System and method of controlling oxygen purge of three-way catalyst

Patent metadata

Field	Value
Publication number	US-10731583-B2
Application number	US-201916380428-A
Country	US
Kind code	B2
Filing date	Apr 10, 2019
Priority date	Dec 3, 2018
Publication date	Aug 4, 2020
Grant date	Aug 4, 2020

Abstract

A method of controlling oxygen purge of a three-way catalyst may include: performing a fuel cut-off; determining whether a fuel cut-in condition is satisfied after the fuel cut-off; calculating an optimum valve overlap according to an intake amount, an engine rotation speed, and an ignition timing if the fuel cut-in condition is satisfied after the fuel cut-off; controlling a CVVD apparatus to be at the optimum valve overlap; and performing the oxygen purge at the optimum valve overlap.

First claim

What is claimed is:

1. A system of controlling oxygen purge of a three-way catalyst, comprising:
an engine including a combustion chamber, an intake valve equipped at the combustion chamber and configured to selectively supply air or an air-fuel mixture into the combustion chamber, an ignition plug equipped at the combustion chamber and configured to ignite and burn the air-fuel mixture, and an exhaust valve equipped at the combustion chamber and configured to selectively discharge exhaust gas in the combustion chamber to an outside of the combustion chamber;
a continuously variable valve duration (CVVD) apparatus configured to adjust an intake duration of the intake valve and an exhaust duration of the exhaust valve; and
a controller configured to control an ignition timing of the ignition plug, the intake duration, and the exhaust duration based on a driving condition of a vehicle,
wherein the three-way catalyst is disposed on an exhaust pipe downstream of the engine and configured to purify emission contained in the exhaust gas, and
wherein the controller controls the CVVD apparatus to be an optimum valve overlap according to an intake amount, an engine rotation speed, and the ignition timing and performs oxygen purge at the optimum valve overlap when entering a fuel cut-in where fuel is injected again after a fuel cut-off where a fuel injection is stopped.

2. The system of claim 1 , wherein the controller adjusts the optimum valve overlap by maintaining a current intake duration and controlling an exhaust valve close (EVC) timing according to the current intake duration.

3. The system of claim 1 , wherein the controller adjusts the optimum valve overlap by maintaining a current exhaust duration and controlling an intake valve open (IVO) timing according to the current exhaust duration.

4. The system of claim 1 , wherein the controller maintains a current exhaust valve open (EVO) timing and a current intake valve close (IVC) timing and controls an EVC timing and an IVO timing according to the optimum valve overlap.

5. The system of claim 1 , wherein the controller performs the fuel cut-off when a temperature of the TWC is higher than a predetermined temperature.

6. The system of claim 5 , wherein the oxygen purge is performed by controlling a fuel injection amount to be a rich air-fuel ratio.

7. A method of controlling oxygen purge of a three-way catalyst, comprising:
performing a fuel cut-off;
determining, by a controller, whether a fuel cut-in condition is satisfied after the fuel cut-off;
calculating, by the controller, an optimum valve overlap according to an intake amount, an engine rotation speed, and an ignition timing if the fuel cut-in condition is satisfied after the fuel cut-off;
controlling a continuously variable valve duration (CVVD) apparatus to be at the optimum valve overlap; and
performing the oxygen purge at the optimum valve overlap,
wherein the CVVD apparatus is configured to adjust an intake duration of an intake valve and an exhaust duration of an exhaust valve.

8. The method of claim 7 , wherein the controlling a CVVD apparatus comprises:
maintaining a current intake duration; and
controlling an exhaust valve close (EVC) timing according to the current intake duration.

9. The method of claim 7 , wherein the controlling a CVVD apparatus comprises:
maintaining a current exhaust duration; and
controlling an intake valve open (IVO) timing according to the current exhaust duration.

10. The method of claim 7 , wherein the controlling a CVVD apparatus comprises:
maintaining a current exhaust valve open (EVO) timing and a current intake valve close (IVC) timing;
controlling an IVO timing; and
controlling an EVC timing according to the optimum valve overlap and the controlled IVO timing.

11. The method of claim 7 , wherein the controlling a CVVD apparatus comprises:
maintaining a current EVO timing and a current IVC timing;
controlling an EVC timing; and
controlling an IVO timing according to the optimum valve overlap and the controlled EVC timing.

12. The method of claim 7 , further comprising determining, before performing the fuel cut-off, whether a temperature of a TWC is higher than a predetermined temperature,
wherein the fuel cut-off is performed only when the temperature of the TWC is higher than the predetermined temperature.

13. The method of claim 12 , wherein the oxygen purge is performed by controlling a fuel injection amount to be a rich air-fuel ratio.

Assignees

• Hyundai Motor Co Ltd
• Kia Motors Corp

Inventors

• Choung Jin Woo
• Kwon Kiyoung

Classifications

• F02D41/1454

  the characteristics being an oxygen content or concentration or the air-fuel ratio · CPC title

• F02D41/027 Primary

  to purge or regenerate the exhaust gas treating apparatus · CPC title

• F02D13/0261

  Controlling the valve overlap · CPC title

• F02D13/0215

  changing the valve timing only · CPC title

• F01N3/101 Primary

  Three-way catalysts · CPC title