Thin-Walled Fuel Path Strain Sensor for Compact Pressure Measurement
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Solution Overview
Problem
Existing fuel pressure measuring devices in internal combustion engines face challenges in accurately measuring fuel pressure without increasing the size of the path member and maintaining a simplified structure, particularly due to the need for sealing structures and complex installations when using stem-based strain gauges.
Innovation Solution
A fuel pressure measuring device that incorporates a thin-walled portion in the path member, allowing a strain sensor to be directly affixed to measure pressure without a separate stem, eliminating the need for sealing structures and simplifying the design, while also incorporating temperature and pressure correction mechanisms to enhance accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a stem with strain gauge is installed in the fuel injection valve body to measure fuel pressure, then measurement capability is achieved, but the size of the valve body increases and sealing structure becomes complex
Solution Approach 1:
The strain sensor is directly integrated into the path member (fuel rail or injection valve body) itself, merging the measurement function with the structural component. This eliminates the need for a separate stem assembly and its associated sealing structures, thereby maintaining measurement capability while simplifying the overall device structure.
Solution Approach 2:
The separate stem component is extracted from the design and replaced by direct integration of the strain sensor into the path member. This extraction eliminates the complex sealing requirements between stem and body, while preserving the essential pressure measurement function through direct strain detection on the pressurized component.
2Measurement precision
If a stem with strain gauge is installed in the path member to measure fuel pressure, then measurement capability is achieved, but the size of the path member increases
Solution Approach 1:
The strain sensor is directly integrated into the path member structure itself, merging the measurement function with the existing component. This eliminates the need for additional stem length extending from the path member, thereby maintaining measurement capability while minimizing the overall size and length of the path member assembly.
3Measurement precision
If fuel pressure sensor is disposed in the common rail to measure pressure change, then pressure measurement is achieved, but the pressure change is absorbed within the common rail resulting in decreased accuracy
Solution Approach 1:
The strain sensor is positioned at a specific location on the path member where pressure changes are most pronounced and least absorbed - specifically on the high-pressure fuel path near the injection valve. This local positioning ensures that the sensor detects rapid pressure changes during fuel injection events before they are dampened by the larger common rail volume, thereby improving measurement accuracy and reliability.
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 solution enables accurate fuel pressure measurement near the spray hole, reduces the size of the path member, and minimizes errors due to temperature and individual variability, resulting in a more efficient and compact fuel pressure measuring system.
Implementation Method 1
a strain sensor which is installed on the thin-walled portion to measure strain of the thin-walled portion arising from pressure of the fuel in the high-pressure fuel path
Data Source
AI summary
A fuel injection system for use with an internal combustion engine supplies fuel to an injector (fuel injection valve) from a common rail (accumulator) through a high-pressure pipe to spray the fuel from a spray hole formed in the injector. A thin-walled portion is formed in a path member (e.g., an injector body, the high-pressure pipe, or a connector connecting the injector and the high-pressure pipe) and defined by a locally thin wall of the path member. A strain gauge (strain sensor) is affixed to the thin-walled portion to measure strain of the thin-walled portion arising from the pressure of fuel in a high-pressure fuel path.