Engine Cover Electrostatic Discharge via Conductive Pump Case

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Solution Overview

Problem

Internal combustion engine covers made of resin materials like polyurethane foam tend to accumulate electrostatic charges due to the lack of a discharge path, which can adversely affect nearby components such as fuel injectors and spark plugs.

Innovation Solution

Incorporating an electroconductive cylinder head and a fuel pump with an electroconductive pump case connected to the cylinder head, along with a sound insulating engine cover made of polyurethane foam that contacts the pump case, providing a path for electrostatic charges to escape and preventing the engine cover from becoming electrostatically charged.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the engine cover is made of resin material such as polyurethane foam, then the weight and cost are reduced, but the engine cover becomes easily electrostatically charged

Engineering Contradiction:

Improveweight of engine coverVSAvoidelectrostatic charge accumulation

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The patent introduces a fuel pump with an electroconductive pump case as an intermediary component between the electroconductive cylinder head and the electrostatically-prone engine cover. This intermediary structure creates an electrostatic discharge path without requiring modification of the engine cover material itself, allowing the lightweight foam cover to maintain its weight advantages while preventing charge accumulation through the pump case connection path

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If the mounting members and head cover are made of electrically insulating material, then the structure is simpler and cost is reduced, but the electrostatic charge cannot escape

Engineering Contradiction:

Improvestructure of mounting membersVSAvoidelectrostatic discharge path

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent extracts the electrostatic discharge function from the mounting members and head cover structure by introducing a dedicated electroconductive fuel pump system. This separates the structural support function (performed by insulating mounting members) from the electrostatic discharge function (performed by the electroconductive pump case), allowing each component to be optimized independently without compromising either structural simplicity or electrostatic safety

Inventive Principle:

Principle #2Taking out (Extraction)

3Productivity

If the wire harness is positioned between the engine cover and head cover, then the layout is compact, but the electrostatic charge adversely affects fuel injectors and spark plugs

Engineering Contradiction:

Improvecompactness of engine layoutVSAvoidelectrostatic effect on electrical components

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by establishing an electrostatic discharge path through the electroconductive pump case and cylinder head connection before electrostatic charges can accumulate on the engine cover and affect nearby electrical components. This preventive measure neutralizes the potential harmful electrostatic effects while maintaining the compact wire harness positioning between the engine cover and head cover

Inventive Principle:

Principle #9Preliminary anti-action

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 shields the engine cover from electrostatic charging, ensuring reliable operation of nearby components like spark plugs and fuel injectors while maintaining the economic and sound-insulating benefits of polyurethane foam materials.

Implementation Method 1

the engine cover includes a sound insulating material (31) in contact with the pump case. Thereby, an electrostatic charge generated in the engine cover is conducted to the cylinder head via the pump case so that the engine cover is prevented from becoming electrostatically charged

Methodology Applied

Scientific EffectElectrostatic conduction: Conduction (electrical)

Data Source

PatentUS11959415B2Internal combustion engine fitted with engine cover

Publication Date: 2024.04.16 HONDA MOTOR CO LTD

AI summary

In an internal combustion engine (1) comprising an electroconductive cylinder head (3), a head cover (5) attached to the cylinder head, a fuel pump (11) attached to the cylinder head and including an electroconductive pump case electrically connected to the cylinder head, and an engine cover (30) positioned so as to oppose the head cover and the fuel pump, the engine cover includes a sound insulating material (31) in contact with the pump case.