Shared-Core Ignition Coil Layout for Compact DCO Ignition

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Solution Overview

Problem

Existing ignition coils for internal combustion engines using the DCO ignition method are bulky, making them difficult to mount in the engine due to the closed magnetic circuits of iron cores, which contribute to the device's size.

Innovation Solution

The ignition coil design incorporates two sets of primary and secondary coils with shared iron cores forming a closed magnetic circuit, allowing for miniaturization and enhanced magnetic flux amplification through controlled current flow and switching elements to maintain spark duration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If closed magnetic circuits of iron cores are formed in each ignition coil, then magnetic flux is effectively contained, but the device size increases

Engineering Contradiction:
Improvemagnetic flux containmentVSAvoiddevice size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent merges two separate iron cores into a single shared iron core that forms one closed magnetic circuit serving both ignition coils. This consolidation maintains effective magnetic flux containment for both coils while reducing the overall device volume by eliminating redundant magnetic circuit structures.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The shared iron core performs multiple functions by serving as the magnetic circuit for both the first and second ignition coils simultaneously. This multi-functional design allows one iron core to replace what would traditionally require two separate iron cores, thereby reducing device size while maintaining reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Power

If two separate ignition coils are used for DCO ignition method, then sufficient ignition energy is provided, but the device becomes bulky and difficult to mount

Engineering Contradiction:
Improveignition energyVSAvoidmounting ease
Core Design Contradiction:
PowerVSEase of operation

Solution Approach 1:

The patent combines two ignition coil assemblies into a single integrated unit where both coils share a common iron core and are connected to a single spark plug. This merging maintains the high ignition energy required for DCO method while creating a more compact device that is easier to mount in the engine.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent arranges the first and second ignition coils in a nested or closely integrated configuration around the shared iron core, with both coils ultimately connecting to the same spark plug. This nesting approach maximizes space utilization and reduces the overall footprint, making the device easier to mount while preserving the dual-coil ignition capability.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 enables a more compact ignition device with improved energy efficiency and longer spark duration, facilitating easier integration into internal combustion engines while supporting lean fuels and ammonia ignition.

Implementation Method 1

The first iron core passes through an inside of the first primary coil and an inside of the first secondary coil and is configured to electromagnetically couple the first primary coil and the first secondary coil

Methodology Applied
Scientific EffectElectromagnetic coupling: Electromagnetic Induction

Implementation Method 2

One end of the first iron core and one end of the second iron core are connected to each other, and the other end of the first iron core and the other end of the second iron core are connected to each other, to form a closed magnetic circuit

Methodology Applied
Scientific EffectMagnetic flux: Magnetic Field

Data Source

PatentEP4650593A1Ignition coil and ignition device
Publication Date: 2025.11.19 DIAMOND&ZEBRA ELECTRIC MFG CO LTD
  • EP4650593A1 patent drawingFigure 1
  • EP4650593A1 patent drawingFigure 2
  • EP4650593A1 patent drawingFigure 3

AI summary

In first and second primary coils, a direct-current voltage is applied to one end, and the other end is grounded. A first iron core passes through the first primary coil and a first secondary coil. A second iron core passes through the second primary coil and a second secondary coil. One ends, as well as the other ends, of the iron cores are connected, to form a closed magnetic circuit. When a direct-current voltage is applied to the first primary coil, a magnetic flux from the other end to the one end is generated in the first iron core. When a direct-current voltage is applied to the second primary coil, a magnetic flux from the other end to the one end is generated in the second iron core. This enables miniaturization and energy enhancement of an ignition coil for an internal combustion engine to which DCO ignition is applicable.