Students find ways to improve fuel efficiency for Carle’s shuttle buses

By Dan Fischer

Carle Foundation Hospital’s shuttle buses need a lot of energy. Making just over five miles per gallon, a single bus surveyed between Jan. 15-22, 2007 burned nearly 80 gallons of fuel at a cost of over $190.

Three University students are working to change that.

Brad Ptasienski, Rob Snell and Todd Baxter, all seniors in Engineering, are in the Industrial Enterprise Systems Engineering Program (IESE) and were chosen to study ways to improve the shuttles’ fuel efficiency in order to complete their senior design project.

“We’re not generating anything revolutionary,” Snell said. “We’re putting together a whole bunch of concepts and a whole bunch of people in the hopes of producing the end goal of regenerative braking in these buses.”

The students believe implementing the existing system of hydraulic regenerative braking on Carle’s fleet of six shuttles would conserve fuel, thereby reducing costs and emissions.

The system uses hydraulic fluid to pressurize gas during braking. When the vehicle accelerates, the gas expands, sending the fluid into a motor which provides propulsion.

Hydraulic regenerative braking performs especially well on heavy vehicles that make frequent stops because it can capture large amounts of braking energy while also quickly putting the energy to use in acceleration. The students believe those attributes make the system the best choice for Carle.

Because it reuses over 70 percent of braking energy, the system can lead to a 30 percent reduction in fuel consumption. The students project that changing the brakes on Carle’s buses could save the hospital approximately $20,000 per year on its $70,000 annual fuel bill.

Projecting potential savings is part of the students’ attempt to make changes toward more environmentally friendly practices financially worthwhile for businesses.

“From our perspective, the environment effects are the primary focus,” Snell said. “But from Carle’s perspective, the monetary gain is a focus of theirs as well.”

Because the change is cheaper than new engines, Ptasienski predicts that a switch to hydraulic regenerative braking is one of the first changes bus owners would be willing to make. He believes if a few buses are retrofitted with the new braking systems, other owners will follow suit, especially if they see the economic incentive of saving money on fuel.

The three are focusing on producing a realistic plan for Carle rather than actually making any changes on the buses, which could take a year to complete. At this stage, much of the work involves making the plan work financially, rather than mechanically. While the braking system has the potential to save money by conserving energy, it also faces high costs.

“We’ve got a pretty good idea of what we need to do, now we just are trying to figure out how we can do it for an amount of money that is feasible for the hospital,” Ptasienski said.

He said the ultimate goal is to gain funding either from a company or the government that will pay for the project and allow for its implementation, which he believes would make Carle the first hospital in the nation to install hydraulic regenerative braking on its buses.

However, although there are some eventual financial benefits, the main obstacle for Carle is still money. The parts are inexpensive, but installation would be costly. Baxter speculated it could run from $500,000 to $1 million.

Despite the challenges, the three feel fortunate to have the chance to work on the project.

“All the students have to do it for IESE, and we happened to get a really cool project,” Ptasienski said.