WITH the price of diesel fuel going through the roof and an increasing concern about emissions, hybrid electric trucks are looking less like an apparition — a terrifying ghost riddled with questions about expense and reliability — and more like something that inspires appreciation.
“Fleets need to come to grips with the fact that the electric truck is no longer something to dismiss as science fiction,” says Jay Sandler, vice president of commercial products for Workhorse Custom Chassis. “Just like cars, hybrid electric trucks are here now, and may well be everywhere tomorrow.”
How open are minds? Back in March at The Work Truck Show, the National Truck Equipment Association (NTEA) hosted a Hybrid Truck and Alternative Fuels Summit — sponsored by International Truck and Engine Corporation — that drew an overflow crowd at the Indiana Convention Center in Indianapolis. The NTEA also hosted a Hybrid Ride-and-Drive event and a “Stepping Into The Future” pavilion where show attendees viewed the latest hybrid and alternative fuel technology initiatives and products.
“As you dig into this, there's an awful lot going on,” says Doyle Sumrall, the NTEA's director of strategic opportunities. “It's been fun, bringing the parties together to share information. It's providing a good service to the industry. This is new technology in what is a fairly mature market that looks like it has great potential to reduce the operating costs of fleets.”
The NTEA also is facilitating the Light-Duty Hybrid Action Group, a work-truck user group of 21 of the biggest mixed fleets in North America designed to assist the development of cost-effective hybrid trucks. Sumrall says the group features utilities, state, and county transportation departments, and private companies that manage a combined 200,000 commercial vehicles. Many of the 21 companies already have utilized hybrid vehicles in their fleets.
“We're working with them to develop a drive profile,” Sumrall says. “One of the challenges everybody has with the technology is, ‘Can we justify it?’ Short of buying some trucks at premium prices — because the volumes are so low — and putting them in the field and running them for years to find out, you need to have some basis to do the analysis.
“So we're working with some fleets that have some test trucks out there. We're currently working on a drive profile that would be representative of the work activity and driving activity of the trucks. We did a rough-cut economic model, a simple life-cycle cost model, where you take information and put it into the calculator and get a rough idea if the application you have is a good one for hybridization.”
Successful pilot program
One of the leaders is Florida Power & Light Company (FPL), the largest electric utility in Florida, with a fleet of 3600 vehicles that uses approximately 2.5 million gallons of diesel fuel per year.
FPL has operated a successful hybrid utility truck pilot program that is now being expanded, replicated, and enhanced. It started in 2001, when George Survant, director of fleet services for FPL, initiated the development of a Hybrid Utility Truck Working Group within WestStart/CALSTART, a non-profit organization that works with public and private sectors to develop advanced transportation technologies and foster companies that will help clean the air, lessen dependence on foreign oil, reduce global warming, and create jobs.
Survant organized the fleet directors of 13 other utilities around the country to join in the program. The group developed a common specification and issued an industry-wide request for proposals for medium/heavy-duty diesel-electric hybrid utility trucks that would perform identically to existing trucks while reducing fuel consumption, reducing emissions, improving drivability, and increasing functionality by providing on-board electrical power generation.
International and Eaton Corporation were selected as the winning manufacturing team, and the side-by-side testing was completed in 2005 at an independent testing laboratory. The tests suggested that fuel reduction of 40% to 60% could be achieved, along with at least comparable emission reductions.
FPL took possession of three of the initial bucket trucks in November 2005. Subsequent comparisons of actual on-road fuel usage between the fleet's conventional trucks and the hybrid-electric trucks show a 55.3% reduction in fuel consumption for the hybrid units, as well as significant emissions-reduction benefits.
FPL will take delivery of five additional hybrid-electric trucks in August to continue the evaluation process.
“We're very pleased,” says FPL's Bob Schomber. “They've done everything we've expected. You have to love 50% reduction in fuel, and a reduction in emissions. There have been some minor glitches in terms of the mechanical side, but nothing that causes problems.
“The hybrid trucks are perfect for our duty cycle. Our trucks spend a lot of time idling at the side of the road. UPS and FedEx are using the technology, and I think it would be good for a delivery truck like Coca-Cola or Budweiser that makes a lot of stops and starts.”
