USING CYLINDER FIRING HISTORY FOR COMBUSTION CONTROL IN A SKIP FIRE ENGINE

• US 20140278007A1
• Filed: 03/15/2013
• Published: 09/18/2014
• Est. Priority Date: 07/11/2008
• Status: Active Grant

• Current Assignee: Tula Technology, Incorporated
• Original Assignee: Tula Technology, Incorporated
• Inventors: WILCUTTS, Mark A., YUAN, Xin, SWITKES, Joshua P., CARLSON, Steven E., CHANDLER, Christopher W., Hand, Christopher C., YOUNKINS, Matthew A., CHIEN, Li-Chun
• Granted Patent: US 9,664,130 B2
• Time in Patent Office: Days
• US Class Current: 701/104
• CPC Class Codes: F02D 2200/0614 Actual fuel mass or fuel injection amount
• CPC Class Codes: F02D 41/0087 Selective cylinder activation, i.e. partial cylinder operation deceleration cut-off F02D41/123
• CPC Class Codes: F02D 41/3058 the engine working with a variable number of cycles

Abstract

Various methods and arrangements for determining a combustion control parameter for a working chamber in an engine are described. In one aspect, an engine controller includes a firing counter that stores a firing history for the working chamber. A combustion control module is used to determine a combustion control parameter, which is used to help manage combustion in the working chamber. The combustion control parameter is determined based at least in part on the firing history.

Claims

1. An engine controller for an internal combustion engine operated in a skip fire manner, the engine controller comprising:

a firing counter that stores a firing history of a working chamber in the engine; and

a combustion control module that is arranged to determine a combustion control parameter that helps manage combustion in the working chamber wherein the determination of the combustion control parameter is based at least in part on the firing history.

2. An engine controller as recited in claim 1 wherein the combustion control parameter is selected from the group consisting of injection timing, injection pulse width, fuel pressure, ignition dwell time, valve lift and cam phasing.

3. An engine controller as recited in claim 1 wherein the firing history indicates at least one selected from the group consisting of 1) a number of consecutive skips since a fire;

2) a number of skips over a plurality of consecutive working cycles of the working chamber; and

     3) a number of fires and skips over a plurality of consecutive working cycles of the working chamber.

4. An engine controller as recited in claim 1 wherein:

the firing counter is arranged to store a plurality of firing histories for a plurality of working chambers, respectively; and

the firing counter is arranged to store a distinct firing history for each working chamber.

5. An engine controller as recited in claim 4 wherein the firing histories indicate that the working chambers were operated in a skip fire manner such that selected working cycles of selected working chambers are skipped and selected working cycles of selected working chambers are fired and wherein individual working chambers are sometimes skipped and sometimes fired.

6. An engine controller as recited in claim 1 wherein:

the combustion control module is arranged to apply a model that determines puddle dynamics of a puddle that forms on an intake port of the working chamber wherein the model takes into account the firing history and is used to help determine the combustion control parameters.

7. An engine controller as recited in claim 6 wherein the combustion control module is arranged to help determine an amount of fuel to deliver to the working chamber based on a calculation of X and Tau, X representing a fraction of injected fuel that forms a puddle on an intake port for the working chamber and Tau indicating a rate of decay of the deposited fuel into the working chamber.

8. An engine controller as recited in claim 7 wherein the combustion control module is further arranged to assign a first value to Tau if there was an intake event during a selected working cycle of the working chamber and to assign a second, different value to Tau if there was no intake event during the selected working cycle.

9. An engine controller as recited in claim 7 wherein the combustion control module is further arranged to calculate the fuel delivery amount, X and Tau independently for each of the plurality of working chambers.

10. An engine controller as recited in claim 1 wherein the calculation of the amount of fuel to deliver to the working chamber is further based on one of the group consisting of 1) engine temperature;

2) manifold absolute pressure;

     3) air charge;

     4) cam timing; and

     5) firing histories of other working chambers in the plurality of working chambers.

11. An engine controller as recited in claim 1 wherein when the firing history indicates more skips, the combustion control module is arranged to selectively perform one selected from the group consisting of:

1) increase the amount of fuel delivered to the working chamber; and

     2) decrease the amount of fuel delivered to the working chamber based on the firing history.

12. An engine controller as recited in claim 1 wherein when the firing history indicates more skips, the combustion control module is arranged to perform one selected from the group consisting of:

1) further advance spark timing based on the firing history; and

     2) further retard spark timing.

13. An engine controller as recited in claim 1 wherein the firing history includes a parameter that helps indicate at least one selected from the group consisting of:

1) whether the working chamber was fired or skipped; and

     2) conditions under which the working chamber was fired or skipped.

14. A method for manipulating a combustion control parameter for a working chamber of an engine, the method comprising:

storing a firing history for the working chamber; and

determining a combustion control parameter that is used to help manage combustion in the working chamber wherein the determination of the combustion control parameter is based at least in part on the firing history.

15. A method as recited in claim 14 wherein the combustion control parameter is selected from the group consisting of injection timing, injection pulse width, fuel pressure, ignition dwell time, valve lift and cam phasing.

16. A method as recited in claim 14 wherein the firing history indicates at least one selected from the group consisting of 1) a number of consecutive skips since a fire;

2) a number of skips over a number of consecutive working cycles of the working chamber; and

     3) a number of fires and skips over a plurality of consecutive working cycles of the working chamber.

17. A method as recited in claim 14 further comprising:

storing a plurality of firing histories for a plurality of working chambers, respectively; and

storing a distinct firing history for each working chamber.

18. A method as recited in claim 14 wherein the firing histories indicate that the working chambers were operated in a skip fire manner such that selected working cycles of selected working chambers are skipped and selected working cycles of selected working chambers are fired and wherein individual working chambers are sometimes skipped and sometimes fired.

19. A method as recited in claim 14 further comprising:

determining an amount of fuel to deliver to the working chamber based on a fuel puddle model calculation of X and Tau, X representing a fraction of injected fuel that forms a puddle on an intake port for the working chamber and Tau indicating a rate of decay of the deposited fuel into the working chamber.

20. A method as recited in claim 19 further comprising:

assigning a first value to Tau if there was an intake event during a selected working cycle of the working chamber and assigning a second, different value to Tau if there was no intake event during the selected working cycle.

21. A method as recited in claim 19 further comprising:

calculating the fuel delivery amount, X and Tau independently for each of the plurality of working chambers.

22. A method as recited in claim 14 further comprising:

selectively adjusting the amount of fuel delivered to the working chamber based on the firing history wherein the firing history indicates a sequence of skips and fires.