Fuel Injector Sensor Jacket Bonding for Deformation Detection
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Solution Overview
Problem
Existing injectors with sensors attached via conventional adhesive bonds face limitations in controllability and signal transmission due to inadequate contact surface area, leading to suboptimal detection of injector wall surface deformations caused by pressure changes.
Innovation Solution
A jacket bond is employed, covering the entire contact area between the sensor's bottom wall and the injector's facing wall, as well as a partial or entire area of the sensor's side walls, providing an enlarged contact surface and prestressing the sensor during curing to enhance signal transmission and controllability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional adhesive bond is used to attach the sensor to the injector, then the sensor can be mounted on the injector, but the contact surface area is insufficient leading to weak signal transmission
Solution Approach 1:
The bonding method transitions from a conventional point or small-area bond to a jacket bond that wraps around the sensor, utilizing the lateral surface area of the sensor housing. This dimensional expansion from a flat contact interface to a three-dimensional enveloping bond significantly increases the effective contact surface area between sensor and injector, thereby improving signal transmission quality.
2Measurement precision
If the jacket bond covers the entire contact area including side walls, then the contact surface is enlarged improving signal transmission, but the manufacturing complexity increases
Solution Approach 1:
The jacket bond serves multiple functions simultaneously: it provides mechanical attachment of the sensor to the injector, creates an enlarged contact surface for improved strain transmission, and offers structural support and protection. By consolidating these multiple functions into a single bonding feature that wraps around the sensor, the design achieves enhanced deformation detection without proportionally increasing manufacturing complexity.
3Measurement precision
If the sensor is prestressed during curing, then the signal transmission is enhanced, but the manufacturing process becomes more complex
Solution Approach 1:
The prestressing of the sensor is performed during the curing process of the jacket bond, before the bond fully hardens. By applying the prestressing force in the preliminary stage when the adhesive is still pliable, the sensor is pre-loaded to optimize its strain transmission characteristics. This preliminary action ensures enhanced signal strength while integrating the prestressing step into the existing curing process rather than adding a separate manufacturing operation.
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 results in improved signal strength and controllability of the injector, with enhanced durability and protection of the sensor from external damage, allowing for precise control of injection processes.
Implementation Method 1
the bond is a jacket bond... the jacket bonding comprises the entire contact area between the bottom wall of the sensor and the facing wall area of the injector and at least a partial area of a side wall of the sensor... a deformation, in particular expansion or compression, of a wall surface of the injector is transmitted more extensively or more intensively to the sensor
Data Source
Figure 1
Figure 2~4a
AI summary
The invention relates to a fuel injector comprising an injector body 1 and a nozzle body 2 with a bore 4a accommodating a nozzle needle 5, wherein the nozzle needle 5 is translationally movable in the bore 4a, and a nozzle needle tip 7 cooperating with a nozzle body seat 8, wherein the nozzle body seat 8 is associated with at least one nozzle opening 9, which is controlled by the nozzle needle 5 and connected to a high-pressure line 10, 10a for fuel in the injector body 1 and the nozzle body 2, and wherein a sensor 12, attached to the injector by means of an adhesive bond, is provided for detecting a deformation of a wall of the injector. According to the invention, an injector with a sensor 12 for determining a deformation of a wall caused by the fuel guided through the injector is provided, which is improved with regard to its controllability. This is achieved by the fact that the adhesive bond is a sheath bond 13.The sheath bonding 13 comprises the entire contact surface between a bottom wall 14 of the sensor 12 and the facing wall surface 15 of the injector and at least a partial surface of a side wall 16a, 16b, 16c, 16d of the sensor 12.