Motors & Drives Information

Oshkosh Truck Corp. has developed a hybrid drive system for use in severe-duty, military and commercial truck applications. The new hybrid technology, which the company calls ProPulse, has been installed on an overhauled and updated Heavy Expanded Mobility Tactical Truck (HEMTT) military truck. The ProPulse HEMTT is functional and has a cargo hauling capability, of 16.5 tons.

The project design starred a year and a half ago and the actual construction of the truck took six months. Included on the truck is Oshkosh's Command Zone electronics system with real-time diagnostics and prognostics capability (see related story).

"Oshkosh Truck began looking into the feasibility of a hybrid drive system about five years ago," said Chris Yakes, senior project engineer at Oshkosh. "We started looking into the technology, but did not have any definite plans. And then customers, both commercial and military, started asking us questions about hybrid systems and their feasibility. Once customers started asking questions, we began to look at the technology more carefully.

"We worked with hybrid system suppliers and integrators, companies that were developing complete systems and components for OEMs, trying to fit their technology and systems to our trucks. However, we found out that the technology just was not feasible."

Many of the systems proposed and tested required a large and heavy battery pack, which Oshkosh said greatly diminished payload capacity. In addition, the vehicle did not meet the performance requirements for torque, speed on grade, etc. The conclusion was that hybrid systems would not work in severe service applications.

Then about three years ago, Oshkosh took a second look at the hybrid drive technology, this time with the idea of integrating components into a system of its own. "We found that if we took care of the integration in-house, we could put together a system to do what we needed it to do," said Yakes. "We went out and studied the market and spent time working with many different component suppliers--motors, generators, battery and other storage systems, wiring, controllers, monitoring equipment--and picked what we believed was the best and most cost-effective components.

"This time, we let the performance requirements of the vehicle as a whole drive the system design. We let the vehicle platform drive down into the component requirements and the system design."

# posted by Medical Information : 4:13 AM