Fuel System Purpose

Fuel (chemical energy) is stored in the fuel tank until it is pumped, filtered, pressurized, and delivered to the carburetor or injection system. The fuel must be mixed with air either before the combustion chamber (indirect injection – low pressure system) or inside the combustion chamber (direct injection – high pressure system), where it is then burned. For the cleanest burning and most efficient mixture under moderate load conditions the mass ratio is close to 14.7 parts of air to 1 part of gasoline (i.e., stoichiometric ratio). The purpose of the fuel system is to store, transfer, clean, and then mix the fuel with air.