University of Michigan Continuum Solar Car
The Continuum, the University of Michigan’s solar car, on display during this year’s North American International Auto Show, is unlike anything else in Cobo Hall.
The winner of the 2008 10-day, nearly 2,500-mile North American Solar Challenge, the Continuum could easily pass as Hollywood’s idea of a spacecraft from another planet.
The ninth in a series of solar cars built by the university’s Solar Car Teams since 1989, the Continuum features a solar energy collecting system commonly used for large solar power plants — the first successful integration of such a system into a vehicle.
The heart of the system is gallium-arsenide multijunction photovoltaic cells, which produce nearly 50 percent more power than the previously employed silicon photovoltaic cells. They are enhanced by a system of parabolic mirrors that reflect additional sunlight onto the cells.
Located on the upper surface of the carbon-fiber body, the nearly 2,500 solar cells generate only about as much power as a hair dryer. But that’s enough to propel the 475-pound vehicle (around 650 pounds with driver) to a top speed of 87 mph, although the car rarely exceeds 50 mph during a race.
Any energy not used to drive the vehicle is stored in a 5-kilowatt lithium-polymer battery, which powers the electric motor when the clouds come out.
Like a large tricycle, the Continuum runs on three wheels. The front wheel steers and drives the car with an in-wheel electric motor. The motor is capable of regenerative braking.
Another innovation found on the Continuum is that the driver is now in a seated position rather than lying down as in previous versions. However, there is still no air conditioning and scant ventilation.
The Continuum also features a custom-built suspension, uniquely designed disk brakes and 20-inch low-friction solar radial tires.
In order to improve aerodynamics, necessary to reducing energy consumption, Michigan solar cars have implemented a variety of technical innovations. Solar Car Teams have used computational fluid dynamics (CFD) tools to produce some of the most aerodynamic vehicle shapes on the road.
Those innovations include narrow window fairings, which open to allow the car’s wheels to turn. Another is the development of the 3-wheeled vehicle, further reducing the car’s already small coefficient of drag.
While car manufacturers in Cobo’s main hall will be touting fuel economy of 40 and 50 mpg, they can’t touch the Continuum — it’s infinite, as long as the sun is shining.