PRESSURE REGULATOR VALVE FOR ENGINE FUEL SYSTEM
A fuel system for an internal combustion engine includes a low pressure fuel pump and a pressure regulator valve. The pressure regulator valve is placed at the inlet to the low pressure fuel pump to regulate the fuel pressure and fuel flow in the system.
1 . A fuel system for an internal combustion engine, the fuel system comprising:
a fuel pump having an inlet for receiving fuel from a fuel source, the fuel pump having an outlet for providing pressurized fuel;
a bypass flow path extending from the outlet toward the inlet; and
a pressure regulator valve connecting the bypass flow path to the inlet, wherein the pressure regulator valve includes:
a fuel passage that fluidly connects the fuel source to the inlet of the fuel pump; and
a plunger in the fuel passage, wherein the plunger is displaced by fuel pressure in the bypass flow path to close the fuel passage in the pressure regulator in response to the fuel pressure in the bypass flow path exceeding a threshold pressure.
2 . The fuel system of claim 1 , wherein the pump is a low pressure pump and the fuel system includes a high pressure pump downstream of the low pressure pump.
3 . The fuel system of claim 2 , further comprising a rail connected to the high pressure pump, the rail for distributing pressurized fuel to a plurality of fuel injectors of the internal combustion engine.
4 . The fuel system of claim 3 , wherein the low pressure pump and the high pressure pump are each driven by a cam shaft, and the cam shaft is driven by an output shaft of the internal combustion engine.
5 . The fuel system of claim 1 , wherein the pressure regulator valve includes an opening connected to the bypass flow path, and the plunger is located between the opening and the fuel passage.
6 . The fuel system of claim 1 , wherein the pressure regulator valve includes:
a valve inlet to the fuel passage, the valve inlet being connected to the fuel source; and
a valve outlet from the fuel passage, the valve outlet being connected to the inlet of the fuel pump.
7 . The fuel system of claim 6 , wherein the plunger in the fuel passage is displaced by pressurized fuel in the bypass flow path from a first position to a second position, and in the first position fuel is allowed to flow through the fuel passage from the valve inlet to the valve outlet and in the second position the plunger obstructs fuel flow from the valve inlet to the valve outlet and fluidly disconnects the fuel source from the inlet of the fuel pump.
8 . The fuel system of claim 7 , wherein the pressure regulator valve includes an opening in fluid communication with the bypass flow path.
9 . The fuel system of claim 7 , wherein the plunger is configured to progressively reduce fuel flow through the fuel passage from the valve inlet to the valve outlet as the plunger is displaced from the first position toward the second position.
10 . The fuel system of claim 1 , further comprising a pressure relief valve between the bypass flow path and an upstream side of the pressure regulator valve, wherein the pressure relief valve is configured to vent fuel from the bypass flow path to the upstream side in response to the fuel pressure in the bypass flow path exceeding a second pressure threshold greater than the pressure threshold.
11 . A pressure regulator valve for a fuel pump, the pressure regulator valve comprising:
a plunger; and
a body that is elongated between a first end and an opposite second end, the body defining a fuel passage therein, and the plunger is located in the fuel passage, wherein the body includes:
an opening at the first end, the opening configured to receive fuel from a fuel pump bypass flow path;
a valve inlet to the fuel passage configured to receive fuel from a fuel source, the valve inlet located on a side of the body between the first end and the second end of the body;
a valve outlet from the fuel passage configured to provide fuel from the fuel passage to the fuel pump, the valve outlet located on the side of the body between the first end and the second end of the body, wherein:
the plunger is movable from a first position in the fuel passage toward a second position in the fuel passage in response to a pressurized fuel in the fuel pump bypass flow path;
in the first position the plunger allows fuel from a fuel source to flow through the valve inlet into the fuel passage and through the valve outlet to the fuel pump; and
in the second position the plunger is located in the fuel passage to block the valve inlet and obstruct fuel flow into the fuel passage from the fuel source.
12 . The pressure regulator valve of claim 11 , wherein the plunger extends from a first plunger end to a second plunger end, and the first plunger end is oriented toward the first end of the body and the second plunger end is engaged with a biasing member, the biasing member being configured to bias the first plunger end toward the first end of the body.
13 . The pressure regulator valve of claim 12 , wherein the biasing member is a spring located in the body.
14 . The pressure regulator valve of claim 11 , wherein the plunger includes:
a first end portion oriented toward the first end of the body;
a second end portion oriented toward the second end of the body; and
a neck connecting the first end portion to the second end portion.
15 . The pressure regulator valve of claim 14 , wherein:
in the first position the neck of the plunger is located between the valve inlet and the valve outlet and the fuel passage extends around the neck; and
in the second position the first end portion of the plunger is located between the valve inlet and the valve outlet.
16 . The pressure regulator valve of claim 14 , wherein the neck is tapered from the first end portion toward the second end portion so that a flow volume around the neck between the valve inlet and the valve outlet progressively decreases as the plunger moves from the first position toward the second position.
17 . The pressure regulator valve of claim 14 , wherein:
the fuel passage includes a first cross-sectional size; and
the first end portion and the second end portion each include a second cross-sectional size that corresponds substantially to said first cross-sectional size.
18 . The pressure regulator valve of claim 14 , wherein the opening, the valve inlet, and the valve outlet are substantially the same size.
19 . The pressure regulator valve of claim 14 , wherein:
the opening extends along a longitudinal axis of the body; and
the valve inlet and the valve outlet extend through the body orthogonally to the longitudinal axis.
20 . The pressure regulator valve claim 19 , wherein the valve inlet and the valve outlet are aligned with one another along a second axis that is orthogonal to the longitudinal axis.