Kenworth-Eaton Hybrid Makes Clean Deliveries

By Tom Berg, Truck Editor | September 28, 2010

A special label on the hood suggests what it is, but otherwise you'd have to look closely to see any special equipment on the KW T300 hybrid. It looks like other KW mediums in the Dunn Lumber fleet.

Eaton's electric hybrid drive train, depicted here in a public-utility "trouble truck," includes a 6-speed UltraShift transmission, 60-horsepower/340-lb.-ft. motor generator, two lithium-ion batteries and electronic controls.

Cummins-made Paccar PX 6 supplies diesel power, as it will in future Kenworth and Peterbilt medium-duty hybrids.

Electronic controls (in aluminum box) sit atop cooling system, both hung on the frame behind the cab. Lithium-ion batteries are in a nearby box.

To the left of the transmission selector is the LCD readout that tells what the hybrid system is doing. At far right is a time-saving Garmin GPS street-navigation unit.

Test Set

Truck: Kenworth T300 conventional-cab 4x2 w/10-5/8- x 5/16-in. steel main rails; GVW 32,000 pounds

Engine: Paccar PX 6 (Cummins ISB), 240 hp @ 2,300 rpm, 560 lb.-ft. @1,600 rpm

Transmission: Eaton electric hybrid system

Front Axle: 12,000-lb. Dana Spicer E-12021 on 12,000-lb. taperleafs

Rear Axle: 21,000-lb. Dana Spicer 21060S on 20,000-lb. Reyco 79KB taperleafs,w/5.57:1 ratio

Wheelbase: 236 inches

Brakes: Bendix S-cam air w/Bendix ABS

Body: Northend 20-ft. tilt-up steel flatbed

With diesel fuel costing around $3.50 per gallon and probably going higher, is it time to be looking at hybrid-drive trucks? If a hybrid can cut 35 percent off your fuel bill, as this Kenworth-Eaton vehicle is doing for its owner in Seattle, Wash., is it something you'd consider? Sure, you might say — after somebody else wrings out the bugs, and the upfront cost of these contraptions comes down.

One of those somebodies is Robert Dunn, chief executive officer of Dunn Lumber Co., a building supply retailer in the Seattle area. He has previously approved the purchase of progressive componentry in his fleet of delivery trucks, including automated mechanical transmissions in heavy road tractors, and was excited about the prospect of buying the hybrid. Partly through its fleet of well-maintained delivery trucks, Dunn tries to foster an image of quality, and the hybrid would add some "green" to the new truck's handsome blue paint.

"Let's do it," he told his fleet manager, Mark Geyer, and they got the special T300 last summer. They've labeled it "diesel electric" to call the public's attention to its unusual power train. Kenworth wanted to display it at the annual meeting of the Hybrid Truck Users Forum (HTUF) in September, but Dunn kept it out so I could drive it — pretty nice, I thought.

On the price front, Eaton Corp. announced that it was putting its electric hybrid systems into production, and several truck builders, including Kenworth, said they'd begin assembling hybrids starting later in '08.

Regular production lowers asking prices and tempts orders, leading to higher volumes that bring prices down further. Hybrids are becoming affordable, and the pre-production vehicles already out there and working are showing that, after some teething problems, they are reliable, too.

HTUF members, acting as a consortium, have obtained three types of diesel-electric vehicles now at work: public utility trucks, whose crews use man buckets, booms and power tools to fix downed lines and other damage to electric power grids; walk-in vans, operated by large package delivery fleets (many acquired independent of HTUF coordination); and medium-duty delivery trucks, run by a smattering of private fleets. Dunn's T300 falls in the third category, and is the first hybrid sold by Kenworth, based in nearby Kirkland, Wash.

The Class 7 T300 hybrid is a pre-production vehicle. Kenworth has split its midrange T series into several weight-based models, including a Class 6 T270 and Class 7 T370, which will have hybrid drive as an option. They will use Eaton Corp.'s electric propulsion system, which includes a 6-speed Fuller UltraShift AMT linked to a 60-horsepower electric motor-generator and two lithium-ion batteries operating at 340 volts.

Sophisticated electronic controls coordinate the workings of the hybrid components with a 240-horsepower Paccar PX 6 diesel, a private-branded Cummins ISB. The engine has EPA-'07 specs, so exhales through a particulate filter; that and many other advances over '06 diesels means this engine emits absolutely no smoke or odor. It and a PX 8/ISC are now the only engines available in Kenworth and Peterbilt midrange trucks, as Paccar (which owns the two companies) has dropped the Caterpillar C7. The hybrid is Dunn's first Cummins-powered T300, and so far it's worked well, says Geyer, who previously had spec'd Cat diesels. The "two-pedal" UltraShift is Dunn's first.

