es•sen•tial pow er:
energy consumption not involved in moving a truck
by Paul Abelson, technical editor
The U.S. Department of Energy (DOE) is tasked with making energy use more efficient generally, and more specifically, reducing our dependence on foreign energy sources — meaning oil. They work with private industry on cooperative research, matching funds on projects that will help achieve these goals.
DOE projects that of more than 3 million commercial vehicles, 400,000 are involved in long-haul operations, and another 400,000 in short- and medium-duty vocations, in which engines idle for significant periods. By reducing idling an average of four hours a day, we can cut fuel use by more than 1.17 billion gallons and reduce the cost of engine wear by $1 billion or more annually.
Real world input
To determine the best ways to achieve these reductions, DOE assembled engineers and research scientists from all the major truck builders, engine and accessory (generator sets and auxiliary heaters) manufacturers, research laboratories and others with an interest, in Washington, DC, for a workshop Dec. 12 and 13.
OOIDA member Mike Swiger, well known for his participation in the Technology and Maintenance Council (TMC) and Society of Automotive Engineers (SAE), addressed the workshop from his truck by cellular phone. He reminded attendees that in the real world, idling doesn’t just take place at truckstops. He also noted that adding auxiliary power units and other devices costs the owner-operator the 12 percent excise tax, tax on fuel used by the device, and a weight penalty that may reduce revenues.
Marty Fletcher, director of technology and training for U.S. Xpress Enterprises, seconded his remarks. Fletcher stated idling accounts for between 4 and 6 percent of his company’s total fuel bill.
Fleet and operator concerns that must be addressed before any system can be successful are: initial cost, maintenance, cost of operation, reliability and durability, excise and sales taxes, road tax on fuel and weight.
Participants expect the demand for advanced essential power systems to grow, primarily due to external influences. Anti-idling regulations will become common in more jurisdictions, and they will be increasingly enforced for environmental (and — my observation — for revenue enhancement) reasons. Fuel prices eventually will increase as we work out of the recession. Engines designed to meet tighter emissions standards will not tolerate prolonged idling. Engine warranties will be tied to hours of operation, not miles traveled.
Just as with electronic devices, costs of essential power system components will decrease as usage (and therefore manufacturing volume) increases. First, operations must prove the benefits (profits) of using these devices. Acceptance will follow only after credible fleets and respected owner-operators measure results in their operations. This industry has had too many suppliers claim to save unbelievable quantities of fuel with devices of, at best, questionable merit.
There is another reason why the government is taking a systematic approach to fuel savings, idle reduction and improved efficiency. DOE wants to see us, as a nation, reduce dependency on foreign oil, but they know this industry needs proof, not just claims. One major purpose of the workshop is to develop ways to prove savings in ways acceptable to suppliers and users alike. DOE is going beyond R&D (research and development). They speak of R&D3, or R&D + D2, meaning research and development, plus demonstration and deployment. That takes R&D all the way to your trucks. And that will require input from suppliers, manufacturers and users.
Strategies discussed at the workshop included short-, medium- and long-term solutions and improvements. Short-term solutions include generator sets, auxiliary fuel-fired heaters and ventilation fans, all of which are available now. Shore power, bringing 120-volt current to the truck, is already developed. Trucks are available today wired to accept household current for “hotel loads,” the demand for electricity to run refrigerators, televisions, microwaves and all the other amenities that turn trucks into comfortable living units. The problem is that very few truckstops are wired to provide 120-volt electricity. If truckstop electrification is to be an effective solution, expensive construction will be needed. Other challenges include the need to provide power at locations other than truckstops, and social challenges, such as those faced by PNV, ranging from damage due to careless driving to shorts and corrosion caused by human wastes.
One company, IdleAire, proposes to provide stopping areas with devices that supply electric current, heat, air conditioning and cable TV. A press event was held last year at the Hunts Point Market in New York, and a test unit is being set up in a New York Thruway rest area. Reports are that the Hunts Point unit was not operational, and heat and cold air output at the Thruway location was marginal at best. Also, due to the towers required to support these overhead devices, the number of parking spaces is reduced. Trucks may be wired, but until capital requirements and additional sources of electric power are available, truckstop and enroute electrification will not be practical.
Fuel cells are anywhere from five to 10 years from development. As they are commercialized, they may affect or eliminate the need for truckstop electrification. (See “What are fuel cells and why should I care?” on page 78.)
