A group of Georgia Tech students are converting a school bus into a hydraulic hybrid, a technology that works best with large vehicles used in stop-and-go driving conditions, like delivery trucks and, of course, buses.
The hydraulic hybrid bus uses a diesel engine to power a pump that charges an accumulator. When the bus is accelerating, the accumulator then powers the hydraulic motors with built-up pressure, but when it's braking, the pump motors reverse and recapture that energy. UPS introduced delivery trucks with this technology just a few years ago, but what makes this school bus stand out is that it will also run on recycled biodiesel from used cooking oil.
The converted bus, destined for Atlanta's Mary Lin Elementary School, will result in a 20 percent fuel savings over a traditional bus. The team estimates the cost of one conversion at $20,000, but if an entire fleet were converted, the cost would go down to more like $8,000 - $10,000 per bus. With the steady rise of diesel prices, the return on investment could be as little as five years.
This particular project was funded through a $50,000 grant from Ford to prove the cost and energy saving benefits of this technology to public schools.
via Wired Autopia
