Idle reduction

Idle reduction describes technologies and practices that minimize the amount of time drivers idle their engines. Avoiding idling time has a multitude of benefits including: savings in fuel and maintenance costs, extending vehicle life, and reducing damaging emissions. An idling engine consumes only enough power to keep itself and its accessories running, therefore, producing no usable power to the drive train.

For cargo ships, the need to run the ship's engines for power in port is eliminated by techniques collectively described as cold ironing.

Idle reduction equipment is aimed at reducing the amount of energy wasted by idling trucks, rail locomotives or automobiles. When a vehicle's engine is not being used to move the vehicle, it can be shut off entirely — thereby conserving fuel and reducing emissions— while other functions like accessories and lighting are powered by an electrical source other than the vehicle's alternator. Each year, long-duration idling of truck and locomotive engines emits 11 million tons of carbon dioxide, 200,000 tons of oxides of nitrogen, and 5,000 tons of particulate matter into the air.

There are other technologies that can reduce the use of fuel to heat or cool the cab when the vehicle is traditionally idling overnight. These can be battery or fuel powered but in either case, use less fuel, do no harm to the vehicle's engine, and add far fewer or even no additional emissions into the atmosphere. Vehicles other than long haul trucks, including police, military, service trucks, news vans, fire trucks, ambulances, and hydraulic bucket trucks can be equipped and retrofitted with mobile power idle reduction systems, similar to a rechargeable battery. The systems are usually installed in the trunk and can provide up to 10 hours of additional power for equipment operation without engine engagement. When used by law enforcement and the military, idle reduction technology increases mission capability by extending operational time and providing increased situational awareness and safety.

Idle reduction is a rapidly growing trend in US federal, state, local and fleet policy. Idling contributes significantly to the transportation sector’s portion of yearly greenhouse gas emissions. The US Department of Energy is putting forth a huge effort through the Energy Efficiency and Renewable Energy Program to increase public awareness about decreasing petroleum use; idle-reduction being one of the methods. The Alternative Fuels and Advanced Vehicles Data Center is a reliable resource for information regarding idle-reduction methods such as fuel-operated heaters, auxiliary power units and truck stop electrification.

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