by J. Martin Kohler

Across North America all stops have been pulled. Industry, government and academia have not only rolled up their sleeves, but they have united in a single effort. Under the sponsorship of the Department of Energy (DOE), General Motors and Yahoo!, attention has been turned to designing and building a full size hybrid-electric SUV that will provide true utility and comfort for the real-world end-user.

The Future Truck Program (as it's officially called), it is now in the second year of its scheduled four year program. In 1999, the D.O.E. selected 15 universities from across the United States and Canada to participated in Future Truck. GM then provided each of the 15 universities from across the United States and Canada with a new 1500 4WD Suburban and $10,000 in seed money. The mandate given these universities was to design a reliable hybrid-electric SUV/truck platform with a high degree of consumer appeal and acceptability.

“So what is a hybrid-electric vehicle?”

Each hybrid-electric Suburban had to be user friendly. The hybrid-electric non-conventional propulsion systems had to be transparent to the end-user. Once a year for the next 4-years, these universities along with their Suburbans have and will continue to compete against one another in a series of 12-events. So what is a hybrid-electric vehicle? It's defined as a vehicle that has one or more energy or propulsion systems that provides power to the vehicle. The other defining element is that at least one of those systems must be electric.

The two top priorities (as identified by the DOE and GM) that each university team would first need to address were 1) improving fuel economy, and 2) reducing greenhouse gases. Two other events that each university team would compete in that will be of interest to the RV towing enthusiast were the Trailer Towing competition and even the Off-Road competition. The complete list of events also included: Qualifying and Handling (breaking, handling and center of gravity); Consumer Appeal; Safety (where the design modifications in compliance with the Federal Motor Vehicle Safety Standards); Reducing Tail Pipe Emissions; Acceleration; a Written Design Report; and Vehicle Inspection.

At the end of the first round of competitions, West Virginia University (WVU) tied with the University of Maryland for first place (over all). Third and fourth places went to Virginia Tech and the University of California at Davis, respectively. In the towing competition WVU finished second behind Georgia Tech. However WVU came in first in the Reduction of Green House Gases and placed well in the Off-Road and Fuel Economy competitions. Even more amazing than the 115-degree temperatures the teams found themselves competing in at the Desert Proving Grounds near Phoenix, were the ingenious hybrid-electric propulsion systems each university had come up with and the methods and extent that some teams went to in reducing the weight of the Suburban.

For example, one Suburban had been equipped to receive a hydrogen fuel cell (as soon as one becomes available). The hydrogen fuel cell will be capable of keeping the DC battery pack (that powers the DC electric motors) charged and will do so with zero emissions. Another team completely replaced the steel chassis with one fabricated from aluminum. Another design combined a battery pack for city driving and a Saturn engine as the propulsion system to keep the Suburban rolling when operating at steady-state highway speeds.

With the WVU team tying for first place overall, placing first in the Reduction of Greenhouse Gases, placing second in Trailer Towing and doing well in Fuel Economy, Holiday Rambler wanted to see just how close to the "real world" this particular hybrid-electric Suburban was. On a balmy August morning, with a new 27-foot Holiday Rambler Alumascape in tow, WVU set out to execute a weekend of trailer towing and camping in the Appalachian Mountains east of Morgantown, WV. The driving and towing capabilities exhibited by the WVU hybrid-electric were pretty amazing. But before we look in detail at how well these two units performed together, let's find out something about the team that heralds from the venue John Denver sings about in the song "Country Roads, Take Me Home."

To begin with, there is Chris Atkinson, Associate Professor of Mechanical Engineering at WVU. Chris is the University mentor for the hybrid-electric team. Jason Conley, an engineer student working on his master's degree, is the student team captain. The WVU team is comprised of a dozen members, all who are students working on degrees in mechanical and electrical engineering (many on their master's degrees), computer science and related fields. GM also assigns a dedicated mentor to work with each team. We discovered that WVU has a strong history of research and development in alternative fuel vehicles. Their reputation made them an excellent candidate for the Future Truck Program.

The Alumascape travel trailer was also an excellent candidate for doing a real-time RV towing and camping test. The Alumascape has an average dry weight of 5,930 pounds. The hitch weight is 860 pounds. The Alumascape used in this weekend event was a slideout unit that could comfortably sleep eight of the WVU team members. This group of engineering students and their mentor were as impressed with the technology they discovered in the design of the Alumascape as people who are not familiar with hybrid-electric Suburban technology are amazed with that technology.

Towing the Alumascape with the WVU Suburban involved addressing Interstate mountain grades of between 5 to 7%, at towing speeds of 55 mph. The design of the Alumascape is such that the weight of the unit is held to a minimum without compromising the integrity and strength of the structure. The WVU hybrid-electric Suburban (per the design requirements of the Future Truck Program) is required to tow up to 7,000 pounds.

A load-leveling device was used to distribute the weight at the trailer hitch forward through the Suburban and back to the tandem axles of the Alumascape. Keep in mind that this hybrid-electric Suburban has an additional 300-pounds of battery pack tucked underneath and below the rear of the chassis. But even with 300 additional pounds of weight in the rear, the Alumascape's hitch weight was never an issue.

The Alumascape tracked very well, with a level of stability that precluded the need for any kind of sway control device. Leaf springs and gas-modulated shock absorbers contribute to the Alumascape's excellent road manners and behavior. Even when being passed on the Interstate by wave after wave of 18-wheelers, the air turbulence generated had little if any effect on the straightforward movement of the Alumascape. During lane changes the synergy between the Suburban and Alumascape yielded stable, very friendly trailering characteristics. During braking scenarios an adjustable electric brake controller actuated the all-wheel (4-wheels) electric braking system that's standard on the Alumascape.

