Vehicle air conditioning system

A vehicle with an air conditioning system, comprising:

• a vehicle body structure defining a passenger compartment and an engine compartment;
• a vehicle speed sensor configured to measure speed of the vehicle body structure;
• a diesel engine installed within the engine compartment and having an exhaust particulate collection mechanism, the diesel engine being configured to periodically operate in a regeneration mode in which particulate matter collected within the exhaust particulate collection mechanism is reduced;
• an air handler within the vehicle body structure and having a fresh air inlet configured to draw fresh air into the air handler from outside the vehicle body structure, a plurality of air outlets configured to direct air out of the air handler into the passenger compartment and a recirculation inlet configured to draw air from within the passenger compartment into the air handler, the air handler being configured to operate in a fresh air mode and a recirculation mode, such that in the fresh air mode fresh air enters the air handler through the fresh air inlet and in the recirculation mode fresh air is prevented from entering the air handler and air instead enters the air handler via the recirculation inlet;
• and
• an controller coupled to the vehicle speed sensor, the diesel engine and the air handler, the controller being configured such that in response to determining that:
• 1) the diesel engine is operating in the regeneration mode;
• 2) the air handler is operating in the fresh air mode;
• and
• 3) the vehicle body structure is moving below a first predetermined speed,
• the air handler is switched to operate in the recirculation mode.

A method for operating a vehicle air conditioning system, comprising:

• providing a vehicle body structure with an air conditioning system that includes an air handler that directs movement of air therethrough in a fresh air mode and a recirculation mode, such that in the fresh air mode fresh air enters the air handler from outside the vehicle body structure through a fresh air inlet and is directed into a passenger compartment within the vehicle body structure, and in the recirculation mode fresh air is prevented from entering the air handler via the fresh air inlet and instead air enters the air handler via a recirculation inlet from the passenger compartment;
• providing signals to a controller of the air conditioning system indicating the air handler is operating in the fresh air mode;
• providing signals to the controller indicating current speed of the vehicle body structure;
• providing signals to the controller indicating that a vehicle engine has switched operation from a first operating state to a second operating state different from the first operating state;
• and
• having the controller change operation of the air handler from the fresh air mode to the recirculation mode in response to the vehicle engine switching from the first operating state to the second operating state and the vehicle speed being below a first predetermined speed.