Idle (engine)
Encyclopedia
When an engine running on idle or idles, the engine runs without any loads but the engine accessories.
Effort has been made to reduce the amount of time engines spend idling, chiefly due to fuel economy
and emissions
concerns, although some engines can also be damaged if kept idling for extended periods. In the United States, about a billion gallons (3.8 billion liters) of fuel is consumed by idling heavy-duty truck and locomotive engines each year. Many newer semi-trucks have small auxiliary power unit
s (APUs) to run accessories more efficiently while the truck is parked. Hybrid vehicle
s typically shut down their internal combustion engine
s while stopped, although some conventional vehicles are also including start-stop system
s to shut off the engine when it would otherwise idle.
Effort has been made to reduce the amount of time engines spend idling, chiefly due to fuel economy
Fuel economy in automobiles
Fuel usage in automobiles refers to the fuel efficiency relationship between distance traveled by an automobile and the amount of fuel consumed....
and emissions
Exhaust gas
Exhaust gas or flue gas is emitted as a result of the combustion of fuels such as natural gas, gasoline/petrol, diesel fuel, fuel oil or coal. According to the type of engine, it is discharged into the atmosphere through an exhaust pipe, flue gas stack or propelling nozzle.It often disperses...
concerns, although some engines can also be damaged if kept idling for extended periods. In the United States, about a billion gallons (3.8 billion liters) of fuel is consumed by idling heavy-duty truck and locomotive engines each year. Many newer semi-trucks have small auxiliary power unit
Auxiliary power unit
An auxiliary power unit is a device on a vehicle that provides energy for functions other than propulsion. They are commonly found on large aircraft, as well as some large land vehicles.-Function:...
s (APUs) to run accessories more efficiently while the truck is parked. Hybrid vehicle
Hybrid vehicle
A hybrid vehicle is a vehicle that uses two or more distinct power sources to move the vehicle. The term most commonly refers to hybrid electric vehicles , which combine an internal combustion engine and one or more electric motors.-Power:...
s typically shut down their internal combustion engine
Internal combustion engine
The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...
s while stopped, although some conventional vehicles are also including start-stop system
Start-stop system
In automobiles, a start-stop system or stop-start system automatically shuts down and restarts the internal combustion engine to reduce the amount of time the engine spends idling, thereby improving fuel economy and reducing emissions...
s to shut off the engine when it would otherwise idle.