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Anti-idling Technologies

Savings from idle-reduction technologies and practices result from both reduced fuel consumption and reduced engine wear.

Important obstacles stand against the adoption of innovative technologies, of which one of the most important is the lack of practical information coming from independent sources. The objective of these fact sheets is to inform those in the trucking industry about new and emerging advanced technologies that have been tested through the Energotest program (run by FPInnovations), which can help increase fuel efficiency and, at the same time, reduce the environmental impact of freight transportation in Canada.

Description

Idling a truck’s engine is a practice that many drivers engage in. The American Trucking Association (ATA) reports that engine idling times reach six hours per day, and a Caterpillar study indicates that a Class 8 truck idles as much as 1800 hours per year. The ATA study also shows that one hour of idling per day causes twice as much wear in a year than driving an extra 115,000 km over the engine’s life. FPInnovations testing found the fuel consumption of an idling diesel truck engine to be 3-4 L/h.

The reasons invoked to defend engine idling are many, but the most common reasons are: to bring the engine to normal operating temperatures, to keep it warm for an easy restart in cold weather, and to maintain comfortable cab temperatures. FPInnovations conducted a study in winter 2010, which confirmed that there is no need to idle an engine for extended periods after a cold start to warm it up. It is more efficient to idle the engine for a short period and then drive the vehicle or work the machinery at moderate loads until the engine warms up to normal operating temperatures. The tests also confirmed that the engine retains enough heat for easy starting even after being shut down for a few hours and there is no need to idle an engine for fear of having cold start problems. The tests were conducted at ambient temperatures ranging from -5°C to -2°C. However, estimations indicate that this conclusion holds at lower temperatures.

Savings from idle-reduction technologies and practices result from both reduced fuel consumption and reduced engine wear. The following is a brief summary of some of the anti-idling products available.

Auxiliary Power Units (APU)

An APU is essentially a small AC generator powered by a diesel or gasoline engine. The electric power can be used to power auxiliary systems such as air conditioners, heaters, lighting, and entertainment devices. Fuel consumption tests done by FPInnovations at Energotest^TM of two APUs found their fuel consumption to be 0.8 to 1.0 L/h.

Battery-Powered Air Conditioners

These devices have their own dedicated batteries and charging system. Due to the limited battery capacity, they are better suited to keeping a cab cool as opposed to cooling a warm cab. They must be properly sized for the application. Air conditioners powered by an APU do not have this limitation.

Cab Heaters

Cab heaters are powered by diesel fuel. They use a circulation fan to heat the cab and sleeper, and units are available that will heat the engine coolant through a heat exchanger as well. The coolant is circulated by a 12V DC pump. Fuel consumption for these devices can be as low as 0.2 L/h.

Engine Block Heaters

Electric-powered engine block heaters can be powered by 110V or 220V AC. The devices incorporate a heater element that installs into the engine’s coolant jacket and can be combined with thermostats that activate the device once the coolant temperature drops below a predetermined level. In addition to coolant heaters, heaters are available that will warm engine oil and heating elements to warm intake air.

Diesel-fuelled engine block heaters are powered by diesel fuel, and maintain adequate coolant temperatures for easy engine starting at cold temperatures. They are often used in conjunction with cab heaters to maintain coolant at desired temperatures for easy engine starting at cold temperatures. They use a 12V DC pump to circulate the warm coolant to the engine block. These devices can be combined with timers and thermostats to pre-warm the engine at a predetermined time, or to activate once temperatures drop below a predetermined level.

Coolant Energy Recovery Device

Often an engine is left running to maintain cab temperatures at comfortable levels. In applications where these incidents are limited to 1 to 2 hours, a coolant energy recovery device can be used. After the engine is shut down, the truck’s heater will work until the coolant in the heater core reaches ambient temperatures. The engine still retains a significant amount of heat, but since the coolant is not being circulated by the water pump, the heater only works for a short period. A coolant energy recovery device uses a small 12V DC pump to circulate warm engine coolant to the heater core to heat the cab. These devices can maintain cab temperatures at comfortable levels even after the engine has been shut down for up to 2 hours at ambient temperatures as low as -5°C. This was confirmed by the tests conducted by FPInnovations.

Scope of Application

There are models of anti-idling devices for all classes of vehicles. Each device has specific application, so careful consideration must be made with respect to the operating conditions the vehicle works in to ensure the right product is purchased for the application.

Return on Investment

The economic impact of the various anti-idling devices is based on the payback period, which is calculated by dividing the total additional cost of the device by the net savings it provides. Even though significant engine wear occurs when idling, the return on investment analysis presented will be limited to the savings that result from reduced fuel use. The amount of unnecessary idle hours varies by operation and the climates that the truck works in. The following payback scenario example is for an APU installed on a tractor-trailer combination that works on long-distance hauls.

Payback calculation example for an APU:

• The tractor works 200 days per year with 6 hours of unnecessary idle per day.
• Purchase cost is estimated at $8 500 per unit.
• Fuel consumption is 3.5 L/h and 1.0 L/h for the truck engine and the APU, respectively. The annual reduction in fuel use would be 3 000 L:
  200 days × 6 h × (3.5 L − 1 L) = 3000 L
• At a diesel fuel price of $1.10/L, the annual savings would be: 3 000 L × $1.10/L = $3,300.
• The payback period would be: $8 500 / $3 300 = 2.57 years or 31 months. FPInnovations Program Innovation Transport (PIT) partners estimated that APU repair and maintenance costs are roughly $1 000 per year. These costs are not included in the payback calculation, but should be considered as should the reduced engine wear.

