Hybrids and Plug-in Hybrids: Efficiency for Today

March 26, 2006 – Vol.11 No.1

HYBRIDS AND PLUG-IN HYBRIDS: EFFICIENCY FOR TODAY.

The Bush Administration has proposed a mild 1.8 mile per gallon increase in fuel economy standard for light trucks, SUVs and vans under 8500 pounds. The new standard could be phased in between 2007 and 2011.

The American Council for an Energy Efficient Economy (ACEEE) notes that the new light truck fuel economy requirements would account for roughly one-seventh of the approximately 5 million barrels per day in oil import reduction by 2025 proposed by the President.

Since the first days of his first term Bush has said that he wants market forces to solve problems, not government intervention.

The vehicle companies, at their leisure, seem willing to come forth with energy saving - thus problem solving - technologies. But, advocacy groups like the ACEEE want government to step in and hasten the introduction of those technologies. The change is needed now, they say, not decades in the future.

Significant increases in fuel economy, even for vehicles above 8500 pounds, is available with hybrid technologies. However, extreme fuel economy increases could be available with plug-in hybrid electric vehicle (PHEV) technology.

PACCAR, the parent company of light, medium and heavy duty trucks built under the Peterbuilt, Kenworth, and DAF brands, has announced it has hastened the commercialization of hybrid technology for selected variations of its medium-duty trucks. The availability of PACCAR hybrids will be by 2008, they say. The company has been working with Eaton’s Hybrid Power Systems group to supply the technology.

PACCAR is looking for a 30-percent improvement in fuel economy with its hybrids.

The first to go the PHEV extreme is DaimlerChrysler, which has announced it will build up to 40 PHEV vans for a limited commercial venture. The company will place PHEV-converted Dodge Sprinter vans with selected customers in California, Kansas City, New York and other locations around the U.S.

The vehicles will be able to drive the first 20 miles, or so, each day on electricity stored in their battery packs. Drivers, through a switch on the dash, will determine which mode to be in, hybrid or all-electric. Off-duty the Sprinter PHEVs can be plugged into the grid for recharging.

DaimlerChrysler will build the Sprinter PHEVs in two different versions, one with a five-cylinder diesel, the other with a V-6 gasoline engine. The diesel PHEV is expected to get better overall fuel economy, but the gasoline V-6 will likely have less toxic emissions.

In terms of dramatic increases in fuel economy a conventional hybrid might yield the best results in day-long, stop-and-go, bus or delivery service, whereas a PHEV might do better in commuting situations.

A PHEV in a daily commute could run the first 20 miles on all electric mode then rest (and possibly be plugged to the grid) in a parking lot throughout the day waiting for the reverse trip home.

A PHEV working in all-day, stop-and-go driving would quickly go through the first 20 miles of all-electric driving, perhaps in the first half hour of the day. The remaining 7.5 hours, or so, of the day would be in conventional, but still efficient, hybrid mode. The extra expense to the PHEV technology might not prove itself in fuel savings over a stock hybrid in full-day, stop-and-go driving.

So if DaimlerChrysler's PHEV experiment fails - overall fuel economy isn’t great - it may be the application, not the technology itself. We’ll see.

Visit the ACEEE at http://aceee.org/ Paccar at http://www.paccar.com/ , Eaton Hybrid Power Systems at http://www.truck.eaton.com/hybrid.htm