Adjustable Doser Valve Stop for Diesel Fuel Flow
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Solution Overview
Problem
Conventional doser valves in diesel engines have a preset stop stroke distance, which cannot be adjusted, leading to potential variations in fuel flow rates due to production tolerances, and the brazing process can impede fuel flow by allowing braze material to migrate into small passages, affecting atomization.
Innovation Solution
The doser valve design allows for adjustable stop placement during manufacturing, with the stop being fixed after testing to achieve desired flow rates, and uses a press-fit seat to prevent braze material migration, minimizing pressure drop and ensuring proper atomization through axial and radial/tangential passages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the stop is set to a preset stroke distance and remains immovable, then the valve structure is simple, but the fuel flow rate varies due to production tolerances
Solution Approach 1:
The stop is made adjustable rather than fixed, allowing the stroke distance to be dynamically modified during assembly or maintenance to compensate for production tolerances and achieve consistent fuel flow rates
Solution Approach 2:
The stroke distance parameter can be adjusted by repositioning the stop along the armature, enabling fine-tuning of the fuel delivery quantity to match actual flow requirements
2Ease of manufacture
If brazing is used to join components, then the manufacturing process is efficient, but braze material migrates into small passages and impedes fuel flow
Solution Approach 1:
The brazing process is completely removed from the manufacturing process. Instead of joining components through brazing, the patent uses interference fits and mechanical retention methods that do not introduce contaminating materials into the fuel passages
Solution Approach 2:
The patent converts the potential harm of material migration by eliminating the brazing process entirely, using alternative joining methods that inherently prevent contamination of the fuel flow paths
3Strength
If the seat is brazed into the housing, then the joint is strong, but pressure drop increases and atomization is affected
Solution Approach 1:
The brazing mechanical system is replaced with an interference fit mechanical system. The seat is retained in the housing through precise dimensional interference that creates a strong joint without requiring thermal joining processes
Solution Approach 2:
The interference fit is designed with specific local tolerances and dimensional relationships between the seat outer diameter and housing bore that create an optimal balance between joint strength and minimal obstruction to fuel flow
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 approach ensures consistent fuel delivery by adjusting the stop position to match actual flow requirements and prevents braze material from impeding fuel flow, resulting in improved atomization and reduced pressure drop compared to prior art.
Implementation Method 1
When the solenoid assembly 102 is energized, electromagnetic forces attract the armature 112 to the stop 106
Implementation Method 2
the force of the spring 116 returns the armature 112 and poppet 114 to their original positions
Data Source
AI summary
A doser valve with a seat comprising at least one axially located slot from an outer surface of the seat and at least one radial/tangential extending passage in fluid communication with the at least one axially located slot and an exit passage out of the seat.