INNOVATION IN SOLAR VEHICLES: FROM THE IDEA TO THE PROTOTYPE IN LESS THAN 24 MONTHS

The article aims to describe the integrated path used for the conceptual, functional and constructive design of an exclusive solar vehicle. The project was based on the massive implementation of concurrent engineering and quality tools, rarely used in such an integrated way. New and attractive design, 3D CAD modelling, details design, structural and fluid dynamic validations, in-scale rapid prototyping, functional tests, multi-objective optimization, parts manufacturing and assembly. Thanks to this approach, the solar prototype presents high technological contents, especially in terms of materials, structures and processes, together with their optimizations. Furthermore, large CNC-machined multi-material molds, hybrid manufacturing solutions: everything was used to speed up phases permitting to move from the initial idea to the final prototype in 24 months. Since June 2018, the solar vehicle is on the road, transporting 4 people, weighing less than 300kg, reaching speeds of 120km/h and able to run hundreds of km without fuel.

section_content: This short article summarizes the incredible adventure of a group of researchers that led to the design and construction of one of the few multi-vehicle solar vehicles in the world, and its use to cross a large part of the United States. Everything started from the sporting passion for automotive competitions and from the previous experience in the field of solar vehicles, which led to the creation of a solar single-seater in recent years. With this vehicle we took part in several races on different continents bringing back valuable successes. However, the category of singleseater solar vehicles did not seem to represent a real technological challenge as it appeared to be the category of multipassenger vehicles. Known under the name of 'cruiser' car, this relatively recent category in the racing scene obliges designers to face particularly complex technical problems, linked to the specific needs of solar mobility. Solar cars have to be imagined by the designers around the fundamental concept of energy efficiency. This condition requires important technical choices that, combined with the race regulation requirements, lead to exclusive and very innovative prototypes. Besides, everything was made possible only thanks to the use of concurrent engineering and its design tools, within a more general approach to Total Quality Management (TQM) (Fragassa et al. 2014).
section_name: Introduction

section_content: Specifically, the following phases and tasks were considered:
section_name: Materials and Methods

section_content:  build a four-wheeled vehicle, quadricycle  minimize the overall dimensions of spacemaximize the space where to house the solar panels  carry 4 passengers safely  balance weights and vehicle dynamicsprovide adequate space for vehicle components such as: engines, suspensions  provide adequate space for electrical components such as: engines, suspensions,guarantee fast access systems for access in case of maintenance  optimize the aerodynamic profile by reducing air resistanceguarantee a phenomenon of downforce in order to reduce the rolling resistance  correctly convey part of the air for cooling and ventilation  ensuring the internal liveability of the spaces and the installation of auxiliary devices  insert elements such as doors, air vents, lights, arrows, license plate in line with the standardsuse shapes that can be built with available materials and technologies  provide for the possibility of registration and registration of the vehicle
section_name: Discussion and Conclusion

section_content: Acknowledgment: This research has been supported by the Italian Ministry of Foreign Affairs and International Cooperation thought the Joint Research Projects as Particular Relevance, with a project named ' Two Seats for a Solar Car ' within the Executive Programme of Cooperation between Italy and Serbia in the field of Science and Technology.

section_name: Cristiano Fragassa

section_content: Dept Industrial Engineering University of Bologna Bologna, Italy cristiano. fragassa@unibo. it
section_name: Cristiano Fragassa

section_content: Dept Industrial Engineering University of Bologna Bologna, Italy giangiacomo. minak@unibo. it
section_name: Giangiacomo Minak

section_content: Onda Solare Solar Car Association Castel San Pietro, Italy info@ondasolare. com
section_name: Stefano Maglio

section_content: Industrial Design Department University of Arts Belgrade Belgrade, Serbia marko-design@hotmail. com
section_name: Marko Lukovic