Deposit mitigation for gaseous fuel injectors

Patent metadata

Field	Value
Publication number	US-10830198-B2
Application number	US-201615754944-A
Country	US
Kind code	B2
Filing date	Aug 26, 2016
Priority date	Aug 27, 2015
Publication date	Nov 10, 2020
Grant date	Nov 10, 2020

Abstract

A method for deposit mitigation in a gaseous fuel injector that introduces a gaseous fuel through a gaseous fuel orifice directly into a combustion chamber of an internal combustion engine includes at least one of a) reducing the ago length of the gaseous fuel orifice by substantially between 10% to 50% of a previous length of a previous gaseous fuel orifice showing deposit accumulation above a predetermined threshold; b) providing the gaseous fuel orifice with an inwardly and substantially linearly tapering profile; c) determining deposit mitigation is needed; and performing at least one of the following deposit mitigation techniques i) increasing gaseous fuel injection pressure wherein deposit accumulation is reduced during fuel injection; and ii) decreasing gaseous fuel temperature wherein a rate of deposit accumulation is reduced; and d) injecting compressed air through the gaseous fuel orifice during shutdown of the internal combustion engine; whereby torque loss in the internal combustion engine due to deposit accumulation in the gaseous fuel orifice is reduced below a predetermined value.

First claim

What is claimed is:

1. A method for deposit mitigation in a gaseous fuel injector that introduces a gaseous fuel through a gaseous fuel orifice directly into a combustion chamber of an internal combustion engine comprising at least one deposit mitigation chosen from:
a) reducing a length of the gaseous fuel orifice of the gaseous fuel injector by substantially between 10% to 50% of a length of a gaseous fuel orifice, of another gaseous fuel injector, showing deposit accumulation above a predetermined threshold;
b) providing the gaseous fuel orifice with an inwardly and substantially linearly tapering profile;
c) determining deposit mitigation is needed and
performing at least one deposit mitigation technique chosen from:
i) increasing gaseous fuel injection pressure whereby deposit accumulation is reduced in the gaseous fuel orifice during gaseous fuel injection; and
ii) decreasing gaseous fuel temperature whereby a rate of deposit accumulation is reduced in the gaseous fuel orifice; and

d) injecting compressed air through the gaseous fuel orifice during shutdown of the internal combustion engine,
wherein torque loss in the internal combustion engine due to deposit accumulation in the gaseous fuel orifice is reduced below a predetermined value.

2. The method of claim 1 , wherein the at least one deposit mitigation is chosen to be providing the gaseous fuel orifice with the inwardly and substantially linearly tapering profile, and further comprising providing the gaseous fuel orifice with a difference between an outlet-opening diameter and an inlet-opening diameter in a range substantially between 3 micrometers and 50 micrometers.

3. The method of claim 1 , wherein the at least one deposit mitigation is chosen to be determining deposit mitigation is needed and performing the at least one deposit mitigation technique, the determining deposit mitigation is needed includes at least one determining deposit mitigation is needed technique chosen from:
a) estimating a level of deposit accumulation and
determining deposit mitigation is needed when the estimated level of deposit accumulation is greater than a predetermined value;
b) counting a number of engine cycles and
determining deposit mitigation is needed when the number of engine cycles is greater than a predetermined value; and
c) timing an elapsed amount of time and
determining deposit mitigation is needed when the elapsed amount of time is greater than a predetermined value.

4. The method of claim 1 , further comprising increasing injection pressure by advancing fuel injection timing in the compression stroke for the gaseous fuel.

5. The method of claim 4 , wherein gaseous fuel injection timing is advanced by at least 40 crank angle degrees.

6. The method of claim 4 , further comprising advancing fuel injection timing when the internal combustion engine is operating without boost.

7. The method of claim 4 , wherein the gaseous fuel injector is one of a plurality of gaseous fuel injectors associated with respective combustion chambers in the internal combustion engine, the method further comprises skip-firing one or more combustion chambers and increasing the fueling in remaining combustion chambers wherein the total amount of fueling remains the same.

