Eaton Corp., International Truck and Engine Corp., Peterbilt Motors Co., and DaimlerChrysler are all working on efforts to make hybrid diesel-electric truck platforms commercially viable options for fleets, mainly in the light- and medium-duty segments.

At the recent Hybrid Truck Users Forum (HTUF) in Kalamazoo, MI, Eaton, International, and Peterbilt all unveiled pre-production models of hybrid medium-duty trucks that can help fleets improve a variety of vehicle characteristics — primarily fuel economy — by meshing the traditional diesel engine with an electrical power system, without forcing fleets to change their operational patterns.

HTUF is a joint program between California-based technology consortium WestStart-Calstart and the U.S. Army's National Automotive Center (NAC) to speed up the development of hybrid drivelines for both military and commercial uses.

Eaton and International are planning to build more than 20 pre-production diesel-electric hybrid medium-duty trucks earmarked for the utility industry. Electric utility Florida Power & Light (FPL) is buying the first group of these vehicles.

FPL's experience is crucial in determining the commercial prospects for this vehicle package in the near future, said Tom Cellitti, vp & gm for International's Medium Vehicle Center. “If this pilot program is successful, we propose to start full line production of these hybrid trucks by 2006,” he said.

George Survant, director of fleet services for FPL and chair of the HTUF utility working group, told Fleet Owner that while the predicted fuel economy improvement of 40% to 60% for these diesel-electric hybrids has been the main focus of the project, other benefits are becoming readily apparent.

“The sweet thing about hybrids is that they burn less fuel, generate fewer emissions…and allow for much quieter operation of the aerial boom [via the truck's electric power system] in residential neighborhoods,” he said.

Peterbilt and Eaton, by contrast, are using a different hybrid setup to achieve similar benefits. The two displayed a Peterbilt Model 320 spec'd for refuse applications using an Eaton Hydraulic Launch Assist (HLA) system at the HTUF meeting.

“HLA can be quickly tailored for maximum fuel economy or enhanced productivity through quicker acceleration and shorter cycle times. Additionally, the system increases brake life and reduces engine and transmission wear, potentially extending component life and lowering service costs,” said Peterbilt chief engineer Craig Brewster.

DaimlerChrysler plans to test a “plug-in” HEV version of its Dodge Sprinter vans in early 2005. The test involves three Sprinter HEVs: a diesel-electric version operated by the Kansas City Regional Transit Authority; and two gasoline-electric vehicles run by electric utility Southern California Edison and the South Coast Air Quality Management District.

The OEM said the HEV Sprinter offers fuel consumption savings of 10% to 50%, depending on the type of driving application, as HEVs are most fuel efficient in stop-and-go situations.