FPL fuels the hybrid vehicles with B20 (20% biodiesel fuel produced from soybeans), which provides an additional 20% reduction in petroleum use and a further substantial reduction in harmful emissions as shown in testing conducted by the Environmental Protection Agency (EPA).
FPL continues to serve as the lead user for the Hybrid Utility Working Group, which has all of the initial 24 pre-production hybrid trucks deployed and is conducting fleet trials on them as part of a national pilot project. The group is also preparing requirements for Class 5 applications, reviewing plug-in hybrid possibilities, and has collected future fleet purchase commitments for an additional 100 hybrid trucks.
The two biggest questions prospective fleets have about hybrid trucks:
- Are they reliable?
- Are they economically viable?
To address the reliability issue, a definition of hybrid and an explanation of the systems are necessary.
A hybrid vehicle is defined as one that has more than one source of power. In a hybrid electric vehicle (HEV), the diesel engine is coupled with electric motor/generator(s) and batteries (or other electrical storage devices) to create the hybrid system. In a hybrid hydraulic vehicle (HHV), the engine is coupled with hydraulic pump/motor(s) and hydraulic accumulators to create the hybrid system.
Eaton's hybrid-electric power systems consist of an automated clutch, electric motor/generator, motor controller/inverter, energy storage, automated manual transmission, and an integrated supervisory Hybrid Control Module. Hybrid electric systems have much higher energy storage capacity, and generally have low to moderate power capabilities. Hybrid electric systems also can provide engine-off PTO capability for those needing work-site hydraulic operations and an auxiliary electric power source from the vehicle, making them valuable in vehicles whose work day takes them off the highway and to a job site, where the truck's power is used to operate other tools and equipment.
Hybrid electric vehicles require a sophisticated level of integration and partnership between truck makers, engine manufacturers, and suppliers of the drivetrain and major electrical components. Eaton last year started offering complete, integrated Hybrid Drive Units to truck OEMs that include an automated clutch, electric motor/generator, motor controller/inverter, energy storage, automated manual transmission, and an integrated supervisory Hybrid Control Module for the utility, telecom, municipality, and other medium-duty city delivery vocations.
In a parallel hybrid hydraulic system, the conventional vehicle powertrain is supplemented by the addition of the hydraulic system. The system is suited for vehicles that operate in stop-and-go duty cycles, such as refuse trucks and buses. It provides improved fuel economy through regeneration of braking energy, longer brake life, and increased productivity due to the extra power the HLA system provides. Fuel economy and emissions reductions of 20% to 30% and paybacks in two to three years are possible with this technology. Eaton plans to commercialize the HLA system in refuse trucks this year, followed by other applications.
In a series hybrid hydraulic system, the conventional vehicle driveline is replaced by the hybrid system. Energy is transferred from the engine to the drive wheels through fluid power. The system is suited to a broader number of applications than parallel hydraulic hybrids and provides improved fuel economy (as achieved through operating the engine at a “sweet spot” of best fuel consumption facilitated by the CVT functionality of the series hybrid system), through regeneration of braking energy, and by shutting the engine off when not needed. Fuel economy improvements up to 70% are possible with this technology.
Jeffrey Carpenter, senior chief engineer for Eaton, says the company attacked reliability first by using its technology in field tests and customer applications. He says that FedEx, which has been using 18 hybrid units for two years, has achieved 99% uptime — meaning that the units are available for the next shift 99% of the time.
“As we went through those field tests with the prototypes, we started getting more commercially focused,” he says. “We went through our traditional American partner and said, ‘We're ready to go into production.’ They said that not only did they want that uptime metric, but they wanted us to provide a classic reliability story for them, too. So then we started to put in focus fleets and their particular chassis and started running trucks of various fleet sizes and started growing reliability with them to old traditional metrics. That's looking very positive.
“We built the original field test for UPS last summer, and they're satisfied with reliability. They purchased two much larger fleets with two different OEMs and rolled them out to them. Fuel savings of 30% to 50% are very representative of our earlier field tests with them.”
Carpenter says there is not a lot of difference in truck-equipment installation between hybrids and traditional trucks.
