Dynamic valve control in a skip fire controlled engine

Patent metadata

Field	Value
Publication number	US-11261807-B2
Application number	US-202117183856-A
Country	US
Kind code	B2
Filing date	Feb 24, 2021
Priority date	Jul 31, 2012
Publication date	Mar 1, 2022
Grant date	Mar 1, 2022

Abstract

Various methods and arrangements for improving fuel economy and noise, vibration, and harshness (NVH) in a skip fire controlled engine are described. An engine controller dynamically selects a gas spring type for a skipped firing opportunity. Determination of the skip/fire pattern and gas spring type may be made on a firing opportunity by firing opportunity basis.

First claim

What is claimed is:

1. A method of controlling an internal combustion engine having a plurality of cylinders during skip fire operation of the engine, each cylinder including at least one associated intake valve and at least one associated exhaust valve, wherein during the skip fire operation of the engine at a selected displacement, at least one of the cylinders is sometimes skipped and sometimes fired, the method comprising:
(i) determining that a first skipped working cycle in a first selected cylinder will not be fired during the skip fire operation of the engine;
(ii) actuating a first intake valve associated with the first selected cylinder such that the first intake valve is open during at least a portion of an intake stroke of the first skipped working cycle;
(iii) holding the at least one exhaust valve associated with the first selected cylinder closed during an exhaust stroke associated with the first skipped working cycle; and
(iv) actuating the first intake valve during at least a portion of the intake stroke of a first fired working cycle that occurs after the first skipped working cycle in the first selected cylinder, the first fired working cycle being the first working cycle in the selected cylinder that is fired after the first skipped working cycle during the skip fire operation of the engine.

2. A method as recited in claim 1 wherein the first skipped working cycle immediately follows an earlier fired working cycle in the first selected cylinder.

3. A method as recited in claim 1 further comprising repeating (i)-(iv) for each skipped working cycle that immediately follows an earlier fired working cycle in the same cylinder.

4. A method as recited in claim 1 wherein at least one additional skipped working cycle occurs in the first selected cylinder between the first skipped working cycle and the first fired working cycle.

5. A method as recited in claim 4 wherein:
the first intake valve is not actuated during any of the at least one additional skipped working cycle(s) that occur in the first selected cylinder between the first skipped working cycle and the first fired working cycle; and
holding the at least one exhaust valve associated with the first selected cylinder closed during each of the at least one additional skipped working cycle(s).

6. A method as recited in claim 5 wherein the first skipped working cycle immediately follows an earlier fired working cycle in the first selected cylinder.

7. A method as recited in claim 4 wherein the first intake valve is actuated during a selected one of the at least one additional skipped working cycle(s) that occur in the first selected cylinder between the first skipped working cycle and the first fired working cycle.

8. A method as recited in claim 1 wherein the internal combustion engine is a compression ignition engine.

9. A method as recited in claim 1 wherein the internal combustion engine is a diesel engine.

10. A method as recited in claim 1 wherein the internal combustion engine is a spark ignition engine.

11. A method as recited in claim 1 wherein cams are used to actuate the valves associated with the selected cylinder.

12. A method of operating an internal combustion engine having a plurality of cylinders, each cylinder having at least one associated intake valve and at least one associated exhaust valve, the method comprising:
directing skip fire operation of the internal combustion engine using an air springs with re-intake valve management scheme, wherein during the skip fire operation of the internal combustion engine at a selected displacement, at least one of the cylinders is sometimes skipped and sometimes fired.

13. A method as recited in claim 12 wherein the air springs with re-intake valve management scheme includes:
for each first skipped working cycle within a selected one of the cylinders that immediately follows a fired working cycle within the selected cylinder, causing an air charge to be introduced into the selected cylinder during such first skipped working cycle; and
for each first fired working cycle that immediately follows a skipped working cycles within the selected cylinder, causing the air charge within the cylinder to be refreshed during an intake stroke associated with such first fired working cycle.

14. A method as recited in claim 12 wherein cylinder working cycles are selectively skipped or fired during the skip fire operation of the internal combustion engine and the air springs with re-intake valve management scheme includes:
for each skipped working cycle, holding the at least one exhaust valve associated with the cylinder in which such skipped working cycle occurs closed during an exhaust stroke associated with such skipped working cycle.

15. A method as recited in claim 14 wherein the air springs with re-intake valve management scheme further includes:
for each first skipped working cycle that immediately follows one of the fired working cycles within a selected one of the cylinders, causing an air charge to be introduced into the selected cylinder during such first skipped working cycle; and
for each first fired working cycle that immediately follows one of the skipped working cycles within the selected cylinder, causing the air charge within the cylinder to be refreshed during an intake stroke associated with such first fired working cycle.

16. A method as recited in claim 12 wherein the air springs with re-intake valve management scheme reduces oil consumption relative to a valve management scheme in which combustion gases are exhausted during fired working cycles and no air charge in introduced during the first skipped working cycles.

17. A method as recited in claim 12 wherein the internal combustion engine is a spark ignition engine.

18. A method as recited in claim 12 wherein the internal combustion engine is a compression ignition engine.

19. A method as recited in claim 12 wherein the internal combustion engine is a diesel engine.

20. An engine controller configured to direct operation of an internal combustion engine having a plurality of cylinders in a skip fire manner, each cylinder having at least one associated intake valve and at least one associated exhaust valve, the engine controller comprising:
a fire/skip sequence generator, wherein the fire/skip sequence generator generates a sequence of skip/fire decisions; and
a firing controller configured to direct skip fire operation of the internal combustion engine using an air springs with re-intake valve management scheme, wherein during the skip fire operation of the internal combustion engine at a selected displacement, at least one of the cylinders is sometimes skipped and sometimes fired.

21. An engine controller as recited in claim 20 wherein the firing controller is further configured to, during the skip fire using the air springs with re-intake valve management operation of the engine:
for each first skipped working cycle that immediately follows one of the fired working cycles within a selected one of the cylinders, cause an air charge to be introduced into the selected cylinder during such first skipped working cycle; and
for each first fired working cycle that immediately follows one of the skipped working cycles within the selected cylinder, cause the air charge within the cylinder to be refreshed during an intake stroke associated with such first fired working cycle.

22. An engine controller as recited in claim 20 wherein the firing controller is further configure

Assignees

• Tula Technology Inc

Inventors

• Fuschetto Jerry F
• Younkins Matthew A
• Soliman Ihab S
• Wilcutts Mark A
• Carlson Steven E
• Serrano Louis J

Classifications

• F02D41/0005 Primary

  during deceleration · CPC title

• F02D41/0087

  Selective cylinder activation, i.e. partial cylinder operation (deceleration cut-off F02D41/123) · CPC title

• F01N2900/08

  said parameters being related to the engine · CPC title

• F02D13/06

  Cutting-out cylinders · CPC title

• F01N9/00 Primary

  Electrical control of exhaust gas treating apparatus (monitoring or diagnostic devices for exhaust-gas treatment apparatus F01N11/00; conjoint electrical control of two or more combustion engine functions F02D43/00) · CPC title