Single-Port EGR Probe Using CO2 Optical Measurements
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Solution Overview
Problem
Existing EGR probes are limited in measuring fast valve-time scale and crank-angle variations due to capillary-probe-based diagnostic systems, and oxygen sensors face challenges with diffusion, temperature, and pressure variations, leading to inefficiencies and increased NOX emissions in internal combustion engines.
Innovation Solution
A rapid and accurate EGR probe system using a combined light source with a signal and reference light source, a processor, and optical cables to measure CO2 concentrations in engine intake or exhaust manifolds, allowing for the separation of signal and reference components and normalization to determine CO2 concentrations within the fluid stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If capillary probes are used to extract CO2 samples from the intake manifold, then spatial distribution of CO2 can be measured, but the temporal response is too slow to capture fast valve-time scale and crank-angle variations
Solution Approach 1:
The patent replaces the mechanical capillary probe system with an optical measurement system. Instead of physically extracting samples through capillary action, the system uses optical fibers to transmit light signals through the intake manifold to detect CO2 concentration optically, eliminating the mechanical sampling bottleneck and enabling fast temporal response while maintaining spatial measurement capability.
Solution Approach 2:
The patent introduces optical fibers as an intermediary medium between the measurement device and the intake manifold. The optical fibers serve as a non-intrusive conduit that allows light to pass through the fluid stream without physical contact, enabling rapid measurement of CO2 concentration distribution without the temporal delays inherent in mechanical sample extraction.
2Measurement precision
If oxygen sensors are used to measure EGR fraction, then cycle-to-cycle variations can be detected, but the sensors suffer from diffusion limitations, temperature sensitivity, and pressure variations
Solution Approach 1:
The patent replaces the electrochemical oxygen sensor system with an optical detection system. Instead of relying on diffusion through porous ceramics and electrochemical reactions, the system uses optical fibers to transmit light and detect CO2 concentration directly, eliminating the reliability issues associated with temperature sensitivity, pressure variations, and diffusion limitations of oxygen sensors.
Solution Approach 2:
The patent changes the measurement parameter from oxygen concentration (which is affected by temperature and pressure) to CO2 concentration (which is less sensitive to these variations). By measuring CO2 instead of O2, the system achieves more reliable EGR fraction measurements that are not significantly affected by temperature and pressure fluctuations.
3Productivity
If conventional diagnostic systems are used, then basic EGR measurement is possible, but they cannot provide rapid processing and accurate measurement of fast temporal fluctuations
Solution Approach 1:
The patent implements continuous optical measurement through the intake manifold using optical fibers. Instead of periodic sampling, the system maintains continuous light transmission and detection, enabling real-time monitoring of CO2 concentration fluctuations. This continuous measurement approach provides both rapid processing and high precision for capturing fast temporal variations in EGR fraction.
Solution Approach 2:
The patent substitutes conventional mechanical sampling and analysis systems with a continuous optical measurement system. The optical fiber-based system enables simultaneous spatial mapping and rapid temporal detection by transmitting light signals continuously through the intake manifold, eliminating the sequential steps of sampling, transport, and analysis that limit processing speed in conventional systems.
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
The EGR probe system enables rapid processing and accurate measurement of spatial and temporal CO2 fluctuations, enhancing engine efficiency and reducing NOX emissions by providing data for optimizing engine performance and emissions control.
Implementation Method 1
The samples extracted using capillary probes are analyzed remotely using absorption spectroscopy or mass spectrometry, or other analytical technique, to determine CO2 concentration.
Implementation Method 2
A rapid and accurate EGR probe system using a combined light source with a signal and reference light source, a processor, and optical cables to measure CO2 concentrations in engine intake or exhaust manifolds
Data Source
AI summary
A diagnostic system having a single-port EGR probe and a method for using the same. The system includes a light source, an EGR probe, a detector and a processor. The light source may provide a combined light beam composed of light from a mid-infrared signal source and a mid-infrared reference source. The signal source may be centered at 4.2 μm and the reference source may be centered at 3.8 μm. The EGR probe may be a single-port probe with internal optics and a sampling chamber with two flow cells arranged along the light path in series. The optics may include a lens for focusing the light beam and a mirror for reflecting the light beam received from a pitch optical cable to a catch optical cable. The signal and reference sources are modulated at different frequencies, thereby allowing them to be separated and the signal normalized by the processor.