Fuel Injector Housing Stop Absorbs Armature Kinetic Energy
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Solution Overview
Problem
High fuel pressures in direct injection systems cause pintle bounce back when the fuel injector is turned off, leading to unmetered and under-atomized fuel dispensing, increased noise, and reduced injector life due to the additional mass of the sliding armature increasing impact force on the nozzle seat.
Innovation Solution
A housing stop is introduced to absorb kinetic energy from the sliding armature when the fuel injector is turned off, redirecting the energy away from the nozzle seat and reducing the impact force on the pintle, thereby preventing bounce back.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sliding armature is added to lift the pintle at high fuel pressures, then the pintle can be reliably opened, but the impact force on the nozzle seat increases causing pintle bounce back
Solution Approach 1:
A decoupling mechanism is introduced as an intermediary between the sliding armature and the pintle. This mechanism allows the armature to transfer only the necessary force to open the pintle while preventing the transmission of excessive impact forces that would cause bounce back, thus resolving the contradiction between reliable opening and excessive impact force
Solution Approach 2:
The decoupling mechanism is designed to absorb and dissipate excess kinetic energy before it reaches the pintle-nozzle seat interface. By providing this cushioning effect in advance, the system prevents pintle bounce back while maintaining sufficient force to overcome high fuel pressure and reliably open the injector
2Manufacturing precision
If fuel pressure is increased to improve atomization, then spray quality improves, but the force required to lift the pintle increases making dead lift difficult
Solution Approach 1:
The system transitions from a static spring-based force application to a dynamic sliding armature mechanism that can generate high instantaneous forces on demand. This dynamic approach allows the injector to overcome high fuel pressures for improved atomization while the decoupling mechanism prevents excessive force transmission during closing that would cause bounce back
3Force
If the sliding armature mass is increased to provide sufficient lifting force, then pintle opening is achieved, but the impact force on closing increases leading to noise and reduced injector life
Solution Approach 1:
The decoupling mechanism serves as a mediator that separates the function of generating lifting force from the function of controlling impact force. It allows a relatively light armature to generate sufficient lifting force through dynamic acceleration while the decoupling mechanism absorbs the excess energy during closing, preventing damage and reducing noise, thus extending injector life
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 solution effectively reduces unwanted fuel dispensing and noise, while extending the life of the fuel injector by dissipating kinetic energy into the housing stop instead of the nozzle seat, resulting in a 50% decrease in Dynamic and Static Flow Shift during durability tests.
Implementation Method 1
when a current is applied to a coil winding within the fuel injector, a magnetic field is generated that urges the pintle/ball assembly away from the nozzle seat
Implementation Method 2
the sliding armature, also known as a decoupled armature or flying armature, that in response to the magnetic field, accelerates towards and strikes a pintle stop like a slide hammer to provide a combination of kinetic energy and static force
Implementation Method 3
A housing stop is introduced to absorb kinetic energy from the sliding armature when the fuel injector is turned off, redirecting the energy away from the nozzle seat and reducing the impact force on the pintle
Data Source
AI summary
A fuel injector that includes a sliding armature, decoupled armature, or flying armature movable between a pintle stop and a housing stop. Flying armatures are generally used to increase the total force applied to the pintle stop for lifting the pintle off a nozzle seat to open the fuel injector. When the fuel injector is turned off, a housing stop is arranged to absorb kinetic energy present in the flying armature so that the kinetic energy is not imparted to the nozzle seat.