‘Innovation’ is a word that comes easily to the engineers who create the trucks that populate our roads and worksites. But ‘expensive’ is not a word that truck buyers like to use, ever. So when the latest technology is defined first and foremost by high cost or multi-year return on investment, acceptance will necessarily be slow.

Until, perhaps, the price of diesel fuel skyrockets.

The future of the hybrid truck sits in that context now. All except the most well-endowed private or government fleet has had to think twice about buying into the hybrid idea, despite real running-cost advantages, because the purchase premium has been many thousands of dollars. So the commercialization process — by which growth in manufacturing volume brings unit prices down — has been less than speedy. But we’re slowly getting there.

"With the cost of diesel near or at $5 a gallon, customers across the board have become increasingly interested in hybrids," says Denny Slagle, recently installed as president of Mack Trucks.

"At Mack, we’re currently focusing on refuse because this is a key market segment for us and the technology is so well suited to ‘stop-and-go’ applications, where fuel economy improvements of up to 50 percent are achievable. But as fuel prices increase, so does the business case for hybrids in other segments of our industry. Suddenly, the nine or so percent improvement in fuel economy achievable with a hybrid long-haul tractor seems a lot more attractive, especially to a fleet running hundreds of them.

"But the key, and quite frankly the challenge, is developing a market for heavy-duty trucks in general — bridging the gap from where we as an industry are today with a handful of developmental trucks to the kind of robust market we need to invest in large-scale production. We think government incentives like those established for hybrid cars would be very useful in helping move this process forward. And how the market evolves is going to drive how soon the technology is commercialized and how soon these products become widely available."

The hybrid long-haul truck that Slagle speaks of is the subject of much development work, but fuel-efficiency gains in the nine-percent range pale in comparison to the 20-to-50-percent rate available in some vocational applications. Even with fuel costs as high as they are, however, this new motivation to look harder at hybrids is likely an emotional response that may not translate directly into signatures on purchase orders quite yet.

So says Kevin Beaty, Eaton‘s business unit manager for hybrid electric powertrains, a man who’s awfully keen to see acceptance of the hybrid idea — and volume manufacturing — take off.

"Fuel at more than $4.00 a gallon, I don’t know if it’s a true tipping point," he told Today’s Trucking. "When we do an analysis with fuel at US$4.25 instead of US$3.85, it makes things better, but it’s not a go/no-go point."

That’s because the upcharge for a diesel/electric hybrid medium-duty truck is mighty high. It remains in the US$40,000 range, says Jeff Sass, Kenworth‘s director of marketing planning and research. And $50,000 for a typical utility truck with an e-PTO. Those figures are generally true across the OEM board, but Sass figures they’re not necessarily deal breakers, even in a P&D truck.

"Today it’s affordable if you have the right application," he says, "depending on how long you keep the truck. Payback in six or seven years is likely. But not if you make just two or three stops a day. Sixteen or 17 stops is a different story.

"Utility, that’s where you see the real advantage. You’ll get payback in three to five years. It could even be two.

Two Volvo FE hybrid garbage collectors are on the
road in Sweden, promising to use about 20 percent less diesel fuel.

"The hybrid is really going to make a difference," Sass adds, though he acknowledges that it will happen sooner in the U.S. than in Canada. That’s because American buyers can get tax credits up to US$12,000 on a hybrid truck purchase, while Canadians get nothing at all.
 

There have been environmental justifications for hybrid powertrains all along, of course, and in some quarters they’ve been compelling. Allied to that, there are also public relations gains to be had in a world that increasingly values the ‘green’ ideal. Very public companies like Federal Express and United Parcel Service have extensive hybrid as well as alternate-fuel fleets partly because their public image is important.

UPS recently ordered 200 hybrid electric vehicles — the largest commercial order of such trucks by any company — as  well as another 300 trucks running on compressed natural gas (CNG). All 500 are to be parcel-delivery vans built by Freightliner Custom Chassis, with Eaton supplying the hybrid power system.

Image is just as important for the beverage bottling company or the pickup-and-delivery operation of an LTL carrier. Both of those applications have been getting more attention lately, and earlier this year Coca-Cola Enterprises placed a big order for 120 trucks also featuring the Eaton hybrid electric drivetrain. Most of those trucks will be Kenworths, built at the Paccar plant in Quebec.

Utility trucks have led the way toward commercial viability because they can take serious advantage of battery power to raise a bucket without using the noisy, thirsty diesel to run a PTO. While a hybrid P&D truck, depending on how and where it’s used, is said to be able to reduce fuel consumption by as much as 30 percent, a utility truck that makes heavy use of its e-PTO can almost double that figure.

