Fuel Injector Valve Body Bounce Control via Elastic Coefficient
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Solution Overview
Problem
Fuel injectors with electromagnetic opening and closing mechanisms experience high colliding speeds between movable and stator cores, leading to rebound issues and potential damage, as well as variations in injection amounts due to the rebound wave in the ti-q line relationship.
Innovation Solution
A fuel injector design incorporating a coil, stator core, movable core, and an elastic-force applying portion with adjustable elastic coefficients to control the valve body's movement, ensuring Ffc−Ffo≦L×K, thereby restricting the bounce of the movable core and stabilizing the injection amount.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the coil is energized to open the valve body, then the valve body opens the injection port, but the movable core collides with the stator core at high speed causing rebound and injection amount variation
Solution Approach 1:
The patent introduces a buffer member positioned between the movable core and the stator core. This buffer member absorbs the impact energy when the movable core collides with the stator core, preventing rebound and reducing injection amount variation. The cushioning action occurs before damage or performance degradation can occur, maintaining reliable fuel injection.
2Speed
If the movable core collides with the stator core at high speed, then the valve opens quickly, but damage to the movable core or stator core may occur
Solution Approach 1:
The buffer member is positioned to contact the movable core before it strikes the stator core. This arrangement cushions the impact in advance, reducing the colliding speed and preventing damage to both the movable core and stator core while maintaining quick valve opening capability.
Solution Approach 2:
The buffer member acts as an intermediary element between the movable core and the stator core. It mediates the collision by absorbing impact energy, protecting both the movable core and stator core from direct high-speed contact and potential damage.
3Reliability
If the elastic coefficient of the elastic-force applying portion is increased, then the bounce of the movable core is restricted, but the valve opening force may be insufficient
Solution Approach 1:
The patent optimizes the elastic coefficient of the elastic-force applying portion to balance two requirements: it must be high enough to restrict bounce and ensure stability, but not so high that it prevents adequate valve opening. This parameter optimization allows the system to achieve both stability and sufficient opening force.
Solution Approach 2:
The buffer member provides cushioning that complements the elastic-force applying portion. By absorbing impact energy before it causes rebound, the buffer member allows the elastic-force applying portion to use a moderate elastic coefficient that provides stability without compromising valve opening force.
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 reduces the colliding speed of the movable core, minimizes injection amount variations, and prevents damage to the core components by maintaining a balanced elastic and fuel-pressure force ratio, ensuring accurate fuel injection.
Implementation Method 1
The coil generates a magnetic flux when is energized. The stator core generates a part of a magnetic circuit as a passage of the magnetic flux, and generates an electromagnetic force.
Implementation Method 2
The elastic-force applying portion is elastically deformable according to a movement of the valve body to apply an elastic force to the valve body in a valve-closing direction.
Data Source
AI summary
A fuel injector includes a valve body moved together with a movable core and opening an injection port, and an elastic-force applying portion being elastically deformable according to a movement of the valve body to apply an elastic force to the valve body in a valve-closing direction. An elastic coefficient of the elastic-force applying portion is set to meet a condition that Ffc−Ffo≦L×K. In this case, a fuel-pressure valve-closing force of when the valve body is closed is referred to as Ffc, and the fuel-pressure valve-closing force of when the valve body is completely opened is referred to as Ffo. A movement distance of the valve body from a time point that the valve body is closed to a time point that the valve body is completely opened is referred to as L. The elastic coefficient is referred to as K.