Injector Release Detection via Exhaust Gas Metrics
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Solution Overview
Problem
In exhaust after-treatment systems, unintended release of hydrocarbons from injectors can occur, leading to waste and increased emissions, as these releases are not reliably detected, especially when not commanded to open, affecting NOx reduction and particulate filter regeneration.
Innovation Solution
A method involving a controller that generates metrics such as oxygen concentration and temperature differences across emissions devices to determine reductant release from an injector, adjusting engine operation based on these metrics compared to thresholds related to engine parameters, thereby indicating and addressing unintended reductant release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the injector is commanded closed to prevent reductant release, then reductant waste is reduced, but detection reliability of unintended release deteriorates
Solution Approach 1:
The system continuously monitors exhaust gas parameters (oxygen concentration, temperature) and compares them against expected values to detect unintended injector release. This feedback mechanism allows the system to identify malfunctions even when the injector is commanded closed, resolving the contradiction between preventing waste and detecting failures.
Solution Approach 2:
The patent replaces direct mechanical monitoring of the injector with indirect chemical/thermal sensing of exhaust gas composition and temperature. By substituting mechanical detection with chemical analysis of exhaust parameters, the system can reliably detect unintended release without additional mechanical sensors at the injector location.
2Measurement precision
If multiple sensors are added to improve detection accuracy, then measurement precision improves, but device complexity increases
Solution Approach 1:
The system uses existing exhaust gas sensors (oxygen sensors, temperature sensors) that serve multiple functions: monitoring normal exhaust conditions, detecting injector malfunctions, and controlling after-treatment operations. This multi-functionality approach improves detection accuracy without adding dedicated sensors, thereby avoiding increased device complexity.
Solution Approach 2:
The patent analyzes changes in exhaust gas parameters (oxygen concentration differences, temperature differences) over time and across different locations to detect injector release. By using parameter variations rather than requiring additional sensors, the system achieves high measurement precision while maintaining relatively simple device architecture.
3Productivity
If exhaust temperature is increased to improve NOx reduction and soot oxidation, then emission control effectiveness improves, but risk of after-treatment device degradation increases
Solution Approach 1:
The system monitors exhaust gas temperature and oxygen concentration in real-time, providing feedback to control the after-treatment operations. This feedback allows the system to optimize temperature for effective NOx reduction and soot oxidation while preventing excessive temperatures that could degrade the after-treatment devices.
Solution Approach 2:
The patent implements dynamic control of exhaust gas temperature and reductant injection based on real-time conditions. The system adjusts operational parameters dynamically to achieve effective emission control while maintaining temperatures within safe limits for after-treatment device longevity.
Data Source
AI summary
Methods and systems for operating an engine that includes a catalyst and a particulate filter are described. In one example, release of reductant from an injector may be determined according to a plurality of metrics so that reliability of a release indication may be improved. In addition, operation of an engine may be adjusted responsive to the release indication so that exhaust system temperatures may be maintained.