Patent ID: 7318414

Claim:
A multi-pressure fuel injection system for use with an engine, comprising; a fuel supply for the system; a fuel pump connected to the fuel supply and adapted to be operated at a predetermined speed; at least one fuel injector, a main fuel line, providing fluid connection from the outlet of the fuel pump to the at least one fuel injector; a fuel by-pass line with flow constraint having one end connected to some location on the main fuel line including the outlet of the fuel pump avoiding fuel rail and fuel injector, and the other end connected to some location in the fuel supply, including the inlet of the fuel pump, to provide fuel flow back to the fuel supply when the system is operating; and a fuel by-pass control in the fuel by-pass line, capable of opening and closing almost instantaneously, changing the pressure of the system between two designed pressure states, including a higher pressure state and a lower pressure state thereby essentially instantaneously changing the pressure of the fluid in the main fuel line between the two pressure states and the rate of fuel delivery at the at least one fuel injector.