“The detroit Diesel engine and the Unique Mobility electric motor operate simultaneously.”

So what exactly did WVU do to make their stock 2000 model year Suburban 1500 4WD into a hybrid-electric SUV?

First, they replaced the 5.7-liter V8 with a 4.2-liter Detroit Diesel. This turbocharged diesel is an in-line six-cylinder engine that develops 160 horsepower and 310-ft. lb. of torque.

Next they replaced the 4-speed automatic with a 3500 New Venture 5-speed manual transmission. At the first Future Truck Competition in Arizona last June, WVU lost points in one event because the judges believed that the consumer typically wants the feature of an automatic transmission. However, the New Venture works very well, shifting smoothly and responsively.

Next WVU took a New Venture transfer case, modified the rear housing so that a 75 kW DC Unique Mobility electric motor could be integrated into the drive system. Two sprockets (one on the rotating shaft of the electric motor and one on the drive shaft inside the rear of the transfer case (there is a 2.2 to 1.0 gear reduction ratio) allows the electric motor to be permanently connected to the drive shaft via a chain drive.

Using a computer program, WVU modeled and designed the rear of the transfer case to insure it could accept the loads that would be applied by the electric motor.

Between 3000 rpm and 8000 rpm the 75 kW motor consistently yields 100 horsepower and 177-ft. lb. of torque.

This means that all together the WVU Suburban has a total of 260 horsepower and 487-ft. lb. of torque available. Through the system of sprockets and the chain drive, as long as the driveshaft is turning the electric motor is also turning.

The Detroit Diesel engine and the Unique Mobility electric motor operate simultaneously. The diesel engine is used as the primary source of power for most loads. The electric motor runs in the assist mode and augments the drive train with power when there are power transients (changes in the amount of power needed). This is done to accommodate peak power demands. During braking—or when coasting—the electric motor is instantly transformed (by a vehicle systems computer) into an alternator to recharge the battery pack. At steady state highway speeds, when the diesel engine is propelling the vehicle, the electric motor is directed by the computer to go into its alternator mode and charge the battery pack.

As noted, the battery pack is located below the floor, between the rear axle and the bumper. This pack includes a total of 27, 12VDC sealed lead acid batteries that are housed inside an aluminum case. The batteries are wired in series (one battery is connected to the next, which is connected to the next, and so forth). In this configuration the battery pack is capable of generating 327 volts of Direct Current. The design of the battery case is such that in the event of a collision it can withstand a force of 20Gs. The batteries are strapped down inside the aluminum battery case. WVU has added isolating devices so the battery pack can be completely isolated when needed.

The WVU Suburban uses a unique quad-cad catalytic converter designed and built by Cyrex. The Cyrex performs four very important functions. First it acts as a particulate trap, trapping up to 95% of the diesel particulate thatÕs produced when diesel fuel combusts. The vehicle systems computer determines when raw fuel needs to be injected into the particulate trap to burn off the trapped particles (this is how the trap is cleaned). To see how well it works you can wipe your finger on the inside of the tail pipe and there's no residue or diesel soot to be found. This burn-off process is totally transparent to the driver. The catalytic converter also reduces hydrocarbons and CO by 95%. The Cyrex includes a lean NOX catalyst and also performs the functions of a muffler.

The standard hydraulic power steering unit has been replaced with an electric unit built by Delphi. This unit is powered from the chassis battery. When the front wheels turn the unit senses a pressure drop and the power steering comes on.

A ram-air-inducted inter-cooler by SpearCo has been added to cool the intake air prior to combustion in the diesel engine. By cooling the air the density of the air is increased, thereby improving the combustion. Other modifications include the use of a laptop computer as the vehicle systems control module or computer. In a factory equipped Suburban the engine and the automatic transmission communicate with one another via control modules. Having replaced the engine and transmission, WVU elected to use a laptop computer to fill the function.

So how does all of this come together to power this hybrid-electric Suburban? When you push down on the accelerator, the flow of fuel and air increases to the diesel engine. Power is added by the electric motor as determined by the laptop control module. Three imputes go into the control module; 1) the state of charge in the battery pack charge; 2) the speed of the vehicle and 3) the position of the fuel pedal (throttle).

In city driving (traffic) and based on the battery pack's state-of-charge, the laptop control module directs the engine to provide a certain level of power and the electric motor to provide a certain level of power. The control module tries to get as much power from the Detroit Diesel as possible and when the engine can't supply enough the electric motor augments the vehicle with the power necessary to meet the immediate demand.

If the battery pack is low, the control module directs the diesel engine to ramp up and directs the electric motor to swap over into its alternator mode to regenerate or charge the battery pack. Just as with any Suburban, going into 4WD is done by pushing the "shift on the fly" push-button on the dash.

As evidenced by what is going on in the program called Future Truck, "Necessity truly is the mother of invention." At think tanks all across North America, issues like improving fuel economy, reducing greenhouse gases, etc. are not considered problems. Instead, they are seen as challenges and fun ones at that. "Good job" to all 15 university teams on the creative thinking that's taking place and a really BIG THANKS to the team at WVU.

J. Martin Kohler is a freelance writer based in Northern California, and author of several Holidays features.

To find out more about the COMPETITION, visit the Future Truck Web site at: www.futuretruck.org

To learn more about the WEST VIRGINIA UNIVERSITY TEAM, go to www.futuretruck.org/teams/wvu.html

OR, visit WVU TEAM SITE at: www.cemr.wvu.edu/~hev