For this short trip, Geyer directed me into Seattle's hilly Queen Anne area, a neighborhood of million-dollar views and equally pricey old homes, some under rehabilitation. Dunn sells a lot of lumber and supplies to owners up there and, of course, delivers them. Streets are narrow, and access to some of the properties is somewhat cramped, so many runs there are made by smaller Isuzu low-cabovers that he inherited when he took this job.

But larger trucks also go there, and one thing Dunn drivers are used to, and I was not, is where to place the truck on the slim streets. Long mirror arms extend from the sides of the T300's narrow (by today's standards) cab, and it seemed like I would whack trees and poles with the right-side mirror. Gradually I learned to judge the truck, and in the meantime didn't clip anything.

Hilly streets in Queen Anne are a good test of any power train, as I found about a year and a half earlier, when Geyer let me drive a then-new T3 equipped with a smooth-working C7-Allison duo. We made a real delivery on that run, but with the hybrid, we just passed through, carting a 2,400-pound pallet of 2x4s for ballast.

While I like AMTs for their solid, no-mushiness feel, I observed that the self-shifting Eaton in the hybrid was occasionally a little awkward. It upshifed on one or two uphill gradients where it should have stayed in a lower gear, and caused the engine to bog a bit. But it recovered by quickly downshifting. If Allison people were along they'd laugh their tails off, I commented to Geyer, because this is exactly what they're talking about when they preach about the advantages of "continuous power." Engine power flows through the driveline even as the fully automatic transmission is shifting up or down. He nodded, because Allisons in other Dunn trucks are good performers.

As with a full manual, the engine pauses as the Eaton AMT changes gears. It "float shifts" with the clutch engaged by carefully modulating throttle and the gear-changing mechanisms. Unlike medium-duty manual trannies, the UltraShift 6-speed has no synchronizers, so clutchless shifting doesn't hurt it if done properly. Eaton engineers have gotten the software so finely tuned that it never misses.

From a standstill, each of the automatic clutch engagements was flawless — smooth, sure and with absolutely no chatter, even when starting out on a hill in 2nd or 3rd gear. As with other UltraShifts, this one has no clutch pedal, so you just move your right foot from the brake pedal to the accelerator, and the rest is automatic. If a driver thinks he can do better, he can punch Manual and control the up- and downshifting. But using the Manual mode is not really a necessity, and actually I pretty much left the selector alone and we went up, down and around all those Queen Anne Streets just fine.

Electric launch occurred a few times, and regeneration happened often because downhill sections required frequent braking. That's when the motor on the driveline becomes a generator, sending voltage to the lithium-ion batteries in a box along a frame rail. You can feel the drag when you take your foot off the accelerator and, if that's not enough braking force for a situation, touch the air-brake pedal. The engine also had a Jake Brake that provided more retarding power, and we used it while we drifted down a long hill toward the end of our jaunt.

A liquid crystal display hung on the dash showed what was happening in the system —engine power, hybrid power, or braking regeneration. It also showed the extent of charge in the batteries. The LCD was a little hard to read, but production trucks will get a color display that's larger and brighter. Next to the LCD was a Garmin 7200 GPS navigation system, which Geyer has installed on most of the Dunn trucks. We didn't use it this day, but on regular runs it helps drivers find new addresses and saves "huge amounts of time," he said.

Between hybrid and Jake retarding, the service brakes on this truck won't be working hard, and Geyer expects savings in brake wear. It's too soon to know how much, because as of a month ago, the truck had accumulated only 6,000 miles. But the 32,000-pound-gross-weight hybrid got 6.85 miles per gallon in mostly urban delivery service in one recent month, versus 5.06 mpg for other trucks ofthe same weight. But fuel savings alone will take about 10 years to pay back the hybrid's premium of $20,000 against the T300'schassis price of about $75,000. Kenworth is working to qualify the hybrid for federal tax credits, which would quicken a return on investment.

Up until now, most hybrid trucks I've heard of cost half again to twice as much as a straight diesel vehicle, so maybe Dunn got a good deal, or maybe component prices are already coming down, or both.

Except for a couple of dump trucks that Mack assembled for the U.S. Air Force using a Volvo electric hybrid drive train (CE March '07), no manufacturer has developed hybrids strictly for construction duties. Eaton and Peterbilt are readying a diesel-hydraulic hybrid for trash pickup service, and I've got to think that a hydraulic system would have a place in dump or mixer trucks, but we'll see as development continues.

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