Systems and methods for closed crankcase ventilation and air filtration

A system for providing combustion air to an internal combustion engine, the system comprising:

• a crankcase ventilation unit that receives unrefined blowby gas from a crankcase of the internal combustion engine, that separates oil from the unrefined blowby gas with an air-oil separator, and that discharges refined blowby gas;
• an air cleaner housing having a flowpath therethrough from upstream to downstream;
• and
• a conduit that connects the crankcase ventilation unit to the air cleaner housing so as to deliver the refined blowby gas to the air cleaner housing, thereby forming a closed crankcase ventilation system;
• wherein the air cleaner housing comprises:
• a first chamber that receives intake air through a first port;
• a second chamber downstream of the first chamber that receives intake air from the first chamber and that receives refined blowby gas from the conduit through a second port;
• a third chamber downstream of the second chamber that receives a mixture of intake air and refined blowby as from the second chamber and that discharges the mixture through a third port;
• a primary filter element that filters the intake air as it passes from the first chamber to the second chamber;
• and
• a secondary filter element that filters the mixture as it passes from the second chamber to the third chamber.