Method of monitoring an exhaust gas aftertreatment system
AssigneeFord Global Technologies, LLC
InventorsFrederik De Smet, Kim Ford, Marcus Timothy Davies
Life of this patent
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Abstract
The subject matter of the disclosure relates to a method of diagnosing NOx storage catalyst during the operation of a motor vehicle. The method uses two diagnosis sub-methods having various sensitivities with respect to sulfur contamination of the NOx storage catalyst. The results of the two sub-methods are used to ascertain proportions of aging of the NOx storage catalyst resulting from thermal aging and sulfur contamination.
Claims18
A method of ascertaining a state of aging of a NOx storage catalyst of a motor vehicle having an internal combustion engine, comprising:
- ascertaining a first proportion of aging of the NOx storage catalyst caused by thermal aging via a first method, where the first method includes a first sensitivity factor;
- ascertaining a second proportion of aging of the NOx storage catalyst caused by sulfur loading via a second method, where the second method includes a second sensitivity factor, and where the first sensitivity factor and the second sensitivity factor are fixed factors for sulfur sensitivity of the first method and the second method, respectively;
- ascertaining an overall state of aging of the NOx storage catalyst from both the first proportion and the second proportion;
- and
- triggering an operation for desulfurization of the NOx storage catalyst based on the first proportion, the second proportion, the first sensitivity factor, and the second sensitivity factor.
A motor vehicle, comprising:
- an internal combustion engine,
- a NOx storage catalyst, and
- a control unit having instructions to:
- ascertain a first proportion of aging of the NOx storage catalyst caused by thermal aging via a first method, where the first method includes a first sensitivity factor;
- ascertain a second proportion of aging of the NOx storage catalyst caused by sulfur loading via a second method, where the second method includes a second sensitivity factor, and where the first sensitivity factor and the second sensitivity factor are fixed factors for sulfur sensitivity of the first method and the second method, respectively;
- indicate the NOx storage catalyst is degraded based on the first proportion;
- and
- trigger an operation for desulfurization of the NOx storage catalyst based on the first proportion, the second proportion, the first sensitivity factor, and the second sensitivity factor.
A method, comprising:
- determining a first aging factor of a NOx storage catalyst based on a first model that includes as inputs an upstream air-fuel ratio upstream of the NOx storage catalyst integrated over a period of time and a downstream air-fuel ratio downstream of the NOx storage catalyst integrated over the same period of time;
- determining a second aging factor of the NOx storage catalyst based on a second model that includes as inputs an upstream NOx flow amount upstream of the NOx storage catalyst and a downstream NOx flow amount downstream of the NOx storage catalyst;
- calculating a sulfur aging state of the NOx storage catalyst based on the first aging factor, the second aging factor, a first sulfur sensitivity factor of the first model, and a second sulfur sensitivity factor of the second model, wherein the first sulfur sensitivity factor is a fixed factor of the first model, and wherein the second sulfur sensitivity factor is a fixed factor of the second model;
- and
- increasing engine air-fuel ratio in order to carry out a desulfurization responsive to the sulfur aging state exceeding a threshold sulfur aging state.
Dependencies are inferred from the claim text.