Exhaust Gas Sensor Monitoring with VDE Six-Pattern Diagnostics
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for monitoring exhaust gas sensor degradation in vehicles face challenges due to variability in injector ramping during fuel shut-off transitions, particularly in V-8 engines, which affect the accuracy and efficiency of six-pattern diagnostics.
Innovation Solution
Implementing a variable displacement engine (VDE) mode prior to fuel shut-off transitions, ensuring a 1:1 ratio of exhaust gas sensors to cylinders by selectively activating and deactivating intake and exhaust valves, thereby reducing injector ramping variability and allowing each sensor to monitor a single cylinder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single exhaust gas sensor monitors four cylinders in a V-8 engine, then device complexity is reduced, but measurement precision deteriorates due to injector ramping variability affecting six-pattern diagnostics
Solution Approach 1:
The patent segments the monitoring function by dedicating one exhaust gas sensor to monitor only one cylinder during the diagnostic phase. This is achieved by deactivating three of four injectors in a bank, isolating the sensor's monitoring task to a single cylinder's exhaust stream. This segmentation eliminates the variability caused by multiple injectors ramping simultaneously, thereby improving measurement precision for detecting sensor degradation through six-pattern diagnostics.
2Productivity
If fuel shut-off transition is used for six-pattern monitoring, then productivity is improved by reducing monitor completion time, but reliability deteriorates due to high variability in injector ramping affecting diagnostic accuracy
Solution Approach 1:
The patent applies preliminary action by deactivating three of four injectors in a bank before initiating the fuel shut-off transition for six-pattern monitoring. This pre-conditioning of the engine state ensures that only one injector is active during the diagnostic window, eliminating ramping variability. The preliminary injector deactivation maintains the benefits of fuel shut-off (reduced monitor completion time) while ensuring reliable diagnostic accuracy through consistent, variable-free sensor response measurement.
Data Source
AI summary
A method of monitoring an exhaust gas sensor coupled in an engine exhaust in an engine is provided. The method includes entering into a variable displacement engine (VDE) mode wherein intake and exhaust valves of a first subset of cylinders of the engine are activated and intake and exhaust valves of a second subset of cylinders of the engine are deactivated prior to a reduced traction fuel shut-off transition; and executing a six-pattern diagnostic during fuel shut-off to identify exhaust gas sensor degradation.