Integrated Sensor Unit for Mass Flow Measurement Drift
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hot film anemometers experience drift in measured values due to particle or condensate deposits on heated areas, which affects the accuracy of mass flow measurement.
Innovation Solution
A ram-pressure probe sensor unit with integrated sensors for static pressure, differential pressure, and temperature, along with a computing unit, processes these variables to calculate mass flow, volumetric flow, and enthalpy flow, while a nanostructured surface prevents particle deposition and an additional gas analysis sensor detects harmful substances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If hot film anemometers are used to measure mass flow, then mass flow measurement is achieved, but particle or condensate deposits on heated areas cause drift in measured values
Solution Approach 1:
The invention extracts the measurement function from a single hot film sensor to a multi-sensor system including static pressure sensor, differential pressure sensor, and temperature sensor. This extraction allows each sensor to perform its specific function independently, preventing the drift problem that affects hot film anemometers when particles or condensates deposit on heated areas.
Solution Approach 2:
The invention changes the measurement parameters from relying solely on heated area cooling (hot film) to measuring static pressure, differential pressure, and temperature separately. This parameter change eliminates the drift issue because these parameters are not affected by particle or condensate deposits in the same way heated surfaces are.
2Reliability
If multiple sensors and computing unit are integrated in a sensor unit, then measurement stability and accuracy are improved, but device complexity increases
Solution Approach 1:
The invention merges multiple sensors (static pressure sensor, differential pressure sensor, temperature sensor) and a computing unit into a single integrated sensor unit. This combining allows the system to achieve high measurement stability and accuracy through multiple measurement parameters while presenting a compact, unified device structure to the user.
Solution Approach 2:
The integrated sensor unit performs multiple functions simultaneously: measuring static pressure, differential pressure, temperature, and calculating mass flow, volumetric flow, and enthalpy flow. This multi-functionality is achieved within a single device structure, making the complex system versatile and applicable to various measurement scenarios.
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 configuration provides stable and accurate measurements by preventing drift and enabling long-term reliability, suitable for various applications including internal combustion engine control.
Implementation Method 1
The invention is based on the principle of ram-pressure probe measurement, in which a reproducible differential pressure is produced as a function of the speed and the density of the fluid
Implementation Method 2
The gas flow is directed over a heated area of the sensor. The heated area cools down on account of the flowing gas. The value of this cooling is the initial basis for determining the mass flow
Data Source
AI summary
The static pressure, the differential pressure, and the temperature must be known in order to be able to determine the mass flow rate, the volumetric flow under standard conditions, or the enthalpy flow of a fluid. Desired variables are detected by individual sensors located in an integrated sensor unit, and the values detected by the individual sensors are then processed in a computing unit that is also integrated in the sensor unit. The sensor unit outputs a value, which also takes other parameters and/or physical constants into account, to a control unit that is connected downstream. Some of the computing is advantageously done in the sensor unit so that some load is relieved from the control unit.