“You still have the mechanical interface from the engine flywell to the transmission clutch housing,” he says. “We put our motor inside that area, so it's kind of seamless. The next challenge is, you have to install batteries somewhere on the vehicle, in addition to the 12-volt battery, so you have to find a location for those. Once you find the location for the battery box, you string some high-voltage wires. You have to be cautious on how to run that so you don't get tangles and somebody's not going to have access to them. That runs from the battery box to the motor.
“Then there's some cooling involved. Your motor is liquid-cooled and the device that converts battery energy from DC to AC is liquid-cooled, so there is a cooling circuit for that and the heat exchanger, and that has to be packed somewhere on the vehicle. And that heat exchanger is independent of the engine on a separate circuit.”
Eaton created an installation guide with all the tips and requirements for putting a hybrid system on a vehicle, and made it available at roadranger.com.
Workhorse introduced its first hybrid truck platform at The Work Truck Show — the W62 walk-in truck platform for the heavier duty (19,500 and 23,500 lb GVWR) category of walk-ins.
Last summer, Workhorse was challenged by its parent company, International, to develop an effective way of integrating electric hybrid components from Eaton into the new W62 chassis to fulfill an order for UPS.
At the time, Workhorse already had partnered with Azure Dynamics Corporation on orders of electric hybrid versions of its W42 chassis (9400 to 16,000 lb GVWR) — series electric hybrids using the gasoline-powered versions (GM Vortec 6L and 4.8L engines) of the truck. In this process, a contracted supplier added the hybrid components in the final stage of manufacturing with minor design changes.
With the W62, the challenge facing the Workhorse engineers was to design a more intimate integration of parallel hybrid components with existing chassis hardware for the diesel version powered by International's V-6 VT-275 diesel engine (200 horsepower, 440 lb-ft of torque). It also would be a design that required a significantly different manufacturing process, with hybrid components added far earlier in the build cycle. The design team began in August 2006 to develop the best way to integrate Eaton's various components, such as its automated mechanical transmission. By the end of November, the design work was completed and the new manufacturing process established.
Workhorse's Sandler says the results look promising, with early projections indicating a 30% to 50% savings in fuel costs.
“It's very satisfying, along with all the other truck choices we've created, that we're also on the leading edge of green walk-in truck technology,” Sandler says. “This W62 is an excellent example of what's possible in the area of creating better choices for both the environment and the bottom line. We think the walk-in truck market holds a lot of promise.”
Brake life extended
FPL's field trials are assessing expected reduced maintenance in hybrids. Because it can recover braking energy, a hybrid system can extend brake life by reducing brake wear.
“During regenerative braking, a hybrid system slows the vehicle by converting its kinetic energy into stored electrical or hydraulic energy, via a generator or pump, reducing the need to use the conventional brakes to stop,” FPL says in a release. “Hybrid systems have been shown in some demonstrations to extend maintenance intervals for service brakes by several hundred percent. Reducing the number of brake jobs over the life of the vehicle would significantly affect life-cycle cost.
“Hybrid systems also have no clutch or torque converter. They generate less heat in the engine and gears by requiring smaller RPM excursions. Less heat reduces the burden on the cooling system; reduces the destructive effect on hoses, wiring, and other ancillaries in the engine compartment; and causes slower degradation of the lubricant thereby extending engine life.
“Hybrids may also extend the maintenance intervals of trucks when the interval is based on either engine hours or fuel throughput. Hybrid strategies that shut the engine down during times it would normally idle will reduce engine hours for the same work period. Sharing of peak power demands and taking on PTO functions will reduce conventional engine fuel throughput. Some hybrid systems may extend maintenance intervals by 30% or more.”
Bob Aquaro, vice president of product development for Mitsubishi Fuso, says he has seen dramatically increased interest in the use of the hybrid battery in powering other equipment.
“We took a demonstration hybrid to The Work Truck Show in Atlanta last year because we were looking at some market feedback,” he says. “The interesting thing for me was that we didn't get a lot of feedback on using it as a delivery van. People were more interested in what the capabilities were — the battery system with regard to powering other equipment.
