Air-enriched gaseous fuel direct injection for an internal combustion engine

Patent metadata

Field	Value
Publication number	US-10233871-B2
Application number	US-201514738837-A
Country	US
Kind code	B2
Filing date	Jun 13, 2015
Priority date	Dec 17, 2012
Publication date	Mar 19, 2019
Grant date	Mar 19, 2019

Abstract

A method for introducing a gaseous fuel into a combustion chamber of an internal combustion engine includes forming a non-ignitable mixture of the gaseous fuel and a gas including oxygen in a predefined mixture mass ratio within a predetermined range of tolerance having a pressure suitable for directly introducing the non-ignitable mixture into the combustion chamber during at least the compression stroke; and introducing the non-ignitable mixture directly into the combustion chamber.

First claim

What is claimed is:

1. A method for introducing a gaseous fuel into a combustion chamber of an internal combustion engine comprising:
forming in an apparatus, as a function of engine operating conditions, a mixture of said gaseous fuel and a gas comprising oxygen having a pressure suitable for directly introducing said mixture into the combustion chamber during at least the compression stroke; and
injecting said mixture directly into the combustion chamber;
wherein said mixture has a mass ratio between said gas comprising oxygen and said gaseous fuel less than the upper flammability limit mass ratio such that said mixture is non-ignitable.

2. The method of claim 1 , further comprising at least one of:
(a) wherein when said gaseous fuel comprises methane, said mixture comprises a mixture mass ratio (mass of gas comprising oxygen : mass of gaseous fuel) between 0:1 and 8.8:1;
(b) wherein when said gaseous fuel comprises methane, said mixture comprises a mixture mass ratio (mass of gas comprising oxygen : mass of gaseous fuel) between 0:1 and 2:1;
(c) wherein when said gaseous fuel comprises methane, said mixture comprises a mixture mass ratio (mass of gas comprising oxygen : mass of gaseous fuel) between 0.25:1 and 1:1; and
(d) adjusting a mixture mass ratio between said gas comprising oxygen and said gaseous fuel in said mixture as a function of engine operating conditions.

3. The method of claim 1 , further comprising:
pressurizing said gaseous fuel as a function of engine operating conditions;
compressing said gas comprising oxygen; and
mixing said gaseous fuel and said gas comprising oxygen.

4. The method of claim 1 , further comprising:
pressurizing said gaseous fuel as a function of engine operating conditions;
compressing said gas comprising oxygen;
mixing said gaseous fuel and said gas comprising oxygen; and at least one of:
(a) storing said gas comprising oxygen after said compressing;
(b) wherein a pressure of said gas comprising oxygen is less than a pressure of said gaseous fuel when mixing;
(c) wherein a pressure of said gas comprising oxygen is equal to a pressure of said gaseous fuel within a predetermined range of tolerance when mixing;
(d) wherein a pressure of said gas comprising oxygen is greater than a pressure of said gaseous fuel when mixing;
(e) wherein said mixing occurs inside a fuel injector;
(f) wherein said mixing occurs upstream of a fuel injector;
(g) further comprising regulating a bias pressure between said gaseous fuel and said gas comprising oxygen;
(h) further comprising regulating a bias pressure between said gaseous fuel and said gas comprising oxygen; and adjusting said bias pressure as a function of engine operating conditions; and
(i) further comprising regulating a bias pressure between said gaseous fuel and said gas comprising oxygen; and adjusting said bias pressure during transient engine operating conditions.

5. The method of claim 3 , further comprising metering said gas comprising oxygen into said mixture as a function of a differential pressure across a control valve when mixing.

