Truckstop Idle-ology
Caterpillar trots out its electrically driven solution for idling 18-wheelers.
Steve Mitchell
Copy Editor
The chaotic cacophony of a Class 8 engine idling overnight at a truckstop is like fingernails on a blackboard to David Orr, commercial manager of MorElectric Technology at Cat Electronics.
"Listen to that," he said, nodding toward an empty Freightliner tractor idling 50 feet away in the huge lot behind the Sacramento '49er Travel Plaza in California.
"Can you imagine trucks like that on either side of you at 2 in the morning?"
Besides the racket, there's the cost of fuel to run the A/C, heater, television and other electrical appliances that over-the-road drivers use each night. The U.S. Environmental Protection Agency says 11% of the fuel used in Class 8 trucks is burned up during idling - roughly 1,800 gallons per truck per year.
That's why Caterpillar is developing electrically driven accessories that - literally with the flip of a toggle switch - will enable drivers to rest quietly and comfortably in their cabs while saving their fleets thousands of dollars in diesel fuel each year. The company figures its new idle management system for on-highway trucks can improve fuel economy by up to 8%.
Added bonuses, according to Orr, include improved engine accessories reliability and durability, appeasing truckstop neighbors and less wear and tear on the environment.
CAT'S MORELECTRIC TECHNOLOGY
Called Cat MorElectric, the technology electrically drives various engine accessories to improve fuel economy (with on-road fuel savings of up to 2%, according to Caterpillar) and be the enabler to reduce the long-standing habit of idling.
First off, the 7.3 kW Caterpillar Mor-Electric generator replaces the standard alternator altogether, providing three times the electrical power capacity and twice the fuel efficiency.
Today's 12- or 24-volt alternator is near the top of the list of unreliable components in heavy-duty applications, Orr said. Replacing it with the new fully enclosed water-cooled generator ends the headache of sand and debris gumming up the works and damage prompted by roasting under-the hood temperatures.
The next part of the MorElectric equation is the HVAC (heating, ventilating and air conditioning) module.
Anticipated to be installed under the tractor passenger seat, the HVAC will bring together all the heating and A/C components into one easy to service module. The hermetically sealed system features a compressor, condenser, evaporator, fan assemblies and other A/C components.
That frees up a lot of space in the engine compartment. Gone, for instance, is the A/C compressor, along with compressor belts and pulleys. And there's no longer the need for a condenser in front of the radiator.
"Think of (the HVAC module) like a window air conditioner," Orr said. "The HVAC can be removed from the tractor as easily as the old window A/C, swapped out in less than an hour. Or it can be unplugged and sent in for routine maintenance."
No need for refrigeration-trained technicians or refrigeration service equipment. "The entire unit can be unplugged and a new one can be put in the trunk of a taxi and driven out to the driver," the Cat engineer said.
And by combining all the HVAC elements into one solid package, the problem of leaking refrigerant through the hoses is eliminated because these are replaced by rigid tubing.
IDLE MANAGEMENT SOLUTIONS
With the MorElectric system and the electric HVAC system onboard, Caterpillar can now look toward alternatives to idling the main engine.
That's where Caterpillar's new auxiliary power unit (APU) comes in, providing electric power to both the truck's electrical system and HVAC. This 0.5-liter, two-cylinder engine was designed to complement the MorElectric system, allowing the driver to turn off the main engine when stopped for the night and use the much more fuel-efficient APU (or genset).
The APU consumes only 0.2 gallons of fuel per hour, compared with the nearly one gallon per hour sucked up by an idling truck engine.
The 407-pound APU was designed by Caterpillar with two speeds in order to deliver the required amount of power when needed. Unlike fixed-speed generator sets, the Cat Electronics APU will run at 1,800 rpms the majority of the time, like when the driver is sleeping, and at 2,800 rpms during temperature extremes, to automatically provide all the creature comforts in the cab. That means all the heating, cooling and electric power - including battery charging - without idling the main engine.
SHOREPOWER OPTION
The fourth part of Caterpillar's fuel-saving technology is the MorElectric Shore Power Package, which provides electric power much like an RV at a campground. The demonstration at the truckstop in California was an opportunity for Caterpillar and the Sacramento Municipal Utility District (SMUD) to show off the fuel savings and emissions reduction opportunities available by using shorepower.
Trucks with the MorElectric system can be equipped with an optional shorepower package, which includes all the hardware needed to power the truck's "hotel loads." It's all part of a program called Truck Stop Electrification (TSE), where state and federal government agencies are working to install shorepower plug-in parking spaces along interstate corridors.
And while the benefits to the environment, noise abatement issues and dependence on foreign oil can't be dismissed as side issues, it's the savings to fleets that attracts the most attention.
The MorElectric system can mean a fuel savings of 2% on the road, and another 6% from reduced idling, according to Caterpillar. That's a total tank savings of up to 8% for a typical long-haul Class 8 truck.
Here's how Cat did its figuring: The improved fuel economy brought about by the revolutionary electrically driven accessories is up to 2% on road. For a truck that travels 125,000 miles a year at 6.5 mpg, that's a savings of 385 gallons a year.
By connecting to a shorepower terminal for the 1,838 hours the Department of Energy says the average truck idles per year, and where shorepower is used 75% of the time, you can save up to 1,240 more gallons. That makes for a total of 1,625 gallons of fuel not used. And at recent California diesel prices of $2.50 per gallon, the savings is $4,063 per truck, per year, according to William R. Warf, project manager for energy efficiency and customer research and development for SMUD.
Take away $247 for the cost of the electrical power purchased at the terminal, and you still have a net savings of $3,816 per year.
Orr said the MorElectric System has a commercially viable payback period that keeps improving as fuel prices go up.
He said the MorElectric system is still undergoing field tests, with several trucks operating regular routes with the system installed. The system is targeted for commercial introduction in the second quarter of 2006.
Meanwhile, Caterpillar is pursuing for other original equipment manufacturers and fleets for additional applications and field tests. Orr emphasized that the MorElectric system is not an add-on or an aftermarket product.
He said the system will be sold and serviced through a variety of truck OEMs and sold independent of Cat engines.