“A bucket truck is running off a lithium-ion battery that's part of the drive system. They were more interested in, ‘Can I use the battery to do something else? Can I run a pump? Can I run an aerial device? Can I shut the engine off and not have to run the engine to run the pump? Can I get rid of the PTO?’ The benefit is obviously you're using the electric battery to control the bucket, so the engine's not idling and not using fuel.”
Aquaro says Mitsubishi Fuso is using its hybrid trucks exclusively in Japan and won't be introducing them in the US for at least three years. But others are working with various applications off the battery.
Tests of a utility truck prototype with Eaton's electric hybrid system indicated that it can function with its diesel engine off most of the time at a line repair site.
Oshkosh Truck Corporation has produced the first heavy-payload defense truck with an electric hybrid drive. The HEMTT-LHS tactical defense truck features Oshkosh's ProPulse electric hybrid-drive propulsion system. Although initially designed for military trucks, the company expects the system will also be used in commercial vehicle applications.
The ProPulse system consists of a diesel engine, running at a constant speed, which turns a generator that powers electric motors at each differential. The generator is powerful enough that, when not driving the vehicle, it can produce enough AC electrical output to power an airfield, hospital, command center, or up to 300 homes.
As for economic viability, Eaton's Carpenter says it's a function of increasing the volume of trucks.
“As this matures into an above-10,000 market, we'll be very cost competitive,” he says. “We'll start making the payback equations that customers come up with, whether it's three, five, or seven years. That's very dependent on how many miles they drive the truck each day. Somebody driving the truck five miles a day is not going to get nearly the quick payback as somebody driving 100 miles a day.
“But those guys with five-mile-a-day usage are very concerned with the green image. We get it constantly: ‘We can sell more water, we can sell more flowers, we can deliver more soft drinks with that green image plastered on the side of our truck.’ Although you can't quantify that in the cost of the system, it comes into every conversation with that customer.
“I think with most of the first-time users, the reliability question was answered, and they're willing to pay a little more up front to be first-time users, for various reasons. So you're going to see a lot of those early adopters. When those early adopters start buying and drive up the volume, it will reduce the price for everybody else.”
For most fleets, hybrid technology remains too expensive. But Workhorse's Sandler says the picture is brighter for hybrids because of 2007 emission requirements that have increased the cost of diesel engines $4,000 to $10,000 over 2006 models, with more requirements and price increases coming in 2010. On top of that are higher fuel costs.
Workhorse recently developed two hybrid electric versions of its walk-in truck chassis for two different parcel delivery companies, Purolator of Canada and UPS. Sandler says that because they are custom builds, neither version is cheap, but both hold promise.“From a price standpoint, as orders go up, production costs will come down,” he says. “But advancements in technology will also be key, particularly in terms of battery storage capacity. And I don't think we're far away from that.“At present, the hybrid battery pack is the most expensive component we add to make a hybrid electric truck. With more efficient battery storage, a fleet of ‘plug-in trucks’ would work quite well.”
He says they would “fuel up” by plugging into an electrical outlet of a configured voltage. Cost effectiveness would be enhanced by doing this between midnight and 5 am, when the power grid has the least amount of demand and power might be purchased more cheaply. So a fleet would buy this “fuel” from the power company. Preferably this would also be “clean” power, as power companies develop nuclear plants, natural gas systems, solar power, geothermal energy, and other “green” ways of generating electricity. In any case, the power would be from something more efficient than an internal combustion engine. That will result in an electric-powered vehicle for most of the day. Sandler says a small gas or diesel engine would provide supplemental energy, if needed. For a walk-in truck, this would probably be a 2L or 2.5L engine that would run the generator. So when the battery charge drops to a certain level, the generator automatically starts up and recharges the batteries. At the end of a typical day, 70% of the truck's energy may have come from the overnight plug-in and 30% from the on-board generator, putting regular fuel consumption at 50 to 60 mpg or more for stop-and-go driving. Sandler says pick-up and delivery fleets, which serve local routes with a lot of stop-and-go driving, likely will lead the way in this hybrid revolution.
“Parcel delivery fleets have been the leaders in experimenting with hybrid electric trucks thus far because in the near term, that is where hybrid electric technology can provide the greatest cost savings,” he says. “I expect bakeries, textile rental operations, and other local delivery fleets will also be early adopters of this technology.”
