Fuel tank

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A fuel tank (also called a petrol tank or gas tank) is a safe container for flammable fluids, often gasoline or diesel fuel. Though any storage tank for fuel may be so called, the term is typically applied to part of an engine system in which the fuel is stored and propelled (fuel pump) or released (pressurized gas) into an engine. Fuel tanks range in size and complexity from the small plastic tank of a butane lighter to the multi-chambered cryogenic Space Shuttle external tank.


The fuel tanks for B-25 bombers B-25 bomb bay gas tanks.jpg
The fuel tanks for B-25 bombers
Fill caps on a BMW automobile for hydrogen (left) and for gasoline (right) fuel tanks Wasserstoffeinfullstutzen eines BMW.jpg
Fill caps on a BMW automobile for hydrogen (left) and for gasoline (right) fuel tanks


Typically, a fuel tank must allow or provide the following:

Plastic (high-density polyethylene HDPE) as a fuel tank material of construction, while functionally viable in the short term, has a long term potential to become saturated as fuels such as diesel and gasoline permeate the HDPE material.

Considering the inertia and kinetic energy of fuel in a plastic tank being transported by a vehicle, environmental stress cracking is a definite potential. The flammability of fuel makes stress cracking a possible cause of catastrophic failure. Emergencies aside, HDPE plastic is suitable for short term storage of diesel and gasoline. In the U.S., Underwriters Laboratories approved (UL 142) tanks would be a minimum design consideration.

Fuel tank construction

Fuel tank for the Apollo Lunar Module, 1960s Apollo Lunar Module Fuel Tank.jpg
Fuel tank for the Apollo Lunar Module, 1960s

While most tanks are manufactured, some fuel tanks are still fabricated by metal craftsmen or hand-made in the case of bladder-style tanks. These include custom and restoration tanks for automotive, aircraft, motorcycles, boats and even tractors. Construction of fuel tanks follows a series of specific steps. The craftsman generally creates a mockup to determine the accurate size and shape of the tank, usually out of foam board. Next, design issues that affect the structure of the tank are addressed - such as where the outlet, drain, fluid level indicator, seams, and baffles go. Then the craftsmen must determine the thickness, temper and alloy of the sheet he will use to make the tank. After the sheet is cut to the shapes needed, various pieces are bent to create the basic shell and/or ends and baffles for the tank. Many fuel tanks' baffles (particularly in aircraft and racecars) contain lightening holes. These flanged holes serve two purposes, they reduce the weight of the tank while adding strength to the baffles. Toward the end of construction, openings are added for the filler neck, fuel pickup, drain, and fuel-level sending unit. Sometimes these holes are created on the flat shell, other times they are added at the end of the fabrication process. Baffles and ends can be riveted into place. The heads of the rivets are frequently brazed or soldered to prevent tank leaks. Ends can then be hemmed in and soldered, or flanged and brazed (and/or sealed with an epoxy-type sealant) or the ends can be flanged and then welded. Once the soldering, brazing or welding is complete, the fuel tank is leak-tested. [1]

In the aerospace industry, the use of Fuel Tank Sealants is a common application for high temperature integral fuel tanks. This provides excellent resistance to fluids such as water, alcohols, synthetic oils and petroleum-based hydraulic fluids. [2]

Automotive fuel tanks

Metal fuel tank for a 1996 Opel Blazer Opel Blazer 1996 Fuel Tank.jpg
Metal fuel tank for a 1996 Opel Blazer
Fuel cell for a 1998-2001 Porsche GT3 Cup racing car Porsche GT3 trunk (front) (6293634244).jpg
Fuel cell for a 1998-2001 Porsche GT3 Cup racing car

Passenger vehicles

A larger fuel-tank results in a greater range for the car between refills, however the weight and space requirements of a larger tank are undesirable, especially in smaller cars. The average fuel tank capacity for cars is 50–60 L (12–16 US gal). [3]

The most common materials for fuel tanks are metal or plastic. Metal (steel or aluminium) fuel tanks are usually built by welding stamped sheetmetal parts together. Plastic fuel tanks usually built using blow molding, which allows more complex shapes to be used.

Some vehicles include a smaller reserve tank to be used when the main fuel tank is empty. Some other vehicles, typically 4WD vehicles, have a large secondary tank (or "sub-tank") to increase the range of the vehicle.

Racing fuel cell

A racing fuel cell has a rigid outer shell and flexible inner lining to minimize the potential for punctures in the event of a collision or other mishap resulting in serious damage to the vehicle. It is filled with an open-cell foam core to prevent explosion of vapor in the empty portion of the tank and to minimize sloshing of fuel during competition that may unbalance the vehicle or cause inadequate fuel delivery to the motor (fuel starvation). [4]


Layout of a modern airliner's main fuel tanks Jet-liner's main fuel tanks.PNG
Layout of a modern airliner's main fuel tanks

Aircraft typically use three types of fuel tanks: integral, rigid removable, and bladder.

