Methods and systems for adjusting a direct fuel injector

Patent metadata

Field	Value
Publication number	US-10240554-B2
Application number	US-201715596981-A
Country	US
Kind code	B2
Filing date	May 16, 2017
Priority date	May 16, 2017
Publication date	Mar 26, 2019
Grant date	Mar 26, 2019

Abstract

Methods and systems are provided for reducing direct injector fueling errors due to injection variability in a transition region of a direct injector map. Fuel injection, including usage of one or more direct and port injected fuel pulses, may be planned based on engine operating conditions including engine temperature and driver demand. Responsive to any of the direct injected fuel pulses having a pulse-width that lies in a high variability transition region of the direct injector, the fuel injection may be adjusted via adjustments to a number and/or split ratio of the injections so as to not operate in the transition region.

First claim

The invention claimed is:

1. A method for an engine, comprising:
estimating an initial ratio of port injected fuel relative to direct injected fuel on a combustion cycle based on engine operating conditions; and
responsive to a direct fuel injection at the initial ratio being in a transition region of a direct injector map, updating the initial ratio to move the direct fuel injection out of the transition region,
wherein the transition region is positioned between a ballistic region and a lift region of the direct injector map, and wherein direct injector variability in the transition region is higher than each of the ballistic region and the lift region.

2. The method of claim 1 , wherein the updating is based on a pulse-width of the direct fuel injection relative to each of a ballistic-to-transition border and a lift-to-transition border of the direct injector map.

3. The method of claim 2 , wherein the updating includes, responsive to a distance of the direct fuel injection pulse-width from the ballistic-to-transition border of the direct injector map being smaller than the distance of the direct fuel injection pulse-width from the lift-to-transition border of the direct injector map, decreasing a direct injected fuel mass to move from the pulse-width from the transition region into the ballistic region of the direct injector map, while increasing a port injected fuel mass.

4. The method of claim 3 , wherein the updating further includes, responsive to a distance of the direct fuel injection pulse-width from the ballistic-to-transition border of the direct injector map being larger than the distance of the direct fuel injection pulse-width from the lift-to-transition border of the direct injector map, increasing the direct injected fuel mass to move from the pulse-width from the transition region into the lift region of the direct injector map, while decreasing the port injected fuel mass.

5. The method of claim 4 , wherein the initial ratio of port injected fuel relative to direct injected fuel includes multiple direct injections on the combustion cycle, and wherein the increasing and decreasing is based on a number of the multiple direct injections.

6. The method of claim 5 , wherein the updating further includes adjusting the number of the multiple direct injections by decreasing the number of the multiple direct injections to move the pulse-width from the transition region into the lift region.

7. The method of claim 6 , wherein the decreasing is responsive to an unadjusted number of the multiple direct injections being higher than a threshold.

8. The method of claim 5 , wherein the updating further includes adjusting the number of the multiple direct injections by increasing the number of the multiple direct injections to move the pulse-width from the transition region into the ballistic region.

9. The method of claim 8 , wherein the increasing is responsive to an unadjusted number of the multiple direct injections being lower than a threshold.

10. The method of claim 5 , wherein the multiple direct injections include multiple direct injections in an intake stroke and/or a compression stroke of the combustion cycle, and wherein the updating further includes updating a split ratio of direct injected fuel delivered in the intake stroke relative to the compression stroke.

11. A method, comprising:
during a first condition, responsive to a pulse-width of one of multiple direct injection fuel pulses of a combustion cycle lying within a transition region of a direct injector map, reducing a number of the multiple direct injection fuel pulses while maintaining a split ratio of direct injected to port injected fuel; and
during a second condition, responsive to the pulse-width of the one of the multiple direct injection fuel pulses of the combustion cycle lying within the transition region of the direct injector map, adjusting the split ratio of direct injected to port injected fuel.

12. The method of claim 11 , wherein adjusting the split ratio includes, when more direct injected fuel mass is needed to move the one of the multiple direct injection fuel pulses out of the transition region, increasing the split ratio of direct injected fuel to port injected fuel over the combustion cycle, and when less direct injected fuel mass is needed to move the one of the multiple direct injection fuel pulses out of the transition region, decreasing the split ratio of direct injected fuel to port injected fuel over the combustion cycle.

13. The method of claim 11 , wherein adjusting the split ratio includes maintaining the number of multiple direct injection fuel pulses in the combustion cycle.

14. The method of claim 11 , wherein adjusting the split ratio includes adjusting the number of multiple direct injection fuel pulses in the combustion cycle, as well as a fuel mass delivered in each of the multiple direct injection fuel pulses.

15. The method of claim 11 , wherein during the first condition, the pulse-width of each of the reduced number of multiple direct injection fuel pulses is in a full lift region of the direct injector map.

16. The method of claim 11 , wherein the first condition includes higher engine load and the second condition includes lower engine load.

17. An engine system, comprising:
an engine cylinder;
a direct injector for fueling the cylinder;
a port injector for fueling the cylinder; and
a controller with computer readable instructions stored on non-transitory memory for:
estimating an initial fuel injection profile for a combustion cycle of the cylinder based on engine speed-load and engine temperature, the initial fuel injection profile including an initial split ratio of direct injected fuel to port injected fuel delivered via multiple direct injection fuel pulses, at least one of the multiple direct injection fuel pulses having a pulse-width in a transition region of the direct injector; and
modifying the initial fuel injection profile to change the split ratio of direct injected fuel to port injected fuel so that the at least one of the multiple direct injection fuel pulses is moved out of the transition region.

18. The system of claim 17 , wherein the modifying includes increasing or decreasing a port injected fuel mass relative to a total direct injected fuel mass based on the pulse-width of the at least one of the multiple direct injection pulses relative to an upper pulse-width limit of a ballistic region and a lower pulse-width limit of a lift region of the direct injector.

19. The system of claim 18 , wherein decreasing the total direct injected fuel mass includes decreasing a number of the multiple direct injection fuel pulses to move the pulse-width of each of the decreased number of multiple direct injection fuel pulses into the lift region, and wherein increasing the total direct injected fuel mass includes increasing the number of the multiple direct injection fuel pulses to move the pulse-width of each of the increased number of total direct injection fuel pulses into the ballistic region.

Assignees

• Ford Global Tech Llc

Inventors

• Sanborn Ethan D
• Hollar Paul
• Thomas Joseph Lyle
• Dusa Daniel

Classifications

• F02D41/3094 Primary

  the fuel injection being effected by at least two different injectors, e.g. one in the intake manifold and one in the cylinder · CPC title

• F02D41/04

  Introducing corrections for particular operating conditions (F02D41/14 takes precedence) · CPC title

• F02D2200/0614

  Actual fuel mass or fuel injection amount · CPC title

• F02D41/402 Primary

  Multiple injections · CPC title

• F02D41/40

  with means for controlling injection timing or duration · CPC title