Fuel Injector Pressure Sensor Using Curved Flow Path Deformation
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Solution Overview
Problem
Existing fuel pressure detection devices for fuel injectors are not suitable for integration into existing internal combustion engines without significant structural changes, as they increase the size of the fuel injector and require additional components like prestressing devices, making them unsuitable for practical use.
Innovation Solution
A device with a curved or kinked fuel flow path in the measuring element area, where increased pressure causes the flow path to align straight, generating mechanical stress detectable by a piezoelectric element without the need for a prestressing device, and a rigid connection to the injector housing, allowing for integration without size or design changes to the fuel injector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a piezo element is pressed against the injector housing by means of a prestressing device, then the fuel pressure can be detected, but the device complexity and manufacturing costs increase
Solution Approach 1:
The invention extracts and eliminates the prestressing device from the measurement system. Instead of using a separate prestressing mechanism to press the piezo element against the housing wall, the solution uses the natural deformation of the curved inlet bore wall under fuel pressure to provide the necessary contact force, thereby simplifying the device structure and reducing manufacturing costs while maintaining measurement capability
Solution Approach 2:
The inlet bore wall deformation under fuel pressure serves the dual purpose of both containing the fuel and providing the prestressing force for the piezo element. The system uses its own operational pressure to generate the measurement force, eliminating the need for an external prestressing device and achieving self-service functionality
2Measurement precision
If a prestressing device is used to press the piezo element against the injector housing, then the fuel pressure can be detected, but the overall size of the fuel injector increases
Solution Approach 1:
The invention removes the prestressing device and its associated mounting structures, thereby reducing the overall volume of the fuel injector. The measurement function is achieved using only the inlet bore wall deformation, which requires no additional space beyond what is already present in the standard injector design
Solution Approach 2:
The invention merges the fuel containment function of the inlet bore with the measurement function by using the same curved bore wall deformation for both purposes. This integration eliminates the need for separate measurement chambers or mounting spaces, maintaining compact injector dimensions
3Measurement precision
If the piezo element is arranged on the outside of the fuel injector near the inlet bore, then the fuel pressure can be detected through wall deformation, but additional structural changes to the internal combustion engine are required
Solution Approach 1:
The invention creates a universal measurement solution that can be integrated into existing fuel injectors without modification. By using the naturally occurring inlet bore wall deformation and eliminating the need for prestressing devices or external mounting structures, the system becomes adaptable to standard engine installations without requiring structural changes to the internal combustion engine
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 the detection of fuel pressure with minimal effort and without additional space or structural changes to the fuel injector, reducing manufacturing costs and allowing for use in existing engines, while maintaining accurate pressure monitoring.
Implementation Method 1
a piezoelectric element (51), in particular a piezoelectrically active ceramic element, which generates a voltage signal when it is acted upon by compressive stress
Implementation Method 2
The hydraulic forces, which lead to a reduction in the curvature of the flow path, generate a mechanical stress in the wall delimiting the flow path for the fuel and thus a deformation that can be detected
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to a device (50) for detecting a fuel pressure (P) for a fuel injector (10; 10a), comprising a measuring element (52) designed as a piezoelectric element (51; 51a) for detecting the fuel pressure (P), wherein the measuring element (52) is configured to detect a deformation in a wall of a fuel supply device that limits the flow path to a high-pressure chamber (28) formed in an injector housing (11). According to the invention, the fuel supply device provides a curved or kinked flow path for the fuel in the region of the measuring element (52).