Fuel Tank Protection System for Motor Vehicles

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Solution Overview

Problem

Current solutions for protecting the fuel tank during a rear impact in motor vehicles are ineffective in preventing deformation and the associated risk of fire while maintaining compliance with passive safety requirements and avoiding excessive vehicle mass increase.

Innovation Solution

A protection system is mounted on the exterior surface of the vehicle floor, featuring a body limiter and rear axle limiters that deflect the second compartment upwards during an impact, preventing contact between the spare wheel or LPG tank and the fuel tank, and utilizing the rear axle as a force transmission channel to avoid compression.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a rigid reinforcement structure is mounted inside the body to protect the fuel tank during collision, then the protection effectiveness is improved, but the vehicle mass increases significantly

Engineering Contradiction:
Improvefuel tank protection effectivenessVSAvoidvehicle mass
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent introduces a body limiter as an intermediary component mounted on the lower surface of the second compartment. This body limiter acts as a mediator between the impacting object (spare wheel or LPG tank) and the fuel tank, deflecting the impact force away from the fuel tank. By using this intermediary structure, the patent achieves effective fuel tank protection without requiring heavy rigid reinforcement structures, thus resolving the contradiction between protection effectiveness and vehicle mass.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the second compartment is allowed to move freely during impact, then the structure simplicity is maintained, but the fuel tank cannot be protected from compression

Engineering Contradiction:
Improvefuel tank protectionVSAvoidprotection system structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs dynamic protection by allowing the body limiter to rotate around the rear axle during impact rather than using fixed rigid constraints. The body limiter is designed to deflect upwards when subjected to impact force, dynamically redirecting the compression force away from the fuel tank. This dynamic mechanism provides effective protection while maintaining structural simplicity, avoiding the need for complex multi-component restraint systems.

Inventive Principle:
Principle #15Dynamics

3Reliability

If the body limiter is made rigid to prevent compartment deformation, then the fuel tank protection is improved, but the impact force cannot be effectively distributed

Engineering Contradiction:
Improvefuel tank protectionVSAvoidimpact force distribution
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The patent optimizes the geometric parameters of the body limiter, including its length, width, and mounting position relative to the rear axle. By carefully selecting these parameters, the body limiter achieves the right balance between rigidity and flexibility - rigid enough to deflect impact forces away from the fuel tank, yet capable of rotating to distribute the impact force across a larger area through the rear axle structure. This parameter optimization resolves the contradiction between protection effectiveness and force distribution.

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 solution reduces fuel tank deformation and the risk of fire during rear impacts, while maintaining vehicle safety standards without increasing the vehicle's mass, by effectively distributing impact forces and preventing direct contact between the spare wheel/LPG tank and the fuel tank.

Implementation Method 1

The body limiter rotates around the rear axle, causing the second compartment to move upwards

Methodology Applied
Scientific EffectRotation:

Implementation Method 2

In the event of a rear-end collision, the body limiter rotates around the rear axle

Methodology Applied
Scientific EffectMechanical Force:

Implementation Method 3

The rear axle is thus used as a new force transmission path to prevent compression of the rear compartment

Methodology Applied
Scientific EffectForce transmission:

Data Source

PatentEP3800112B1Motor vehicle comprising a system for protecting the fuel tank
Publication Date: 2023.11.15 RENAULT SA
  • EP3800112B1 patent drawingFigure 1
  • EP3800112B1 patent drawingFigure 2~3
  • EP3800112B1 patent drawingFigure 4a~4b

AI summary

A motor vehicle comprising a floor (12) including a first compartment (16) for receiving a fuel tank (18) and a second compartment (20) upstream of said first compartment (16) and separated from said compartment by a rear axle (26) to which two rear wheels (14) are connected. The vehicle includes a protection system (30) mounted on the outer surface of the floor and configured to deflect the second compartment (20) upwards in the event of a rear impact to the vehicle.