Hydrocarbon Sensor Chamber Segmentation for Flow-Independent Measurement
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Solution Overview
Problem
The inability to precisely measure hydrocarbon concentration in the intake air of an internal combustion engine leads to inefficient fuel injection and potentially poorer exhaust gas values due to unknown hydrocarbon levels.
Innovation Solution
A sensor arrangement with a gas-permeable element and temperature sensors is placed in a sensor chamber decoupled from the gas flow line, allowing for precise measurement of hydrocarbon concentration independent of volume flow, and includes a heating element and semiconductor components for accurate temperature-dependent signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor is positioned directly in the gas flow line to measure hydrocarbon concentration, then the measurement can be performed at the actual flow location, but the measurement accuracy deteriorates due to dependence on volumetric flow rate variations
Solution Approach 1:
The measurement system is segmented into two separate locations: the gas flow line and the sensor chamber. The sensor is isolated from the main gas flow by positioning it in a separate chamber connected via a connection piece, allowing independent optimization of measurement conditions without being affected by flow rate variations in the main line.
Solution Approach 2:
A connection piece acts as an intermediary between the gas flow line and the sensor chamber. This intermediary component transfers the gas sample from the flow line to the sensor chamber, enabling indirect measurement that is independent of the volumetric flow rate in the main gas line.
2Measurement precision
If the sensor is positioned back relative to the pipe in a sensor chamber to enable flow-independent measurement, then measurement accuracy improves, but the device complexity increases
Solution Approach 1:
The connection piece and sensor chamber are designed as an integrated unit that combines multiple functions: gas sample transfer, flow conditioning, and sensor housing. This merging of components achieves flow-independent measurement while minimizing the overall structural complexity compared to separate independent components.
3Device complexity
If a gas-permeable element is added between the line and sensor chamber to simplify sensor design, then the sensor design becomes simpler, but the measurement response time may be affected
Solution Approach 1:
A gas-permeable element is introduced as a porous barrier between the gas flow line and the sensor chamber. This porous material allows gas molecules to pass through while maintaining the physical separation, simplifying the sensor design by enabling direct exposure to the gas sample without complex sealing arrangements, while the pore structure facilitates rapid mass transfer.
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 precise control of the internal combustion engine by accurately determining hydrocarbon concentration, optimizing air-fuel ratio, reducing fuel consumption, and minimizing emissions.
Implementation Method 1
A gas-permeable element can be arranged between the line and the sensor chamber
Implementation Method 2
the at least one sensor comprises at least one heating element for heating a gas stream
Implementation Method 3
at least one first and one second temperature sensor, wherein the at least one heating element is arranged between the first and second temperature sensors
Data Source
Figure 1~2
Figure 3
AI summary
An apparatus for measuring a hydrocarbon concentration of a gas stream in a line (100) comprises at least one sensor (101) for measuring a hydrocarbon concentration, the position of said sensor being set off in relation to the line (100).