Method and system for extending dilution limit of a prechamber spark ignition engine

Patent metadata

Field	Value
Publication number	US-11268434-B1
Application number	US-202016998539-A
Country	US
Kind code	B1
Filing date	Aug 20, 2020
Priority date	Aug 20, 2020
Publication date	Mar 8, 2022
Grant date	Mar 8, 2022

Abstract

A system includes an engine having a main combustion chamber and a prechamber containing a spark plug. The prechamber is in fluid communication with the main combustion chamber through at least one orifice. An engine intake line provides intake air to the engine. An engine exhaust line receives exhaust gases from the engine. An exhaust gas recirculation line transports a portion of the exhaust gases from the engine exhaust line to the engine intake line, forming an exhaust gas recirculation loop through the engine. The system includes a reformer having a reactor containing a catalyst-coated substrate. The reformer generates a gaseous reformate from a fuel. The system includes a prechamber feed line to transport a stream of the gaseous reformate from the reformer to the prechamber.

First claim

What is claimed is:

1. A system, comprising:
an engine comprising:
a main combustion chamber; and
a prechamber containing a spark plug, the prechamber disposed at least partially within the main combustion chamber and in fluid communication with the main combustion chamber through at least one orifice;

an engine intake line having an inlet end in communication with an ambient environment and an outlet end in communication with the engine, the engine intake line to provide intake air to the engine;
an engine exhaust line having an inlet end in communication with the engine and an outlet end in communication with the ambient environment, the engine exhaust line to receive exhaust gases from the engine;
an exhaust gas recirculation line in communication with the engine intake line and the engine exhaust line, the exhaust gas recirculation line to selectively transport a portion of the exhaust gases from the engine exhaust line to the engine intake line and thereby form an exhaust gas recirculation loop through the engine;
a reformer comprising a reactor containing a catalyst-coated substrate, the reformer to generate a gaseous reformate from a fuel;
a prechamber feed line in fluid communication with the reformer and the prechamber, the prechamber feed line to transport a stream of the gaseous reformate from the reformer to the prechamber; and
an exhaust feed line in fluid communication with the engine exhaust line and the reactor, the exhaust feed line to transport a stream of the exhaust gases from the engine exhaust line to the reactor,
wherein the exhaust feed line includes a mixing section in which the fuel contacts the stream of the exhaust gases; and
wherein the exhaust feed line includes the mixing section in which a supply of air contacts the stream of the exhaust gases.

2. The system of claim 1 , wherein the prechamber feed line includes the mixing section in which a supply of air contacts the stream of the gaseous reformate.

3. The system of claim 2 , wherein the prechamber feed line is connected to an intake port of the prechamber, and further comprising a valve disposed in the intake port to selectively permit flow from the prechamber feed line into the prechamber.

4. The system of claim 1 , further comprising an exhaust vent line in fluid communication with the engine exhaust line and a portion of an environment containing the reformer, the exhaust vent line to transport the stream of the exhaust gases from the engine exhaust line to the portion of the environment containing the reformer, the stream of the exhaust gases transported by the exhaust vent line to provide heating to the reformer.

5. The system of claim 1 , wherein the reformer further comprises a vaporizer in fluid communication with the reactor, the vaporizer arranged to receive the fuel and output a vaporized fuel to the reactor for generation of the gaseous reformate.

6. The system of claim 1 , further comprising a valve disposed in the exhaust gas recirculation line to control flow of the exhaust gases from the engine exhaust line to the engine intake line.

7. The system of claim 6 , further comprising a cooling device disposed in the exhaust gas recirculation line and operable to remove heat from the exhaust gases flowing from the exhaust gas recirculation line into the engine intake line.

8. The system of claim 7 , further comprising:
a compressor disposed in the engine intake line and operable to compress flow in the engine intake line; and
a turbine disposed in the engine exhaust line and driven by the exhaust gases flowing through the engine intake line, the turbine operatively coupled to the compressor.

