Exhaust Gas Sensor Ambient Humidity Detection
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Solution Overview
Problem
Existing engine control systems fail to effectively account for ambient humidity fluctuations, which can negatively impact engine efficiency, fuel economy, and emissions by not adequately adjusting operating parameters such as air-fuel ratio, spark timing, and exhaust gas recirculation.
Innovation Solution
An exhaust gas sensor is used to measure ambient humidity during engine non-fueling conditions, allowing for adjustments to these parameters to optimize engine performance, with the sensor operating in dual modes to detect humidity and air-fuel ratio, and implementing adjustments such as reducing EGR flow and adjusting spark timing based on humidity readings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate sensor is used to measure ambient humidity, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The exhaust gas sensor is designed to perform multiple functions: it measures both exhaust gas composition and ambient humidity. During non-combustion periods, the sensor measures ambient humidity in the intake air, while during combustion it measures exhaust gas composition. This eliminates the need for a separate humidity sensor and reduces system complexity while maintaining measurement precision.
Solution Approach 2:
The existing exhaust gas sensor serves itself by utilizing its own measurement capabilities to detect ambient humidity during non-combustion periods. The sensor leverages its position in the intake system and its electrochemical measurement principle to self-determine humidity levels without requiring additional dedicated humidity sensing components.
2Productivity
If engine operating parameters are adjusted based on humidity, then engine efficiency is improved, but control complexity increases
Solution Approach 1:
The control system performs preliminary measurements of ambient humidity during non-combustion periods before actual combustion occurs. This advance measurement allows the system to pre-calculate and prepare optimal operating parameters (air-fuel ratio, spark timing, EGR) for the upcoming combustion cycle, improving efficiency while using straightforward control logic.
Solution Approach 2:
The system continuously monitors ambient humidity levels and uses this feedback to dynamically adjust engine operating parameters. The exhaust gas sensor provides ongoing humidity measurements during non-combustion periods, and the control system responds by modifying air-fuel ratio, spark timing, and EGR settings to optimize combustion efficiency under varying humidity conditions.
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 improved engine efficiency and reduced emissions by accurately accounting for humidity fluctuations, maintaining optimal performance across varying driving conditions.
Implementation Method 1
U.S. Pat. No. 5,145,566 discloses a method to detect ambient humidity via an electrochemical oxygen pumping device
Data Source
AI summary
Various systems and methods are described for operating an engine in a vehicle in response to an ambient humidity generated from an exhaust gas sensor. One example method comprises, during engine non-fueling conditions, where at least one intake valve and at least one exhaust valve of the engine are operating, generating an ambient humidity from the exhaust gas sensor and, under selected engine combusting conditions, adjusting an engine operating parameter based on the ambient humidity.