Fuel tanks have been implicated in aviation disasters, being the cause of the accident or worsening it (fuel tank explosion). [6] [ failed verification ] For example:

In some areas, an aircraft's fuel tank is also referred to as an aircraft fuel cell.

Water supply

Water supply systems can have primary or backup power supplied by diesel-fueled generators fed by a small "day tank" and a much larger bulk storage fuel tank. [9] [10]


Proper design and construction of a fuel tank play a major role in the safety of the system of which the tank is a part. In most cases intact fuel tanks are very safe, as the tank is full of fuel vapour/air mixture that is well above the flammability limits, and thus cannot burn even if an ignition source were present (which is rare).

Bunded oil tanks are used for safely storing domestic heating oil and other hazardous materials. Bunding is often required by insurance companies, rather than single skinned oil storage tanks.

Several systems, such as BattleJacket and rubber bladders, have been developed and deployed for use in protecting (from explosion caused by enemy fire) the fuel tanks of military vehicles in conflict zones. [11]

For stationary fuel tanks, an economical way to protect them from hazards like extremes of temperature and vehicle crashes is to bury them. However, buried tanks are difficult to monitor for leaks. This has led to concern about environmental hazards of underground storage tanks.

See also

Related Research Articles

<span class="mw-page-title-main">Liquid hydrogen</span> Liquid state of the element hydrogen

Liquid hydrogen (H2(l)) is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H2 form.

<span class="mw-page-title-main">Static electricity</span> Imbalance of electric charges within or on the surface of a material

Static electricity is an imbalance of electric charges within or on the surface of a material or between materials. The charge remains until it is able to move away by means of an electric current or electrical discharge. Static electricity is named in contrast with current electricity, where the electric charge flows through an electrical conductor or space, and transmits energy.

An inerting system decreases the probability of combustion of flammable materials stored in a confined space. The most common such system is a fuel tank containing a combustible liquid, such as gasoline, diesel fuel, aviation fuel, jet fuel, or rocket propellant. After being fully filled, and during use, there is a space above the fuel, called the ullage, that contains evaporated fuel mixed with air, which contains the oxygen necessary for combustion. Under the right conditions this mixture can ignite. An inerting system replaces the air with a gas that cannot support combustion, such as nitrogen.

<span class="mw-page-title-main">Flux (metallurgy)</span> Chemical used in metallurgy for cleaning or purifying molten metal

In metallurgy, a flux is a chemical cleaning agent, flowing agent, or purifying agent. Fluxes may have more than one function at a time. They are used in both extractive metallurgy and metal joining.

<span class="mw-page-title-main">Gas cylinder</span> Cylindrical container for storing pressurised gas

A gas cylinder is a pressure vessel for storage and containment of gases at above atmospheric pressure. High-pressure gas cylinders are also called bottles. Inside the cylinder the stored contents may be in a state of compressed gas, vapor over liquid, supercritical fluid, or dissolved in a substrate material, depending on the physical characteristics of the contents. A typical gas cylinder design is elongated, standing upright on a flattened bottom end, with the valve and fitting at the top for connecting to the receiving apparatus.

<span class="mw-page-title-main">Self-sealing fuel tank</span> Fuel container that automatically seals when puctured

A self-sealing fuel tank is a type of fuel tank, typically used in aircraft fuel tanks or fuel bladders, that prevents them from leaking fuel and igniting after being damaged.

<span class="mw-page-title-main">High-density polyethylene</span> Class of polyethylenes

High-density polyethylene (HDPE) or polyethylene high-density (PEHD) is a thermoplastic polymer produced from the monomer ethylene. It is sometimes called "alkathene" or "polythene" when used for HDPE pipes. With a high strength-to-density ratio, HDPE is used in the production of plastic bottles, corrosion-resistant piping, geomembranes and plastic lumber. HDPE is commonly recycled, and has the number "2" as its resin identification code.

<span class="mw-page-title-main">Diesel exhaust fluid</span> Standardized aqueous urea solution for exhaust aftertreatment

Diesel exhaust fluid is a liquid used to reduce the amount of air pollution created by a diesel engine. Specifically, DEF is an aqueous urea solution made with 32.5% urea and 67.5% deionized water. DEF is consumed in a selective catalytic reduction (SCR) that lowers the concentration of nitrogen oxides in the diesel exhaust emissions from a diesel engine.

<span class="mw-page-title-main">Pipe (fluid conveyance)</span> Tubular section or hollow cylinder

A pipe is a tubular section or hollow cylinder, usually but not necessarily of circular cross-section, used mainly to convey substances which can flow — liquids and gases (fluids), slurries, powders and masses of small solids. It can also be used for structural applications; hollow pipe is far stiffer per unit weight than solid members.

