Ignition Coil Rib Structure for Igniter Heat Dissipation

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Solution Overview

Problem

Existing ignition coils face challenges in effectively dissipating heat from the igniter to the outer core, particularly when the gap between the igniter and the outer core is large, leading to inefficient heat transfer and potential temperature increases due to increased electric power consumption.

Innovation Solution

The ignition coil design incorporates a case-side rib or connector-side rib that presses the igniter against the outer core, ensuring intimate contact and enhanced heat dissipation through a tapered configuration that increases the protruding amount towards the high-voltage side, allowing for effective heat transfer from the igniter to the outer core.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the gap between the igniter and the outer core is large, then the igniter can be easily positioned and assembled, but heat dissipation efficiency deteriorates

Engineering Contradiction:

Improveease of assemblyVSAvoidheat dissipation efficiency

Core Design Contradiction:

Ease of operationVSTemperature

Solution Approach 1:

The case-side rib acts as an intermediary mechanical element that transmits pressing force from the coil case to the igniter, enabling reliable contact without requiring precise manual positioning. The rib mediates between the assembly convenience of a larger gap and the heat transfer requirement of intimate contact.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The case-side rib is pre-formed on the coil case interior surface with a taper shape that automatically guides and presses the igniter into proper contact position with the outer core during assembly, eliminating the need for complex positioning operations or tight tolerances.

Inventive Principle:

Principle #10Preliminary action

2Power

If electric power consumption is increased, then the ignition output is improved, but the igniter temperature increases

Engineering Contradiction:

Improveignition outputVSAvoidigniter temperature

Core Design Contradiction:

PowerVSTemperature

Solution Approach 1:

The invention converts the harmful heat generated by increased electric power consumption into a beneficial thermal transfer opportunity. By ensuring intimate contact between the igniter and outer core through the case-side rib, the heat that would otherwise raise igniter temperature is efficiently conducted to the outer core, which has higher heat capacity and better thermal management.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If the case-side rib has a large protruding amount, then the igniter is firmly pressed against the outer core, but the manufacturing precision requirement increases

Engineering Contradiction:

Improvecontact reliabilityVSAvoidrib dimension precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The case-side rib employs a taper shape parameter change, where the protruding amount gradually increases from the base toward the tip. This geometric parameter variation allows the rib to flexibly adapt to manufacturing tolerances while maintaining reliable contact pressure on the igniter, reducing the need for high-precision dimensional control.

Inventive Principle:

Principle #35Parameter changes

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 improves heat dissipation efficiency from the igniter to the outer core, preventing heat transfer inefficiencies and maintaining the igniter's temperature within a safe range even with increased electric power consumption.

Implementation Method 1

heat generated by the switching element of the igniter can be dissipated to the outer core via the heat sink and the resin

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

The secondary coil is configured to generate an induced electromotive force upon interruption of the electric power supply to the primary coil

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS11776739B2Ignition coil for internal combustion engine

Publication Date: 2023.10.03 DENSO CORP

AI summary

An ignition coil includes a primary coil, a secondary coil, a center core, an outer core, an igniter, a coil case and an electrically-insulative fixation resin. On an interior surface of the coil case on a bottom part side in a mounting direction, there is formed a case-side rib to protrude from the interior surface of the coil case to a high-voltage side in an axial direction. The case-side rib has a taper shape such that the protruding amount of the case-side rib to the high-voltage side in the axial direction increases in the mounting direction toward the bottom part side. The case-side rib is arranged to abut a corner portion of the igniter on the bottom part side in the mounting direction and on a low-voltage side in the axial direction and thereby press the igniter against the outer core.