Car gas tank: device
Auto Terms,  Car device,  Engine unit

Car gas tank: device

When a buyer chooses an electric car, the first thing he pays attention to is the range, which is indicated in the technical literature. This parameter depends on the battery capacity and the technical features of the vehicle's power plant. Often, such a car is capable of covering at least several tens of kilometers. The maximum that the automaker of budget models offers is a couple of hundred kilometers on a single charge.

In this respect, vehicles powered by liquid or gaseous fuels have a significant advantage. Depending on the type of engine, the weight of the car and other parameters, the car can travel up to a thousand kilometers. But one element that is part of the car's fuel system (read about the types of vehicle devices here), has a key effect on this parameter. This is a fuel tank.

Let us consider what is the peculiarity of this seemingly simple machine detail. What materials can it be made of, what is the device of this element in modern cars and common breakdowns.

What is a car fuel tank

A fuel tank is a container specially designed for a specific car model. It is an integral part of the fuel system. Without it, no matter how serviceable the power unit is, it will not be able to work. In older cars, the gas tank was just a tank with a specific volume.

Car gas tank: device

In modern cars, it is a whole system, which can include a large number of additional elements. An example of this is the adsorber system (read more about it separately).

One tank is enough for a car. Trucks often have two gas tanks. This is due not only to the gluttony of the power unit, but also to the need to reduce visits to gas stations, since not every gas station is adapted for servicing large vehicles.

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As the name suggests, the part is designed to store fuel. Thanks to this, the car is able to cover long distances. In addition to this main purpose, the gas tank provides the following action:

  1. Prevents fuel vapors from entering the environment. This allows the vehicle to meet high environmental standards. Plus, near a modern car, even with a full gas station, you can not hear the smell of gasoline.
  2. Prevents fuel leakage during vehicle operation.

This tank is designed so that the car can cover about 500 kilometers. Since each engine has its own consumption, the size of the gas tank will adjust to this parameter. Compared to a gasoline power unit, a diesel engine consumes significantly less fuel (why this is so, it is described here), so its tank may be smaller.

Types of fuel tanks

Regardless of the type of fuel tank, its task does not change: it must provide maximum fuel safety. For this reason, it is hermetically sealed, but ventilation is no less important for it, since evaporating gasoline is able to raise the pressure in the line, which can harm some parts of the car's fuel system.

Gas tanks differ from each other in material of manufacture, shape and volume. We'll talk about materials a little later. As for the shape, it depends on the design of the car. The lower part of the part is in most cases flat, and the upper part follows the contours of the bottom and parts located under it.

Car gas tank: device

As we have already discussed, the volume of the tank also depends on the type of motor and its gluttony. Car manufacturers always strive to achieve the perfect balance between vehicle performance and weight when developing car models.

If the fuel tank in the car is very large, then when the gas tank is full, the car will behave as if it is carrying excess weight, which, in fact, is when the gas tank is full. This directly affects the car's handling and fuel consumption (a loaded car requires more fuel in order for the engine to continue to provide the necessary dynamism).

In total, there are three categories of gas tanks:

  1. For small cars. Citikars are always equipped with low-power ICEs with a small volume. Usually, the fuel consumption and weight of such cars is low, so the power unit does not need a large supply of fuel. Usually the volume of this tank does not exceed thirty liters.
  2. For passenger cars. In this case, the volume of the tank can be up to 70 liters. Sometimes there are models with an 80-liter tank, but these are mainly those cars under the hood of which there is a motor with a decent volume. The key factor on the basis of which the volume of the gas tank for a particular car is selected is how far the car will be able to cover without refueling (the minimum indicator should be 400 kilometers).
  3. For trucks. This is a separate category of transport, since depending on the operating conditions (for example, the transportation of heavy loads in mountainous regions), the consumption of diesel fuel for such vehicles can be much higher than that declared by the manufacturer. For this reason, many truck models are equipped with two fuel tanks. Their total volume can be up to 500 liters.
Car gas tank: device

Fuel tank material

In addition to ensuring uninterrupted autonomous operation of the internal combustion engine due to the fuel reserve, gas tanks differ in the material of manufacture. Moreover, this parameter depends not so much on the desire of the motorist as on the safety requirements for the operation of vehicles.

