Hybrid Trucks: Moving Fast

Fleet evaluations show promise and development continues, while users have tips for getting purchasing money.

Tom Berg • Senior Equipment Editor

Hybrids have become the automotive equivalent of Mom and apple pie: Thanks to the success of Toyota's Prius, Americans have come to believe that the clean-running, fuel-saving vehicles will help clear the air and shake off dependence on foreign oil, which in turn will make us healthier and more secure.

Truck operators aren't so sure, because hybrids are expensive, pushing payback beyond fiscal reason. But government incentives can offset some of the steep premiums, and there are ways to get such funds. Meanwhile, development continues on batteries and powertrains, prototype hybrids are showing considerable promise, and volume production will eventually bring down upfront prices.

Those are among the points made at the seventh meeting of the National Hybrid Truck Users Forum, held in Seattle in September. Organized by WestStart-CalStart, hosted by Paccar and sponsored by Eaton Hybrid Power Systems, the meeting had record attendance of about 300, including nearly 100 fleet people, according to Bill Van Amburg, WestStart-CalStart's senior vice president and HTUF's principal coordinator. A full day of presentations was followed by a half-day ride-and-drive event featuring 19 hybrid trucks and buses.

HTUF is made up of suppliers, government agencies and users, and their ongoing efforts have cut about two years off development of hybrid trucks, said Paul Skalney, executive director of the U.S. Army's National Automotive Center, one of HTUF's original members. The Army continues to test fighting vehicles and tactical cargo trucks with hybrid powertrains, and its vast fleet will eventually include many of them. Partly because of military development contracts, suppliers are working toward the "commercialization" of trucks and buses that, in turn, will lower component costs and help the military afford the high-tech, fuel-saving vehicles. Between annual meetings, HTUF's working groups have been writing specifications for certain vehicle types, and some are already in service.

"We are on the cusp of production," Van Amburg declared, noting that Eaton has struck deals with Freightliner LLC, International Truck and Engine, and Paccar, whose truck-building arms will begin assembling medium- and heavy-duty trucks by early next year. These will be standard production trucks using Eaton's diesel-electric system. Kenworth has sold one T300 diesel-electric hybrid to a lumber retailer in Seattle, which so far reports fuel savings of 30 percent. Two other T300s, retrofitted by Azure Dynamics and Allison Transmission, are delivering fresh foods in New York City. Peterbilt has made electric and hydraulic hybrids and will build more next year. One is a Model 320 refuse chassis with Eaton's Hydraulic Launch Assist that will soon go into service (see sidebar on page 112).

Over-the-road tractors are being developed for Wal-Mart Transportation by Peterbilt, using Eaton's electric system, and International, with an ArvinMeritor electric system. The International ProStar tractor will be ready in early 2009, while the Peterbilt 386 is now running and was on display at the HTUF meeting. Attendees were invited to drive it and 18 other hybrid buses and trucks around a stadium parking lot, where the vehicles' strong acceleration was evident.

Many had Eaton electric systems, which add a motor-generator, automated mechanical transmission, a bank of batteries and electronic controls to each bus or truck's diesel engine. They are "parallel" hybrids that can run on electric or diesel power or both. "Series" hybrids are also under development, though none were available for driving at the meeting. They operate like locomotives, with the diesel running a generator that produces electricity that propels the truck and charges batteries; those also store braking energy captured by the generator. A battery electric delivery truck from Great Britain was also among the driveable vehicles, and it was silent and quick.

Electric and hydraulic hybrids each have advantages, and development and fleet testing are beginning to sort out which is best for different applications. Presenters suggested that the military, public utilities and long-haul carriers will probably go with electric hybrids, because all require auxiliary electric power to operate subsystems (computers and weapons, booms and tools, and "house" accessories, respectively) while vehicles are parked. Trash collection trucks might best use simpler hydraulic systems to capture braking power and help with launching. Pick-up and delivery trucks, including package vans, could go either way.

Business Case

Building a business case for hybrids is difficult, because their substantial cost premiums push potential paybacks way out. This is especially true of OTR trucks, whose fuel savings from hybrid powertrains are likely to be less than 10 percent. Until purchase prices come down, government incentives can help, several presenters said. Incentives range from congressionally mandated federal tax credits, which only recently have been sorted out, to outright grants in California, Texas and New York City. Money is available to municipal and commercial fleets if users know where to look.

For example, King County, Wash., formed a consortium with surrounding municipalities, and applied for and got $400,000 from federal sources, said Win Mitchell, the county's fleet director. That provided $40,000 for each of 10 buses.

"If you want to get money, engage your politicians," he advised HTUF members. "Get political support by hosting meetings around the country, then have local politicians and policy makers turn to Washington. It works."

Once educated about hybrid buses and trucks and how much they can contribute to fuel savings and clean air, politicians will quickly jump on the "green" bandwagon, he and others said.

Hybrids makes sense in the quest for clean air and fuel savings because they use existing fuels like ultra low sulfur diesel and biodiesel, along with the existing infrastructure, said Jim Williams of International Truck and Engine. Hydrogen, which is bandied by some as the fuel of the future, needs an entirely new infrastructure for production, distribution and storage of the pressurized element, and for pumping it into vehicles. Biodiesel alone is an effective way to cut fuel use, and can precede conversion to hybrids, said Mitchell of King County. Biodiesel is how its fleets began reducing their use of traditional diesel

Predicting fuel savings can help build a business case, and the federal Environmental Protection Agency is developing protocols for measuring potential savings in a variety of truck and bus applications, starting with trash trucks, said Cheryl Bynum of the agency's Ann Arbor, Mich., laboratories. The testing methods are more detailed than those already devised by industry groups, and can be used on dynamometers as wells as streets and roads. EPA hopes to publish the protocols by winter's end.

