Differential fuel injection

Patent metadata

Field	Value
Publication number	US-10344702-B2
Application number	US-201313925323-A
Country	US
Kind code	B2
Filing date	Jun 24, 2013
Priority date	Jul 16, 2012
Publication date	Jul 9, 2019
Grant date	Jul 9, 2019

Abstract

A system and methods for operating four in-line cylinders with common rail injection is described that comprises operating a first cylinder group without a compression and power stroke injection, but with an exhaust stroke injection while operating a second cylinder group with at least a compression stroke injection. In this way, the unburned fuel injected during the exhaust stroke enriches the exhaust-gas flow and further allows heating of the exhaust aftertreatment system. In one example provided, the first cylinder group is further configured to operate in an exhaust heating mode while also operating in a power generating mode.

First claim

The invention claimed is:

1. A method for operating four in-line cylinders with common rail injection, comprising:
in a first mode, operating a first cylinder group of two cylinders without compression and power stroke injections and with an exhaust stroke injection, while operating a second cylinder group of two cylinders with at least a compression stroke injection, and no ignition event takes place in the first cylinder group during operation in the first mode, and during the operation in the first mode, no fuel injections to the first cylinder group and the second cylinder group overlap.

2. The method of claim 1 , wherein each of the exhaust and compression stroke injections have a fuel quantity that exceeds a threshold.

3. The method of claim 2 , wherein the compression stroke injection of the second cylinder group further includes multiple injections comprising a pre-injection and a main-injection, and the pre-injection comprises an injection of fuel in a quantity that is less than the threshold.

4. The method of claim 3 , wherein the exhaust stroke injections occur based on one of an exhaust temperature and an engine output.

5. A method for operating four in-line cylinders with common rail injection, comprising:
in a first mode that includes an engine output being less than a power threshold, operating a first cylinder group without a compression stroke injection and with a first exhaust stroke injection while operating a second cylinder group with at least a first compression stroke injection; and
in a second mode that includes the engine output increasing above the power threshold, operating the first cylinder group with a second compression stroke injection and a second exhaust stroke injection while operating the second cylinder group with at least a third compression stroke injection, where a first quantity of fuel injected by the first exhaust stroke injection is greater than a second quantity of fuel injected by the second exhaust stroke injection.

6. The method of claim 5 , wherein the method further includes, in a third mode, operating all four in-line cylinders with a fourth compression stroke injection and no exhaust stroke injection.

7. The method of claim 5 , wherein, in the second mode, at least one compression stroke injection in the second cylinder group and at least one exhaust stroke injection in the first cylinder group occur concurrently.

8. The method of claim 5 , wherein during both the first and the second mode, an exhaust gas temperature is below a temperature threshold.

9. The method of claim 5 , wherein the first cylinder group comprises a first cylinder and a third cylinder and the second cylinder group comprises a second cylinder and a fourth cylinder in an engine firing order, and wherein operating the first cylinder group with the second compression stroke injection and the second exhaust stroke injection while operating the second cylinder group with at least the third compression stroke injection further comprises operating the first cylinder with a compression stroke injection, concurrently to operating the third cylinder with an exhaust stroke injection, operating the second cylinder without an intake stroke injection, and operating the fourth cylinder without a power stroke injection; and
operating the second cylinder with a compression stroke injection, concurrently to operating the fourth cylinder without an exhaust stroke injection, operating the first cylinder without a power stroke injection, and operating the third cylinder without an intake stroke injection.

10. The method of claim 6 , further comprising, during a fourth mode, operating all four in-line cylinders with a fifth compression stroke injection and a third exhaust stroke injection.

11. A method for operating an engine with a common fuel rail, comprising:
directly injecting a first amount of fuel to each cylinder of a first cylinder group during a respective exhaust stroke while injecting a second amount of fuel to each cylinder of a second cylinder group during a respective compression stroke and not injecting fuel to each cylinder of the second cylinder group during a respective exhaust stroke of the second cylinder group,
and also injecting a third amount of fuel to one or more cylinders of the first cylinder group during a compression stroke of the one or more cylinders, wherein the third amount is based on the first amount, and wherein the third amount is smaller than the second amount.

12. The method of claim 11 , further comprising post-injecting fuel to the one or more cylinders of the first cylinder group during a power stroke of the one or more cylinders.

13. The method of claim 11 , wherein directly injecting the first amount of fuel to each cylinder of the first cylinder group during the respective exhaust stroke comprises directly injecting the first amount of fuel to each cylinder of the first cylinder group in a respective exhaust stroke over a number of exhaust strokes of the first cylinder group while an exhaust temperature is below a temperature threshold.

14. The method of claim 11 , wherein the engine comprises an even number of cylinders, wherein the even number of cylinders further includes at least four cylinders that are fired in an engine firing order, wherein the first cylinder group comprises all odd-numbered cylinders of the engine firing order and the second cylinder group comprises all even-numbered cylinders of the engine firing order, and wherein:
directly injecting the first amount of fuel to each cylinder of the first cylinder group during the respective exhaust stroke comprises directly injecting a main injection of fuel into each odd-numbered cylinder only during an exhaust stroke, where the main injection of fuel into each odd-numbered cylinder comprises a largest amount of fuel injected into each odd-numbered cylinder in a given cylinder cycle, and
injecting the second amount of fuel to each cylinder of the second cylinder group during the respective compression stroke comprises injecting a main injection of fuel into each even-numbered cylinder during a compression stroke, where the main injection of fuel into each even-numbered cylinder comprises a largest amount of fuel injected into each even-numbered cylinder in a given cylinder cycle.

15. The method of claim 14 , wherein the main injections are non-overlapping injections that are delivered to one cylinder at a time.

16. The method of claim 11 , wherein the first cylinder group comprises a first cylinder and a third cylinder and the second cylinder group comprises a second cylinder and a fourth cylinder, wherein when the second cylinder is in an exhaust stroke, the fourth cylinder generates power via a compression stroke injection, and when the fourth cylinder is in an exhaust stroke, the second cylinder generates power via a compression stroke injection.

Assignees

• Ford Global Tech Llc

Inventors

• Yacoub Yasser Mohamed Sayed

Classifications

• F02D41/025

  by changing the composition of the exhaust gas, e.g. for exothermic reaction on exhaust gas treating apparatus · CPC title

• F02D41/401

  Controlling injection timing (F02D41/402 takes precedence) · CPC title

• F02D2250/11

  Oil dilution, i.e. prevention thereof or special controls according thereto · CPC title

• F02D41/0082 Primary

  per groups or banks (F02D41/0087 takes precedence) · CPC title

• F02D41/34 Primary

  with means for controlling injection timing or duration · CPC title