I’ve heard drivers say they don’t idle because they have inverters. They run their accessories on 120-volt current. The problem is inverters draw electricity from the truck’s batteries, and the lead-acid batteries we use today must be recharged. Batteries’ ability to supply current is measured as reserve capacity, the number of minutes a battery or system can deliver 25-amps and still be able to start the vehicle. With a 100-watt TV and a 75-watt VCR, an 8-amp refrigerator, a 4-amp satellite unit, a 5-amp CB and two dozen 1-amp clearance/marker lamps, you could have a 56-amp drain. If your batteries have a 250-minute reserve capacity (4.2 hours at 25 amps), you could run your batteries down in under two hours, especially in cold weather when more power is needed for starting, and the batteries’ capacity is reduced by the cold.
Some trucks already have high-output (900 CCA or more) batteries for starting, with isolated deep-cycle batteries to power hotel loads with the engine off. Work is progressing on new truck batteries with higher energy density. Nickel-cadmium, nickel-metal hydrate and lithium-ion models are already proven in small devices (cell phones, laptop computers, etc.) but need to be scaled up dramatically.
Eliminating idling isn’t the only strategy the workshop looked at to save energy. Dramatic savings, perhaps 9 percent or more, can be realized through the reduction of parasitic energy losses under the hood. That 9 percent will be realized while running down the road. Another strategy under examination is the reclamation and use of waste energy. Both of these strategies may be practical within four to five years.
The “More Electric Truck”
Energy is lost when water pumps, fans, power steering pumps and alternators are driven by belts from the engine, and when compressors and oil pumps are gear-driven. These devices can all be driven electrically, eliminating energy consumed by flexing belts and turning pulleys. Electric drives also free these components from their location at the plane in front of the engine, giving engineers the option to locate them in more efficient locations. Aerodynamicists can then design narrower, more efficient front ends and hoods.
With remote, in-line pumps, water lines can be coupled direct between the engine and radiator. A side benefit is repairs can be made by simply disconnecting a hose, rather than having to dismount the water pump. Instead of having a belt drive the air conditioner, compressor and hydraulic power steering pump, each can be driven directly. The air conditioner can then be operated independently of the engine.
Twelve volts will not be adequate to drive all the electrically powered accessories in this “More Electric Truck” (MET), nor will conventional alternators. New engines will have flywheels that serve as motors and generators. There will be magnets in the flywheels and windings in the housings. They will operate at 42 volts (36-volt nominal, 42-volt charging, just as today’s 12-volt systems charge 14 volts) or more. The MET, with improved storage batteries, will use the starter motor-generator as an auxiliary retarder, capturing some of the truck’s inertia and converting it to electricity to be stored and used later. One possible use could be for auxiliary power to help climb hills or accelerate to highway speeds.
DOE hopes to demonstrate a “More Electric Truck” by mid-2004.
Reclamation of otherwise wasted energy can be augmented with turbo-compounding (used originally in World War II aircraft) and turbo-alternators. “Turbo” refers to using a turbine to capture energy in the exhaust. We use turbo-chargers to drive blowers that increase the volume of combustion air in our engines. Turbo-compounding takes exhaust heat but uses it to help turn the driveshaft through gears. Turbo-alternators, as the name implies, convert waste exhaust heat to electricity by driving an alternator rather than a blower or shaft.
Another means of creating electricity is thermo-electric generation. When current passes through two attached but dissimilar metals, one heats and the other cools. This Peltier Effect, first demonstrated in 1834 by French physicist Jean Peltier, is how most portable 12-volt coolers work. The principle works in reverse, too. When one of the metals is heated, electric current can be created, and a circuit can be designed to capture the current. Devices can be mounted on manifolds, exhaust pipes and even the engine block. They can power instruments and electronic sensors. Devices today produce up to 20 watts at 3.3 volts with up to 40 percent efficiency. Prototype units will produce as much as a kilowatt (1,000 watts) for use by emissions control devices and to help power the MET.
In order to speed development, so more energy (oil) can be saved sooner, DOE is encouraging parallel development, with different industry groups working on different projects simultaneously rather than consecutively. While much of this may seem like science fiction, it is not that far in the future. Some of the technologies are being demonstrated today as part of the 21st Century Truck Initiative spearheaded by the U.S. Army.
In closing the workshop, Sid Diamond, workshop project manager for DOE, urged the participants to “rise above company interests to address the national issues. They affect the health, welfare and wealth of our nation.” He called fuel use “our national substance abuse.”
You can do your part now. Investigate the economics and payback of either a generator set or, if the initial cost is too great, a fuel-fired heater system. Install a ventilator to help when it’s not too hot. Set a personal goal of reducing your idling as much as possible. You’ll be helping your bottom line, and your country.