TECHNICAL FIELD

The present disclosure relates generally to a fuel system that has more than one fuel pump.

BACKGROUND

Some fuel systems include more than one fuel pump from which fuel is delivered to support operation of an engine. The fuel pumps may be driven at full speed and excess fuel may be diverted by a pressure regulator which may be located within a fuel tank or downstream of the fuel tank with diverted fuel returned to the fuel tank through a conduit. Running two fuel pumps at full speed increases the electrical draw of the fuel system and the cost to run the fuel system. Further, some systems are arranged so that failure of one fuel pump renders the system inoperable to supply fuel to the engine to support operation of the engine, even in a limited capacity. Improved control of the fuel pumps, the flow rate of fuel delivered from the fuel pumps, vapor handling and other features or improvements are desired separately or in combination.

SUMMARY

In at least some implementations, a fuel pump assembly includes a first fuel pump and a second fuel pump. The first fuel pump has an electric motor, a pumping element that is driven by the motor, an inlet through which fuel enters the first fuel pump and an outlet through which fuel is discharged from the first fuel pump. The second fuel pump has an electric motor, a pumping element that is driven by the motor, an inlet through which fuel enters the second fuel pump and an outlet through which fuel is discharged from the second fuel pump. The assembly also includes a passage communicated with the outlet of the first fuel pump and with the outlet of the second fuel pump, a fuel outlet in communication with the passage and through which fuel exits the fuel pump assembly, and a valve having an inlet in communication with the passage between the outlet of the first fuel pump and the outlet of the second fuel pump. The valve also having an outlet through which fuel exits the passage and a valve body that controls fuel flow through the valve.

In at least some implementations, the valve is electrically operated to control movement of the valve body between open and closed positions. In at least some implementations, at least one of the first fuel pump motor and the second fuel pump motor is driven by a pulse width modulated signal. In at least some implementations, during at least some operating conditions, fuel from both the first fuel pump outlet and the second fuel pump outlet is discharged from the assembly through the fuel outlet.

In at least some implementations, the assembly also includes a pressure regulator having an inlet in communication with the passage between the valve and the second fuel pump outlet, an outlet from which fuel exits the passage and a valve body between the inlet and the outlet. The valve body is responsive to a pressure of fuel at the pressure regulator inlet that is above a threshold pressure to permit fuel to flow through the pressure regulator outlet. In at least some implementations, a reservoir is provided that has an interior and a divider in the interior, and the interior includes a first portion on one side of the divider that is in communication with the first fuel pump inlet and a second portion on the other side of the divider that is in communication with the second fuel pump inlet. The outlet of the valve may be in communication with the second portion of the interior. In at least some implementations, a first check valve carried by the divider that permits fuel flow from the second portion to the first portion. In at least some implementations, a second check valve carried by the divider that permits fuel flow from the first portion to the second portion. In at least some implementations, a first check valve carried by the divider that permits fuel flow from the second portion to the first portion, and which includes a second check valve carried by the divider that permits fuel flow from the first portion to the second portion.

In at least some implementations, a pressure regulator has an inlet in communication with the passage between the valve and the second fuel pump outlet, an outlet from which fuel exits the passage and a valve body between the inlet and the outlet. The valve body may be responsive to a pressure of fuel at the pressure regulator inlet that is above a threshold pressure to permit fuel to flow through the pressure regulator outlet, and the pressure regulator outlet is in communication with the second portion of the interior.

In at least some implementations, a fuel pump assembly, includes a first fuel pump having an electric motor, a pumping element that is driven by the motor, an inlet through which fuel enters the first fuel pump, a first outlet through which fuel is discharged from the first fuel pump and a second outlet through which fuel is discharged from the first fuel pump. A second fuel pump has an electric motor, a pumping element that is driven by the motor, an inlet through which fuel enters the second fuel pump and an outlet through which fuel is discharged from the second fuel pump. A passage is communicated with the first outlet of the first fuel pump and with the outlet of the second fuel pump, a fuel outlet is in communication with the passage and through which fuel exits the fuel pump assembly, and a valve has an inlet in communication with the second outlet of the first fuel pump, an outlet through which fuel exits the valve, and a valve body that controls fuel flow through the valve. The valve body is closed to inhibit or prevent fuel flow through the valve, more fuel exits the first fuel pump through the first outlet.

In at least some implementations, the assembly includes a reservoir that has an interior and a divider in the interior, and the interior includes a first portion on one side of the divider that is in communication with the first fuel pump inlet and a second portion on the other side of the divider that is in communication with the second fuel pump inlet. In at least some implementations, the passage has a second end through which fuel exits the passage and the second end is communicated with the second portion of the interior.

In at least some implementations, the assembly includes a passage communicated at one end with the valve to receive fuel that flows through the valve, and a jet or restricted orifice located in the passage downstream of said one end, and the jet or restricted orifice has a smaller flow area than the adjacent portions of the passage and the jet or restricted orifice controls the flow rate of fuel in the passage.

In at least some implementations, the assembly includes a pressure regulator having an inlet in communication with the passage, an outlet from which fuel exits the passage and a valve body between the inlet and the outlet. The valve body may be responsive to a pressure of fuel at the pressure regulator inlet that is above a threshold pressure to permit fuel to flow through the pressure regulator outlet, and the pressure regulator outlet may be in communication with the second fuel pump inlet.

In at least some implementations, the assembly includes a reservoir having an interior and a divider in the interior, and the interior includes a first portion on one side of the divider that is in communication with the first fuel pump inlet and a second portion on the other side of the divider that is in communication with the second fuel pump inlet, and the interior is sealed and capable of containing fluid at above atmospheric pressure. The assembly may also include a fuel pressure regulator that has an inlet communicating with the second portion of the reservoir interior, an outlet communicating with the first portion of the reservoir interior, and a valve body between the fuel pressure regulator inlet and the fuel pressure regulator outlet that is normally closed to prevent fuel flow through the fuel pressure regulator until the pressure at the fuel pressure regulator inlet is above a threshold pressure wherein the valve body moves to an open position and fuel from the second portion of the reservoir interior flows into the first portion of the reservoir interior. In at least some implementations, the assembly also includes a second fuel pressure regulator having an inlet in communication with the passage, an outlet from which fuel exits the passage and a valve body between the second fuel pressure regulator inlet and the second fuel pressure regulator outlet. The second fuel pressure regulator valve body being responsive to a pressure of fuel at the second fuel pressure regulator inlet that is above a threshold pressure to permit fuel to flow through the second fuel pressure regulator outlet, and wherein the second fuel pressure regulator outlet is in communication with the second fuel pump inlet.

In at least some implementations, a passage is communicated at one end with the valve to receive fuel that flows through the valve, and a jet or restricted orifice located in the passage downstream of said one end, wherein the jet or restricted orifice has a smaller flow area than the adjacent portions of the passage and the jet or restricted orifice controls the flow rate of fuel in the passage, and wherein the passage includes an inlet arranged so that fluid flow through the jet or restricted orifice draws fluid through the inlet and into the passage.

