Alongside the increase in greenhouse gas emissions, one interesting field of research on reducing them is the optimization of automotive aerodynamics. This communication focuses on transforming the negative drag effect of the incident airflow into a positive effect, harnessing the force of the air itself to propel the vehicle forward and thereby reducing fuel consumption.

A channeling system has been designed based on a deflector located on the vehicle roof, acting as a cavity, which captures, channels, and redirects air to the rear vacuum zone, providing higher pressures.

Initially, the device's effectiveness was verified using CFD, and then, the deflector was physically constructed and incorporated in a 1:12 scale car model. In total, 756 comparative experimental tests were conducted with and without the deflector in a wind tunnel, also of own creation, demonstrating the following main achievements:

- Aerodynamic drag is reduced, as negative values are converted into positive ones under all conditions. Moreover, initially positive values are further amplified, resulting in the generation of an additional propulsive force that enhances the vehicle's forward motion.

- At a speed of 76 km/h, the deflector provides an energy efficiency of 3.3%.

As a summary, Figure 1 is presented. Figure 1a, which represents a standard car, shows that the air trajectory at the rear follows the red arrows, with a vacuum underneath acting as a brake. However, Figure 1b shows that incorporating the deflector leads to airflow redirection and the reduction of the vacuum zone, illustrated by green arrows.

https://ibb.co/tp9MNKpy

Figure 1. Airflow path: a) vehicle without deflector; b) vehicle with built-in deflector.

The feasibility analysis at technical, economic, social, and environmental levels is favorable for all vehicle propulsion alternatives. Therefore, the results of this research have served to register this invention as a utility model (ES1303991 U) at the Spanish Patent and Trademark Office.