Controlling nitrogen oxide emissions in the exhaust gas of an internal combustion engine
AssigneeFord Global Technologies, LLC
InventorsFrederik De Smet, Mario Balenovic, Vijay Krishnaswamy
Life of this patent
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Abstract
A method is provided for controlling nitrogen oxide emissions in the exhaust gas of an internal combustion engine by means of successive actuation of catalytic converters in the exhaust tract and of the internal combustion engine, wherein the catalytic converters or the internal combustion engine are actuated in succession if the actuation of a first device is not sufficient for reducing the nitrogen oxide emissions. An arrangement for carrying out the method is also provided.
Claims17
A method for controlling nitrogen oxide emissions in exhaust gas of an internal combustion engine, in an exhaust tract of which there are arranged at least one nitrogen oxide storage catalytic converter (LNT) and at least one catalytic converter for selective catalytic reduction (SCR), at least one nitrogen oxide sensor, an introduction device arranged upstream of the SCR for a reducing agent, and a control device, comprising:
- measuring or estimating nitrogen oxide values in an exhaust tailpipe region;
- detecting an upward deviation of the nitrogen oxide values in the exhaust tailpipe region from a setpoint value;
- responsive to detecting the upward deviation, actuating the introduction device in order to provide a first correction of the nitrogen oxide values in the exhaust tailpipe region;
- if the nitrogen oxide values are still deviated upward from the setpoint value after the actuation of the introduction device, performing a first adjustment of the internal combustion engine to regulate a regeneration of the LNT in order to provide a second correction of the nitrogen oxide values in the exhaust tailpipe region;
- and
- if the nitrogen oxide values are still deviated upward from the setpoint value after the first adjustment of the internal combustion engine, performing a second adjustment of the internal combustion engine to regulate an operating mode of the internal combustion engine in order to provide a third correction of the nitrogen oxide values in the exhaust tailpipe region.
A method, comprising:
- responsive to a tailpipe NOx level exceeding a setpoint, adapting a base reductant storage amount for a first aftertreatment device, including determining a first difference between the tailpipe NOx level and the setpoint and adapting the base reductant storage amount according to the first difference;
- supplying reductant to the first aftertreatment device according to the adapted base reductant storage amount;
- responsive to the adapted base reductant storage amount exceeding a maximum reductant storage amount, adapting a regeneration parameter for a second aftertreatment device, including determining a portion of an adaption signal that overflows from the adaption of the base reductant storage amount when NOx storage in a selective catalytic reduction (SCR) device is at a limit, the portion determined by determining a second difference between the adapted base reductant storage amount and the maximum reductant storage amount, and adapting the regeneration parameter according to the second difference;
- and
- regenerating the second aftertreatment device according to the adapted regeneration parameter.
A system, comprising:
- a lean NOx trap (LNT) positioned in an exhaust passage coupled to an engine;
- a selective catalytic reduction (SCR) device positioned in the exhaust passage in series with the LNT;
- a reductant injector configured to supply reductant to the SCR device;
- a sensor positioned in the exhaust passage downstream of the LNT and the SCR and configured to measure a tailpipe NOx level;
- and
- a controller storing instructions executable to:
- responsive to the tailpipe NOx level being within a threshold range from a setpoint, inject reductant, via the reductant injector, to the SCR device according to a base reductant storage amount and regenerate the LNT according to a regeneration parameter, the base reductant storage amount determined based on conditions of the SCR device;
- responsive to the tailpipe NOx level being outside the threshold range from the setpoint, adapt the base reductant storage amount for the SCR device and inject reductant, via the reductant injector, to the SCR device according to the adapted base reductant storage amount;
- and
- responsive to the adapted base reductant storage amount exceeding a maximum reductant storage amount, adapt the regeneration parameter for the LNT and regenerate the LNT according to the adapted regeneration parameter.
Dependencies are inferred from the claim text.