Integrated Mass Flow Meter for Transient Exhaust Gas
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing mass flow measurement systems for fluid mixtures face errors due to synchronization issues and flow disturbance under transient conditions, particularly in measuring exhaust gas emissions from vehicles, where concentration and flow rate changes are rapid, and require bulky, costly, and complex setups for accurate regulatory compliance.
Innovation Solution
A compact, multi-species mass flow measurement system with a laser-based gas concentration detector integrated within an averaging pitot tube, minimizing flow disturbance and using additive manufacturing for flexibility, which calculates mass flow rates with co-located sensors to eliminate time delays and reduce calibration needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate probes are used for measuring species concentration and bulk fluid flow rate, then measurement coverage is improved, but synchronization error increases under transient conditions
Solution Approach 1:
The patent combines the species concentration detector and bulk fluid flow rate detector into a single integrated probe assembly. Both detectors are positioned to measure parameters at the same location and time within the fluid stream, eliminating the time delay and synchronization errors that occur when separate probes are used. This merging of measurement functions into one co-located device ensures that concentration and flow rate data are simultaneously captured, providing accurate mass flow rate calculations under transient conditions.
2Measurement precision
If concentration probe is placed in close proximity to flow measurement probe, then synchronization is improved, but flow rate signal disturbance increases
Solution Approach 1:
The probe assembly is segmented into distinct functional zones: the flow rate detector (such as a hot wire anemometer) occupies one spatial region while the species concentration detector (such as a laser-based sensor) occupies another. This segmentation allows both detectors to be closely positioned for synchronization while maintaining sufficient spatial separation to minimize mutual interference and flow signal disturbance.
3Measurement precision
If traditional analyzers are used for exhaust gas measurement, then measurement capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces traditional mechanical and chemical analysis systems with laser-based optical detection. Instead of using complex mechanical analyzers that require moving parts, calibration gases, and extensive calibration procedures, the system employs laser spectroscopy to directly measure species concentrations. This substitution of mechanical systems with optical fields simplifies the overall device architecture, reduces moving parts, eliminates the need for calibration gas cylinders, and lowers operational complexity while maintaining measurement accuracy.
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 system provides accurate, real-time mass flow rate measurements with reduced complexity and cost, suitable for permanent vehicle installation, enhancing regulatory compliance and industrial applications by minimizing measurement errors and space requirements.
Implementation Method 1
a laser-based gas concentration detector integrated within an averaging pitot tube
Implementation Method 2
an integral fluid static pressure port... the pressure sensed at the static pressure port and the temperature sensed by the thermocouple
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A chemical species mass flow meter measurement system for use in fluid mixture streams includes a chemical species concentration detection analyzer physically located within a fluid volume flow rate sensing probe along with bulk temperature and pressure sensing devices for relating to standard conditions. The system uses concentration detection analyzers specifically suited to the intended application. Applications include the measurement of exhaust mass emissions from vehicles, the fuel economy of vehicles, as well as the measurement of the mass flow rate of chemical species of interest in general industrial processes.