Common rail fuel supply system with high pressure accumulator
AssigneeStanadyne, Inc.
InventorIlija Djordjevic
Life of this patent
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Abstract
A self-regulating direct injection fuel delivery system for a motor vehicle includes a common rail having an accumulator including a relatively large fuel volume. The accumulator is connected in fluid communication with a distributor having a relatively small fuel volume and at least one fuel injector nozzle is connected in direct fluid communication with the distributor. A high-pressure pump for delivering fuel to the common rail is provided and a flow control device is interposed between the pump and the common rail for selectively delivering fuel to one of the accumulator and the distributor and then the other of the accumulator and the distributor.
Claims34
A direct injection fuel delivery system for a motor vehicle, comprising:
- a common rail including an accumulator having a relatively large fuel volume connected in fluid communication with a distributor having a relatively small fuel volume;
- at least one fuel injector nozzle connected in direct fluid communication with the distributor;
- a high pressure pump having an inlet and a discharge for delivering fuel to the common rail;
- flow control means interposed between the pump and the common rail for selectively delivering fuel to one of the accumulator or the distributor and then the other of the accumulator or the distributor;
- wherein the flow control means controlling both a first flow path between the pump and the distributor and a second flow path between the pump and the accumulator for selectively delivering fuel to one of the distributor and accumulator, respectively;
- a pressure control valve is situated in a third flow path between the accumulator and the distributor which defines said fluid communication therebetween, said pressure control valve preventing flow from the distributor to the accumulator but permitting flow from the accumulator to the distributor when the pressure in the accumulator exceeds the pressure in the distributor by a predetermine differential;
- and
- a supply flow path wherein the pump discharge is selectively connected in fluid communication with the first flow path or the second flow path;
- and
- a bypass flow path wherein the pump discharge is selectively connected in fluid communication with the pump inlet, thereby bypassing the common rail.
A common rail fuel injector assembly for a motor vehicle including a high pressure fuel pump that has an inlet and a discharge for supplying fuel to a plurality of fuel injector nozzles that are fluidly connected to a fuel distributor, the common rail fuel injector assembly comprising:
- an accumulator connected in fluid communication with the fuel pump, the accumulator having an accumulator internal volume for containing a reservoir of fuel in fluid communication with the distributor;
- flow control means interposed between the pump and the accumulator for selectively delivering fuel to the accumulator when a pressure of fuel therein drops below a predetermined value and wherein the flow control means comprises,
- a supply flow path wherein the pump discharge is selectively aligned with the accumulator;
- and
- a bypass flow path wherein the pump discharge is selectively aligned with the puma inlet.
A common rail fuel injection assembly for a motor vehicle including a high pressure fuel pump that has an inlet and a discharge for delivering fuel to at least one fuel injector nozzle and a common rail including an accumulator connected in fluid communication with a distributor, the injection assembly comprising:
- a flow control device interposed between the pump and the common rail for selectively delivering fuel to one of the accumulator and the distributor and then the other of the accumulator and the distributor;
- wherein the flow control device controls both a first flow path between the pump and the distributor and a second flow path between the pump and the accumulator;
- wherein the flow control device comprises:
- a supply flow path wherein the pump discharge is selectively connected to the first flow path or the second flow path;
- a bypass flow path wherein the pump discharge is selectively connected to the pump inlet;
- and
- a control valve for selectively aligning the pump discharge with the first flow path, the pump discharge with the second flow path, and the pump discharge with the bypass flow path
- wherein the control valve comprises:
- a first operator disposed within the first flow path;
- a second operator cooperatively engageable with the first operator and being disposed within the second flow path;
- wherein at less than a first predetermined pressure within the control valve the second operator is biased into engagement with the first operator so that the first operator aligns the pump discharge with the first flow path only, and at greater than the first predetermined pressure, the second operator is urged away from engagement with the first operator thereby aligning the pump discharge with the second flow path and when a second predetermined pressure within the control valve is exceeded, the second operator moves to a location wherein the pump discharge is aligned with the bypass flow path.
A fuel supply system for a plurality of fuel injection nozzles in a vehicle engine, comprising:
- a fuel supply pump having a discharge pressure of at least about 50 bar;
- a fuel accumulator fluidly connected to the pump discharge such that fuel in the accumulator is maintained at a pressure of at least about 40 bar;
- a distributor rail that is fluidly connected to the accumulator for receiving high pressure fuel and that is fluidly connected to each of said plurality of fuel injection nozzles;
- means cooperating with the fluid connection between the accumulator and the distributor rail for maintaining fuel in the distributor rail at a lower pressure than the pressure in the accumulator;
- and
- injection control means for selectively opening and closing the fluid connection between each nozzle and the distributor rail, whereby fuel is selectively injected into the engine by each nozzle.
A method of supplying fuel to a plurality of fuel injection nozzles at a target delivery pressure in a distributor rail having a common distributor volume fluidly connected to each of the nozzles, comprising:
- maintaining fuel at a pressure higher than the target delivery pressure, in an accumulator having an accumulator volume;
- maintaining a differential pressure between the higher pressure in the accumulator and the target pressure in the distributor rail, through a fluid connection between the accumulator and the distributor rail;
- measuring the pressure in the distributor rail;
- responsive to said measured pressure in the distributor rail and the target pressure in the distributor rail, operating a pressure control valve in the fluid connection between the accumulator and the distributor rail to control said fuel flow into the distributor rail;
- whereby as the measured pressure in the distributor rail drops as a result of fuel injection, fuel at the higher pressure of the accumulator flows into the distributor rail to maintain the target pressure therein.
Dependencies are inferred from the claim text.