Apparatus and methods for modifying a battery electric vehicle for wheelchair access
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Solution Overview
Problem
Battery electric vehicles (BEVs) pose a challenge for wheelchair accessibility due to their high voltage batteries located below the vehicle floor, which cannot be easily modified to achieve optimal ramp angles without compromising battery safety and ground clearance.
Innovation Solution
The method involves installing a high voltage battery assembly at a lower elevation and configuring a height adjustment device to move the vehicle body between a lowered and raised position, allowing for optimal ramp angles and maintaining battery protection during transit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the high voltage battery assembly is lowered to achieve optimal ramp angles for wheelchair accessibility, then wheelchair accessibility is improved, but ground clearance and battery protection are compromised
Solution Approach 1:
The patent implements a height adjustment device that enables the vehicle body to dynamically change its height between a lowered position (for wheelchair accessibility with optimal ramp angles) and a raised position (for battery protection during transit). This dynamic adjustment allows the system to optimize for different operational requirements at different times, resolving the contradiction between accessibility and protection.
2Shape
If the vehicle floor is lowered to achieve ADA-compliant ramp slopes, then ramp angle is improved, but battery ground clearance is reduced
Solution Approach 1:
The height adjustment device allows the vehicle to adopt different configurations: in the lowered position, the floor is at optimal height for ADA-compliant ramp angles (1:4 slope or less); in the raised position, ground clearance is restored to protect the battery during transit. This dynamic reconfiguration resolves the geometric contradiction between ramp angle and ground clearance.
3Shape
If the high voltage battery assembly is relocated to a lower elevation, then ramp over angle is improved, but vulnerability to road debris increases
Solution Approach 1:
The system dynamically adjusts the vehicle body height relative to the battery assembly. During ingress/egress operations, the lowered position creates optimal ramp over angles for wheelchair access. During transit, the raised position elevates the battery assembly above the threat zone for road debris, thereby resolving the contradiction between ramp geometry and debris protection.
Solution Approach 2:
The height adjustment device is activated in advance before transit operations to raise the vehicle body and position the battery assembly at a protected elevation, preventing exposure to road debris before the vehicle encounters potential hazards during movement.
Data Source
AI summary
To provide access to individuals having mobility disabilities, an OEM battery electric vehicle may be modified to include one or more of a wheelchair ramp, a lowered floor, a lowered battery, an adjustable suspension, and supplemental impact protection. The adjustable suspension of the modified vehicle may be operated to position the body of the vehicle alternatively between a lowered position and a raised position. In the lowered position, at least one of the ramp angle and length may be reduced relative to a comparable ramp in the OEM vehicle. In the raised position, the vehicle ground clearance may be slightly less than, approximately equal to or greater than the ground clearance of the OEM vehicle at GVWR.