Vehicle Hood Elevation System for Impact Energy Absorption

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Solution Overview

Problem

The deformation of a vehicle hood during impact is hindered by its proximity to engine compartment components, limiting energy absorption, while minimal clearance between the hood and engine compartment components improves driver visibility and aerodynamics.

Innovation Solution

A hood elevation system using a motor and spring actuator that selectively moves the hood between elevated and lowered positions, allowing for energy absorption and retraction, with a self-locking mechanism to resist downward forces during impacts, enabling efficient energy absorption and cost savings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If clearance between the hood and engine compartment components is increased to facilitate hood deformation during impact, then energy absorption capability is improved, but driver visibility and aerodynamics deteriorate

Engineering Contradiction:

Improveenergy absorption capabilityVSAvoiddriver visibility and aerodynamics

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The hood is designed to be dynamically repositionable between a lowered normal position and an elevated impact position. The actuator system enables the hood to move vertically, providing minimal clearance during normal operation for optimal visibility and aerodynamics, while creating increased clearance space when needed for impact energy absorption.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the spatial parameter (clearance distance) between the hood and engine compartment components based on operational mode. During normal operation, the hood maintains minimal clearance; during impact, the hood is elevated to increase clearance, allowing the deformation space parameter to be optimized for energy absorption.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If a traditional motor-only system is used to elevate the hood, then system complexity is reduced, but the motor size and cost increase due to the need to overcome full spring force

Engineering Contradiction:

Improveactuator system simplicityVSAvoidmotor mass and cost

Core Design Contradiction:

Device complexityVSWeight of moving object

Solution Approach 1:

The spring acts as a counterweight element that stores potential energy when compressed during hood lowering. This spring force opposes the motor's lifting action, effectively reducing the net force the motor must exert to elevate the hood. The motor only needs to overcome the difference between spring force and hood weight, significantly reducing motor size and cost.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The spring, which initially appears to be an additional component increasing complexity, actually reduces the motor burden. The spring's elastic potential energy becomes a beneficial force that assists the motor during hood elevation, converting what could be seen as a system complication into a force-multiplying advantage.

Inventive Principle:

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

3Reliability

If the hood is elevated continuously to maximize energy absorption, then impact protection is improved, but driver visibility and aerodynamics deteriorate during normal operation

Engineering Contradiction:

Improveimpact protectionVSAvoiddriver visibility and aerodynamics

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The hood positioning system is dynamically adjustable, allowing the hood to be in a lowered position during normal operation for optimal visibility and aerodynamics, and elevated position when impact is detected or anticipated. This dynamic repositioning ensures that impact protection and normal performance requirements are both satisfied at different times.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system operates periodically, switching between normal operation mode (hood lowered) and impact protection mode (hood elevated). The actuator system enables this periodic transition based on sensor input or operational conditions, ensuring the hood provides protection only when necessary while maintaining optimal performance during normal driving.

Inventive Principle:

Principle #19Periodic 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

The system enhances energy absorption during impacts, maintains improved driver visibility and aerodynamics, and allows for efficient retraction and recompression of the hood actuator, reducing structural loads and costs.

Implementation Method 1

The motor is operatively connected to the hood and configured to selectively cause the hood to move from its elevated position to its lowered position and thereby compress the spring

Methodology Applied

Scientific EffectSpring compression and elastic potential energy storage: Spring

Implementation Method 2

The spring may elevate the hood without the assistance of the motor or the spring and the motor may cooperate to exert force on the hood to elevate it

Methodology Applied

Scientific EffectElastic potential energy conversion to kinetic energy: Elasticity

Data Source

PatentUS7374008B1Hood elevation system

Publication Date: 2008.05.20 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A hood elevation system for a vehicle includes an actuator configured to selectively move at least a portion of a vehicle hood between an elevated and a retracted position. The hood elevation system also includes a motor and a spring. The spring biases the hood toward its elevated position, and the motor is configured to retract the hood, thereby compressing the spring.