Fuel tank - online puzzles

A fuel tank (or petrol tank ) is a safe container for flammable fluids. 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.

Uses

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

Storage of fuel : the system must contain a given quantity of fuel and must avoid leakage and limit evaporative emissions.

Filling: the fuel tank must be filled in a secure way, without sparks.

Provide a method for determining level of fuel in tank, gauging (the remaining quantity of fuel in the tank must be measured or evaluated).

Venting ( if over-pressure is not allowed, the fuel vapors must be managed through valves).

Feeding of the engine (through a pump).

Anticipate potentials for damage and provide safe survival potential. 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.