Fuel Injector Armature Control via Adaptive Current Waveforms
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Solution Overview
Problem
Conventional hydraulically actuated fuel injection systems experience armature bouncing during the opening stroke, leading to inefficient fuel supply control, shot-to-shot variations, and increased emissions due to manufacturing tolerances and operational changes over time.
Innovation Solution
A closed-loop control system applies specific current waveforms to the open and close coils of a fuel injector armature, including acceleration, de-latching, deceleration, and latching currents to manage armature motion and reduce bouncing, using adaptive current or voltage forms to stabilize armature movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional open coil solenoid control is used to actuate the armature, then the armature can be shifted to the open position to allow fuel injection, but the armature bounces or repeatedly impacts against the open coil during the opening stroke, making it difficult to control the armature motion and resulting in shot-to-shot variations
Solution Approach 1:
The patent applies dynamic current waveform control to the open coil solenoid, transitioning from static conventional control to dynamic adaptive control. The controller adjusts the current waveform in real-time based on feedback from the position sensor, enabling precise control of armature acceleration and deceleration to eliminate bouncing while maintaining reliable fuel injection actuation
Solution Approach 2:
The patent implements a closed-loop feedback system using a position sensor to monitor armature position and provide feedback to the controller. This feedback enables the controller to adjust the current waveform dynamically, ensuring the armature reaches the open position without bouncing and maintains stable positioning, thereby improving both reliability and ease of operation
2Productivity
If manufacturing tolerances are relaxed to reduce costs, then production efficiency increases, but shot-to-shot variations increase due to variations in armature diameter and coil characteristics
Solution Approach 1:
The patent uses parameter changes in the electrical domain to compensate for mechanical variations. By dynamically adjusting current waveform parameters (amplitude, duration, shape) based on feedback from position sensors, the system compensates for manufacturing tolerances in armature diameter and coil characteristics, allowing relaxed manufacturing specifications while maintaining consistent fuel injection performance
Solution Approach 2:
The patent replaces reliance on precise mechanical tolerances with an electrical control system. Instead of depending on tightly controlled mechanical dimensions, the system uses adaptive electrical current waveforms and feedback control to achieve consistent armature motion, thereby decoupling production efficiency from manufacturing precision requirements
3Speed
If the armature is moved quickly to minimize bouncing during pilot fuel injection, then injection timing improves, but the ability to control and meter small quantities of fuel is lost
Solution Approach 1:
The patent applies dynamic current waveform control that adapts the acceleration profile to the specific injection requirements. For pilot fuel injection, the controller uses optimized current waveforms that provide sufficient acceleration for rapid response while incorporating deceleration phases that prevent bouncing, enabling both high speed and precise fuel quantity control through adaptive waveform shaping
Solution Approach 2:
The patent uses periodic or pulsed current waveforms with carefully controlled timing and duration. By applying current in specific pulses with appropriate intervals, the system achieves rapid armature response for quick injection timing while the pulsed nature allows precise control of the opening duration and fuel quantity, resolving the contradiction between speed and precision
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 reduces shot-to-shot variations, improves fuel injection accuracy, and enhances engine stability and emissions compliance by minimizing armature bounce and adapting to operational changes.
Implementation Method 1
The magnetic force generated in the open coil solenoid will shift an armature into the open position
Implementation Method 2
The magnetic force generated in the close coil solenoid will shift the armature into a closed position
Implementation Method 3
The high pressure working fluid then acts on an intensifier piston to compress an intensifier spring and hence compress fuel
Data Source
AI summary
A method and system controls motion of an armature 112 of a fuel injector 100. The armature moves between an open coil 118 and a close coil 116 of the injector. Acceleration current of a certain polarity is applied to the open coil 118 with the armature disposed at the close coil 116. De-latching current of a polarity opposite of the certain polarity is applied to the close coil 116 to release magnetic latch on the armature thereby accelerating movement of the armature towards the open coil 118. Deceleration current is applied the close coil 116 thereby decelerating the armature prior to reaching the open coil. Latching current of the certain polarity is applied to the open coil 118 prior to or just after impact of the armature 112 with the open coil 118 to magnetically latch the armature to the open coil 118 thereby reducing bounce of the armature at impact.