Intake Oxygen Sensor Learning Across Pressure Range
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Solution Overview
Problem
Conventional oxygen sensors struggle to accurately learn intake oxygen concentration over a range of air pressures, especially in engines with an exhaust gas recirculation (EGR) system due to exhaust gas interference in the intake path.
Innovation Solution
A system comprising an intake oxygen sensor and an electronic control unit that measures intake air oxygen concentration, determines engine operating conditions, and controls a valve to sweep air pressure across a range of pressures to learn accurate intake oxygen concentration values, even when the engine is in an over-run condition, thereby reducing exhaust gas interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional oxygen sensors are used to measure oxygen concentration in the exhaust path, then the sensor can provide exhaust oxygen concentration values, but it cannot accurately provide intake oxygen concentration values over a range of air pressures
Solution Approach 1:
The system performs preliminary learning of intake oxygen concentration values at various air pressures during over-run conditions before normal engine operation. The ECU stores these learned values and uses them to accurately determine intake oxygen concentration during actual engine operation across different pressure conditions, eliminating the need for real-time measurements during fuel injection.
Solution Approach 2:
The intake oxygen sensor serves dual purposes: it measures oxygen concentration during normal operation and also enables the system to self-calibrate by learning pressure-dependent characteristics during over-run conditions. The system uses its own operational data to improve its measurement accuracy without requiring external calibration equipment.
2Productivity
If exhaust gas recirculation (EGR) system is used in the engine, then engine efficiency can be improved, but intake oxygen concentration learning becomes inaccurate due to exhaust gas in the intake path
Solution Approach 1:
The system extracts the EGR valve from the learning process by detecting over-run conditions (when the EGR valve is closed and no fuel is injected). During these specific time windows, the system isolates the intake air path from recirculated exhaust gas and uses this clean period to accurately learn intake oxygen concentration values without EGR interference.
Solution Approach 2:
The system skips the periods when EGR is active and only performs learning during brief over-run conditions. By rushing through the identification and utilization of these short time windows, the system accumulates sufficient learning data despite the limited availability of clean measurement opportunities in an EGR-equipped engine.
3Measurement precision
If a valve is controlled to sweep air pressure across a plurality of pressures to learn intake oxygen concentration, then accurate learning across pressure range is achieved, but the system requires detection of over-run conditions and fuel injection status
Solution Approach 1:
The ECU continuously monitors engine operating conditions including fuel injection status and oxygen sensor readings. This feedback mechanism enables the system to automatically detect over-run conditions and trigger the learning process only when appropriate, creating a self-regulating system that manages complexity through intelligent condition-based activation rather than continuous complex control.
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
This approach enables accurate learning of intake oxygen concentration across various pressures, enhancing engine control system accuracy and fuel efficiency by minimizing the impact of exhaust gas recirculation on sensor readings.
Implementation Method 1
The intake oxygen sensor is configured to measure an oxygen concentration of intake air and output a signal indicative of an intake oxygen concentration value
Data Source
AI summary
System and method for learning an intake oxygen concentration of an engine. In one embodiment, the system includes an intake oxygen sensor and an electronic control unit. The intake oxygen sensor is configured to measure an oxygen concentration of intake air and output a signal indicative of an intake oxygen concentration value. The electronic control unit is configured to receive the signal indicative of the intake oxygen concentration value, determine whether fuel is being injected into an engine, determine whether the engine is operating in an over-run condition, control a valve to sweep an air pressure of an intake path of the engine across a plurality of air pressures, and store information indicative of intake oxygen concentration values across the plurality of air pressures to learn the intake oxygen concentration of the engine.