill it up to the stop, there will be some air left in it. When the car rolls, fuel can overflow from side to side, and this is fraught with a dangerous situation. We all know from the theoretical course of a driving school which of the tankers is more prone to capsizing: filled to the top or half empty. A significant mass of fuel, moving inside the tank, can also upset the balance of the machine. How do they deal with it? Partitions are made inside the tank to prevent overflow - their dimensions and location are carefully calculated.

Each tank is equipped with a ventilation system. In the heat, the fuel tends to evaporate, and the increased vapor pressure can even break the tank. And when gasoline or diesel fuel is produced, the pressure in the tank drops - it can flatten. The ventilation system not only prevents this, but also traps fuel vapors, preventing them from escaping into the atmosphere. Special valve prevents fuel spillage when the vehicle rolls over or leans heavily.

In modern tanks, as a rule, an electric fuel pump module is also built in. Important to remember: pumps for modern systems car power supplies do not like to work “dry”, because of this they quickly fail. Therefore, do not let the fuel run out completely, try to refuel as soon as the reserve light comes on, because fuel pump It's not cheap, and the cost of replacing it...

Do you smell?

In most cases, access to the pump module is possible from the passenger compartment passenger car(often with removed or raised back seat). But it happens that you have to remove the entire tank from the car, and this is almost impossible without a lift or a garage pit. However, sometimes the pump works properly, but the tank still needs to be dismantled due to damage. How so, you ask, because it is very durable? It's true, but ... A bad head can break even more.

In my practice, there were three significant cases. In the first, the owner of the “middle-aged” already foreign car complained about the rattle from under the bottom while driving. It seemed to her that the muffler sagged and touched the asphalt. Having looked under the bottom with a flashlight, I found that one of the steel bands on which the fuel tank hung had burst from old age and corrosion! Naturally, it was impossible to fix the malfunction on the street, and we drove slowly and carefully to the nearest service. Fortunately, we were able to repair the damaged tape, rather than looking for a new one.

Another situation: once in the country, I felt a strong smell of gasoline emanating from the car. It was a wake-up call: it shouldn't smell like that. Looking under the bottom, I saw that fuel was actively dripping from a hole in the bottom of the tank. Broke? No, it looks like someone was trying to drain the gasoline in my absence: the hole was like a chisel, a random stone “caught” on the highway will not leave such. Then it was possible to “turn” the hole a little, drain the remaining fuel, remove the fuel intake, get into the tank with a hand and close the hole with a “sandwich” of a bolt with a nut and four washers (two steel and two rubber). "Sandwich", I must say, served for several years.

But in the third case, the tank of the SUV was pierced in "combat" conditions, and despite the fact that it was covered from below with reliable steel protection. Removing it showed that gasoline was leaking from under the rivet, which apparently secures the internal partition. No one undertook to weld the place of damage: the craftsmen are afraid to approach gas tanks with a welding machine, even if the tank has lain empty or filled with water for a week (everyone is well aware of the consequences of an explosion of fuel vapors). A new tank, even without fuel equipment, pulls on 30 40 thousand rubles. It was possible to manage at lower costs: the damage was sealed with the composition " cold welding».

sledgehammer strike

Fuel tanks are made of steel, aluminum or special plastic (polyethylene). How durable is plastic? I learned about this from the story of an employee of the UAZ plant. When a single 68-liter tank was developed for the Patriot instead of two 36-liter tanks located on the sides, multilayer plastic was proposed as a material. The commission that accepted the sample doubted its strength. One of its representatives was offered a sledgehammer: they say, hit with all your might and see what happens. He hit - and the sledgehammer rebounded, almost injuring him. Buck was unharmed.

Why do we stand up for the strength of the tank so much? That's right, we are afraid of an explosion of fuel in case of damage. But it is not so much an explosion that is dangerous, but a spill of the same gasoline and a large burning area, because it is not gasoline that burns, but its vapors. In addition, they are very difficult to extinguish. The same applies to diesel fuel: its vapors do not flare up as readily as gasoline ones, but it is even more difficult to extinguish spilled diesel fuel.

