Variation Ride Comfort of a Converted Electric Vehicle Using 6 DOF Vehicle Vibration Model

Calcina C.C.; Calcina C.C.; Vidal Y.S.; Luque J.C.; Quispe W.B.; Tavares A.A.; Saldias C.P.; Arapa C.D. · SSRG International Journal of Mechanical Engineering (2026) · DOI: 10.14445/23488360/ijme-v13i6p101

Resumen

This study evaluates the changes in ride comfort in a Ford Ka after an electric vehicle conversion. The Ford Ka was selected because of its strong presence. in the Brazilian market, making it a representative example for large-scale retrofit programs. Changing the combustion engine with an electric motor and battery pack changes the vehicle’s mass distribution, modifying its vertical dynamic behavior and the vibration levels experienced by occupants. A six degree of freedom (6-DOF) half vehicle model was constructed in MATLAB/Simulink to simulate the vertical dynamics of the vehicle body, the front and rear unsprung masses. and both seating points. Four road excitation cases were simulated: the positive and negative step inputs, a sinusoidal input, and a speed reducer input. Vertical acceleration data at each seat position were processed using the ISO 2631-1 Wk frequency weighting filter, and ride comfort was evaluated using the weighted Root Mean Square Acceleration (RMS) and the Vibration Dose Value (VDV). Both indicators increased after conversion across most scenarios, with the rear seat showing the most pronounced changes. VDV rose by up to 17.5% under sinusoidal excitation, while RMS increases of 15-25% were recorded depending on seating position and excitation type. These findings show that the stock suspension, calibrated for the original combustion-engine configuration, is no longer adequate after retrofitting and that suspension retuning should be treated as a required step in any serious electric conversion program.

Instituciones: Universidad Nacional de San Agustín de Arequipa