9. A method for operating an engine, comprising:
generating a stream of hydrogen-rich gaseous reformate in a reformer located outside of an engine cylinder, the generating comprising contacting a fuel with a catalyst-coated substrate in a reactor of the reformer;
for each of a plurality of operating cycles of the engine,
providing a first combustible mixture comprising a portion of the hydrogen-rich gaseous reformate in a prechamber of the engine;
providing a second combustible mixture in a main combustion chamber of the engine;
spark igniting the first combustible mixture in the prechamber to generate a plurality of flame jets;
ejecting the plurality of flame jets from the prechamber into the main combustion chamber, whereby the flame jets ignite the second combustible mixture in the main combustion chamber;
ejecting exhaust gases generated from igniting the second combustible mixture out of the main combustion chamber;
directing at least a portion of the exhaust gases ejected out of the main combustion chamber to the reformer; and
diluting the second combustible mixture for a subsequent operation cycle with at least one of air and a portion of the exhaust gases ejected out of the main combustion chamber in a previous operation cycle.

10. The method of claim 9 , wherein generating a stream of hydrogen-rich gaseous reformate in a reformer located outside of an engine cylinder comprises generating hydrogen-rich gaseous reformate comprising hydrogen and carbon monoxide.

11. The method of claim 9 , wherein directing the at least a portion of the exhaust gases to the reformer comprises providing the at least a portion of the exhaust gases as a stream of exhaust gases and feeding the stream of exhaust gases into the reactor.

12. The method of claim 11 , further comprising at least one of injecting the fuel into the stream of exhaust gases that is fed into the reactor and injecting air into the stream of exhaust gases that is fed into the reactor.

13. The method of claim 11 , wherein directing the at least a portion of the exhaust gases to the reformer comprises heating the reformer by contacting the reformer with the at least a portion of the exhaust gases.

14. The method of claim 9 , wherein contacting a fuel with a catalyst-coated substrate in a reactor of the reformer comprises providing gasoline or methanol as the fuel.

15. The method of claim 14 , further comprising vaporizing the fuel prior to contacting the fuel with the catalyst-coated substrate.

16. The method of claim 9 , further comprising cooling the portion of the exhaust gases prior to diluting the second combustion mixture with the portion of the exhaust gases, wherein a dilution level of the second combustible mixture with at least one of the air and the portion of the exhaust gases is up to 50%.

17. A method for operating an engine, comprising:
generating a stream of hydrogen-rich gaseous reformate in a reformer located outside of an engine cylinder, the generating comprising contacting a fuel with a catalyst-coated substrate in a reactor of the reformer;
for each of a plurality of operating cycles of the engine,
providing a first combustible mixture comprising a portion of the hydrogen-rich gaseous reformate in a prechamber of the engine;
providing a second combustible mixture in a main combustion chamber of the engine;
spark igniting the first combustible mixture in the prechamber to generate a plurality of flame jets;
ejecting the plurality of flame jets from the prechamber into the main combustion chamber, whereby the flame jets ignite the second combustible mixture in the main combustion chamber;
ejecting exhaust gases generated from igniting the second combustible mixture out of the main combustion chamber; and
directing at least a portion of the exhaust gases ejected out of the main combustion chamber to the reformer;

diluting the second combustible mixture for a subsequent operation cycle wi

Assignees

• Aramco Services Co
• Saudi Arabian Oil Co

Inventors

• Voice Alexander
• Engineer Nayan
• Yu Xin

Classifications

• Y02T10/30

  Use of alternative fuels, e.g. biofuels · CPC title

• Y02T10/12

  Improving ICE efficiencies · CPC title

• F02B19/108

  with fuel injection at least into pre-combustion chamber, i.e. injector mounted directly in the pre-combustion chamber · CPC title

• F02M21/0227 Primary

  Means to treat or clean gaseous fuels or fuel systems, e.g. removal of tar, cracking, reforming or enriching · CPC title

• F02B19/12 Primary

  with positive ignition (engines with non-timed positive ignition, and with incandescent chambers F02B9/08) · CPC title