Engine Humidity Sensor Control for Intake Air Measurement

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Solution Overview

Problem

Existing engine control systems face inaccuracies in determining specific humidity due to water vapor produced by the engine, leading to improper adjustments of engine operating parameters, especially during low airflow and short engine shutdown periods.

Innovation Solution

A system that includes a humidity determination module to set a second specific humidity equal to a predetermined value when water vapor from the engine affects the humidity sensor, using a counter module to track airflow conditions and a filtering module to adjust humidity values, ensuring accurate engine control by distinguishing between ambient and engine-produced water vapor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a humidity sensor is used to measure relative humidity in the intake system, then engine operating parameters can be adjusted based on humidity, but the measurement becomes inaccurate when water vapor from engine exhaust affects the sensor

Engineering Contradiction:

Improveengine control adaptability to humidity conditionsVSAvoidhumidity measurement accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system performs preliminary action by tracking engine shutdown timing and using a counter to identify when the engine has been off long enough for exhaust water vapor to dissipate. This allows the ECU to pre-determine whether humidity sensor readings will be accurate before making control decisions, preventing inaccurate measurements from corrupting the control data.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The counter module acts as an intermediary between the humidity sensor and the ECU control logic. It mediates the data flow by filtering out measurements taken during periods when engine water vapor would contaminate the sensor, allowing only valid measurements to reach the control system.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If the ECU continuously adjusts operating parameters based on humidity sensor readings, then engine performance can be optimized, but improper adjustments occur when engine-produced water vapor is present

Engineering Contradiction:

Improveengine performance optimizationVSAvoidcontrol parameter accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system implements feedback by continuously monitoring engine operating state (running vs. shutdown) and using this information to gate the humidity control logic. The counter tracks shutdown duration and provides feedback to the ECU about whether current humidity readings should influence control parameters, creating a reliable feedback loop that prevents erroneous adjustments.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system applies dynamics by making the humidity-based control logic conditional rather than static. The ECU dynamically switches between using humidity sensor data for control adjustments and ignoring it based on real-time engine state and shutdown duration, allowing the control system to adapt its behavior to current operating conditions.

Inventive Principle:

Principle #15Dynamics

3Speed

If the ECU uses humidity data during all operating conditions, then control responsiveness is maintained, but measurement reliability deteriorates during low airflow and short shutdown periods

Engineering Contradiction:

Improvecontrol responsivenessVSAvoidhumidity measurement reliability

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The control logic is segmented into distinct operational modes based on engine state and shutdown duration. The counter divides the operating conditions into reliable measurement periods (after sufficient shutdown time) and unreliable periods (during or immediately after shutdown), allowing the ECU to apply appropriate control strategies for each segment.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system changes the operational parameter of humidity-based control on/off based on shutdown duration. When the counter indicates insufficient shutdown time, the ECU disables humidity-based adjustments; when sufficient shutdown time has elapsed, the ECU re-enables them, dynamically changing the control parameter state to match measurement reliability.

Inventive Principle:

Principle #35Parameter changes

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 ensures accurate engine operating parameter control by differentiating between ambient and engine-produced humidity, preventing improper adjustments and maintaining engine performance during varying conditions.

Implementation Method 1

a humidity sensor in an intake system of the vehicle

Methodology Applied

Scientific EffectRelative humidity measurement: Hygrometer

Data Source

PatentUS9249764B2Engine control systems and methods with humidity sensors

Publication Date: 2016.02.02 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A system for a vehicle includes a humidity determination module, a specific humidity module, and a parameter control module. The humidity determination module determines a first specific humidity of air based on a relative humidity of the air measured by a humidity sensor in an intake system of the vehicle. The specific humidity module sets a second specific humidity of the air equal to one of the first specific humidity and a predetermined specific humidity of the air in response to a comparison of a mass air flowrate (MAF) into an engine and a predetermined flowrate. The parameter control module controls at least one operating parameter of an engine based on the second specific humidity.