Fuel Injector Control Valve Spring Guide for Low-Friction Alignment
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Solution Overview
Problem
Fuel injectors face issues with shot-shot variation in fueling due to friction caused by concentricity or parallelism errors in the control valve assembly, and increased fuel pressure and temperature lead to fuel lacquer formation, further increasing friction.
Innovation Solution
A control valve member with a magnetic armature and a spider spring or integral seat-spring member is used, which includes a central core with radially extending resilient limbs or arms to guide the valve member between closed and open positions, reducing friction and maintaining precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the spool is guided with minimal clearance inside the hydraulic bore to reduce friction, then the friction is reduced, but the alignment precision between the solenoid and armature must be extremely high, which increases manufacturing cost and complexity
Solution Approach 1:
The patent introduces a separate spool guide component as an intermediary element between the spool and the hydraulic bore. This guide component provides precise alignment and support for the spool, eliminating the need for extremely tight tolerances in the hydraulic bore machining. The guide acts as a mediator that ensures accurate positioning while allowing for standard manufacturing tolerances in the main body.
Solution Approach 2:
The patent divides the alignment and guidance function into separate components: the hydraulic bore, the spool guide, and the spool itself. By segmenting the guidance function from the main valve body, the design allows each component to be manufactured with standard tolerances while achieving the required overall alignment precision through the assembled structure.
2Device complexity
If conventional control valve members are used, then the structure is simple, but friction increases due to concentricity or parallelism errors, causing shot-shot variation in fueling
Solution Approach 1:
The spool guide serves as a mediator component that ensures precise alignment between the spool and solenoid, eliminating the negative effects of concentricity or parallelism errors. This separate guide component maintains consistent spacing and alignment, thereby reducing friction and eliminating shot-shot variation in fueling while adding only moderate structural complexity.
Solution Approach 2:
The spool guide provides preemptive alignment and support for the spool, preventing misalignment and friction issues before they occur. By establishing precise geometric relationships in advance through the guide component, the design compensates for potential manufacturing tolerances and operational deviations, ensuring consistent fueling performance.
3Force
If the spool is guided with very precise alignment to avoid friction from sideloads, then friction is reduced, but the machining cost increases significantly
Solution Approach 1:
The patent segments the alignment function from the main valve body by introducing a separate spool guide component. This allows the hydraulic bore to be machined with standard, cost-effective tolerances, while the spool guide is separately manufactured and assembled to provide the precise alignment needed to minimize friction and sideloads on the spool.
Solution Approach 2:
The spool guide acts as an intermediary component that provides precise alignment between the spool and solenoid without requiring the main valve body to be machined with extremely tight tolerances. This mediator component absorbs the alignment requirements, allowing cost-effective machining of the primary structure while still achieving low-friction 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
The solution effectively minimizes friction and maintains precise alignment, reducing shot-shot variation and preventing fuel lacquer formation, thereby improving the accuracy and reliability of fuel injection.
Implementation Method 1
when the solenoid is electrically energized, a magnetic field attracting the armature and spool assembly toward the solenoid is generated
Implementation Method 2
an electromagnetic solenoid provided with a central bore
Implementation Method 3
a spider spring provided with a plurality of resilient limbs radially extending from a common core
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A control valve member (44) of a fuel injector control valve assembly (14) adapted to be arranged in a control valve chamber (42) wherein it is guided in translation along a valve axis (X2) between a closed position forbidding fuel to exit a spill orifice (58) and an open position enabling fuel to exit said spill orifice (58), the control valve member (44) comprising a magnetic armature (102) to which is fixed a seat member (104). The armature (102) is adapted to cooperate with an electromagnetic solenoid (36) in order for the seat member (104) be move between the closed position wherein it is in sealing abutment against a fixed seating face (60), and the open position wherein said seat member (104) is lifted away from said fixed seating face (60). The control valve member (44) further comprises a spring member adapted to guide in translation along the valve axis (X2) the seat member (104) in the control valve chamber (42).