Methods for exhaust aftertreatment of an internal combustion engine and exhaust aftertreatment system

By employing a dual-temperature NOx storage catalyst with cerium oxide and barium carbonate, and an adapted regeneration strategy, the system addresses cold start emissions and regeneration challenges, enhancing exhaust aftertreatment efficiency and reducing fuel consumption.

DE102018118085B4Active Publication Date: 2026-06-18VOLKSWAGEN AG
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Patent Information

Application Number
DE102018118085
Authority / Receiving Office
DE · DE
Patent Type
Patents
Current Assignee / Owner
Filing Date
2018-07-26
Publication Date
2026-06-18
Estimated Expiration
2038-07-26

AI Technical Summary

Technical Problem

Current exhaust aftertreatment systems for internal combustion engines face challenges in minimizing pollutant emissions, particularly during the cold start phase and NOx storage catalyst regeneration, which can negatively impact the conversion performance of the SCR catalyst.

Method used

The system employs a NOx storage catalyst with low- and high-temperature storage components (cerium oxide and barium carbonate) and an SCR catalyst, with a regeneration strategy that adapts to different temperature ranges, using unburned hydrocarbons and reducing agents to minimize cross-coupling and extend the temperature range of NOx treatment.

Benefits of technology

This approach enhances exhaust aftertreatment efficiency, reduces fuel consumption, and minimizes the negative impact of NOx storage catalyst regeneration on SCR conversion rates, ensuring effective NOx reduction across varying temperatures.

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Abstract

A method for exhaust aftertreatment of an internal combustion engine (10) with an exhaust system (20) in which a NOx storage catalyst (28) with a low-temperature storage component (48) made of cerium oxide and a high-temperature storage component (52) made of barium carbonate as well as an SCR catalyst (34) and / or particulate filter (30) with an SCR coating (32) arranged downstream of the NOx storage catalyst (28) in the flow direction of an exhaust gas of the internal combustion engine (10), comprising the following steps: - Modeling the loading state of the NOx storage catalyst (28), wherein - the charging of the low-temperature storage component (48) is determined by a first model for the charging of the low-temperature storage component (48), and - the loading of the high-temperature storage component (52) is determined by a second model for the loading of the high-temperature storage component (52), - Regenerating the NOx storage catalyst (28) by introducing unburned hydrocarbons into the exhaust system (20) of the combustion engine (10) when the high-temperature storage component (48) has reached a defined loading level and the SCR catalyst (34) or the particulate filter (30) with the SCR coating (32) has an operating temperature at which selective catalytic reduction of nitrogen oxides is possible, wherein - depending on whether the SCR catalyst (34) or the particulate filter (30) with the SCR coating (32) has an operating temperature at which selective catalytic reduction of nitrogen oxides is possible, at least two threshold values ​​are used, wherein - a first threshold value is provided at which a regeneration of the NOx storage catalyst (28) is carried out when the SCR catalyst (34) or the particulate filter (30) with the SCR coating (32) has reached its operating temperature and wherein - a second threshold is provided at which regeneration of the NOx storage catalyst (28) takes place independently of the temperature of the SCR catalyst (34) or the particulate filter (30) with SCR coating (32).
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