6. The method of claim 3 , further comprising:
pressurizing said gaseous fuel as a function of engine operating conditions;
compressing said gas comprising oxygen;
mixing said gaseous fuel and said gas comprising oxygen; at least one of:
(a) wherein said compressing comprises at least one of:
employing energy in exhaust gases of said internal combustion engine to compress said gas comprising oxygen;
employing energy available in momentum of a vehicle propelled by said internal combustion engine to compress said gas comprising oxygen;
employing a power take-off of said internal combustion engine to compress said gas comprising oxygen;
employing a compression stroke of a cylinder in said internal combustion engine to compress said gas comprising oxygen;
employing a hydraulically driven compressor; and
employing an electrical compressor;
(b) wherein compressing said gas comprising oxygen comprises at least two stages of compression, a first stage compression and a second stage compression;
(c) wherein compressing said gas comprising oxygen comprises at least two stages of compression, a first stage compression and a second stage compression; and further comprising cooling said gas comprising oxygen between compression stages.

7. The method of claim 3 , wherein gaseous fuel pressure before said mixing equals a pressure of said mixture to within a predetermined range of tolerance and a pressure of said gas comprising oxygen before said mixing is less than said pressure of said mixture.

8. The method of claim 7 , wherein said pressure of said gas comprising oxygen is one third of said pressure of said mixture to within a predetermined range of tolerance.

9. The method of claim 3 , wherein said mixing comprises:
introducing said gas comprising oxygen into a mixing-compressing apparatus;
introducing said gaseous fuel into said mixing-compressing apparatus after said gas comprising oxygen; and
compressing said mixture.

10. The method of claim 9 , further comprising:
pumping said gaseous fuel in a liquefied state; and
vaporizing said gaseous fuel from a liquefied state to a gas state, whereby said pumping pressurizes said gaseous fuel in said gas state.

11. The method of claim 1 , wherein at least one said gas comprising oxygen is air; and said gaseous fuel is at least one of natural gas, ethane, methane, propane, biogas, landfill gas, dimethyl ether, hydrogen and mixtures thereof.

12. The method of claim 1 , further comprising:
pressurizing air to a first pressure;
cooling air at the first pressure; and
pressurizing the cooled air to a second pressure.

13. The method of claim 12 , further comprising:
pressurizing air to a first pressure;
cooling air at the first pressure; and
pressurizing the cooled air to a second pressure; and at least one of:
wherein the step of cooling comprises circulating air at said first pressure through a heat exchanger employed to transfer heat to a cryogenic fluid; and
wherein the step of cooling comprises storing air at said first pressure in an accumulator located within a cryogenic tank.

14. The method of claim 1 , further comprising at least one of:
(a) adjusting a mixture mass ratio between said gas comprising oxygen and said gaseous fuel by controlling mass flow rate of air into a mixing apparatus by adjusting a duty cycle of a control signal employed to open and close a valve through which air passes upstream of said mixing apparatus;
(b) selectively introducing said mixture into said combustion chamber as a function of engine operating conditions wherein said mixture is introduced during at least one of transient engine operating conditions and selected regions of an engine operating map;
(c) storing said mixture prior to selective introduction of said mixture into said combustion chamber.

15. The method of claim 1 , wherein said mixture is selectively formed and injected into said combustion chamber as a function of engine operating conditions.

16. An apparatus for introducing a gaseous fuel into a combustion chamber of an internal combustion engine comprising:
a supply of said gaseous fuel;
a supply of a gas comprising oxygen;
a mixture forming apparatus for forming a mixture between said gas comprising oxygen and said gaseous fuel; and
an injection valve for directly introducing said mixture into said combustion chamber;
wherein a mass ratio between said gas comprising oxygen and said gaseous fuel in said mixture is less than the upper flammability limit mass

Assignees

• Westport Power Inc

Inventors

• Huang Jian
• Hill Philip G
• Munshi Sandeep
• Mctaggart-Cowan Gordon P

Classifications

• F02B47/08

  the substances including exhaust gas · CPC title

• F02M67/02

  the gas being compressed air, e.g. compressed in pumps (arrangements or adaptations of such pumps F02B) · CPC title

• F02M21/0275

  for in-cylinder direct injection, e.g. injector combined with spark plug · CPC title

• F02D41/38

  of the high pressure type · CPC title

• F02M21/0209

  Hydrocarbon fuels, e.g. methane or acetylene · CPC title