8. The method of claim 1 , wherein the at least one deposit mitigation is chosen to be determining deposit mitigation is needed and performing the at least one deposit mitigation technique, the determining deposit mitigation is needed includes at least one determining deposit mitigation is needed technique chosen from:
operating in a part of an engine map of the internal combustion engine where combustion chamber temperature increases above a predetermined value; and
estimating a nozzle temperature of the gaseous fuel injector is above a predetermined value.

9. The method of claim 1 , further comprising decreasing heat transfer between engine coolant of the internal combustion engine and the gaseous fuel wherein gaseous fuel temperature decreases.

10. The method of claim 1 , further comprising capturing compressed air from a combustion chamber of the internal combustion engine.

11. The method of claim 10 , wherein the internal combustion engine is in an engine braking mode.

12. The method of claim 1 , wherein the gaseous fuel injector is a dual fuel injector that also introduces a liquid fuel through a liquid fuel orifice directly into the combustion chamber, the method further comprising at least one other deposit mitigation chosen from:
a) reducing a length of the liquid fuel orifice of the dual fuel injector by substantially between 10% to 50% of the length of the gaseous fuel orifice, of the another gaseous fuel injector, showing deposit accumulation above a predetermined threshold;
b) providing the liquid-fuel orifice with an inwardly and substantially linearly tapering profile;
c) determining deposit mitigation is needed and
performing at least one deposit mitigation technique chosen from:
i) increasing liquid fuel injection pressure wherein deposit accumulation in the liquid fuel orifice is reduced during fuel injection; and
ii) decreasing liquid fuel temperature wherein a rate of deposit accumulation in the liquid fuel orifice is reduced;

wherein deposit accumulation in the liquid fuel orifice is reduced below a predetermined level.

13. The method of claim 12 , further comprising providing the liquid fuel orifice with a difference between a liquid fuel orifice outlet-opening diameter and a liquid fuel orifice inlet-opening diameter in a range substantially between 3 micrometers and 50 micrometers.

14. The method of claim 12 , further comprising increasing heat transfer from the liquid fuel to the gaseous fuel wherein liquid fuel temperature decreases.

15. The method of claim 12 , further comprising increasing injection pressure by advancing fuel injection timing in the compression stroke for at least one of the liquid fuel and the gaseous fuel.

16. The method of claim 15 , wherein liquid fuel injection timing is advanced by at least 20 crank angle degrees.

17. A gaseous fuel injector for directly introducing a gaseous fuel into a combustion chamber of an internal combustion engine comprising:
a gaseous fuel injection valve;
a gaseous fuel orifice extending between a first chamber downstream from the gaseous fuel injection valve and outside the gaseous fuel injector; the gaseous fuel orifice having at least one deposit mitigation feature chosen from:
a length of the gaseous fuel orifice of the gaseous fuel injector is reduced by substantially between 10% to 50% of a length of a gaseous fuel orifice, of another gaseous fuel injector, showing deposit accumulation above a predetermined threshold; and
the gaseous fuel orifice comprising an inwardly and substantially linearly tapering profile;
wherein torque loss in the internal combustion engine due to deposit accumulation in the gaseous fuel orifice is reduced below a predetermined value.

18. The gaseous fuel injector of claim 17 , wherein outside the gaseous fuel injector is inside the combustion chamber of the internal combustion engine.

19. The gaseous fuel injector of claim 17 , wherein a difference between an outlet-opening diameter and an inlet-opening diameter of the gaseous fuel orifice is in a range substantially between 3 micrometers and 50 micrometers.

20. The gaseous fuel injector of claim 17 , wherein the gaseous fuel injector is a dual fuel injector that also introduces a liquid fuel into the combustion chamber, the d

Assignees

• Westport Power Inc
• Westpoint Power Inc

Inventors

• Soleri Dominique J
• Ouellette Patric
• Karimi Sharif Hamed

Classifications

• F02M2200/46

  Valves, e.g. injectors, with concentric valve bodies · CPC title

• F02M2200/06

  Fuel-injection apparatus having means for preventing coking, e.g. of fuel injector discharge orifices or valve needles · CPC title

• F02M65/008 Primary

  of injectors only · CPC title

• F02M43/04

  Injectors peculiar thereto · CPC title

• F02M25/14

  adding anti-knock agents, not provided for in subgroups F02M25/022 - F02M25/10 · CPC title