Fuel pressure control for engine fuel systems

Patent metadata

Field	Value
Publication number	US-2017191440-A1
Application number	US-201715462373-A
Country	US
Kind code	A1
Filing date	Mar 17, 2017
Priority date	Apr 13, 2015
Publication date	Jul 6, 2017
Grant date	—

Abstract

An apparatus includes an input module structured to interpret a fuel pressure command indicative of a target fuel pressure within an accumulator and a target fuel injection characteristic, a pump module structured to control a pump assembly to provide fuel to the accumulator to maintain the target fuel pressure within the accumulator, an injector module structured to control a plurality of fuel injectors to inject fuel into an engine based on the target fuel injection characteristic, a pressure module structured to interpret pressure data regarding an actual fuel pressure within the accumulator and to determine a pressure difference between the target fuel pressure and the actual fuel pressure, and a modulation module structured to determine a final fuel injection command responsive to the pressure difference exceeding a first magnitude threshold where the final fuel injection command is based on the pressure difference and the target fuel injection characteristic.

First claim

What is claimed is:

1 . An apparatus, comprising:
an injector circuit structured to control a plurality of fuel injectors to inject fuel into an engine based on a target fuel injection characteristic; a pressure circuit structured to determine a pressure difference between a target fuel pressure and an actual fuel pressure within the accumulator; and a modulation circuit structured to modulate a final fuel injection command responsive to the pressure difference exceeding a first threshold, wherein the final fuel injection command is based on the pressure difference and the target fuel injection characteristic.

2 . The apparatus of claim 1 , wherein the modulation circuit is further structured to determine the final fuel injection command based on the pressure difference exceeding the first threshold for a duration of time that exceeds a time threshold.

3 . The apparatus of claim 2 , wherein the modulation circuit is further structured to interpret the fuel pressure command to determine a final fuel injection command limit defining a maximum threshold value for the final fuel injection command.

4 . The apparatus of claim 3 , wherein the maximum threshold value and the target fuel injection characteristic are at least one of a fuel injection duration, an amount of fuel injected, a fuel flow rate through the plurality of fuel injectors, an engine power, and an engine torque.

5 . The apparatus of claim 4 , wherein the modulation circuit is further structured to adjust the final fuel injection command limit to limit the final fuel injection command such that the pressure difference is reduced below a second threshold, wherein the second threshold is less than or equal to the first threshold, and wherein the final fuel injection command limit remains constant while the pressure difference is less than the second threshold until a release condition is met.

6 . The apparatus of claim 5 , wherein the final fuel injection command limit is maintained above an authority limit.

7 . The apparatus of claim 6 , wherein the modulation circuit is further structured to determine that the release condition is met when the final fuel injection command drops a threshold amount below the authority limit.

8 . The apparatus of claim 3 , wherein the modulation circuit is further structured to redefine the final fuel injection command limit to a fraction of a previous final fuel injection command, wherein a previous pressure difference between the target fuel pressure and the actual fuel pressure within the accumulator responsive to the previous final fuel injection command is less than the first threshold, and wherein the target fuel pressure is based on a fuel pressure command based on a position of at least one of an accelerator pedal and a throttle.

9 . The apparatus of claim 3 , wherein the modulation circuit is structured to control the final fuel injection command limit responsive to the pump assembly reaching a saturation condition.

10 . An apparatus, comprising:
means for injecting fuel into an engine based on a target fuel injection characteristic; means for determining a pressure difference between a target fuel pressure and an actual fuel pressure within an accumulator, and modulating a final fuel injection command responsive to the pressure difference exceeding a first threshold for a duration of time greater than a time threshold.

11 . The apparatus of claim 10 , further comprising a means for receiving a fuel pressure command indicative of the target fuel pressure and the target fuel injection characteristic, wherein the means for receiving is further structured to receive a final fuel injection command limit defining a maximum threshold value for the final fuel injection command, and wherein the maximum threshold value includes at least one of a fuel injection duration, an amount of fuel injected, a fuel flow rate through the plurality of fuel injectors, an engine power, and an engine torque.

12 . The apparatus of claim 11 , wherein the means for determining and modulating is further structured to redefine the final fuel injection command limit based on the pressure difference exceeding the first threshold for a duration of time that exceeds the time threshold.

13 . The apparatus of claim 12 , further comprising means for providing fuel to the accumulator to maintain the target fuel pressure within the accumulator, wherein the final fuel injection command limit is redefined to a fraction of a previous final fuel injection command, and wherein a previous pressure difference between the target fuel pressure and the actual fuel pressure within the accumulator responsive to the previous final fuel injection command is less than the first threshold.

14 . The apparatus of claim 12 , wherein the means for determining and modulating is further structured to adjust the final fuel injection command limit to limit the final fuel injection command such that the pressure difference is reduced below a second threshold, and wherein the second threshold is less than or equal to the first threshold.

15 . The apparatus of claim 14 , wherein the final fuel injection command limit is maintained above an authority limit defining a minimum threshold value corresponding with the maximum threshold value of the final fuel injection command limit.

16 . The apparatus of claim 11 , wherein the means for determining and modulating is further structured to modulate the final fuel injection command limit responsive to a pump assembly reaching a saturation condition.

17 . A system, comprising:
a controller communicably coupled to a pump assembly, a pressure sensor, and a plurality of fuel injectors, the controller structured to:
control the plurality of fuel injectors to inject fuel into an engine based on a target fuel injection characteristic;
determine a pressure difference between a target fuel pressure and an actual fuel pressure within an accumulator; and
determine a final fuel injection command responsive to the pressure difference exceeding a first threshold for a duration of time greater than a time threshold, wherein the final fuel injection command is based on the pressure difference and the target fuel injection characteristic.

18 . The system of claim 17 , wherein the target fuel pressure is based on a fuel pressure command based on a position of at least one of an accelerator pedal and a throttle, and wherein the position is determined by a position sensor.

19 . The system of claim 17 , wherein the pump assembly includes a high pressure pump configured to pressurize an amount of fuel to the target fuel pressure and an inlet metering valve configured to control the amount of fuel pressurized by the high pressure pump, wherein the controller is further structured to determine the final fuel injection command responsive to the inlet metering valve reaching a saturation condition.

20 . The system of claim 17 , wherein the controller is further structured to adjust the final fuel injection command such that the pressure difference is reduced below a second threshold, and wherein the second threshold is less than or equal to the first threshold.

Assignees

• Cummins Inc

Inventors

• Bays Mark N
• Tidwell Michael R

Classifications

• F02D2200/0404

  Throttle position · CPC title

• F02D2200/0602

  Fuel pressure · CPC title

• F02D41/3863 Primary

  by controlling the flow out of the common rail, e.g. using pressure relief valves · CPC title

• F02D2200/602

  Pedal position · CPC title

• F02M63/0225

  Fuel-injection apparatus having a common rail feeding several injectors (F02M63/0003 takes precedence); Means for varying pressure in common rails; Pumps feeding common rails · CPC title