Engine Air Control Valve (ACV)

The air control valve (ACV) is a normally-open valve that is located on the engine air intake.

When the particulate filter requires regeneration and the TRU exhaust temperature is very low (for example, during minimal engine loading and/or extremely cold weather), the ACV is used for active-assist regeneration.

During active-assist regeneration, the ACV changes the air-to-fuel ratio in order to raise exhaust temperatures high enough for the doser to activate and regenerate the particulate filter.