These elements of the fuel system are made from:

  • Plastics. This material is suitable for both diesel and gasoline vehicles. Since plastic is lighter than metal counterparts, it is widely used in modern automotive industry. During the manufacture of the part, a special material is used that is chemically neutral to gasoline and diesel fuel. Also, the product can withstand minor mechanical stress (the car “sat down” on the bottom in the mud), so that the tank is not damaged by minor impacts, but in comparison with the same metal counterparts, it is less durable.
  • Aluminum. This material is used in the manufacture of tanks intended for cars, under the hood of which there is a gasoline engine. But some diesel cars can also be equipped with such gas tanks. Aluminum does not rust, therefore it does not need additional protection from moisture. It is also lighter than its steel counterpart. The only drawback is the expensive breakdown repair.
  • Become. Since this metal has a large weight and high strength, such modifications of containers are most often found on trucks. If the car is equipped with HBO (about what it is, read here), then the gas storage tank will necessarily be made of steel. The reason is that the fuel for the machine must be in the tank under high pressure.
Car gas tank: device

Products are made from a solid sheet of metal, which is processed by stamping and then welding of joints. Due to the minimum number of seams, such a tank will provide maximum protection against fuel leaks. Since neither aluminum nor plastic is able to withstand such pressure, they are not used for the production of LPG tanks.

Vehicle fuel tank device

As we have seen, there is no single shape for a gas tank. It all depends on the structural features of the car body, in particular the bottom and structural elements located in the rear axle area (in the case of light vehicles) or between the axles (in the case of trucks).

Usually, the geometry of these parts is quite complex, since the upper part of the product must exactly repeat the shapes of adjacent parts. In this case, the tank must be positioned so that it is not the lowest part of the car, which excludes the breakdown of the element when it hits the ground. The easiest way to shape is a plastic part, which is why such modifications are often found in modern cars.

The gas tank device includes the following elements:

  • Filler neck;
  • Fuel line;
  • Ventilation outlet;
  • Drainer;
  • Fuel level control elements;
  • Adjacent devices that ensure the efficiency of the fuel system.

Depending on the car model, there may be a fuel pump inside the fuel tank (mainly for injection vehicles), a float and a fuel level sensor. Although the fuel pump does not belong to the gas tank device, the design of many models implies the installation of this mechanism inside it. If the machine is equipped with an adsorber (for modern models the presence of this system is mandatory), then the system will necessarily be associated with tank ventilation. The tank will also have a special valve that regulates the pressure so that it is at atmospheric level.

The operation of the fuel pump leads to the fact that the fuel level in the tank drops, and at the same time a vacuum is formed. If the tank were hermetically sealed, the vacuum in it would gradually increase the load on the fuel pump, and it would quickly fail. The increase in pressure in the tank occurs due to the fact that the valve passes atmospheric air into the tank when the car is started.

Car gas tank: device

But when the power unit is not working and the car is idle for a long time, the process of gasoline evaporation occurs. This increases the pressure in the tank. To keep it at atmospheric level, there is a special valve. We will talk a little more about this system later.

The availability of certain parts depends on the type of vehicle. Let's consider some elements of the gas tank in more detail.

Installation site and insulation

The gas tank is a reservoir that is often installed under the bottom in the area of ​​the rear axle in passenger cars. This arrangement minimizes its damage due to impacts when the car overcomes difficult sections of the road with potholes and bumps (this is often found on rough terrain), because the front of the car is already seriously loaded due to the engine. In this case, the container is not placed closer to the trunk, so that when it hits the back of the car, the deformation of the tank or its breakdown does not cause an explosion as a result of an accident.

Car gas tank: device

To secure the element to the body, the automaker uses long strap clamps to pull the reservoir from underneath the vehicle. Usually, an exhaust pipe passes next to the gas tank (about what device the car's exhaust system has, it is described in another review). To prevent the fuel from heating up in it, the pipe is insulated with thermal insulation materials.

The filler neck extends to one side of the machine. For this, the vehicle body has a corresponding opening with a small hatch. In modern cars, the filler door can be equipped with a lock that can be opened from the passenger compartment or with a separate key.

On one side, a fuel line is connected to the tank. Through this line, the fuel is supplied to the actuators, which mix gasoline (or diesel fuel) with air and supply it to the working cylinders of the power unit.

Some car models are equipped with a gas tank protection. Basically it is a metal plate. A steel tank guard is not required for a conventional vehicle. Basically, such protection is installed on vehicles that are designed to drive over rough terrain with difficult road surfaces.

Car gas tank: device

For trucks, the fuel tank will mostly be located behind the front axle, but not under the bottom, and it is mounted on the side of the frame. The reason is that most often such cars, when they get into an accident, receive mainly frontal rather than lateral damage. It is forbidden to change the location of the gas tank during the tuning process.

Filler neck

As the name suggests, this element is used to fill the car with fuel. Depending on the car model, this hole will be located on the rear fender on the left or right side of the body. True, this applies to passenger cars. Some minivans have a filler neck near the front fender.

Automakers often install the tank so that the filler neck is on the driver's side. So, according to many experts, there is less chance that the filler pistol will remain in the car after refueling, and an inattentive motorist will forget to put it back on the filling module.

