FUEL SUPPLY

Perfect Power Articles.

 

The injectors require approx. 3bar (42psi) fuel pressure, unless they are special injectors. If the pressure is lowered, then the fuel is inadequately atomized. If the pressure is increased, then the injectors may not open with low battery voltage. 2.5 to 3.5 bar is the best, but consult the injector manufacturer for details.

 

A high-pressure fuel pump must provide this pressure. An inline regulator regulates the pressure before returning the excess fuel to the tank or intermediate fuel tank. The boiling point of fuel depends on the absolute pressure. Under vacuum the fuel boils at room temperature! The critical point is the high-pressure pump inlet pipe: if the pump can create the smallest vacuum, then the fuel will boil, causing you endless trouble. It is therefore essential to keep the suction pipe diameter large (10 mm ID) and pipe as short as possible (200 mm). This can best be achieved by installing an intermediate tank (IT), the system works as follows:

 

The normal low-pressure pump (electrical, or mechanical) fills the small IT via a filter, and the overflow returns to the main tank. This pump must have enough capacity to supply all the used fuel (The volume of fuel required by the engine). The high-pressure pump is located close to the IT. It sucks fuel from the IT and supplies it to the injectors, and after the regulator the unused fuel is returned to the IT. If the IT is properly constructed, it is always full, which avoids any sloshing.

 

Of course the fuel must be filtered. This should not be done in the high-pressure suction pipe. An additional high-pressure filter can be installed before the injectors