Fuel injection operation

Patent metadata

Field	Value
Publication number	US-10041434-B2
Application number	US-201615260215-A
Country	US
Kind code	B2
Filing date	Sep 8, 2016
Priority date	Sep 8, 2016
Publication date	Aug 7, 2018
Grant date	Aug 7, 2018

Abstract

A method of operating an engine with multi-fuel injector per cylinder capabilities to accommodate reaching minimum fuel pulsewidth conditions of any of the injectors under various operating conditions including hot and cold engine starts. The method reduces engine performance and emissions variations resulting from changes in fuel injection mass below minimum mass.

First claim

The invention claimed is:

1. A method for an engine, comprising:
during an engine cold-start,
injecting a fuel during a single cylinder cycle as a port fuel injection from a port injector, and each of an intake stroke direct fuel injection and a compression stroke direct fuel injection from a direct injector; and
responsive to one of the direct injections reaching a minimum direct injection pulsewidth of the direct injector, reducing a ratio of port fuel injection over direct fuel injection while maintaining an overall fuel injection amount for the cycle.

2. The method of claim 1 , wherein the reducing includes, responsive to multiple of the direct injections reaching the minimum direct injection pulsewidth, reducing the ratio of port fuel injection over direct fuel injection while adjusting a ratio of the direct injections to bring an amount of each of the direct injections closer to each other and while maintaining the overall fuel injection amount for the cycle.

3. The method of claim 1 , wherein the reducing includes, responsive to only one of the direct injections reaching the minimum direct injection pulsewidth, reducing the ratio of port fuel injection over direct fuel injection while maintaining a ratio of the direct injections relative to one another and while maintaining the overall fuel injection amount for the cycle.

4. The method of claim 1 , further comprising, responsive to the port fuel injection reaching a minimum port fuel injection pulsewidth of the port injector, disabling the port fuel injection and maintaining a ratio of the direct injections relative to one another and while maintaining the overall fuel injection amount for the cycle.

5. The method of claim 1 , further comprising, during a hot engine restart, injecting fuel, during a single cylinder cycle of the hot start, as a port fuel injection, an intake stroke direct fuel injection, and a compression stroke direct fuel injection; and, responsive to one of the hot start direct injections reaching the minimum direct injection pulsewidth, disabling a smaller of the hot start direct injections while maintaining a ratio of hot start direct injection fuel amount to port injection fuel amount and while maintaining an overall fuel injection amount for the cycle.

6. The method of claim 5 , further comprising, responsive to the hot start port fuel injection reaching a minimum port fuel injection pulsewidth of the port injector, disabling port fuel injection while maintaining a ratio of the direct injections relative to one another, and while maintaining the overall fuel injection amount for the cycle.

7. The method of claim 5 , further comprising, responsive to multiple of the hot start direct injections reaching the minimum direct injection pulsewidth, disabling one of the hot start direct injections while maintaining a ratio of the hot start port injection over direct injection and while maintaining the overall fuel injection amount for the cycle.

8. The method of claim 1 , wherein the ratio of port fuel injection over direct fuel injection is reduced relative to a desired ratio of port fuel injection to direct fuel injection that is determined based on temperature and a combustion event number counted from the engine cold-start.

9. The method of claim 1 , wherein the port fuel injection is injected from a port fuel injector coupled to a port fuel injection rail pressurized at least partly by a high pressure direct injection fuel pump.

10. The method of claim 1 , wherein a start timing of the port and direct fuel injections is adjusted as a function of the reduction in the ratio of port fuel injection over direct fuel injection.

11. A method for an engine, comprising:
injecting fuel during a single cylinder cycle of an engine start as each of a port fuel injection from a port fuel injector, and an intake stroke direct fuel injection and a compression stroke direct fuel injection from a direct fuel injector;
responsive to the engine start being a cold-start and one of the direct injections of the cold-start reaching a minimum direct injection pulsewidth of the direct injector, reducing a ratio of port fuel injection over direct fuel injection; and
responsive to the engine start being a hot-start and one of the direct injections reaching the minimum direct injection pulsewidth of the direct injector, disabling a smaller of the direct injections while maintaining the ratio of port fuel injection over direct fuel injection.

12. The method of claim 11 , wherein, responsive to multiple of the direct injections of the cold-start reaching the minimum direct injection pulsewidth, reducing the ratio of port fuel injection over direct fuel injection while adjusting a ratio of the direct injections relative to one another to bring an amount of each of the direct injections closer to each other and while maintaining an overall fuel injection amount for the cycle.

13. The method of claim 12 , wherein, responsive to only one of the direct injections of the cold-start reaching the minimum direct injection pulsewidth, reducing the ratio of port fuel injection over direct fuel injection while maintaining the ratio of the direct injections relative to one another.

14. The method of claim 13 , wherein, responsive to the port fuel injection of the cold-start reaching a minimum port fuel injection pulsewidth of the port fuel injector, disabling the port fuel injection and maintaining the ratio of the direct injections relative to one another.

15. The method of claim 14 , further comprising, responsive to the hot-start and the port fuel injection reaching the minimum port fuel injection pulsewidth, disabling port fuel injection and maintaining the ratio of the direct injections relative to one another.

16. The method of claim 15 , further comprising, responsive to the hot-start and multiple of the direct injections reaching the minimum direct injection pulsewidth, disabling one of the direct injections while maintaining the ratio of port fuel injection over direct fuel injection.

17. The method of claim 16 , wherein the port fuel injection is injected from a port fuel injection rail pressurized at least partly by a high pressure direct injection fuel pump.

18. The method of claim 11 , wherein a start timing of the port and direct fuel injections is adjusted as a function of reduction in the ratio of port fuel injection over direct fuel injection.

19. The method of claim 11 , further comprising, responsive to warmed-up engine running conditions after engine starting, determining the ratio of port fuel injection over direct fuel injection as a function of speed and load, the engine being a boosted engine compressing intake air with a turbine-driven compressor.

20. An engine system, comprising:
an engine having a cylinders;
a port fuel injector mounted in a port of the cylinder;
a direct fuel injector mounted directly into the cylinder;
a temperature sensor for sensing engine temperature; and
a controller having instructions stored in memory that when executed cause:
during a single cylinder cycle of an engine cold-start, the port fuel injector to inject a port fuel injection, and the direct fuel injector to inject an intake stroke direct fuel injection and a compression stroke direct fuel injection; and
responsive to one of the intake stroke direct fuel injection and compression stroke direct fuel injection reaching a minimum direct injection pulsewidth of the direct fuel injector, adjust a ratio of port fuel injection over direct fuel injection.

Assignees

• Ford Global Tech Llc

Inventors

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

Classifications

• F02D2200/021

  Engine temperature · CPC title

• F02D41/065

  at hot start or restart (F02D41/067 takes precedence) · CPC title

• 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

• F02D41/3809

  Common rail control systems (common rail apparatus F02M55/025, F02M63/0225) · CPC title

• F02D2200/0602

  Fuel pressure · CPC title