Car gas tank: device

The design of this element may also differ in different car models. So, in some gas tanks it is part of the design, but there are also modifications that are connected to the main tank using a filler hose. The filling speed depends on the section of this element.

Most modern tanks are equipped with special protective elements that prevent foreign elements from entering the tank. Also, the device of the latest modifications of fuel tanks includes a system that prevents the leakage of gasoline when the car rolls over (gasoline is a flammable substance, therefore, cars running on this type of fuel are equipped with this system).

Depending on the car model, the neck is twisted with a stopper, which can be equipped with a locking mechanism (opens with a code or a separate key). In older cars, this element is simply a threaded plug. For greater protection, the filler neck is closed with a small hatch (additionally performs an aesthetic function), which can be opened either with a key or with a handle from the passenger compartment.

Fuel lines

A fuel line is used to ensure that the fuel flows freely from the tank into the engine. In the area of ​​connection to the tank, this line is represented by flexible hoses. Although they are more likely to be damaged than their metal counterparts, flexible elements are easier to install and maintain. In the interval from the gas tank to the high pressure fuel pump (for more details about its structure and principle of operation, read separately) in the line, the fuel is supplied under low pressure, therefore, ordinary fuel hoses secured with clamps are sufficient.

Car gas tank: device

If the car uses a battery-type fuel system (for example, CommonRail, which is described here), then after the high-pressure fuel pump the pipeline is rigid, since in this part the fuel is under high pressure. So that the excessive pressure does not damage the elements of the vehicle, the rail is equipped with a pressure regulator (for how it works, read in another article). This valve is connected to the gas tank with a flexible hose. This part of the fuel line is called the return line. By the way, some carburetor engines may have a similar device.

To get to the fuel line connection to the gas tank, in many cars, the rear sofa (its seat) must be raised. There is a technical opening of the tank under it, into which a structure with a fuel pump, a hard filter and a float with a level sensor is inserted.

Fuel level control sensor in the tank

This element is part of the structure to which the fuel pump is attached (applies to gasoline engines). In diesel engines, the float with a sensor has an individual design, and they are located separately from the fuel pump. The fuel level sensor has a simple design. It consists of a potentiometer (mini analogue of a rheostat) and a float.

The principle of operation of the device is as follows. The float is rigidly fixed to the potentiometer rod. Due to the hollow structure filled with air, this element is always on the surface of the fuel. On the other part of the metal rod, the contacts of the electronic element are located. Gradually, the level in the tank decreases, due to which the sensor contacts come closer.

Depending on the set distance, at a certain moment they close, and a low-level light in the gas tank lights up on the dashboard. Usually this parameter is at the level of about 5 liters, but it all depends on the car model (in some cars, the level may not drop so much - only up to 7-8 liters, and the light comes on).

You should not constantly drive with a low fuel level, especially if a gas pump is installed in the gas tank. The reason is that the supercharger heats up during operation, and because of the closed space, the only thing that cools it is fuel. If the level in the tank is always minimal (at seven liters, some cars are able to cover a decent distance - about 100 km.), There is a high probability that the pump will burn out.

Car gas tank: device

So that the driver can determine in advance how much fuel is in the tank, the rheostat is connected to the fuel arrow on the dashboard. When the fuel level drops, the other contacts of the device move apart, which reduces the voltage in the sensor's electrical circuit. Due to a decrease in voltage, the arrow on the tidy deviates in the direction of decreasing readings.

Fuel tank ventilation system

As already mentioned, the pressure in the gas tank is constantly changing. And this does not depend on whether the engine is running or the car is just standing still. When the engine is running, the level in the reservoir drops, which creates a vacuum in it. If the container were to be closed tightly, after some time the pump would be subjected to critical load and would fail.

On the other hand, with a long idle car, gasoline vapors would gradually increase the pressure in the tank, which would sooner or later lead to depressurization. In this case, the damage cannot be predicted in any way, because the tank will rupture at the weakest point, and it will not necessarily be a seam. This is especially true in hot regions in summer. Due to the high ambient temperature, gasoline in the tank heats up and evaporates more actively than in winter.

To prevent both situations, the fuel tanks are equipped with a ventilation system. In modern cars, this system works in conjunction with an adsorber, which captures micro-particles of gasoline and retains them in the tank, but the tank continues to "breathe".

A pressure valve is installed to increase the pressure in the tank. It opens when a vacuum forms in the cavity. Due to this, atmospheric air penetrates inside, which facilitates the operation of the fuel pump.

Car gas tank: device

On the other hand, when the car is refueled, gasoline begins to actively evaporate. To prevent the tank from bursting, it has a separate pipeline that provides ventilation. A gravity valve is installed at the end of the ventilation tube. It prevents fuel spills when the car rolls over.

In modern cars, this gas tank system can be equipped with additional equipment, with the help of which there is a better control of the pressure and temperature of the internal environment.

