TECH

Keep On/Off Trucking

Alternative approach to powering HVAC in diesel rigs

The focus on the noise and emissions effects of idling diesel vehicles continues to grow in many states and communities, drawing even more attention to the economic and environmental issues related to wasteful engine idling. Studies indicate the average US long haul truck engine idles over 1800 hours annually. At an average fuel consumption of 0.9 gph, this figure translates to more than a billion dollars of diesel fuel consumed each year, simply to provide the driver with a comfortable cab during required rest periods. Now, Caterpillar Inc. offers an alternative to idling — the MorElectric System.

Using the same technology that is advancing the development of hybrid automobiles, the MorElectric System involves driving engine accessories electrically, rather than being belt- or gear-driven. The system provides an electrically powered HVAC system that can be removed from the engine compartment. The electric power for this system is delivered by a 7300W high-efficiency generator that replaces the alternator. This base HVAC+generator system has twice the reliability and durability of the conventional automotive-based systems it replaces and provides up to 2% improvement in on-road fuel economy. This improvement arises from the high efficiency of the system’s components and from eliminating operation of the radiator fan for A/C purposes.

With an electric HVAC unit on board, the MorElectric System then can be leveraged to offer 2 cost-effective idling reduction solutions: an APU and plug-in Shore Power. The first couples the base system with a Caterpillar-designed and powered variable-speed APU. With the truck parked and the main engine off, the APU powers the MorElectric HVAC unit, providing the driver with a comfortable cab environment in any ambient condition and with plenty of extra power to run appliances and maintain battery charge. Because the APU shares coolant with the main engine cooling system, typical concerns about starting a diesel engine in cold weather are eliminated. This APU option provides a total fuel economy improvement up to 8% compared to conventional HVAC systems that require the truck’s main engine to remain idling to maintain cab comfort.

Test data results and analysis of truck industry operations predict the impact this technology could have on North American truck fleets. A summary of the February 2005 tests indicate:

• MorElectric APU seasonally averaged fuel consumption is 0.2 gph, which represents a 0.7 gph savings over conventionally engine idling during rest periods.
• This 0.7 gph fuel savings can save 630 to 1260 gal/year/truck.
• At $2/gal, and over 5 years, the MorElectric APU can reduce fuel costs by $6300 to $12,600 per truck, while reducing US dependence on foreign oil.

The other solution couples the base MorElectric System with a feature known as “Shore Power,” which allows a truck to be plugged into a pedestal to operate accessories, similar to An RV plugging in at a campground. Already, New York, California and a few other states are installing these pedestals in some rest areas and truck stops as part of a nationwide initiative known as Truck Stop Electrification, providing a low cost and very low emissions idling solution. However, the system can be used only by vehicles equipped with an electric HVAC system. This idling reduction option can provide total fuel economy reduction up to 10% when compared to conventional truck HVAC systems.

Recently, at one of the trucking industry’s largest conferences, the Technology and Maintenance Council, the US Department of Energy’s Advanced Vehicle Testing Activity and Caterpillar reviewed early results from tests completed on 5 Cox Transfer trucks under a DOE Idling Reduction Demonstration Program, as overseen by DOE’s National Renewable Energy Laboratory and managed by DOE’s National Energy Technology Laboratory. Ongoing testing of Caterpillar’s MorElectric Technology will continue through 2005 on fleets from Cox Transfer, Schneider National, Werner Enterprises and others, as part of DOE’s Office of FreedomCAR and Vehicle Technology and NY state sponsored technology demonstration programs.

“Caterpillar believes that the MorElectric technology offers the trucking industry viable idle management solutions with important benefits to the customer and to the environment,” says David Orr, Cat Electronics MorElectric commercial manager. “The MorElectric system is an intelligent and integrated idle management solution that helps fleet owners save money, improve engine and accessory reliability and durability, and improve cab comfort in any ambient condition.

—SG/RM

Caterpillar Inc,
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