Hybrids At Work

Hybrids now in fleet testing and in actual service include:

• Public-utility "trouble trucks" - International built 24 Class 6 trucks with the Eaton system for an HTUF working group, which parceled them out to American and Canadian utility fleets for evaluation. The system allows engine-off operation at work sites, with stored electricity powering man-buckets and tools, explained Jasna Tomic of WestStart-CalStart, who surveyed users and compiled their responses.

Users report fuel savings of as much as 54 percent compared to straight diesel trucks, though the average is 34 percent and one truck has managed to save only 14 percent in fuel. Duty cycle is important to the results, Tomic said. The higher the highway miles, the lower the fuel savings. Trucks running a lot of stop-and-go miles, where the systems' regenerative braking captures electrical energy that can be used for "launching," do better. At work sites, engines run for only short periods to recharge batteries, which cuts noise and emissions - a major benefit to crews and nearby residents, fleets think - and also saves some fuel. Surveys said there were some teething problem with some trucks, but overall reliability has been very good and availability has been above 99 percent. One truck in Quebec will soon go through a Canadian winter, which will test its cold-climate durability.

Some drivers like the trucks and others aren't so sure, said Glenn Martin, a fleet manager at Florida Power & Light, which has two hybrids. Attitude and habits determine how drivers operate the trucks, which has a big influence on economy. Drivers are used to Allison automatics, which are standard in most of FP&L's trucks, and so they must get accustomed to the Eaton automated mechanical transmissions. Some have complained about lack of "bin space" in the Altec bodies, which sacrifice some tool storage to house the hybrids' batteries. Training can overcome objections, and the trucks have been good image builders and public relations tools for the company.

• Package delivery trucks - United Parcel Service, Purolator Courier and FedEx are evaluating a number of vans, and FedEx Express has the most, with 93 diesel-electric walk-in vans running in the U.S. Sam Snyder, the fleet's chief engineer, reported mostly positive results: Fuel economy is 42 percent better and exhaust emissions are 98 percent less than with straight diesel vans, which, like the hybrids, are built on Freightliner Custom Chassis. Hybrids have four-cylinder Mercedes-Benz diesels instead of the usual six-cylinder M-Bs, but the Fours are no longer available and the Sixes planned for future hybrid trucks will be too powerful.

FedEx Express initially bought 18 hybrids with Eaton systems, then another 75; the second group developed problems serious enough to sideline them twice, but Eaton fixed them and now reliability is 94 percent. The purchase price was twice that of standard vans, making them economically unsound. But FedEx is committed to the concept and plans further buys of the walk-in vans. It also runs two Isuzu diesel-electric vans in Tokyo, and has ordered 20 Ford E-450 van chassis using electric hybrid systems from Azure Dynamics. The Fords will have gasoline engines. Why? "In a word, California," Snyder said. Gasoline engines will meet the state's extra-stringent emissions limits easier than diesels.

• Transit buses - These are the most numerous hybrid vehicles now in service, and the King County Metropolitan Transit District, which serves Seattle and surrounding communities, has 236. These are heavy articulated units, made by New Flyer with Allison diesel-electric systems. Everybody likes them, said Jim Boon, the fleet's manager; they accelerate fast, which pleases drivers and passengers, and their availability has been 98 percent. They save about 35 percent in fuel and their cost per mile is 19 percent less than a control group of 30 straight diesel buses, also made by New Flyer.

The district has ordered another 515 New Flyer hybrids with options for 200 more. Some of the 200 will go to other transit districts, which will piggyback on King County's large order, Boon said. Payback of the hybrids' premium should come in eight years, and the district anticipates keeping them for 12 to 14 years. Only two of the buses' 1,400-plus batteries have malfunctioned so far, he told a questioner, and they were the result of minor manufacturing defects.

Batteries - particularly the lithium-ion type that holds the most promise for electric hybrids - are getting better and must continue to improve, presenters said. Bill Kahn of Peterbilt, who headed a team that engineered the Eaton system into the 386 tractor for Wal-Mart, said the li-ion batteries now in the truck "weigh about 200 pounds compared to 3,000 pounds when we started." As li-ion batteries go into volume production, their now hefty prices should come down.

However, lithium can catch fire if the vehicle crashes or, in the case of military trucks, is shot up or bombed, other presenters noted. An electric system's 340 volts, meanwhile, can put citizen-rescuers and emergency response teams in danger. So can the highly pressurized fluid in hydraulic systems, if hoses or tanks are punctured (though similar fears would apply to gasoline tanks if that technology were new, one presenter pointed out). Training mechanics to work on hybrids will be another challenge, a fleet member in the audience opined.

Quietness - seemingly a welcome attribute amid the bedlam of big cities - can actually be a danger. When running in electric mode, hybrids can be so silent that they sneak up on pedestrians, especially those who are blind. Indeed, drivers of King County Metro's hybrid buses report that they sometimes startle pedestrians as they quietly approach stops. Safety advocates have begun demanding minimum noise levels for hybrid autos, and that could migrate to hybrid buses and trucks. Anyone for an electronic trolley bell?