For the past 20 years, Purdue Solar Racing (PSR) has been designing and building a variety of solar powered vehicles. While these cars have all varied greatly in their designs and manufacturing processes, Shell Eco-marathon’s urban concept category motivated PSR to enter into a completely unexplored realm with its eighth car, Celeritas.
Urban concept vehicles must meet all or most of the necessary safety and weight requirements so that they can be driven on city streets. Celeritas is considered experimentally street-legal, since it is not equipped with air bags. The seven cars designed by PSR before Celeritas have all been “prototype” cars; they look more like futuristic vehicles than like today’s cars. In addition, world-wide solar car races almost exclusively feature what would be considered prototype solar cars. Therefore, when PSR decided to try and tackle an urban concept solar car, we knew we were facing previously unanswered design challenges in the realm of solar racing.
As a barrier-breaking vehicle, it is appropriate that Celeritas is named for the Latin word used in Albert Einstein’s famous equation, e=mc2, where it stands for the “speed of light.” For Celeritas, PSR’s aerodynamic, mechanical, electrical, marketing, and outreach teams all had to work together to design and build a solar car unlike any other that our team–or other solar car teams–had designed before.
The aeronautical team was faced with the challenge of designing a body that incorporated an upright driver and large solar array area that not only looks “cool” but also looks like a “real car.” The mechanical team was faced with designing a more complex suspension and steering to handle city streets and meet higher performance standards. The electrical team took on the huge task of designing and programming seven on-board computers. Not only did these computers need to include functions that are present in PSR’s prototype cars, such as a telemetry system, battery protection system, and motor controller, but our new, urban concept car needed to incorporate many other functions such as cruise control, car lights, and a digital driver display. Finally, the marketing and outreach teams had to communicate to and convince the public that Celeritas, a car powered by nothing but sunlight, could perform all the functions of astreet-legal automobile.
Shell Eco-marathon Americas 2012 in Houston beginning March 29 will be Celeritas’ second race, and to prepare we have armored Celeritas with a wide range of improvements and changes. This includes changes to our motor, suspension systems, and electrical systems.
In addition to improving and optimizing Celeritas, PSR has been hard at work with the design of our team’s ninth solar car, Navitas. The team is using all the knowledge and experience gained from Celeritas to make an even better urban concept vehicle that we hope to bring to Shell Eco Marathon in the next year or two.
Rachel Bodien is a junior majoring in aeronautical engineering at Purdue University, and is secretary of the Purdue Solar Racing team. She is originally from Columbus, Ohio.