Idle

nounStandard termMechanical

The baseline operating speed of an engine when it is running but disconnected from a load.

The minimum rotational speed required to keep an internal combustion engine running smoothly without stalling. At this state, the engine generates just enough power to overcome its own internal friction and drive essential accessories like oil pumps and alternators. Adjusting this setpoint is critical for fuel efficiency and emissions control.

Heard on the job

The generator sounds rough at idle, so we might have a fouled injector.

Also heard as

  • idle speed