Pull into a rest area late at night and you'll hear them–dozens of diesels parked-up, as their drivers sleep. Collectively, long haul truck idling in the United States burns more than 800 million gallons of fuel a year, according to the Argonne National Laboratory (ANL) Center for Transportation Research. Idling buses, locomotives, and ships add to the total, but trucks are, by far, the biggest culprits.
The major reasons for idling include heating and cooling of sleeper cabs and generating electricity for onboard appliances like refrigerators and microwaves. In the severe cold, truckers idle to avoid cold starts and to keep their fuel from turning to slush.
Technology exists that could meet these same needs with greater efficiency. From diesel-fired cab heaters to phase change storage systems, a number of methods are available to truckers to help them slash fuel use and emissions or comply with the laws of some states that restrict idling. Still, economics alone drive most truckers to idling.
Unfortunately a compromise has yet to be made that will satisfy the majority of independently minded truckers. The government is seeding interest by funding several programs. Illinois-based ANL, a part of the DOE, is assisting three federal agencies to write a national idling reduction plan. This would help itinerant truckers comply with regulations as they travel among states. Idling regulations at the local level do little to dispel emissions or conserve fuel on a large scale as drivers simply park one town over, where idling isn't ticketed.
Some truckers have the option of stopping at rest areas equipped with IdleAire stations.
Regulation is already playing a role in the development of cleaner diesels. The EPA began phasing in cleaner trucks starting 2007. One of their directives led to the introduction of low-sulfur diesel fuel the same year, which enabled the adoption of catalytic exhaust systems.
Everyone concerned is watching the California Air Resources Board (CARB), who have developed idling regulations that may limit heavy-duty diesel truck idling and also specify idling emission limits on new trucks. In an interesting twist, diesel auxiliary power units (APUs), if pressed into generating power to meet this regulation, it could end up producing more particulates than their big diesel brothers, since the small units are essentially unregulated.
The CARB regulation may exempt new trucks that meet the stricter standards, although it’s not known how many particulates the low sulfur diesels will generate while at idle. Most emissions data has been collected over whole duty cycles, where only a small portion of the time is spent idling. Yet, unlike many pollution prevention programs, where installing equipment often spells lower efficiencies, idling reduction stands a good chance of lowering both fuel usage and emissions.
Idling reduction equipment falls into two categories: on-board systems and stationary, "shore-side" systems. Two of the many companies working on the stationary side are Shurepower and IdleAire. Shurepower builds 120- and 220-volt pedestals that provide truckers with truck-stop electrical connections, to plug in anything from a simple extension cord to power an auxiliary heater or an entertainment system. Eighteen such units are operating at a rest area in Wilton, N.Y., under the sponsorship of several state and federal agencies.
IdleAire Technologies Corp. of Knoxville, Tenn., on the other hand approaches the problem differently. The company's service module pipes warmed or chilled air into a cab, while furnishing an Internet connection and a couple of outlets at the same time. The company has entered an agreement with Travel Centers of America to install IdleAire systems at its many truck stops.
With either system, a trucker pays an hourly rate for the services. Onboard idle-reduction systems range from simple start-stop arrangements to full-out auxiliary diesel generators. Air heaters from makers such as Espar Heating Systems, burn diesel fuel and draw about 1 amp from the battery while operating. The heaters, already popular in Europe, typically monitor battery voltage and will shut off before draining the battery below the charge needed to crank an engine.
Onboard idle-reduction technologies should also play a part in the usage and control of emissions. There are many companies who market these types of systems, ranging from simple start-stop arrangements to full-out auxiliary diesel generators. They require greater financial commitments than stationary systems on the part of the truckers or the employers who buy them, but the benefit is they work anywhere.
Long after manufacturers have started building cleaner trucks and taken advantage of the low-sulfur diesel fuel, older trucks will be on the roads. Manufacturers, even if they don't wind up supplying APUs themselves, will need to wire trucks to accept electrical appliances connected to an APU or a truck-stop pedestal.
Caterpillar is finding its way past these weight and space limitations with its MorElectric system, which relieves the main engine from driving an air conditioning compressor and instead divides that responsibility between an engine-driven generator and an APU. The company also repackages the air conditioning system into a single unit built with connections for high-mile service.
However, several drivers and fleet managers have brought to light their concerns about idling reduction. With trucks pulling in and out all night, rest areas aren't necessarily the most restful places. For some truckers, that spells the difference between a good night's sleep and a bad one.
Many drivers are worried about the financing of idling-reduction technologies, or the federal excise tax that applies to them, or the weight penalties for carrying them. There's also concern over added maintenance and how the maintenance interval for auxiliary equipment matches up with that of the prime engine. In the end, this thinking may be the biggest impediment to reduced idling.
[Adapted from “Idle Hour,” by Paul Sharke, Associate Editor, Mechanical Engineering, January 2005.]
Unfortunately a compromise has yet to be made that will satisfy the majority of independently minded truckers.
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