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Onboard Idle Reduction Equipment for Heavy-Duty Trucks

Onboard equipment options can easily be integrated onto heavy-duty trucks and can help reduce idle time at truck stops, on roadsides, and during the time trucks spend at ports, terminals, and delivery sites. Learn about the following onboard equipment:

Auxiliary Power Units

Auxiliary power units (APUs) are portable, truck-mounted systems that can provide climate control and power for trucks without idling. These systems generally consist of a small internal combustion engine (usually diesel) equipped with a generator and heat-recovery system to provide electricity and heat. For air conditioning, an electrically powered air-conditioner unit is normally installed in the sleeper, although some systems use the truck's air-conditioning system.

The simplest APU is a direct-fired heater. Developed in the 1950s, these systems can be used to heat both the sleeper cabin and the engine as necessary. Direct-fired heaters cannot provide air conditioning or power for other applications such as a televisions and microwave ovens.

More sophisticated APUs consist of a generator powered by a diesel engine, a compressor, an alternator, and an inverter/charger. These units are fully integrated into the truck's heating, ventilation, and air-conditioning system. In addition, the inverter/charger allows the system to provide electric power to the cab and sleeping compartment.

In the future, we may be able to use a gasoline- or diesel-powered solid oxide fuel cell as a power source for an APU.

Auxiliary power units can help truck drivers comply with local idling ordinances, reduce emissions and noise, and save on the cost of truck fuel and maintenance. Because most APUs are integrated directly into the truck's systems, they offer a high level of convenience. In addition, APUs are a proven technology that is widely available and is even sold as an option on some new trucks.

Auxiliary power units available today range in cost from $1,500 for direct-fired heaters (providing heat only) to $7,000 for APUs with combined cab heat/air conditioning, electric power, and heat to engine and fuel. The APUs can add 300 pounds or more onto the weight of the truck, which has a negligible effect on fuel economy but could reduce the load that weight-limited trucks can carry.

For a list of manufacturers that sell APUs, visit the Available Idle Reduction Equipment page.

Automatic Engine Stop-Start Controls

These controls can sense sleeper temperature and automatically turn the engine on when the sleeper is too warm or cold. Fuel savings using this technology are minimal in extreme temperatures. In addition, this technology adds to engine wear and may disturb the truck driver's sleep. Typical prices for a long-haul truck factory option or retrofit start at $1,200.

Cylinder Deactivation

Cylinder deactivation limits combustion to part of the engine and enables a small reduction of fuel use and emissions. This equipment is not yet commercially available.

Cab and Block Heaters

Fuel-fired heaters provide heat to the cab and the engine block. They use only a fraction of the fuel that would be used by idling the vehicle's primary engine and can be paired with cooling technologies for a complete heating and cooling package.

Air Conditioners

Special air conditioners to cool just the sleeper cab are now available for truck drivers. Some systems use evaporative cooling, and researchers are working on other systems using thermal storage. Options are also available that cool the bed alone.

An alternative to onboard idle reduction equipment is Truck Stop Electrification.