Engine Cover Grommet with Segmented Cavity for Impact Absorption
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Solution Overview
Problem
Vehicle engines face significant energy absorption challenges during hood impacts, as the hood's deformation towards the engine often leaves unabsorbed energy that can cause further damage.
Innovation Solution
The implementation of an engine cover grommet with a passive and active cavity structure, where a pin rests in the passive cavity under normal conditions but moves into the active cavity upon impact, allowing additional vertical movement and energy absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the hood deforms toward the engine to absorb impact energy, then energy absorption is improved, but unabsorbed energy still reaches the engine causing damage
Solution Approach 1:
The grommet's internal cavity is divided into two distinct segments: a passive cavity portion for normal operation and an active cavity portion for impact absorption. This segmentation allows the system to provide different functions in different conditions, enabling additional energy absorption during impacts while maintaining normal connectivity during operation.
Solution Approach 2:
The active cavity portion is pre-configured within the grommet structure to provide cushioning before impact occurs. The cavity is designed with specific dimensions and positioning to ensure that when impact happens, the pin can travel into this pre-prepared space, absorbing energy through controlled deformation before reaching the engine.
2Stability of the object's composition
If the pin is rigidly fixed to prevent movement, then connection stability is improved, but impact energy cannot be absorbed through movement
Solution Approach 1:
The grommet design transitions the connection from a static rigid fix to a dynamic system that adapts based on conditions. During normal operation, the passive cavity maintains stable connection. During impact, the system dynamically allows pin movement into the active cavity, enabling energy absorption through controlled deformation while maintaining connection integrity.
Solution Approach 2:
The system changes its physical parameters based on impact conditions. The grommet material and cavity structure are designed to remain rigid during normal operation for stability, but deform in a controlled manner during impact to absorb energy. This parameter change allows the same structure to provide both stability and energy absorption.
3Loss of energy
If the grommet allows free movement of the pin, then impact energy can be absorbed, but normal operational stability is compromised
Solution Approach 1:
By segmenting the cavity into passive and active portions, the system restricts normal pin movement to the passive cavity, maintaining stability. The active cavity remains available but inaccessible during normal operation, allowing energy absorption only when needed during impact events.
Solution Approach 2:
The passive cavity acts as an intermediary structure that normally constrains the pin to maintain stability. During impact, this intermediary structure allows controlled transition to the active cavity, mediating between the need for stability and the need for energy absorption.
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 design enhances energy absorption and reduces the acceleration of impacting forces reaching the engine, thereby protecting it from damage by dissipating impact energy through the grommet's deformation.
Implementation Method 1
The hood may provide limited protection for an impacting body form to the engine by elastically and plastically deforming to absorb energy
Implementation Method 2
The hood may provide limited protection for an impacting body form to the engine by elastically and plastically deforming to absorb energy
Implementation Method 3
structures to absorb energy during hood deformation toward the engine of the vehicle
Data Source
AI summary
A vehicle comprises an engine compartment and a hood extending over the engine compartment. An engine is situated within the engine and a pin extends from a top side of the engine toward an interior surface of the hood. An engine cover extends between the top side of the engine and the interior surface of the hood. The engine cover includes an engine cover connection and a grommet coupled to the engine cover connection. The grommet has an entrance, a stop, and an internal cavity 143 extending through the grommet from the entrance toward the stop. The internal cavity 143 is divided into a passive cavity portion and an active cavity portion. The pin rests within the passive cavity portion without passing into the active cavity portion under normal operating conditions.