High efficiency exhaust gas return system

An engine system comprising:

• an intake manifold configured to receive a combustible mixture configured to be combusted within a first combustion chamber and a second combustion chamber;
• a throttle upstream of the intake manifold, the throttle configured to at least partially regulate an air flow into the intake manifold;
• an exhaust manifold comprising a first exhaust gas sub-manifold configured to receive combustion products from the first combustion chamber and a second exhaust gas sub-manifold configured to receive combustion products from the second combustion chamber;
• and
• a gas mixer downstream of the throttle and upstream of the intake manifold, the gas mixer comprising:
• a convergent-divergent nozzle comprising a convergent portion and a divergent portion and defining a first gas flow path;
• an air housing comprising an air inlet configured to supply air to the first gas flow path upstream of the convergent-divergent nozzle;
• a gas housing defining a second gas flow path and comprising:
• a first gas inlet configured to receive a secondary gas from the first exhaust gas sub-manifold and allow the secondary gas into the second gas flow path;
• a second gas inlet configured to receive the secondary gas from the second exhaust gas sub-manifold and allow the secondary gas into the second gas flow path;
• a flapper valve comprising a pivoting a valve body that is configured to be urged into a first configuration by gas pressure of gas flow along the first gas inlet to permit gas flow along the first gas inlet and to block gas flow along the second gas inlet, and is configured to be urged into a second configuration by gas pressure of gas flow along the second gas inlet to permit gas flow along the second gas inlet and to block gas flow along the first gas inlet based on gas flow along the second gas inlet;
• and,
• a gas nozzle positioned parallel to and centrally within the first gas flow path in the convergent portion of the convergent-divergent nozzle, the gas nozzle configured to supply the secondary gas to the first gas flow path upstream of the divergent portion.