Exhaust Gas Sensor Performance Monitoring via Deliberate Fuel Perturbation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for determining performance characteristics of an exhaust system, such as exhaust gas transport time and sensor sensitivity, are limited by their reliance on specific engine speeds and fail to detect changes in sensor location or sensitivity effectively, particularly in real-time monitoring scenarios like vehicle operation.
Innovation Solution
A method involving deliberate miss-fueling of a combustion event to produce distinguishable exhaust gases, which are then monitored by an exhaust gas sensor to determine performance characteristics like transport time, sensor sensitivity, and fueling correction values, allowing for real-time monitoring at any engine speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional exhaust system performance measurement methods are used, then measurement can be performed at specific engine speeds, but the system cannot detect sensor location changes or sensitivity changes effectively in real-time operation
Solution Approach 1:
The system performs periodic identification cycles at any engine speed by deliberately creating rich and lean combustion events at specific intervals. These periodic perturbations allow the system to continuously update sensor performance characteristics without requiring specific engine speed conditions, enabling real-time monitoring while maintaining measurement accuracy.
Solution Approach 2:
The system changes operational parameters by deliberately creating rich and lean combustion events that produce distinguishable exhaust gas compositions. By varying the air-fuel ratio parameters during identification cycles, the system can detect sensor responses under different conditions and accurately determine transport time and sensitivity characteristics at any engine speed.
2Productivity
If deliberate miss-fueling is performed to create distinguishable exhaust gas transients, then real-time performance monitoring at any engine speed is enabled, but additional control complexity is introduced
Solution Approach 1:
The system performs preliminary identification cycles that deliberately create rich and lean combustion events before normal operation. These preliminary actions establish baseline sensor performance characteristics and transport time values that are then used during normal fuel control operations, simplifying real-time monitoring without requiring continuous complex control.
Solution Approach 2:
The system uses feedback from the oxygen sensor responses to rich and lean perturbations to continuously update performance characteristics. By monitoring the sensor output during deliberate miss-fueling events and comparing it against expected responses, the system automatically adjusts fuel control parameters and maintains accurate performance monitoring without manual intervention.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables continuous monitoring of exhaust system performance characteristics, including detecting sensor damage or relocation, and optimizing fuel control, thereby improving emission control and reducing potential faults during vehicle operation.
Implementation Method 1
an exhaust gas sensor such as an oxygen sensor
Implementation Method 2
fueling a combustion event in a cylinder at an air-fuel ratio selected to produce exhaust gas
Data Source
AI summary
A method to determine a performance characteristic of an exhaust system of an engine, where the exhaust system includes an exhaust gas sensor that outputs an exhaust gas signal. A combustion event in a cylinder is fueled at an air-fuel ratio selected to produce exhaust gas that is expected to be distinguishable by the exhaust gas sensor from exhaust gas produced by other combustion events, and used to determine the performance characteristic. The performance characteristic may be an exhaust gas transport time of the exhaust system, a sensitivity characteristic of the exhaust gas sensor, or a fueling correction value necessary to restore fueling to, for example, stoichiometry. Such a method is useful to detect physical changes in the exhaust system such as relocating the exhaust gas sensor, or detect if the exhaust gas sensor is damaged or not operating properly.