Optical EGR Probe for CO2 Spatial-Temporal Measurement

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Solution Overview

Problem

Existing EGR probes are not fast enough to measure rapid valve-time scale, crank-angle resolved variations in CO2 concentrations, and face limitations due to diffusion, temperature, and pressure issues, which affects the accuracy of NOX emission reduction in internal combustion engines.

Innovation Solution

A diagnostic system using an EGR probe with a combined light source, a detector, and a processor, featuring a pitch optical cable, lens, and catch optical cable, capable of separating signal and reference light components for precise CO2 concentration measurement, and optionally utilizing a laser light source for improved sensitivity and simultaneous temperature and pressure measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If capillary probes are used to extract CO2 samples from the intake manifold, then spatial sampling capability is improved, but temporal response speed deteriorates due to diffusion limitations

Engineering Contradiction:

Improvespatial sampling capabilityVSAvoidtemporal response speed

Core Design Contradiction:

Measurement precisionVSSpeed

Solution Approach 1:

The patent replaces the mechanical capillary probe system with an optical measurement system. Instead of physically extracting CO2 samples through capillary action, the system uses optical fibers to transmit light through the intake manifold to detect CO2 concentrations optically, eliminating diffusion limitations and enabling rapid temporal response while maintaining spatial sampling capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces light as an intermediary medium to measure CO2 concentrations. Rather than directly contacting the CO2-rich environment with sampling probes, the system uses optical fibers as intermediaries to transmit light through the manifold, allowing non-intrusive, real-time measurement of CO2 distributions without the temporal delays inherent in physical sampling.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If oxygen sensors are used to measure EGR fraction, then temperature compensation is improved, but measurement speed deteriorates due to diffusion requirements

Engineering Contradiction:

Improvetemperature compensationVSAvoidmeasurement speed

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The patent replaces electrochemical oxygen sensors with optical detection systems. Instead of relying on diffusion of gas molecules through porous ceramics and electrochemical reactions, the system uses optical fibers to transmit light through the intake manifold and detects CO2 concentrations directly via optical absorption, achieving both rapid response and temperature compensation capabilities.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If conventional sampling systems are used, then system simplicity is maintained, but measurement accuracy deteriorates due to inability to resolve rapid variations

Engineering Contradiction:

Improvesystem simplicityVSAvoidmeasurement accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent segments the optical measurement system into multiple independent optical fibers distributed throughout the intake manifold. Each fiber acts as an independent sensing element, allowing simultaneous measurement at multiple spatial locations. This segmentation enables the system to resolve rapid spatial and temporal variations in CO2 concentrations while maintaining relative system simplicity through modular architecture.

Inventive Principle:

Principle #1Segmentation

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 rapid and accurate measurement of CO2 concentrations, allowing for efficient optimization of EGR systems, reduced NOX emissions, and improved engine performance by identifying spatial and temporal nonuniformities.

Implementation Method 1

The EGR probe includes a sampling chamber where the light beam passes through the fluid stream... the processor is configured to analyze the detector readings to determine CO2 concentration within the fluid stream

Methodology Applied

Scientific EffectAbsorption Spectroscopy: Absorption Spectroscopy

Data Source

PatentUS9068933B2EGR distribution and fluctuation probe based on CO2 measurements

Publication Date: 2015.06.30 UT BATTELLE LLC

AI summary

A diagnostic system having a laser, an EGR probe, a detector and a processor. The laser may be a swept-λ laser having a sweep range including a significant CO2 feature and substantially zero absorption regions. The sweep range may extend from about 2.708 μm to about 2.7085 μm. The processor may determine CO2 concentration as a function of the detector output signal. The processor may normalize the output signal as a function of the zero absorption regions. The system may include a plurality of EGR probes receiving light from a single laser. The system may include a separate detector for each probe. Alternatively, the system may combine the light returning from the different probes into a composite beam that is measured by a single detector. A unique modulation characteristic may be introduced into each light beam before combination so that the processor can discriminate between them in the composite beam.