Compression ignition engine system with improved regeneration via controlled ash deposits

Patent metadata

Field	Value
Publication number	US-9863298-B2
Application number	US-201414531404-A
Country	US
Kind code	B2
Filing date	Nov 3, 2014
Priority date	Nov 3, 2014
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

An engine system includes an electronically controlled compression ignition engine configured to burn diesel fuel and a high ash oil to produce an exhaust with a temperature and NOx to soot ratio as well as a controlled level of ash deposits on the particulate filter of the system. An aftertreatment system is fluidly connected to the engine and includes a diesel oxidation catalyst, a reductant supply, and a diesel particulate filter coated with a NOx reduction catalyst. The soot load density on the diesel particulate filter can be stabilized by oxidizing soot at about a same rate as the compression ignition engine is supplying soot to the aftertreatment system.

First claim

We claim:

1. A method of operating an engine system comprising:
burning a high ash oil in a compression ignition engine, during a break-in period, to generate an ash deposit on a diesel particulate filter of an aftertreatment system fluidly connected to the compression ignition engine;
burning a diesel fuel and a low ash oil in the compression ignition engine, after the break-in period, to produce exhaust with a temperature and a NOx to soot ratio, wherein a soot load is disposed on at least a portion of the ash deposit;
catalyzing a NOx reduction reaction with a NOx reduction catalyst coated on the diesel particulate filter; and
stabilizing the soot load on at least the portion of the ash deposit by oxidizing soot at a same rate as the compression ignition engine is supplying soot to the aftertreatment system.

2. The method of claim 1 , wherein the break-in period comprises an initial 100 hours of engine operation, an initial 500 hours of engine operation, an engine operation until a first oil change.

3. The method of claim 1 , further comprising:
catalyzing a reaction in the exhaust to combine nitrogen oxide with oxygen into nitrogen dioxide with a diesel oxidation catalyst of the aftertreatment system upstream from the diesel particulate filter; and
supplying a reductant into the exhaust in the aftertreatment system upstream from the diesel particulate filter.

4. The method of claim 3 , wherein the reductant comprises urea.

5. The method of claim 1 , wherein at least the portion of the ash deposit is interposed between a portion of the diesel particulate filter and the soot load.

6. The method of claim 1 , wherein the stabilizing the soot load comprises changing from a first engine operating condition to a second engine operating condition responsive to one or more of a temperature and a NOx to soot ratio of the exhaust at the diesel particulate filter.

7. The method of claim 6 , wherein the changing from the first engine operating condition to the second engine operating condition comprises changing from a first exhaust temperature to a second exhaust temperature.

8. The method of claim 7 , wherein the changing from the first exhaust temperature to the second exhaust temperature is performed in a temperature range corresponding to a temperature at the diesel particulate filter between 180 and 400 degrees C.

Assignees

• Caterpillar Inc

Inventors

• Silver Ronald
• Shull Brandon

Classifications

• F01N3/106

  Auxiliary oxidation catalysts · CPC title

• F01N2900/0412

  using pre-calibrated maps, tables or charts · CPC title

• F01N2550/04

  Filtering activity of particulate filters · CPC title

• F01N2560/026

  for measuring or detecting NOx · CPC title

• F01N13/009

  having two or more separate purifying devices arranged in series · CPC title