Nested Solenoid Valve Layout for Compact Fuel Metering
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Solution Overview
Problem
Solenoid valves in common rail systems face challenges in reducing size while maintaining operational reliability and responsiveness, particularly due to constraints on the length-to-diameter ratio and hardness of sliding portions, which hinders their mountability and fuel metering efficiency.
Innovation Solution
The solenoid valve design incorporates an inner stator with the sliding portions and spring arranged in parallel within a recess, reducing the overall size by integrating the rod and guide within the inner stator, ensuring responsiveness through optimized magnetic flux distribution and improved manufacturability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the solenoid valve size is reduced, then mountability is improved, but the sliding portion length-to-diameter ratio and hardness requirements become difficult to maintain
Solution Approach 1:
The guide is positioned inside the inner stator, and the spring is arranged within the recess of the inner stator in parallel with the sliding portions. This nesting arrangement allows the sliding portions, guide, and spring to occupy the same radial space, effectively reducing the overall solenoid valve size while maintaining adequate sliding portion dimensions for reliable operation
Solution Approach 2:
The sliding portions, guide, and spring are arranged in parallel along the radial direction within the inner stator recess, rather than sequentially along the axial direction. This dimensional reorganization allows compact packaging without compromising the sliding portion length-to-diameter ratio or hardness requirements
2Reliability
If the sliding portions are made harder to improve durability, then reliability is improved, but manufacturability becomes more difficult
Solution Approach 1:
The sliding portions are formed with a hardness of 58-65 HRC through controlled cooling in a mold during manufacturing. This parameter change achieves the required durability while maintaining manufacturability through standard molding and heat treatment processes
3Volume of moving object
If the solenoid valve is made more compact, then mountability is improved, but fuel metering efficiency may be compromised
Solution Approach 1:
By nesting the guide and spring within the inner stator recess, the solenoid valve achieves compact dimensions that improve mountability while preserving the functional dimensions of the valve element and sliding portions necessary for accurate fuel metering
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 allows for a compact solenoid valve design that enhances mountability and responsiveness, maintaining the required sliding portion hardness and length-to-diameter ratio, thus improving fuel metering and reducing physical size while ensuring reliable operation.
Implementation Method 1
The armature is attracted toward the inner stator when the coil is energized
Implementation Method 2
The spring biases the armature in a direction away from the inner stator
Data Source
AI summary
A solenoid valve includes an inner stator and an outer stator that are part of a magnetic circuit. An armature is attracted toward the inner stator when a coil is energized. A spring biases the armature in a direction away from the inner stator. A rod is integrally formed with the armature and integrally reciprocates with the armature. A guide guides reciprocation of the rod. A valve operates by following the rod to open and close a fuel/liquid passage. The spring and sliding portions between the rod and the guide are arranged within a recess portion formed in the inner stator and arranged in parallel to each other while overlapping in the axial direction.