METHOD AND SYSTEM FOR PARTICULATE MATTER CONTROL

• US 20160115878A1
• Filed: 10/22/2014
• Published: 04/28/2016
• Est. Priority Date: 10/22/2014
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: VanDerWege, Brad Alan
• Granted Patent: US 10,323,588 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F02D 17/02 Cutting-out cutting-out engines in multiple engine arrangements F02D25/04
• CPC Class Codes: F02D 2200/021 Engine temperature
• CPC Class Codes: F02D 41/0087 Selective cylinder activation, i.e. partial cylinder operation deceleration cut-off F02D41/123
• CPC Class Codes: F02D 41/1466 the characteristics being a soot concentration or content
• CPC Class Codes: F02D 41/1467 with determination means using an estimation

Abstract

Methods and systems are provided for particulate matter control in an engine configured for skip-fire operation. A cylinder pattern selected for selective cylinder deactivation, including a total number of deactivated/active cylinders as well as individual deactivated cylinder identities, may be adjusted based on an engine soot load, or a parameter indicative of engine soot load such as engine coolant temperature. In addition, reactivated engine cylinders may be transiently operated with split fuel injection to raise combustion surface temperatures.

Claims

1. A method for an engine, comprising:

deactivating a first cylinder pattern of individual cylinder valve mechanisms at a first engine soot load; and

deactivating a second, different, cylinder pattern of individual cylinder valve mechanisms at a second, higher, engine soot load.

2. The method of claim 1, wherein each of the first and second cylinder pattern are further based on one or more of driver demand, engine speed, vehicle speed, engine temperature, engine NVH, and transmission gear selection.

3. The method of claim 1, wherein the first cylinder pattern includes a first total number of deactivated/active cylinders and wherein the second cylinder pattern includes a second, different total number of deactivated/active cylinders, the second number larger/smaller than the first number.

4. The method of claim 1, wherein the first cylinder pattern includes a first set of cylinders and the second cylinder pattern includes a second, different set of cylinders, each of the first and second cylinder pattern including a common total number of cylinders.

5. The method of claim 4, wherein each of the first set of cylinders and the second set of cylinders are selected based on a cylinder firing order.

6. The method of claim 1, further comprising, performing multiple fuel injections per engine cycle in active cylinders at the second engine soot load with the second cylinder pattern, and performing single fuel injection per engine cycle at the first soot load with the first cylinder pattern.

7. The method of claim 6, wherein a total number of injections in the multiple fuel injections per cycle is based on the second cylinder pattern, the total number of injections in active cylinders increased as a total number of cylinders deactivated in the second cylinder pattern increases.

8. The method of claim 1, further comprising, performing single fuel injection in reactivated cylinders at the first engine soot load with the first cylinder pattern, and performing multiple fuel injections per engine cycle at the second soot load with the second cylinder pattern.

9. The method of claim 8, wherein a number of injections in the multiple fuel injections per cycle is based on the second cylinder pattern and a duration of the deactivating the second cylinder pattern, the number of injections in reactivated cylinders increased as a number of cylinders deactivated in the second cylinder pattern increases and/or as the duration of the deactivating the second cylinder pattern increases, the number of injections in reactivated cylinders then decreased as a number of combustion events since the reactivation increases.

10. The method of claim 8, further comprising, retarding start of fuel injection timing by a first, smaller amount while performing single fuel injection in reactivated cylinders at the first engine soot load and retarding start of fuel injection timing by a second, larger amount while performing multiple fuel injections in reactivated cylinders at the second engine soot load.

11. The method of claim 1, wherein deactivating a first cylinder pattern of individual cylinder valve mechanisms includes deactivating a first number of intake and exhaust valves and wherein deactivating a second cylinder pattern of individual cylinder valve mechanisms includes deactivating a second, different number of intake and exhaust valves.

12. A method comprising:

when engine coolant temperature is lower, deactivating a first cylinder pattern of individual cylinder valve mechanisms, and injecting fuel as multiple injections per engine cycle when the first cylinder pattern is reactivated; and

when engine coolant temperature is higher, deactivating a second, different cylinder pattern of individual cylinder valve mechanisms, and injecting fuel as a single fuel injection per engine cycle when the second cylinder pattern is reactivated.

13. The method of claim 12, wherein the first pattern is based on each of driver demand and engine soot load while the second pattern is based on driver demand and not on engine soot load, each of the first and second patterns further based on one or more of engine speed, vehicle speed, and transmission gear selection.

14. The method of claim 12, wherein the first pattern includes a first total number of deactivated/active cylinders, a first set of deactivated cylinders, and a first set of cylinder deactivation mechanisms and wherein the second pattern includes a second, different total number of deactivated/active cylinders, a second, different set of deactivated cylinders, and a second, different set of cylinder deactivation mechanisms.

15. The method of claim 14, wherein a number of injections in the multiple injections per engine cycle to a reactivated cylinder is based on the first total number of deactivated/active cylinders of the first pattern, and further based on a number of deactivation cycles of the reactivated cylinder, the number of injections increased as the first total number of deactivated/active cylinders of the first pattern increases and as the number of deactivation cycles of the reactivated cylinder increases.

16. The method of claim 15, further comprising, when the first cylinder pattern is reactivated, operating reactivated cylinders with more fuel injection timing retard while injecting fuel as multiple injections per engine cycle, and when the second cylinder pattern is reactivated, operating reactivated cylinders with less fuel injection timing retard while injecting fuel as single injection per engine cycle.

17. The method of claim 16, further comprising, when the first cylinder pattern is reactivated, after operating the reactivated cylinders with multiple injections per engine cycle for a number of combustion events, gradually decreasing the number of injections per engine cycle to a single injection per engine cycle.

18. An engine system, comprising:

an engine including a plurality of cylinders;

electrically actuated cylinder valve mechanisms coupled to each of the plurality of cylinders;

a selectively deactivatable fuel injector coupled to each of the plurality of cylinders; and

an engine controller configured with computer readable instructions stored on non-transitory memory for;

deactivating individual cylinder valve mechanisms for one or more of the plurality of cylinders according to a pattern, a total number of deactivated/active cylinders and an order of firing of active cylinders in the pattern adjusted to maintain a temperature of each engine cylinder above a threshold temperature, the threshold temperature based on a soot load of the engine.

19. The system of claim 18, wherein during the deactivating, a number and pattern of cylinder valve mechanisms operating per active cylinder is also based on the soot load of the engine.

20. The system of claim 18, wherein the controller includes further instructions for:

during reactivation of the deactivated individual cylinder valve mechanisms,

increasing each of a number of fuel injections per engine cycle and an amount of fuel injection timing retard in reactivated cylinders as the temperature of the reactivated cylinders falls below the threshold temperature at the reactivation; and

after the temperature of the reactivated cylinders rises above the threshold temperature, resuming single fuel injection per engine cycle in the reactivated cylinders.