Mr. Green Car: Hybrid trucking

By Allen Penticoff
Free-lance Writer

The best part of writing the Mr. Green Car column is all the new things I learn. Starting from some kernel of an idea or new awareness, I do research, find out new and interesting things, and report to you what I discovered. Thanks to a comment by friend Dave Lantz, I looked into hybrid commercial trucks. What I found surprised me.

It turns out the trucking industry is moving swiftly into alternative fuels and fuel-saving technologies. After all, a big truck gobbles down a lot more fuel than a passenger auto, and with a fleet of guzzlers, that can add up to considerable savings if these technologies are pursued. Additionally, many cities are seeking to clear their air and help reduce their environmental impact.

New York City Parks Department is leading the way. Sixty-four percent of their vehicles operate on alternative fuels. They have some all-electric vehicles and solar-powered vehicles, but many are compressed natural gas and/or hybrid powered. Their goal is to have 72 percent of their fleet alternatively fueled by 2010 as part of the city’s goal to reduce carbon dioxide emissions 30 percent by 2017.

Medium-duty trucks—delivery trucks, refuse haulers, dump trucks and others that have to stop and start throughout much of their day—are prime targets for hybrid technology, and the truck manufacturers are gearing up for a great increase in demand for these vehicles. Combining hybrid technology with compressed natural gas (CNG) as a fuel makes for great economy (cheaper fuel) and cleaner air, as natural gas has far fewer pollutants than does diesel fuel. The New York City Parks Department recently acquired 17 Kenworth T370 diesel electric hybrid trucks. These dump/rack trucks are powered by Paccar PX-6 240-horsepower engines with 660-foot pounds of torque that works with an Eaton 60-horsepower electric motor in a parallel hybrid drive system—not unlike a Prius. Like most hybrid systems, it uses regenerative braking to charge its 340-volt lithium-ion batteries. With this system, the truck starts moving under electric power, before the engine kicks in. The electric motor also helps with additional torque when needed, making up for the torque loss due to using CNG rather than diesel fuel.

Pepsi/Tropicana has begun using Peterbuilt trucks using the same system and is expecting a 35 percent increase in fuel efficiency over their non-hybrid new trucks—which are, in turn, 35 percent more efficient than their old fleet of vehicles. They expect the new hybrid/diesel trucks to have fuel economy of 10 miles per gallon (mpg)—a considerable improvement over 4-5 mpg. United Parcel Service is on track to purchase and put into operation 200 new hybrid delivery trucks in eight cities—with 50 already working in Austin, Texas, and 13 in Minneapolis.

I also learned that New York City’s Department of Sanitation has acquired their first CNG-hybrid refuse truck. No truck starts and stops more than a waste hauler, a perfect application for this technology. However, this new Crane Carrier Company truck is equipped with the Bosch Rexroth Hydrostatic Regenerative Braking (HRB) parallel hydraulic hybrid system. In this system, no electricity is involved. I’ll just quote here as I can’t say it any better: “The Rexroth HRB system uses a hydraulic pump/motor connected to the driveline to capture kinetic energy during vehicle braking. When braking, the pump/motor acts as a pump, absorbing energy from the driveline and imparting a retarding force on the drive wheels, pumping hydraulic fluid into a nitrogen-pressurized accumulator. During acceleration, the pressurized gas pushes fluid out of the accumulator, and the pump/motor then acts as a hydraulic motor, adding power to the engine while reducing the fuel required to launch the vehicle.” Neat, huh? This vehicle was featured at the Alternative Fuels & Vehicles National Conference and Expo in Las Vegas this past May.

So, I’ve uncovered the tip of the iceberg. The trucking industry is not the ogre that we think it is. They have concerns for the environment and saving fuel as much as, or more than, we do. They are frequent targets as polluters and befoulers of the air—so we are beginning to see more clean buses and trucks on our streets, and if the cities could afford them, I’m sure there would be more. As we’ve been preaching, going “green” and resolving our environmental problems will create business opportunities and jobs. This is not lost on big business—they see it as the next wave of commerce: get rid of your old, inefficient stuff, and replace it with modern, high-efficiency equipment. I’m sure there will be more green trucking stories to appear in Mr. Green Car in the future as we look into all electric and plug-in hybrid trucks as they appear on the market.

From the June 16-22, 2010 issue