Ignition Coil Staggered Core Design for Ion Current Detection Noise
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Solution Overview
Problem
Conventional ignition coils fail to stabilize ion current detection due to residual magnetism, leading to false noise detection and reduced accuracy in misfire monitoring.
Innovation Solution
The ignition coil design includes a center core and outer core made of magnetic materials with a staggered axial low voltage end configuration, where the center low end surface protrudes relative to the outer low end surface by a distance that ensures residual magnetic noise detection period falls within system requirements, and a cross-section ratio is optimized to minimize magnetic flux leakage and false detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the ion current detector waits for a predetermined period after spark generation to avoid residual magnetism noise, then false detection is reduced, but detection response time increases and system efficiency decreases
Solution Approach 1:
The patent extracts the harmful residual magnetism from the detection system by providing a dedicated discharge path through the third coil connected to ground. This allows the residual magnetism to be separately discharged without affecting the ion current detection signal, enabling immediate detection without waiting periods while maintaining detection accuracy
Solution Approach 2:
The third coil acts as an intermediary element that mediates between the residual magnetism and the detection system. By providing a separate discharge path through this intermediary coil to ground, the residual magnetism is diverted away from the detection circuit, allowing accurate ion current detection to occur immediately without time delays
2Power
If the outer core cross section is increased to enhance ignition energy, then ignition performance improves, but magnetic flux leakage increases causing more residual magnetism noise
Solution Approach 1:
The patent extracts the harmful residual magnetism from the core system by providing a dedicated discharge path through the third coil. This allows the outer core to be optimized for high ignition energy without generating excessive residual magnetism noise, as the noise is separately discharged through the third coil to ground
Solution Approach 2:
The third coil serves as an intermediary that handles the residual magnetism generated by the high-power outer core. By connecting the third coil to ground, it provides a safe discharge path for the magnetic flux leakage, allowing the outer core to operate at high power levels without compromising detection accuracy
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 configuration effectively reduces residual magnetic noise detection periods, enhancing the accuracy of ion current detection and preventing misfire misevaluation by maintaining detection periods within system requirements.
Implementation Method 1
The ignition coil generates therein an inductive magnetic field by terminating electricity supplied to a primary coil of the ignition coil. The inductive magnetic field generates induced electromotive force in a secondary coil of the ignition oil, so that the pair of electrodes of the sparkplug generates spark.
Implementation Method 2
Immediately after generating the spark by forming the inductive magnetic field, residual magnetism remains in the ignition oil.
Data Source
AI summary
An ignition coil includes primary and secondary coils, center and outer cores, and an ion current detector for transmitting an ion current detection output. The center core has an axial upper end defining a center core upper end surface. The outer core has an axial upper end defining an outer core upper end surface. The center core upper end surface axially protrudes upwardly relative to the outer core upper end surface. The center core upper end surface is located at a stagger distance axially from the outer core upper end surface. The stagger distance is defined such that a detection period for residual magnetic noise in the ion current detection output falls within a system requirement period of a control unit.