Fuel Injector Resilient Electrical Link for Nozzle State Detection
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Solution Overview
Problem
Existing fuel injectors face challenges in accurately detecting the open or closed state of the nozzle, leading to inefficiencies in fuel injection control due to manufacturing tolerances and misalignment issues, which affect the reliability of electrical connections and feedback signals for closed-loop control.
Innovation Solution
A resilient electrical link with a coil spring or other resilient elements is used to ensure consistent electrical contact between the valve member and the nozzle body, allowing for detection of the nozzle's open or closed state through an electrical change, extending between the electrical connector and the upper guide member, and incorporating insulation to prevent unwanted connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rigid electrical connections are used between the valve member and nozzle body, then electrical contact reliability improves, but manufacturing precision requirements increase and thermal growth accommodation deteriorates
Solution Approach 1:
The patent changes the physical state and mechanical properties of the electrical connection from rigid to resilient by introducing a coil spring. This resilient electrical link can elastically deform to accommodate manufacturing tolerances and thermal expansion, while maintaining reliable electrical contact. The spring constant and pre-load force are optimized to ensure continuous contact without requiring high manufacturing precision.
Solution Approach 2:
The electrical connection transitions from a static rigid structure to a dynamic resilient system. The coil spring provides continuous adaptive contact pressure that automatically adjusts to thermal growth and manufacturing variations. This dynamic characteristic allows the system to maintain reliable electrical contact under varying operating conditions without requiring tight manufacturing tolerances.
2Strength
If brazed or crimped connections are used for electrical links, then connection strength improves, but manufacturing complexity and cost increase
Solution Approach 1:
The coil spring electrical link is designed to self-adjust and self-maintain optimal contact pressure through its elastic properties. The resilient structure automatically compensates for wear, thermal expansion, and manufacturing variations, eliminating the need for complex brazing or crimping operations. This self-service characteristic simplifies manufacturing while maintaining strong, reliable electrical connections throughout the component's service life.
3Measurement precision
If fixed electrical connections are used, then electrical signal transmission accuracy improves, but thermal growth accommodation deteriorates
Solution Approach 1:
The electrical connection system incorporates a coil spring that changes its mechanical parameters (length, contact pressure) in response to thermal growth. This resilient link maintains consistent electrical contact and signal transmission accuracy across a wide temperature range by elastically accommodating thermal expansion and contraction of the fuel injector components.
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 enhances the accuracy of fuel injection control by reliably transmitting electrical switching signals, improving the timing of fuel injection pulses and reducing the need for costly brazed or crimped connections, while accommodating manufacturing tolerances and thermal growth.
Implementation Method 1
A resilient electrical link with a coil spring or other resilient elements is used to ensure consistent electrical contact between the valve member and the nozzle body
Implementation Method 2
fuel pressure in the chamber urges the valve member towards the valve seat in a closed position of the nozzle
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A fuel injector has a head portion adapted to provide connections from and to an ECU to selectively energize an actuator to start and stop fuel injection pulses, a fuel supply connection for supplying fuel into the injector at an elevated pressure, a fuel return connection for returning fuel at a lower pressure, a fuel injection nozzle having at least one nozzle opening provided at an end of a valve guide, a valve member movable in a chamber defined within the valve guide and biased to close against a valve seat and inhibit fuel injection through the nozzle and to move within the valve chamber away from the valve seat to eject fuel through the nozzle. A circuit is provided for detecting by an electrical change whether the nozzle is open or closed. The circuit includes a conductor extending between the head of the fuel injector, either in an outer region of the body of the injector or through an isolation member for the actuator, to a position generally at a head end of the actuator, a contact member at the head end of the actuator maintained in electrical contact with the conductor and a resilient electrical link between the contact member and one of the valve member and the valve guide.