Malfunctions and defects

The design of the gas tank itself is durable and product breakdowns are not common. Despite this, some motorists had to deal with premature replacement or repair of the fuel tank. The main breakdowns of gas tanks include the following:

  • Natural wear of the tank walls due to the aggressive effects of the fuel. Most often this applies to metal containers.
  • A hole in the wall of the product. Occurs when carelessly driving on difficult roads. This often happens when driving over rough terrain with a large number of overall sharp stones sticking out of the ground.
  • Dents. Such damage most often also occurs when the bottom hits the ground. But sometimes this can happen due to a breakdown of the ventilation system (a vacuum forms in the tank, but the pump continues to cope with its task).
  • Corrosion. In places of damage, the walls of the vessel become thin. At the moment when the damaged area cannot cope with the vapor pressure or vacuum, a fistula is formed and fuel begins to seep. In some cases, corrosion damages the top of the product, which is not easy to diagnose. But in the event of such damage, there will be a constant smell of gasoline near the car.
  • Depressurization of the container at the place of soldering. This usually happens due to a factory defect - either a poorly welded seam, or it was poorly treated with an anti-corrosion agent (applies to steel products).
  • Breakage of the thread. At the filler neck, this happens exclusively due to factory defects, but extremely rarely. Typically, the thread breaks off at the installation site of the fuel level sensor and the fuel pump. This part of the car is rarely serviced, which is why the bolts rust from old age. When a craftsman tries to unscrew them to replace a failed element, often great efforts lead to the breakdown of the stud or nut thread.
  • Natural wear of the seals. Typically, these elements are installed at the installation site of the fuel pump structure and level sensor. Over time, the rubber material loses its properties. For this reason, it is recommended to replace the rubber seal when servicing the fuel pump.

If one of the listed damage is found, it is recommended to replace the fuel tank with a new one. But in many cases the product can be repaired.

Refurbishment of the fuel tank

The gas tank can be repaired if it is not significantly damaged. Deformation in many cases is not eliminated, since, depending on the degree of damage, it only affects the volume of the vessel. But this defect can be eliminated by pulling. In some cases, the walls cannot be bent without cutting them. After such repairs, soldering or welding is required.

Car gas tank: device

You should not try to carry out such work on your own, especially for gasoline tanks. Gasoline vapors are difficult to remove from the container. Sometimes it happens that after several rinsing and drying procedures, the tank still explodes with strong heat (this happens during the welding of the walls). For this reason, it is better to leave the repair work to a professional who knows the intricacies of how to prepare a product for repair. In short, in no case should welding be performed with an empty tank. Usually it is washed well and filled with water. After completing the work, the water is drained, and the tank itself dries well.

The repair of holes is usually solved by applying a patch. Some motorists use adhesives such as two-component "cold welds", but this is already in extreme poverty. It is better to use this method if a hole has formed on the road, and the nearest service station is still far away.

How to choose a fuel tank

Finding a new fuel tank is usually straightforward. Since this product is adjusted to the parameters of the car, then the search must be carried out, starting from the transport model. Only in this case can an identical replacement be selected. If the spare part code is known (indicated on the tank itself), then this is an ideal search option. In the absence of this information, the VIN code comes to the rescue (about where it is located and what information about the car it contains, read here).

If the search is performed by a seller of auto parts, then he just needs to name the car model and year of manufacture. When looking for a part in an online store, it is better to use both the wine code and detailed information about the car. In this case, there is less chance of buying the wrong product.

It is best to buy an original gas tank. But some companies sell analogues of good quality. Among such companies are the Danish company Klokkerholm and the Chinese brand Sailing. While the Chinese manufacturer has gotten a bad reputation for the quality of the auto parts it sells, this is not the case for their gas tanks. You should not buy a cheap product - you will not be able to save money, since after a couple of years a low-quality product will deteriorate, and it will still need to be changed.

So, despite the simple device and purpose, the gas tank plays an important role in the comfortable operation of the vehicle. Like other elements of the fuel system, without it, the car will not be able to cover long distances.

In conclusion, we suggest watching a short video on how you can remove dirt from the gas tank:

How do I clean a very dirty fuel tank?

Questions and answers:

What's in the fuel tank? Depending on the car model, the fuel tank includes: a diesel fuel heater, a fuel pump, a gasoline level sensor, an adsorber system (collects and cleans gasoline vapors).

How does a car's fuel tank work? The gas tank consists of: a filler neck, the container itself (tank), a fuel intake tube, a drain hole with a plug, a fuel level sensor, and a ventilation tube.

Where is the gas tank located? The shape of the fuel tank depends on the design of the car - the most practical location is chosen. Basically, it is located in front of the rear beam under the bottom.

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