Twin variable nozzle turbine exhaust gas recirculation system

An internal combustion engine, comprising:

• a plurality of combustion cylinders;
• a first exhaust manifold and a second exhaust manifold, each said first exhaust manifold and said second exhaust manifold coupled with a plurality of said combustion cylinders;
• at least one intake manifold, each said intake manifold coupled with a plurality of said combustion cylinders;
• a first turbocharger including a first turbine having an inlet and an outlet, and a first compressor having an inlet and an outlet, said first turbine inlet having a controllable variable intake nozzle fluidly coupled with said first exhaust manifold;
• a second turbocharger including a second turbine having an inlet and an outlet, and a second compressor having an inlet and an outlet, said second turbine inlet having a controllable variable intake nozzle fluidly coupled with said second exhaust manifold, said second compressor inlet fluidly coupled with said first compressor outlet;
• an exhaust gas re-circulation duct fluidly interconnecting at least one of said first exhaust manifold and said second exhaust manifold to said at least one intake manifold;
• and
• an exhaust gas re-circulation valve disposed in said exhaust gas re-circulation duct, said exhaust gas re-circulation valve having an inlet in fluid communication with said second exhaust manifold, a first outlet in fluid communication with said first turbine, and a second outlet in fluid communication with said at least one intake manifold.

A turbocharger system for use with an internal combustion engine having a plurality of combustion cylinders, an intake manifold and first and second exhaust manifolds, said turbocharger system comprising:

• a first turbocharger including a first turbine having at least one inlet and an outlet, and a first compressor having an inlet and an outlet, said at least one first turbine inlet including a controllable, variable intake nozzle and being fluidly coupled with the first exhaust manifold;
• a second turbocharger including a second turbine having an inlet and an outlet, and a second compressor having an inlet and an outlet, said second turbine inlet including a controllable, variable intake nozzle and being fluidly coupled with said second exhaust manifold, and said second compressor inlet being fluidly coupled with said first compressor outlet;
• an exhaust gas re-circulation duct interconnecting at least one of said first exhaust manifold and said second exhaust manifold to said intake manifold;
• and
• an exhaust gas re-circulation valve disposed in said exhaust gas re-circulation duct, said exhaust gas re-circulation valve having an inlet in fluid communication with said second exhaust manifold, a first outlet in fluid communication with said first turbine at least one inlet, and a second outlet in fluid communication with said intake manifold.

A method of operating an internal combustion engine, comprising the steps of:

• providing a plurality of combustion cylinders, a first exhaust manifold, a second exhaust manifold and an intake manifold;
• transporting exhaust gas from a plurality of said combustion cylinders to each said first exhaust manifold and said second exhaust manifold;
• providing a first turbocharger including a first turbine having at least one inlet and an outlet, and a first compressor having an inlet and an outlet;
• providing a second turbocharger including a second turbine having an inlet and an outlet, and a second compressor having an inlet and an outlet;
• providing a controllable, variable intake nozzle on each of said first turbine at least one inlet and said second turbine inlet;
• rotatably driving said first turbine with exhaust gas introduced at said first turbine at least one inlet from each said second turbine outlet and said first exhaust manifold;
• rotatably driving said second turbine with exhaust gas introduced at said second turbine inlet from said second exhaust manifold;
• introducing combustion gas at said first compressor inlet;
• transporting combustion gas from said first compressor outlet to said second compressor inlet;
• transporting compressed combustion gas from said second compressor outlet to said intake manifold;
• sensing at least one of operating conditions of said engine and performance of said turbochargers;
• and
• controlling at least one of said controllable variable intake nozzles in response to at least one of said engine operating conditions and said performance of said turbochargers.

A turbocharger and engine emissions control system for use with an internal combustion engine having a plurality of combustion cylinders, an intake manifold and first and second exhaust manifolds, said turbocharger and engine emissions control system comprising:

• a first turbocharger including a first turbine having a first inlet including a controllable variable intake nozzle and an outlet, and a first compressor having an inlet and an outlet, said first turbine inlet fluidly coupled with the first exhaust manifold;
• a second turbocharger including a second turbine having an inlet including a controllable variable intake nozzle and an outlet, and a second compressor having an inlet and an outlet, said second turbine inlet fluidly coupled with said second exhaust manifold, said second compressor inlet fluidly coupled with said first compressor outlet, and said second compressor outlet fluidly coupled with the intake manifold;
• an EGR duct fluidly coupled to said second exhaust manifold and said intake manifold;
• and
• a valve in said EGR duct, said valve having an inlet fluidly coupled to said second exhaust manifold, and an outlet fluidly coupled to said intake manifold.