Study of a low-cost end-fire array for use in electric vehicles

Electric Vehicles (EVs) are expected to be equipped with Acoustic Vehicle Alerting System (AVAS) that effectively allow vulnerable pedestrians to detect from which direction EVs are approaching. In this context, directional sound sources have been proposed to provide an effective warning sound where necessary, without being excessively loud in other directions and thus increasing noise pollution. This work explores the use of a low-cost end-fire array as an AVAS in EVs. For this purpose, a numerical model of the array based on transmission line theory was implemented and the acoustic performance of the array was assessed. A parametric study was found very useful to investigate the influence of the array's geometrical parameters on the system response and in understanding the behaviour of the acoustic radiator. Additionally, the well-established equivalent circuit theory was used to propose an analytical model of the array, which was validated against the numerical model with good agreement.