Fastener-driving tool with one or more combustion chambers and an exhaust gas recirculation system

A fastener-driving tool comprising:

• a housing defining an air chamber;
• a first set of components at least partially within the housing that define a first combustion chamber having a first volume;
• a spark generator configured to generate a spark within the first combustion chamber;
• a second set of components at least partially within the housing that define a second combustion chamber having a second volume greater than the first volume, wherein the second combustion chamber is in fluid communication with the first combustion chamber via multiple openings;
• a cylinder within the housing and defining a piston chamber that is in fluid communication with the second combustion chamber;
• a piston in the piston chamber and movable relative to the cylinder between a pre-firing position and a firing position;
• a driver blade attached to the piston;
• an exhaust gas recirculation (EGR) valve having an EGR valve inlet that is in fluid communication with the piston chamber via an EGR opening defined through the cylinder;
• an EGR valve recirculation outlet that is in fluid communication with an EGR conduit, the EGR conduit having an EGR conduit outlet that is in fluid communication with the air chamber;
• and
• an EGR valve exhaust outlet that is in fluid communication with an exhaust conduit that is in fluid communication with the atmosphere.