Fuel delivery system using two pressure regulators with a single electric fuel pump

What is this patent about?

'877 is related to the field of fuel delivery systems for internal combustion engines, particularly those used in marine applications. Traditional fuel injection systems often return excess fuel to the fuel tank, which is problematic in marine environments due to safety regulations prohibiting pressurized fuel lines and fuel return to the tank. Existing solutions using dual fuel pumps consume excessive power and can lead to vapor lock.

The underlying idea behind '877 is to use a single electric fuel pump in conjunction with two pressure regulators and a vapor separator to efficiently deliver fuel to the engine's fuel injectors and recirculate excess fuel. This design eliminates the need for a second fuel pump and addresses the issue of vapor lock by removing entrained gases from the recirculated fuel.

The claims of '877 focus on a fuel delivery system comprising a single electric fuel pump drawing fuel from a tank and supplying it to fuel injectors, a fuel return line connecting the injectors to the pump via a vapor separator, a first pressure regulator maintaining constant pressure at the injectors, and a second pressure regulator allowing fuel transfer from the vapor separator to the pump while preventing backflow.

In practice, the single electric fuel pump delivers fuel to a fuel rail assembly that distributes it to the fuel injectors. Excess fuel is returned to the pump through a vapor separator, which removes any vapor to prevent vapor lock. The first pressure regulator ensures stable fuel pressure at the injectors, while the second regulator, acting as a check valve, controls the flow of recirculated fuel back to the pump inlet.

This configuration differs from prior approaches by using only one electric fuel pump, reducing power consumption and complexity. The two pressure regulators and vapor separator work together to maintain optimal fuel pressure and prevent vapor lock, addressing the limitations of traditional fuel injection systems and dual-pump solutions, particularly in the demanding environment of marine engines. The vapor separator is key to removing entrained gasses.