Compression ignition engine system with improved regeneration via controlled ash deposits
AssigneeCaterpillar Inc.
InventorsRONALD SILVER, BRANDON SHULL
Life of this patent
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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.
Claims20
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 about a same rate as the compression ignition engine is supplying soot to the aftertreatment system.
An engine system comprising:
- an electronically controlled compression ignition engine configured to burn diesel fuel to produce an exhaust with a temperature and a NOx to soot ratio, the electronically controlled compression ignition engine further configured to burn a high ash oil to generate an ash deposit;
- and
- an aftertreatment system fluidly connected to the engine, the aftertreatment system comprising a diesel oxidation catalyst and a diesel particulate filter having a NOx reduction catalyst coated on the diesel particulate filter,
- wherein the NOx to soot ratio and the temperature correspond to a stable soot load density on the diesel particulate filter, and
- wherein the ash deposit is interposed between NOx reduction catalyst coated on the diesel particulate filter and the stable soot load.
A method of operating an engine system comprising:
- catalyzing a reaction in exhaust of the engine system to combine nitrogen oxide with oxygen into nitrogen dioxide with a diesel oxidation catalyst of an aftertreatment system including a diesel particulate filter;
- catalyzing a NOx reduction reaction with a NOx reduction catalyst coated on the diesel particulate filter;
- forming a layer of ash on at least a portion of the NOx reduction catalyst coated on the diesel particulate filter;
- and
- forming a stable soot load on the diesel particulate filter, wherein the layer of ash is interposed between the diesel particulate filter and the stable soot load.
Dependencies are inferred from the claim text.