Actuator Core Demagnetization for Fuel Injector Reliability
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Solution Overview
Problem
Existing methods for controlling electrically controlled actuators, such as dual coil fuel injectors, face inefficiencies due to constant current profiles that fail to accurately counteract varying residual magnetism and increased friction at different operating conditions, leading to potential coil degradation and increased current requirements.
Innovation Solution
Demagnetizing the core of a first electromagnet to reduce residual magnetism, allowing for reduced current usage in the second electromagnet and minimizing coil degradation by focusing magnetic force on overcoming friction rather than residual magnetism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current is increased in the opening electromagnet to overcome residual magnetism and friction, then the actuator can change state reliably, but coil degradation increases and current capacity requirements increase
Solution Approach 1:
The patent extracts and removes the harmful residual magnetism from the closing electromagnet core through a demagnetization process. By applying a reverse current or alternating current to the closing coil, the residual magnetic field is eliminated, allowing the opening electromagnet to operate without having to overcome this persistent magnetic force, thereby reducing the current required and preventing coil degradation
Solution Approach 2:
The patent applies preliminary anti-action by demagnetizing the closing electromagnet before the opening electromagnet needs to overcome the residual magnetism. This preliminary removal of the harmful magnetic field prevents the need for excessive current in the opening coil, addressing the problem before it arises during normal operation
2Ease of operation
If constant current profile is used to counter residual magnetism, then control simplicity is maintained, but accuracy in counteracting varying residual magnetism deteriorates
Solution Approach 1:
The patent applies preliminary action by demagnetizing the closing electromagnet core before normal operation begins. This preliminary demagnetization ensures that the core starts with minimal residual magnetism, allowing the use of simpler current profiles during operation without sacrificing accuracy in counteracting residual magnetism effects
3Reliability
If current is increased to overcome both residual magnetism and friction at cold temperatures, then actuator operation is maintained, but the possibility of opening coil degradation increases
Solution Approach 1:
The patent removes the residual magnetism component from the total force that the opening electromagnet must overcome. By extracting this magnetic force requirement through demagnetization, the opening coil current can be reduced to only what is needed for friction and inertial forces, extending coil service life even at cold temperatures where friction is higher
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 enhances the utilization of magnetic force, reduces current requirements, and improves the reliability of actuator state changes by eliminating the need to estimate and counteract residual magnetism, thereby minimizing coil degradation and optimizing actuator operation across varying conditions.
Implementation Method 1
residual magnetism that remains in the closing electromagnet core
Implementation Method 2
current is supplied to the closing coil before current is applied to the opening coil. Current is applied to the closing coil with the objective of overcoming residual magnetism that remains in the closing electromagnet core
Data Source
AI summary
A method to improve the performance of an electrically operable actuator is described. The method demagnetizes at least the core of an electromagnet to improve operation of the electrically operable actuator.