Theory of Operation

The operation of the Idle feature group is simple. They are set up to control idle speeds and to limit the time the engine spends in the idle state.

Idle Speed Control - Feature
Idle Speed is controlled by an isochronous governor. This means the idle engine speed will remain constant regardless of load.

The Idle Adjust Switch feature can be enabled only to control idle speed in the cab through the use of the Cruise Control switches. Using these switches the operator can control idle within the established limits of idle speed. This cab control option is especially helpful in reducing cab noise and vibration.

Idle Shutdown - Feature Option
The Idle Shutdown feature is used to limit the amount of idle time. This is a fuel saving feature which automatically shuts the engine down after a programmed time at idle. The Idle Shutdown Timer determines the length of time before the engine shuts down. The timer only starts after a minimum engine speed is achieved with no pedal activity. Pedal activity before the shutdown sequence will reset the shutdown timer to zero.

Idle Shutdown incorporates an additional security measure that monitors the position of the pedals and overrides the timer reset if it detects a relatively long period of constant input. This ensures that Idle Shutdown will still be effective even if the position of the pedals has been artificially changed such as would be achieved through the use of a throttle stick.

If the Idle Shutdown Override Feature is chosen, the operator can bypass the feature during the shutdown sequence. When the engine is ready to shutdown the red stoplight will begin to flash for thirty seconds. Pedal activity during this sequence will override the shutdown. The feature will not attempt to shutdown again until the vehicle is driven or the key switch is cycled.

The shutdown sequence will only turn off the engine. The electrical system and accessories will stay on until the key is turned OFF. Do not use this feature as an automatic "vehicle" shutdown timer as the electrical system will stay active and drain the batteries.

Idle Shutdown Override - Feature Option
This feature option allows the operator to override the engine shutdown timer by altering the position of the accelerator, brake or clutch pedals during the last 30 seconds of the programmed shutdown time. During the last 30 seconds of programmed idle time the Amber dash light will begin flashing. Idle Shutdown Override should be used if the operator relies on engine power for cab heat, air conditioning, etc. Once over-ridden, the idle shutdown feature will not initiate an engine shutdown until after the vehicle has moved and returned to idle, the PTO/remote PTO feature becomes active, or the engine is 'keyed-off', restarted and then returned to idle.

NOTE: Idle Shutdown will only shutdown the engine. The electrical system and accessories will stay on until the key is turned OFF. DO NOT use this feature as an automatic "vehicle" shutdown timer as the electrical system will stay active and drain the batteries.

Idle Shutdown in PTO - Feature Option
The Idle PTO Shutdown feature is used to limit the amount of idle time in PTO. This is another fuel saving feature which automatically shuts the engine down after a programmed time in PTO without activity. The Idle Shutdown Timer determines the length of time before the engine shuts down. The timer only starts after PTO is engaged at a constant speed with no pedal activity. Pedal activity before the shutdown sequence will reset the shutdown timer to zero.

The Idle Shutdown Override Feature works the same in PTO mode as in normal engine operation.

Idle Maximum PTO % Load Shutdown Override - Parameter
The Idle Maximum % Load Shutdown Override prevents an Idle shutdown when PTO/Remote PTO is active and engine load is greater than the Idle Maximum % PTO Load Shutdown Override value.

Ambient Air Temperature Idle Shutdown Override - Feature Option
The Ambient Air Temperature Idle Shutdown Override feature enables and disables Idle Shutdown based on outside air temperature. Three temperature values: "Intermediate", "Hot" and "Cold" are selected during the setup of the feature and these are used to influence when and how Idle Shutdown can be overridden.