Which board to drive up to the column at the gas station? The filler neck can be located either on the right or on the left, this is indicated by a small arrow near the gas station symbol on the instrument panel (although sometimes it is not there). Cars with a tank mouth on the left, I call professional for myself, the rest are designed for white-handed women and tanker services.

Do not forget to close the neck cover and lock the hatch. Cases of fuel drain by intruders are still not uncommon. Although sometimes the tank is so cleverly arranged that it is problematic to pump out fuel. So you can’t help a friend in a difficult situation.

Refueling "pistols" of diesel dispensers have different size. The larger ones are designed for the filler necks of heavy trucks. The necks of some pickups can also have a similar diameter, then refueling under a cork on a cargo column will last a matter of seconds, which is convenient in cold winters. And in commercial vans, on the contrary, there are "passenger" necks - such a paradox.

Interesting fact fuel containers such as airfield tankers can be reported. They have a special device called Dead Man's Switch. When filling the tank at the oil depot, the driver or foreman is obliged to manually interrupt the fuel supply every few minutes, then start it again. This is done so that the system “understands”: the filling is under the control of a person, he is alive, everything is in order with him. If you do not interrupt the filling in time, it will be turned off automatically.

We decided to conduct this experiment due to periodic complaints from car owners about gas stations, which supposedly do not add fuel to the tank and write in social networks that they filled more than the volume of the tank at the gas station.

The rationale for this is filling an almost empty tank with more fuel than indicated in the car's owner's manual.

We delved into the design of the car and found technological prerequisites that explain the different real and documentary (in the performance characteristics of a car) fuel tank volumes. Now we decided to confirm our arguments and set off with five different cars at the filling stations of one of the major fuel market operators.

The test involved two vehicles with diesel engines– Citroën Grand C4 Picasso and Renault Duster and three gasoline cars– Volkswagen Bora, Skoda Octavia A5 and Ford Mondeo. All five cars arrived at the place of the experiment with a minimum amount of fuel left in the tank.

Test preparation

Before starting refueling, we asked the filling station workers to check the accuracy of the filling station. To do this, all gas stations have a special 20-liter measuring container with a high-precision graduation of the neck, which allows you to determine underfilling or overfilling with an accuracy of 20 ml.

After “wetting” the measuring container (mandatory procedure), 20 liters of fuel were poured into it. Mernik confirmed that the column was pouring accurately, after which we began to refuel our cars.

Refueling result

The main condition for refueling the aforementioned cars was filling the tank with fuel right up to the neck, i.e. we have already seen that the fuel is at the very top of the neck. Looking ahead, we note that, in fact, more fuel is placed in the tanks of all 5 vehicles than indicated in the performance characteristics (in one case, by as much as 17 liters!).

Filled first Citroën Grand C4 Picasso. With a 55-liter tank (according to performance characteristics) and a residual one division of the electronic fuel level sensor, 51 liters of diesel fuel were poured into the tank. Excess - 2-4 liters.

Renault Duster in his almost empty tank, he held 62 liters of fuel with factory data of only 50 liters. Excess - 15-17 * l.

In the car VW Bora poured a little more than 52 liters of gasoline with factory data of 55 liters. Taking into account the remainder, the excess of performance characteristics may reach 3-5* l.

Real tank volume Skoda Octavia A5 significantly exceeded the data stated in the performance characteristics. 62 liters were poured into it at a rate of 55 liters. Excess - 12-14 * l

In a 70 liter tank Ford Mondeo with a residual mileage of 26 km fit almost 71 liters of gasoline. Those. real volume excess is 8-9* l.

The results of this test confirmed our theoretical conclusions: the actual volume of the fuel tank differs from that specified by the automaker within significant limits ( from one to 10 or more liters).

So drivers should keep in mind: if you were filled with a few liters more than you expected at the gas station, this is not a reason for a scandal. This is most likely a feature of your fuel tank.

*Including unaccounted for 4-5 liters of fuel below the gas tank float

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