But the opportunities do go further than bucket trucks and, as Mack’s Denny Slagle says, the refuse world is likely to be a key market. Volvo, for instance, has just put two hybrid garbage trucks on the road in Sweden, the first anywhere. The company says it will start producing hybrids routinely in 2009.

Those two Volvo FE garbage collectors combine a 7-liter diesel engine with an I-Shift transmission and the company’s 120-kw I-SAM electric motor, the latter used for launch through about 20 km/h when the main engine kicks in. When the truck stops, the diesel automatically switches off. It uses regenerative braking, of course, as do all hybrids.

These trucks are expected to use about 20 percent less diesel fuel. One of them is also equipped with an extra battery pack that drives the compactor, and this is charged via the main electrical system when the truck is parked overnight.

Freightliner’s drop-frame M2e hybrid beverage truck is engineered
and ready to move, with Eaton’s electric drivetrain behind a Cummins engine.

Hybrid technology is the future in all transport segments, Volvo says, including long-haul and construction sectors in the longer term.

"Hybrid technology will play a major role in the future as the climate issue and oil dependency come into ever sharper focus," says Mats Franzén, engine manager at Volvo Trucks. "No matter which fuels dominate in the future, their supply will be limited. Technology that leads to lower fuel consumption will be of immense interest to our customers, irrespective of the type of haulage operation with which they work. For distribution trucks, fuel consumption may be able to be cut by 20 to 30 percent. In long-haul operations, the percentage reduction will not be as great but since these trucks cover long distances, the total fuel saving will nonetheless be considerable."

Volvo Trucks North America, not incidentally, has just seen its research funding from the Swedish Energy Agency and the U.S. Department of Energy extended. They’ll be providing a three-year grant to Volvo of US$18 million for the development of hybrid technology and engines for alternative fuels, an extension of the one-year research agreement signed between the three parties a year ago. Volvo has undertaken to invest another US$18 million of its own money in the program.

Getting back to the refuse world, and on to the diesel/hydraulic hybrid power train, Bosch Rexroth has just unveiled a new hydrostatic regenerative braking (HRB) system and announced that its parallel hydraulic hybrid system has been selected by the Hybrid Truck Users Forum (HTUF) Refuse Working Group for field tests with garbage trucks in New York City.

The diesel/hydraulic option has had much less attention than diesel/electric to date. Eaton has both on the go, but their electric drivetrain is already in production while their hydraulic work is still at the development stage. 

Bosch Rexroth is all about hydraulics, on the other hand. In its HRB system, a hydraulic unit integrated in the drivetrain presses hydraulic fluid into a high-pressure reservoir when a driver presses the brake pedal, decelerating the vehicle through resistance and storing energy that would otherwise be lost. The reservoir is electronically controlled when accelerating to release pressure and relieve the load on the diesel engine, meaning lowered fuel consumption, fewer exhaust gases, and quieter operation.

Hydraulic hybrid technology, aside from the electronic controls required, is as old as the hills and well understood. It’s also cheaper than the electric alternative, in theory at least, and there’s no reliance on the vagaries of battery chemistry. Not to mention the weight and bulk of those batteries and the cost of replacing them a few years into the truck’s lifespan. Those New York refuse trucks will potentially see fuel consumption and accompanying emissions reduced by 30 to 50 percent.

The Bosch Rexroth folks may have been slow off the mark in addressing the hybrid truck market, and they admit it, but you’ll see them coming on strong in the months ahead. They claim that hydraulic hybrids, compared to the electric equivalent, are "better equipped to cope with the extremely high power-handling requirements of regenerative braking, and they require fewer energy conversion steps that reduce efficiency."

Peterbilt also has hydraulic garbage-collection plans. It will go for full production of the low-cab-forward Model 320 with Eaton’s Hydraulic Launch Assist in the fourth quarter of this year. The system captures the truck’s kinetic energy during braking and stores it in a hydraulic accumulator/pump to help with launch and acceleration.

There’s clearly an enormous amount of activity on the engineering and development fronts, but rather less on the marketing side. Which makes a recent Freightliner move somewhat unique. The company has put Business Class M2e hybrid trucks — M2 106 models with 24-ft van bodies — into a rental fleet with two locations in the Seattle area. It’s a first, and it’s the sort of thinking that will help speed up the commercialization process.

Try it, you’ll like it, is the message.

Liking the hybrid experience is one thing, of course, but writing a cheque is another.