Method for managing temperatures in aftertreatment system

Patent metadata

Field	Value
Publication number	US-10378405-B2
Application number	US-201615001885-A
Country	US
Kind code	B2
Filing date	Jan 20, 2016
Priority date	Jan 20, 2016
Publication date	Aug 13, 2019
Grant date	Aug 13, 2019

Abstract

A method for managing temperatures in an aftertreatment system positioned downstream of an engine. The method includes (1) combusting a rich air/diesel mixture in a cylinder of the engine, and then (2) combusting a lean air/diesel mixture in the cylinder, in the next combustion event in the cylinder, after combusting the rich air/diesel mixture therein. The method further includes repeating steps (1) and (2) in the cylinder and basing a frequency thereof on a desired aftertreatment system temperature.

First claim

What is claimed is:

1. A method for managing energy in an aftertreatment system positioned downstream of an engine, the aftertreatment system comprising a diesel oxidation catalyst, the method comprising:
(a) combusting a lean air/diesel mixture in a cylinder of the engine;
(b) determining whether an aftertreatment system temperature is above a threshold temperature;
(c) combusting a rich air/diesel mixture in the cylinder following the determination that the aftertreatment system temperature is above the threshold temperature;
(d) repeating transitions back-and-forth between (a) and (c) and basing a frequency of (c) on a cylinder temperature relative to a cylinder limit temperature; and
(e) substantially always combusting an additional lean air/diesel mixture in the cylinder, in a next combustion event in the cylinder, after combusting the rich air/diesel mixture therein.

2. The method of claim 1 , wherein the aftertreatment system temperature is a diesel oxidation catalyst temperature.

3. The method of claim 1 , wherein the combusting of the rich air/diesel mixture comprises injecting diesel fuel into the cylinder between 5° before a piston positioned therein is at top dead center and 10° after the piston is at top dead center.

4. The method of claim 1 , further comprising combusting a lean air/diesel mixture in a next cylinder immediately and sequentially after combusting the rich air/diesel mixture in the cylinder, the next cylinder being in a firing order that is immediately and sequentially after the cylinder.

5. The method of claim 1 , further comprising substantially-always combusting a lean air/diesel mixture in a next cylinder sequentially after combusting the rich air/diesel mixture in the cylinder, the next cylinder being in a firing order that is sequentially after the cylinder.

6. The method of claim 1 , further comprising:
determining a desired aftertreatment system temperature; and
basing the frequency of (c) on the desired aftertreatment system temperature relative to a current aftertreatment system temperature.

7. The method of claim 1 , wherein when the aftertreatment system temperature is above a threshold aftertreatment temperature but below a desired aftertreatment temperature, the combusting of the rich air/diesel mixture occurs in between 2% and 45% of the combustion events in the cylinder.

8. A method for managing energy in an aftertreatment system positioned downstream of an engine, the method comprising:
(a) combusting a rich air/diesel mixture in a cylinder of the engine;
(b) combusting a lean air/diesel mixture in the cylinder, in a next combustion event in the cylinder, after combusting the rich air/diesel mixture therein;
(c) repeating transitions back-and-forth between (a) and (b) in the cylinder and basing a frequency of (a) on a desired aftertreatment system temperature rate increase; and
(d) substantially always combusting a lean air/diesel mixture in a next cylinder immediately and sequentially after combusting the rich air/diesel mixture in the cylinder, the next cylinder being in a firing order that is immediately and sequentially after the cylinder.

9. The method of claim 8 , wherein the aftertreatment system comprises a diesel oxidation catalyst (“DOC”), and the method further comprises:
determining whether a DOC temperature is above a threshold DOC temperature; and
combusting the rich air/diesel mixture in the cylinder only when the DOC temperature is above the threshold DOC temperature.

10. The method of claim 8 , wherein the combusting of the rich air/diesel mixture comprises injecting diesel fuel into the cylinder between 5° before a piston positioned therein is at top dead center and 10° after the piston is at top dead center.

11. The method of claim 8 , wherein when the aftertreatment system temperature is above a threshold aftertreatment temperature but below a desired aftertreatment temperature, the combusting of the rich air/diesel mixture occurs in between 2% and 45% of the combustion events in the cylinder.

12. A method for managing energy in an aftertreatment system positioned downstream of an engine, the aftertreatment system comprising a diesel oxidation catalyst, the method comprising:
(a) combusting a lean air/diesel mixture in a cylinder of the engine;
(b) combusting a rich air/diesel mixture in the cylinder; and
(c) repeating transitions back-and-forth between (a) and (b), and when an aftertreatment system temperature is above a threshold aftertreatment temperature but below a desired aftertreatment temperature, (a) occurs in between 2% and 45% of the combustion events in the cylinder.

Assignees

• Deere & Co

Inventors

• Winsor Richard E
• Rosswurm Jacob M

Classifications

• F02D41/024

  to increase temperature of the exhaust gas treating apparatus · CPC title

• F01N2570/14

  Nitrogen oxides · CPC title

• F02D41/1446

  the characteristics being exhaust temperatures · CPC title

• F02D2200/0802

  Temperature of the exhaust gas treatment apparatus · CPC title

• F01N3/035

  with catalytic reactors · CPC title