FPL measured the economic viability of its project in two ways: by extrapolating the side-by-side fuel test results or by averaging the actual fuel savings of the initial three trucks.
During the testing phase, FPL supplied a conventional truck for baseline comparison against the diesel-electric hybrid trucks. Four “mission” or duty cycles were identified.
Mission A (lowest fuel savings): 70 miles driving; three service/site calls; 1.5 hours of hydraulic operation.
Mission B: 70 miles driving; three service/site calls; 1.5 hours of hydraulic operation.
Mission C: 48 miles driving; three service/site calls; three hours of hydraulic operation.
Mission D (highest fuel savings): 38 miles driving; two service/site calls; three hours of hydraulic operation.
The testing determined the following dollar savings associated with use of the hybrid trucks:
Using Mission A (lowest fuel savings), a 40% fuel consumption reduction was achieved. At $2.70 per gallon, the annual fuel savings would be $3,500 per vehicle.
Using Mission D (highest fuel savings), a 60% fuel consumption reduction was achieved. At $2.70 per gallon, the annual fuel savings would be $4,500 per vehicle.
Using actual in-service fuel data for the initial three trucks during 2006, FPL achieved a 55.3% overall fuel reduction for the hybrid units, which translates to an annual fuel savings of approximately $4,000 per vehicle.
Where do hybrids go from here?
The Hybrid Utility Truck Working Group is investigating upgrades to the system. According to FPL's release, current diesel-electric hybrid trucks use a 215-hp International DT466 engine.
“Large engines in this horsepower range are required to get large vehicles moving from a stop, generally the only time peak horsepower is needed,” FPL says. “Because stored battery energy can be used to move the vehicle from a stop, a smaller engine can be applied to the next generation of diesel hybrid, obtaining even better fuel economy and emissions results.”
FPL says the US Army National Automotive Center (NAC) is committed to hybrid technology in new versions of its tactical vehicles and will use the project to develop early field data on hybrid truck operation from a major deployment. FPL says commercial-based military vehicles have benefits for taxpayers because military development costs are kept lower.
“If the military can build off various commercial platforms, the development process will be more affordable and efficient in the long run,” FPL says. “The pilot assessment program signals a significant step towards commercialization. The on-going evaluation and specification changes made by FPL and their partner utilities will accelerate significant hybrid penetration in the near future. By proving themselves in the demanding utility environment, the trucks could then have applications in many other uses, including tree trimming, regional delivery, beverage vehicles, fuel trucks, and shuttle buses.”
Also, UPS will begin testing the first-ever hydraulic hybrid urban delivery vehicle later this year on the road in the Detroit area, and then will bring it to Cleveland for additional testing. The vehicle was developed through a partnership between the EPA, Eaton, UPS, International, and the US Army.
In initial laboratory testing of a UPS package delivery vehicle, the series hydraulic hybrid technology provided a 60% to 70% improvement in fuel economy and more than a 40% reduction in carbon dioxide emissions. The EPA estimates that the technology has the potential to save more than 1,000 gallons per year for each urban delivery vehicle.
Eaton's Carpenter believes hybrid technology is going to grow much faster than originally anticipated.
“The more expensive fuel gets, the more it drives into the solution,” he says. “So I think it's going to ramp up faster than our expectations. We saw mature markets up around 2010. That might hit a little sooner.”
Workhorse's Sandler says it won't be surprising if trucking fleets will just plug into an electrical outlet to refuel in the not-too-distant future. He thinks medium-duty work trucks of all kinds powered mainly by electricity are only five to 10 years away.
“I think this technology will quickly evolve in the next five to 10 years,” Sandler says. “The gas or diesel powertrain will be very different. These future hybrids will have similar horsepower and torque as today's trucks. They will be quieter and for the most part odorless in terms of combustion fumes. The smaller engines they do have will be cleaner-burning and, as they are reduced to a peripheral part of the new power equation, they will significantly reduce the need for oil sources, foreign or domestic.
“These trucks will be a big leap forward in reducing the emissions everyone is concerned about. It will be the most significant change in automotive power we will see in our lifetime.”