General Information

Optimized idle is an optional feature on vehicles equipped with Detroit engines. Optimized idle reduces engine idle time by running the engine only as required when the vehicle is parked.

Optimized idle automatically shuts down and restarts the engine as needed to:

• keep the engine oil temperature between programmed limits;

• maintain battery voltage;

• keep the cab and sleeper areas at the thermostat setting; and

• in coordination with the dual HVAC system (if equipped), maintain the battery and assist in HVAC.

The benefits of the system include reduced engine idle time, fuel savings, reduction of exhaust emissions and noise, increased starter and engine life, and a reduced chance of dead batteries.

Optimized idle operates in the following modes:

• Cold startability mode and battery mode: both modes keep the battery charged and engine oil temperature between programmed limits.

• Interior comfort mode (for sleeper cabs without a dual HVAC system): keeps the cab and sleeper at a constant preset temperature, in addition to all functions available in cold startability and battery modes. Extended and continuous run modes allow the engine to keep running longer if necessary.

• Interior comfort mode with a dual HVAC system: keeps the cab and sleeper at a constant preset temperature, in addition to all functions available in cold startability and battery modes.

In cold startability mode, optimized idle starts the engine when engine oil temperature drops to a programmable preset lower limit. The engine is shut down when engine oil temperature reaches a programmable upper limit, unless the requirements of other active modes require the engine to keep running.

In battery mode, the engine runs for two hours before shutting down. On vehicles without a dual HVAC system, the engine will run an additional two hours in extended mode if necessary, and continuously in continuous mode. When in continuous mode, the driver display will indicate optimized idle status as ‘continuous battery mode.’ Continuous mode may indicate a problem, such as a bad battery.

Interior comfort mode controls the temperature set point, which is the desired temperature of the cab and sleeper, and the comfort zone, which is the allowed temperature deviation from the set point before the engine starts.

Interior comfort mode with a dual HVAC system operates with the following parameters regarding the set point and comfort zone:

• If the bunk area temperature reaches more than 10°F (5.5 °C) above the set point the comfort zone is exceeded and the dual HVAC system immediately requests the engine to start for comfort support cooling.

• Bunk area temperatures 5 to 10°F (2.8 to 5.5°C) above the set point for over twenty minutes will cause the dual HVAC system to request the engine to start for comfort support cooling.

• If the bunk area temperature drops to more than 10°F (5.5 °C) below the set point, the comfort zone is exceeded and the dual HVAC system immediately requests the engine to start for comfort support heating.

• Temperatures 5 to 10°F (2.8 to 5.5 °C) below the set point for over twenty minutes will cause the dual HVAC system to request the engine to start for comfort support for heating.

In extreme ambient conditions, comfort mode may stay on continuously.

When optimized idle is on, it may turn off these functions to reduce stress on the batteries:

• Cab climate control fan

• Sleeper climate control fan

• Mirror heat

• Fuel/water separator heat

• Seat heat

• Advertising light

• Auxiliary circulation fan (windshield)

• Air dryer