<span class="mw-page-title-main">Bunding</span> Retaining wall around pollution source

Bunding, also called a bund wall, is a constructed retaining wall around storage "where potentially polluting substances are handled, processed or stored, for the purposes of containing any unintended escape of material from that area until such time as a remedial action can be taken."

<span class="mw-page-title-main">Sealant</span> Substance used to block the passage of fluids through openings

Sealant is a substance used to block the passage of fluids through openings in materials, a type of mechanical seal. In building construction sealant is sometimes synonymous with caulk and also serve the purposes of blocking dust, sound and heat transmission. Sealants may be weak or strong, flexible or rigid, permanent or temporary. Sealants are not adhesives but some have adhesive qualities and are called adhesive-sealants or structural sealants.

<span class="mw-page-title-main">Piping and plumbing fitting</span> Connecting pieces in pipe systems

A fitting or adapter is used in pipe systems to connect straight sections of pipe or tube, adapt to different sizes or shapes, and for other purposes such as regulating fluid flow. These fittings are used in plumbing to manipulate the conveyance of water, gas, or liquid waste in domestic or commercial environments, within a system of pipes or tubes.

A wet wing is an aerospace engineering technique where an aircraft's wing structure is sealed and used as a fuel tank.

<span class="mw-page-title-main">Oxy-fuel welding and cutting</span> Metalworking technique using a gaseous fuel and oxygen

Oxy-fuel welding and oxy-fuel cutting are processes that use fuel gases and oxygen to weld or cut metals. French engineers Edmond Fouché and Charles Picard became the first to develop oxygen-acetylene welding in 1903. Pure oxygen, instead of air, is used to increase the flame temperature to allow localised melting of the workpiece material in a room environment. A common propane/air flame burns at about 2,250 K, a propane/oxygen flame burns at about 2,526 K, an oxyhydrogen flame burns at 3,073 K and an acetylene/oxygen flame burns at about 3,773 K.

<span class="mw-page-title-main">Composite overwrapped pressure vessel</span> Pressure vessel with a non-structural liner wrapped with a structural fiber composite

A composite overwrapped pressure vessel (COPV) is a vessel consisting of a thin, non-structural liner wrapped with a structural fiber composite, designed to hold a fluid under pressure. The liner provides a barrier between the fluid and the composite, preventing leaks and chemical degradation of the structure. In general, a protective shell is applied for protective shielding against impact damage. The most commonly used composites are fiber reinforced polymers (FRP), using carbon and kevlar fibers. The primary advantage of a COPV as compared to a similar sized metallic pressure vessel is lower weight; COPVs, however, carry an increased cost of manufacturing and certification.

<span class="mw-page-title-main">Radiator (engine cooling)</span> Heat exchangers used for cooling internal combustion engines

Radiators are heat exchangers used for cooling internal combustion engines, mainly in automobiles but also in piston-engined aircraft, railway locomotives, motorcycles, stationary generating plant or any similar use of such an engine.

A liquid nitrogen vehicle is powered by liquid nitrogen, which is stored in a tank. Traditional nitrogen engine designs work by heating the liquid nitrogen in a heat exchanger, extracting heat from the ambient air and using the resulting pressurized gas to operate a piston or rotary motor. Vehicles propelled by liquid nitrogen have been demonstrated, but are not used commercially. One such vehicle, Liquid Air, was demonstrated in 1902.

<span class="mw-page-title-main">Fuel bladder</span>

Fuel bladders, fuel storage bladders are a type of Flexi-bag used as a fuel container. They are collapsible, flexible storage bladders that provide transport and storage for bulk industrial liquids such as fuels.

<span class="mw-page-title-main">Aircraft fuel tank</span>

Aircraft fuel tanks are a major component of aircraft fuel systems. They can be classified into internal or external fuel tanks and can be further classified by method of construction or intended use. Safety aspects of aircraft fuel tanks were examined during the investigation of the 1996 TWA Flight 800 in-flight explosion accident.

<span class="mw-page-title-main">Fuel container</span>

A fuel container is a container such as a steel can, bottle, drum, etc. for transporting, storing, and dispensing various fuels.


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  9. Maciag, Mike (7 June 2007). "Backup Facility to Power Water Works During Outages". Erie Times-News. p. 5B. the Erie Water Works is due to have a 20,000-gallon bulk storage tank and a 5,000-gallon day tank installed to support two diesel-fueled generators serving as backups to the Sommerheim Water Treatment Plant in Erie, Pennsylvania
  10. Comprehensive Everglades Restoration Plan, Section 8, pp 8-3, 8-4, says that small- and medium-sized pumping stations are to be equipped with fuel storage tanks capable of storing seven days capacity, plus "floor-mounted packaged system day tanks" "Section 8" (PDF). Archived from the original (PDF) on 27 September 2007. Retrieved 8 June 2007.
  11. Monitor: Bang but no boom