Systems and methods for reducing rail pressure in a common rail fuel system

Patent metadata

Field	Value
Publication number	US-11015548-B2
Application number	US-201716772096-A
Country	US
Kind code	B2
Filing date	Dec 14, 2017
Priority date	Dec 14, 2017
Publication date	May 25, 2021
Grant date	May 25, 2021

Abstract

Methods and systems, using a controller (20), for performing fuel pressure control operation of an engine (12) having at least one cylinder (16) is disclosed. The controller (20) includes a fuel system control unit (42) configured to control a fuel pressure applied to at least one injector (18) of the engine (12) during a motoring condition period (412) based on a commanded pulse train duration (410). During the motoring condition period (412), no combustion occurs in the at least one cylinder (16) of the engine (12). The commanded pulse train duration is a time period during which the at least one injector (18) of the engine (12) is activated for a drain operation. The fuel system control unit (42) is configured to command the at least one injector (18), for the commanded pulse train duration during the motoring condition period (412), to release fuel from the at least one injector (18) without injecting the fuel into the at least one cylinder (16) of the engine (12).

First claim

What is claimed is:

1. A system for performing fuel pressure control operation of an engine ( 12 ) having at least one cylinder ( 16 ) comprising:
a controller ( 20 ) including a fuel system control unit ( 42 ) configured to control a fuel pressure applied to at least one injector ( 18 ) of the engine ( 12 ) during a motoring condition period ( 412 ) based on a commanded pulse train duration ( 410 ), the motoring condition period ( 412 ) during which no combustion occurs in the at least one cylinder ( 16 ) of the engine ( 12 ), the commanded pulse train duration being a time period ( 410 ) during which the at least one injector ( 18 ) of the engine ( 12 ) is activated for operation,
wherein the fuel system control unit ( 42 ) is configured to command the at least one injector ( 18 ), for the commanded pulse train duration during the motoring condition period ( 412 ), to release fuel from the at least one injector ( 18 ) without injecting the fuel into the at least one cylinder ( 16 ) of the engine ( 12 ).

2. The system of claim 1 , wherein the fuel system control unit ( 42 ) is configured to determine the commanded pulse-train duration based on a critical injector activation time.

3. The system of claim 2 , wherein the critical injector activation time represents a maximum commanded on-time period applied to the at least one injector ( 18 ) to achieve a maximum fuel drain amount from the at least one injector ( 18 ) without delivering the fuel to the at least one cylinder ( 16 ) of the engine ( 12 ).

4. The system of claim 2 , wherein the fuel system control unit ( 42 ) is configured to command the at least one injector ( 18 ) for a commanded on-time period that is less than the critical injector activation time.

5. The system of claim 2 , wherein the fuel system control unit ( 42 ) is configured to command the at least one injector ( 18 ) for a commanded on-time period that is greater than or equal to the critical injector activation time.

6. The system of claim 2 , wherein the fuel system control unit ( 42 ) is configured to generate at least one drain pulse ( 408 ) applied to the at least one injector ( 18 ) during the motoring condition period ( 412 ) based on the critical injector activation time.

7. The system of claim 6 , wherein the at least one drain pulse ( 408 ) has a commanded on-time period that is less than the critical injector activation time.

8. The system of claim 6 , wherein the fuel system control unit ( 42 ) is configured to command two or more injectors ( 18 ) simultaneously using the at least one drain pulse ( 408 ) to increase fuel drainage from the engine ( 12 ).

9. The system of claim 6 , wherein the fuel system control unit ( 42 ) is configured to generate at least one test pulse ( 416 ) applied to the at least one injector ( 18 ) during the motoring condition period ( 412 ) based on the critical injector activation time.

10. The system of claim 9 , wherein the at least one test pulse ( 416 ) has a commanded on-time period that is greater than or equal to the critical injector activation time.

11. A method of performing fuel pressure control operation of an engine ( 12 ) having at least one cylinder ( 16 ) comprising:
receiving a signal indicating that no fuel is delivered to the at least one cylinder ( 16 ) of the engine ( 12 );
detecting a motoring condition based on the received signal;
controlling a fuel pressure applied to at least one injector ( 18 ) of the engine ( 12 ) in the motoring condition based on a commanded pulse train duration ( 410 ); and
commanding the at least one injector ( 18 ), for the commanded pulse train duration, to release fuel from the at least one injector ( 18 ) without injecting the fuel into the at least one cylinder ( 16 ) of the engine ( 12 ).

12. The method of claim 11 , further comprising determining the commanded pulse train duration based on a critical injector activation time.

13. The method of claim 12 , further comprising calculating the critical injector activation time that represents a maximum commanded on-time period applied to the at least one injector ( 18 ) to achieve a maximum fuel drain amount from the at least one injector ( 18 ) without delivering the fuel to the at least one cylinder ( 16 ) of the engine ( 12 ).

14. The method of claim 12 , further comprising commanding the at least one injector ( 18 ) for a commanded on-time period that is less than the critical injector activation time.

15. The method of claim 12 , further comprising commanding the at least one injector ( 18 ) for a commanded on-time period that is greater than or equal to the critical injector activation time.

16. The method of claim 12 , further comprising generating at least one drain pulse ( 408 ) applied to the at least one injector ( 18 ) of the engine ( 12 ) in the motoring condition based on the critical injector activation time.

17. The method of claim 16 , further comprising using the at least one drain pulse ( 408 ) having a commanded on-time period that is less than the critical injector activation time.

18. The method of claim 16 , further comprising commanding two or more injectors ( 18 ) simultaneously using the at least one drain pulse ( 408 ) to increase fuel drainage from the engine ( 12 ).

19. The method of claim 16 , further comprising generating at least one test pulse ( 416 ) applied to the at least one injector ( 18 ) of the engine ( 12 ) in the motoring condition based on the critical injector activation time.

20. The method of claim 19 , further comprising using the at least one test pulse ( 416 ) having a commanded on-time period that is greater than or equal to the critical injector activation time.

Assignees

• Cummins Inc

Inventors

• Carey David M
• Jalal Syed Shah
• Dudek Richard J
• Carlsson Ulf
• Peavler Paul

Classifications

• F02D41/3872 Primary

  characterised by leakage flow in injectors · CPC title

• F02M61/16

  Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14 · CPC title

• F02D41/3863 Primary

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

• F02M67/00 Primary

  Apparatus in which fuel-injection is effected by means of high-pressure gas, the gas carrying the fuel into working cylinders of the engine, e.g. air-injection type (using compressed air for low-pressure fuel-injection apparatus F02M69/08) · CPC title

• F02M51/00

  Fuel-injection apparatus characterised by being operated electrically · CPC title