Diesel Fuel Injector Actuator Spring Damping
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Solution Overview
Problem
The existing electromagnetic actuators in fuel injectors experience oscillations in the control valve spring, disrupting the armature movement and causing disturbances in fuel flow, leading to high-frequency disruptions in multiple injections.
Innovation Solution
An electromagnetic actuator with a fixed electric coil, an axial blind hole, and a compressed elastic device, including a helical compression spring encapsulated by a heat-shrinkable element, which continuously pushes the valve assembly away from the spool, reducing oscillations and stabilizing the armature movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coil spring is used to push the control valve, then the valve can be reset to its initial position, but oscillations are generated that disrupt armature movement and cause high-frequency disruptions in multiple injections
Solution Approach 1:
A damping element is introduced as an intermediary component between the coil spring and the control valve. This damping element absorbs and dissipates the oscillation energy generated by the spring, preventing the harmful vibrations from being transmitted to the armature and control valve, while still allowing the spring to perform its valve reset function
Solution Approach 2:
The invention converts the harmful oscillations generated by the coil spring into beneficial damping effects. By strategically placing damping elements in the spring assembly, the oscillation energy is transformed into heat through internal friction, thereby eliminating the disruptive vibrations while maintaining the spring's elastic recovery function
2Speed
If the armature moves rapidly during injection, then fuel delivery response is improved, but oscillations in the control valve cause high-frequency disruptions that affect multiple injections
Solution Approach 1:
The damping element serves as a mediator that isolates the armature from the oscillations generated by the control valve spring. This allows the armature to move rapidly and precisely without being subjected to the disruptive vibrations, thereby maintaining both high-speed response and injection consistency across multiple injections
3Ease of operation
If the control valve is located in the low-pressure chamber and moves against spring action, then the valve can control fuel flow, but the spring oscillations create disturbances in fuel flow
Solution Approach 1:
The damping element is positioned as an intermediary in the spring assembly to suppress oscillations at their source. This prevents the spring from generating fuel flow disturbances while still allowing the control valve to move freely against the spring action, maintaining ease of valve operation without the harmful side effects
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 armature displacement due to spring oscillations, ensuring consistent fuel delivery and reducing disturbances in the fuel injection process.
Implementation Method 1
The heat-shrinkable element is further heat-shrinked around the elastic member. Furthermore, the heat-shrinkable element has a wall of substantially constant thickness.
Implementation Method 2
The elastic device includes an elastic member and a heat-shrinkable element encapsulating the elastic member. The elastic member is a helical compression spring.
Implementation Method 3
The elastic member is a helical compression spring.
Implementation Method 4
an electromagnetic actuator for a diesel fuel injector. The actuator comprises a fixed electrical coil with an axial blind hole, an elastic device compressed between a pin, and a control rod that moves toward the coil when the latter is electrically energized.
Data Source
Figure 1~2
AI summary
The invention relates to an electromagnetic actuator (20) of a diesel fuel injector (10), the actuator (20) comprising: - a fixed electrical coil (22) provided with an axial blind hole (34), - a resilient device (30) compressed between a pin (32) and a control rod (26) moving towards the coil (22) when the latter is electrically energised, the resilient device (30) permanently urging a valve assembly (28) comprising the control rod (26) attached to a magnetic armature (24) towards a position remote from the coil (22), the valve assembly (28) comprising the resilient device (30) being arranged in a blind hole (34), characterised in that the resilient device (30) comprises a resilient member (36) and a heat-shrinkable element (38) encapsulating the resilient member (36).