EFI Fuel System
 

 Fuel System    Fuel System Explained:
 
   This Fuel System is designed for Electronic Fuel Injection.  This design addresses all of the major safety considerations in fuel systems for experimental aircraft.  A good design will allow fuel to flow freely without developing pockets of air in the fuel lines.  The left and right wing tanks feed into the sump tank.  The fuel sump is the lowest tank and fuel is drawn from near the bottom of the tank.  Each of the wing tanks have sumps for draining off any fuel that may get contaminated with water from condensation in the tank or tainted fuel that gets introduced to the tank.  Each Tank has it's own two gauges, visual and capacitive.  Each tank has it's own vent system which can also return fuel to each tank.  All return fuel from the injectors is cooled by mixing with fuel in the wing tanks.  The "funnel" shapes in the wing tanks allow the returning fuel to be mixed with the remaining fuel in the tank.  At  most all recommended attitudes, return fuel is directed to the sump tank so there is a constant flow of fuel.  If the plane is sitting on it's nose, or if it is in a high angular climb, or descent, the fuel returning from the engine fuel rail return is feed back towards the fuel sump.  The sump holds seven gallons of reserve fuel which can supply the engine for at least 1/2 hour of flight.

   In dragster design the fuel should exit the rear of the tank.  This helps keep positive pressure on the fuel during acceleration.  While this is not a dragster,  the acceleration or climb attitudes can maintain additional positive pressure on the fuel.  This is an advantage for take off .   In descent the sump maintains positive pressure.   Perhaps  I should define positive pressure:  If the fuel pump were not pumping, pressure on the pump would be positive.

   The vent system will not vent fuel out of the plane because the plenum tank at the top allows fuel trapped in the lines to bubble up and vent only air out of the vent tube.  Much like a wine bubbler.  No  fuel should be lost. 

   There are no tank switch valves to have to manage.  Fuel flow is balanced.  There is the required emergency shutoff valve at the rear of the tank which is controlled from the cockpit.   A 1/2" inlet to the sump from each wing tank allows fuel to flow freely into the sump.  Much attention has been given to avoid vapor lock.  Immediately after exiting the sump tank, the fuel passes through a gascolator and a filter, it is then pumped by one or two pumps into the fuel injection rail.  The pumps are at the lowest point in the system.  There are no upward loops in the system to trap air.  Fuel flowing from one wing tank to another via the sump tank during a slip turn is minimal. 

   There are NO (zero) fuel lines in the fuselage of the plane.  All lines are separated from the passenger compartment by at least one sandwich of fiberglass and foam.