Fuel Injection Device Biasing Spring Alignment
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Solution Overview
Problem
In fuel injection valves, the inclination of the biasing spring can cause the winding end portion to be caught inside the fuel passage hole, leading to uneven wear and reduced fuel sealability due to eccentric movement of the movable iron core, resulting in increased impact force on the valve seat and compromised fuel sealability.
Innovation Solution
A configuration where the biasing spring's outer diameter is reduced from the lower end to the upper end, with the upper end contacting the movable iron core, and a regulating unit ensures the shortest distance between the spring end and fuel passage hole is larger than the radial travel distance, preventing the spring from being caught and maintaining proper alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the biasing spring is placed with its lower end contacting the stepped portion of the nozzle body, then the movable iron core is biased upward, but the winding end portion of the spring may be caught inside the fuel passage hole due to spring inclination
Solution Approach 1:
A regulating unit is introduced as an intermediary component between the biasing spring and the nozzle body. This regulating unit restricts the inclination of the biasing spring, preventing the winding end portion from being caught in the fuel passage hole while still allowing the spring to function as a biasing element.
Solution Approach 2:
The patent modifies the structural parameters of the biasing spring by reducing its outer diameter from the lower end toward the upper end. This parameter change ensures that even when the spring inclines, the reduced diameter prevents the winding end portion from entering the fuel passage hole.
2Ease of manufacture
If the spring axis direction becomes inclined due to winding end portion step, then the spring can be installed, but uneven wear is caused in the sliding portion between movable iron core and valve body
Solution Approach 1:
The regulating unit serves as a mediator that controls the spring's inclination angle, allowing the spring to be installed while preventing excessive inclination that would cause uneven wear in the sliding portion.
Solution Approach 2:
By reducing the outer diameter of the biasing spring from lower end to upper end, the spring can accommodate slight inclinations without causing the winding end portion to contact the fuel passage hole, thereby maintaining proper alignment of the sliding portion.
3Force
If the movable iron core becomes eccentric due to spring twisting, then the spring continues to bias the core, but impact force on the valve seat increases
Solution Approach 1:
The biasing spring is designed with a reduced outer diameter from lower end to upper end, which constrains the spring's radial movement and prevents excessive twisting. This maintains the movable iron core's alignment while preserving the biasing force, thereby reducing impact force on the valve seat.
4Ease of operation
If the winding end portion reaches the fuel passage hole, then the spring can contact the movable iron core, but fuel sealability deteriorates due to uneven wear
Solution Approach 1:
The biasing spring's outer diameter is reduced from the lower end toward the upper end, ensuring that the winding end portion maintains a safe distance from the fuel passage hole while still enabling contact with the movable iron core for proper biasing function.
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 stabilizes fuel sealability over long-term use by preventing uneven wear and maintaining the movable iron core's alignment, thus enhancing the fuel injection device's sealing performance.
Implementation Method 1
a biasing spring whose one end contacts the movable iron core, and that biases the movable iron core in a valve opening direction
Implementation Method 2
a magnetic path is formed such that a magnetic flux circulates around a fixed iron core, a movable iron core, a housing, and a large-diameter portion of a cylindrical member; the movable iron core is attracted toward the fixed iron core by a magnetic attraction force generated by the magnetic flux
Data Source
AI summary
For a fuel injection device, a configuration to improve fuel sealability when a valve is closed is provided. Therefore, the fuel injection device includes: a valve body that opens and closes a fuel flow path; a movable iron core in which a fuel passage hole communicating an upstream side and a downstream side is formed, and that operates the valve body toward the upstream side; a biasing spring whose one end contacts the movable iron core, and that biases the movable iron core in a valve opening direction; and a regulating unit that regulates movement of the one end of the biasing spring, in which the shortest distance between the one end of the biasing spring and the fuel passage hole is larger than a radial travel distance of the one end until radial movement of the one end is regulated by the regulating unit.