Methods for diagnostics and operation of an emissions aftertreatment system
AssigneePACCAR Inc
InventorsCharles Wayne Reinhardt SWART, Cynthia Chaffin WEBB, Maarten MEIJER, Varun RAMESH
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Abstract
The present disclosure describes methods for evaluating NOx conversion efficiency of a close coupled SCR unit of an EAS including the close coupled SCR unit and a downstream SCR unit. The determined NOx conversion efficiency of the close coupled SCR unit is used to diagnose the close coupled SCR unit and or EAS and to control operation parameters of the EAS and/or internal combustion engine operably connected to the EAS.
Claims20
A method of operating an internal combustion engine emissions aftertreatment system (EAS) including a close coupled selective catalytic reduction (SCR) unit and a downstream SCR unit, the method comprising:
- operating the EAS at one or more steady state conditions;
- flowing exhaust gas from the internal combustion engine to the close coupled SCR unit;
- flowing the exhaust gas from close coupled SCR unit to the downstream SCR;
- operating the downstream SCR unit to reduce NOx content of the exhaust gas;
- adjusting temperature of the close coupled SCR unit;
- evaluating NOx conversion efficiency of the close coupled SCR unit at a plurality of different temperatures while maintaining other EAS operating conditions at substantially steady state;
- recording the NOx conversion efficiency of the close coupled SCR unit at the plurality of different temperatures;
- and
- adjusting an operation parameter of the EAS based on the recorded NOx conversion efficiency of the close coupled SCR unit at the plurality of different temperatures.
A method of evaluating NOx conversion efficiency of a close coupled SCR unit of an emissions aftertreatment system (EAS) including the close coupled SCR unit and a downstream SCR unit, the method comprising:
- operating the EAS at one or more steady state conditions;
- flowing exhaust gas from the internal combustion engine through the close coupled SCR unit;
- flowing exhaust gas from close coupled SCR unit through the downstream SCR;
- reducing NOx in the exhaust gas in the downstream SCR unit;
- adjusting temperature of the close coupled SCR unit;
- evaluating NOx conversion efficiency of the close coupled SCR unit at a plurality of different temperatures while maintaining other EAS operating conditions at substantially steady state;
- recording the NOx conversion efficiency of the close coupled SCR unit at the plurality of different temperatures;
- and
- evaluating performance of the close coupled SCR unit based on the recorded NOx conversion efficiency of the close coupled SCR unit at the plurality of different temperatures.
An emissions management system for a vehicle including an internal combustion engine and an emission aftertreatment system (EAS) that includes a close-coupled SCR unit and a downstream SCR unit, the emission management system comprising:
- at least one nontransitory processor-readable storage medium that stores one of processor-executable instructions or data;
- and
- at least one processor communicatively coupled to the at least one nontransitory processor-readable storage medium, in operation, the at least one processor:
- receives indications of NOx conversion efficiency of the close-coupled SCR unit at a plurality of temperatures;
- stores the received indications of NOx conversion efficiency of the close-coupled SCR unit operated at a plurality of temperatures in the nontransitory processor-readable storage medium;
- and
- evaluates performance of the EAS using the received indications of NOx conversion efficiency of the close coupled SCR unit at a plurality of temperatures.
Dependencies are inferred from the claim text.