Composite Valve Springs for High Engine Speed

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Solution Overview

Problem

Current metal springs, particularly in the automotive industry, face limitations in weight, performance, and properties such as spring dampening, natural frequency, corrosion, and electrical/thermal conductivity, which hinder their effectiveness in high-performance applications like race cars and engine valve operations.

Innovation Solution

A composite spring is developed using a flexible core with multiple layers of cured resin-impregnated composite fibers wound or braided at various angles to achieve desired helical pitch, diameter, and spring rate, allowing for improved weight reduction and performance while maintaining reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metal springs are used in automotive applications, then reliability and durability are improved, but weight increases and spring dampening performance deteriorates

Engineering Contradiction:

Improvespring reliabilityVSAvoidspring weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent applies composite materials by combining a flexible core with multiple layers of cured resin-impregnated composite fiber wound or braided around it. This composite structure achieves both weight reduction and maintained reliability, as the composite fiber layers provide structural strength while the flexible core enables elastic deformation and spring functionality.

Inventive Principle:

Principle #40Composite materials

2Duration of action of stationary object

If metal springs are used for engine valve operations, then durability is improved, but natural frequency decreases limiting engine maximum speed

Engineering Contradiction:

Improvespring durabilityVSAvoidengine maximum speed

Core Design Contradiction:

Duration of action of stationary objectVSSpeed

Solution Approach 1:

The composite spring construction with cured resin-impregnated composite fiber layers provides higher natural frequency compared to traditional metal springs. The specific fiber orientation (±5-90 degrees relative to longitudinal axis) and multi-layer winding pattern optimize both durability and dynamic response for high-speed engine valve operations.

Inventive Principle:

Principle #40Composite materials

3Reliability

If steel springs are used, then strength and reliability are improved, but corrosion resistance deteriorates

Engineering Contradiction:

Improvespring strengthVSAvoidcorrosion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces steel with composite materials consisting of resin-impregnated composite fiber layers. These composite materials inherently provide corrosion resistance while maintaining the necessary mechanical strength and spring properties, eliminating the corrosion issue associated with steel springs.

Inventive Principle:

Principle #40Composite materials

4Strength

If metal springs are used, then structural integrity is improved, but electrical and thermal conductivity causes unsuitability for particular applications

Engineering Contradiction:

Improvestructural integrityVSAvoidelectrical and thermal conductivity

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The composite spring construction using cured resin-impregnated composite fiber provides structural integrity through the multi-layer wound or braided fiber structure while simultaneously providing electrical and thermal insulation properties that metal springs lack, making it suitable for applications where conductivity is undesirable.

Inventive Principle:

Principle #40Composite materials

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

The composite springs exhibit higher natural frequency, reduced weight, and enhanced performance compared to steel springs, enabling higher engine speeds and weight reduction in automotive applications while maintaining consistent performance over multiple cycles.

Implementation Method 1

a composite spring comprising a flexible core supporting multiple layers of a cured resin-impregnated composite fiber, the flexible core and cured resin-impregnated composite fiber wound or braided to form a spring

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

multiple layers of a cured resin-impregnated composite fiber

Methodology Applied

Scientific EffectCuring: Photopolymerisation

Data Source

PatentUS7857294B2Composite springs and methods of manufacture

Publication Date: 2010.12.28 SPENCER COMPOSITES CORP

AI summary

Composite springs and methods of manufacture are described. The composite springs include a flexible core supporting multiple layers of a cured, resin-impregnated composite fiber wherein resin-impregnated composite fiber is wound or braided over the flexible core and cured on a helical mold to form a spring having a desired helical pitch, diameter and spring rate. The multiple layers of resin-impregnated composite fiber are wound or braided at ±5-90 degrees relative to the longitudinal axis of the flexible core.