Since the duty cycle for a pick-up and delivery vehicle is different from what is presented above, here is an example of a payback scenario for this type of application using a coolant energy recovery device.

Payback calculation example for a coolant energy recovery device:

• The vehicle works 220 days per year with 2 hours of unnecessary idle per day.
• The coolant energy recovery device costs $800.
• Truck idle fuel consumption is 3.5 L/h. The reduction in fuel use calculation is 1 540 L:
  220 days × 2 h × 3.5 L = 1540 L
• The annual savings would be: 1 540 L × $1.10/L = $1 694.
• The payback period would be: $800 / $1 694 = 0.5 years or 6 months. The repair and maintenance costs for this device are estimated at $100 per year.

Specification Considerations

When purchasing anti-idle technologies, the climates that the truck will be working in, the availability of electric power, and the amount of unnecessary idle should be considered in the purchasing decision. An APU is best suited for long highway hauls where the truck is away for extended periods and operating in areas requiring both frequent air conditioning and heating. They are most appropriate when there is a need for high electrical power or for vocational transport (e.g., cold storage). The APU can be ordered as an option on a new truck purchase, or retrofitted to an older truck.

In areas where air conditioning is infrequent and only cab or engine heating is required, a cab heater or an engine heater are often more appropriate.

A coolant energy recovery system is best suited for local pick-up and delivery where idle periods are limited to 2 hours.

The weight of the device is also a consideration, since payload capacity may be reduced, especially in the case of APUs.

The size of the cab should be considered to ensure the device has sufficient capacity to adequately heat or cool the cab in the climates that the vehicle will be working in.

Where electric power is available, electric-powered devices tend to cost less to operate, but these devices are used for maintaining engines at suitable temperatures for easy starting. In cold temperatures where trucks are parked outside, the use of block and oil heaters are recommended for easy starting.

Regulatory Issues

Many jurisdictions within Canada and the United States have regulations that limit the time an engine can idle. These limits range from 3 to 10 minutes.

Diesel-fuelled devices are available that meet California Air Resources Board (CARB) ULEV II standards, which are accepted in all jurisdictions.

Some of the devices discussed will increase vehicle tare weight. Some provinces, such as B.C., will increase the maximum GVW if the truck is equipped with an APU, to encourage their use. Regulations should be reviewed to determine if the jurisdictions that the truck will operate in provide additional weight allowances for APUs. The batteries for battery-powered air conditioners will also increase tare weight.

Maintenance Considerations

The maintenance requirements for each of the different product types vary. Maintenance programs should be developed such that the manufacturers’ recommendations are included. The following are some considerations that should be incorporated into a maintenance program for the different products.

Auxiliary Power Units

Maintenance for the diesel engine which includes changing oil, fuel, air filters, and oil filters.

Air Conditioners

Maintenance for these battery-powered devices includes inspecting and cleaning all the electrical connections and ensuring there is no damage to the batteries and wires. Cleaning debris from the condenser coil is also required.

Fuel-Powered Cab and Block Heaters

Ensuring the exhaust is free of debris and maintaining the fuel system, which includes inspection of hoses and fuel filter changes. For block heaters, ensuring engine coolant is at an adequate level.

Electric Block Heaters

Ensuring the wiring and all connections are tight and secure. Since these devices heat engine coolant, the engine coolant must be at an adequate level for the devices to work.

References

Autotherm corporate Web site. http://www.autothermusa.com/wordpress/ (accessed November 2010).

Gaines, L.; Vyas, A.; Anderson, J. 2006. Estimation of fuel use by idling commercial trucks. Paper No. 06-2567. 85th Annual Meeting of the Transportation Research Board, January 22-26, 2006, Washington, DC.

NALGEP. 2005. Clean communities on the move. National Association of Local Government Environmental Professionals, Washington, DC.

Phillips and Temro Industries. 2009. Application guide and product catalogue ’09. Phillips & Temro Industries, Eden Prairie, MN. http://www.phillipsandtemro.com/UserFiles/File/
2009_Zerostart_Application_Guide_and_Product_catalog.pdf (accessed November 2010).

Surcel, M.-D. 2009. Fuel consumption track tests of fuel-saving technologies for tractor-trailers: Energotest 2009, Fall Edition. FPInnovations, Pointe-Claire, QC. Internal Report IR-2009-11-24. 77 p.

Teleflex Power Systems. n.d. Proheat Air A2/A4 installation manual. Teleflex Canada Limited Partnership, Richmond, BC. http://www.proheat.com/PDFs/925821.pdf (accessed November 2010).

Webasto. 2009. Engine preheating, in-cab heating, bunk cooling. 2009 Webasto Product North America, Inc. Fenton, MI. http://www.webastoshowroom.com/pdf/909012_Truck_Market_Brochure.pdf (accessed November 2010).

Anti-idling policies in the USA 
http://www.epa.gov/smartway/documents/420b06004.pdf (accessed November 2010).

Anti-idling policies in Canada 
http://oee.nrcan.gc.ca/communities-government/transportation/municipal-communities/reports/existing-bylaws.cfm?attr=28 (accessed November 2010).

Date modified:

2012-03-09

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