Multi-stage turbocharging system utilizing VTG turbine stage(s)

Abstract

Multi-stage turbocharging, and more particularly, an advanced multi-stage turbocharging system using the variable turbine power of one or more variable turbine geometry (VTG) turbochargers to adjust compressor boost and exhaust back pressure to engine operating demands. The invention further relates to a turbocharged internal combustion engine, in particular a turbocharged internal combustion engine with at least one high-pressure turbine stage and one downstream low-pressure turbine stage, wherein the high-pressure turbine may be a single-flow or double-flow type, wherein the high pressure or low pressure compressor may be variable geometry, wherein the high pressure or low pressure compressor may be variably bypassed, and wherein the high pressure or low pressure turbine may be provided with an active control variable bypass or wastegate.

1 . An internal combustion engine ( 10 ), comprising: 
 a plurality of combustion cylinders;    at least one exhaust manifold ( 12 ) coupled with said combustion cylinders;    at least one intake manifold ( 11 ) coupled with said combustion cylinders;    a first turbocharger ( 20 ) including a first turbine ( 21 ) having an inlet and an outlet, and a first compressor ( 22 ) having an inlet and an outlet, said first turbine inlet having a controllable variable intake nozzle fluidly coupled with said exhaust manifold and arranged to vary the fluid flow therein; and    a second turbocharger ( 30 ) including a second turbine ( 31 ) having an inlet and an outlet, and a second compressor ( 32 ) having an inlet and an outlet, said second turbine inlet fluidly coupled with said first turbine outlet, said second compressor inlet fluidly coupled with said first compressor outlet, said second compressor outlet fluidly coupled with said intake manifold;    wherein bypass piping ( 3 ) is provided for bypassing said high pressure compressor, with means for restricting ( 4 ) provided in said bypass piping, and    wherein bypass piping ( 1 ) is provided for bypassing said high pressure turbine, with means for restricting ( 2 ) provided in said bypass piping.    
     
     
         2 . The internal combustion engine as in  claim 1 , further comprising a bypass piping ( 8 ) and flow control means ( 9 ) for bypassing said low pressure turbine.  
     
     
         3 . An internal combustion engine ( 10 ), comprising: 
 a plurality of combustion cylinders;    at least one exhaust manifold ( 12 ) coupled with said combustion cylinders;    at least one intake manifold ( 11 ) coupled with said combustion cylinders;    a first turbocharger ( 20 ) including a first turbine ( 21 ) having an inlet and an outlet, and a first compressor ( 22 ) having an inlet and an outlet, said first turbine inlet having a controllable variable intake nozzle fluidly coupled with said exhaust manifold; and    a second turbocharger ( 30 ) including a second turbine ( 31 ) having an inlet and an outlet, said second turbine inlet having a controllable variable intake nozzle fluidly coupled with said first turbine outlet, and a second compressor ( 32 ) having an inlet and an outlet, said second compressor inlet fluidly coupled with said first compressor outlet, said second compressor outlet fluidly coupled with said intake manifold.    
     
     
         4 . The internal combustion engine as in  claim 3 , wherein all exhaust flows through the high pressure turbine ( 21 ) and the low pressure turbine ( 31 ), and wherein all air to the engine ( 10 ) flows through the low pressure compressor ( 32 ) and the high pressure compressor ( 22 ).  
     
     
         5 . The internal combustion engine as in  claim 3 , wherein bypass piping ( 1 ) is provided for the high pressure turbine but not the low pressure turbine.  
     
     
         6 . The internal combustion engine as in  claim 3 , wherein bypass piping ( 8 ) is provided for the low pressure turbine but not the high pressure turbine.  
     
     
         7 . The internal combustion engine as in  claim 3 , wherein bypass piping is provided for the high pressure turbine and the low pressure turbine.  
     
     
         8 . The internal combustion engine as in  claim 3 , further comprising an EGR line ( 7 ) for feeding exhaust gas from the exhaust manifold to the line connecting the low pressure compressor to the high pressure compressor.  
     
     
         9 . An internal combustion engine ( 10 ), comprising: 
 a plurality of combustion cylinders;    at least one exhaust manifold ( 12 ) coupled with said combustion cylinders;    at least one intake manifold ( 11 ) coupled with said combustion cylinders;    a first turbocharger ( 20 ) including a first turbine ( 21 ) having an inlet and an outlet, and a first compressor ( 22 ) having an inlet and an outlet, said first turbine inlet having a controllable variable intake nozzle fluidly coupled with said exhaust manifold; and    a second turbocharger ( 30 ) including a second turbine ( 31 ) having an inlet and an outlet, said second turbine inlet having a controllable variable intake nozzle fluidly coupled with said first turbine outlet, and a second compressor ( 32 ) having an inlet and an outlet, said second compressor inlet fluidly coupled with said first compressor outlet, said second compressor outlet fluidly coupled with said intake manifold, and    further comprising a wastegate or bypass for bypassing said low pressure turbocharger.    
     
     
         10 . The internal combustion engine as in  claim 9 , further comprising a compressor bypass ( 3 ) for bypassing said high pressure compressor.  
     
     
         11 . An internal combustion engine ( 10 ), comprising: 
 a plurality of combustion cylinders;    at least one exhaust manifold ( 12 ) coupled with said combustion cylinders;    at least one intake manifold ( 11 ) coupled with said combustion cylinders;    a first turbocharger including a first turbine having a twin volute ( 23   a ,  23   b ), each volute having an inlet and an outlet, and a first compressor having an inlet and an outlet, said first turbine volutes each fluidly coupled with said exhaust manifold; and    a second turbocharger including a second turbine having an inlet and an outlet, said second turbine inlet having a controllable variable intake nozzle fluidly coupled with said first turbine outlet, and a second compressor having an inlet and an outlet, said second compressor inlet fluidly coupled with said first compressor outlet, said second compressor outlet fluidly coupled with said intake manifold.    
     
     
         12 . The internal combustion engine as in  claim 11 , wherein bypass piping is provided for bypassing each of said first turbine volutes.  
     
     
         13 . An internal combustion engine ( 10 ), comprising: 
 a plurality of combustion cylinders;    at least one exhaust manifold ( 12 ) coupled with said combustion cylinders;    at least one intake manifold ( 11 ) coupled with said combustion cylinders;    a first turbocharger ( 20 ) including a first turbine ( 21 ) having an inlet and an outlet, and a first compressor ( 22 ) having an inlet and an outlet, said first turbine inlet having a controllable variable intake nozzle fluidly coupled with said exhaust manifold; and    a second turbocharger ( 30 ) including a second turbine ( 31 ) having an inlet and an outlet, said second turbine inlet having a controllable variable intake nozzle fluidly coupled with said first turbine outlet, and a second compressor ( 32 ) having an inlet and an outlet, said second compressor inlet fluidly coupled with said first compressor outlet, said second compressor outlet fluidly coupled with said intake manifold, and    further comprising bypass piping for bypassing said high pressure turbine.    
     
     
         14 . The internal combustion engine as in  claim 1 , wherein at least one of said compressors is a variable geometry compressor.  
     
     
         15 . The internal combustion engine as in  claim 3 , wherein at least one of said compressors is a variable geometry compressor.  
     
     
         16 . The internal combustion engine as in  claim 9 , wherein at least one of said compressors is a variable geometry compressor.  
     
     
         17 . The internal combustion engine as in  claim 11 , wherein at least one of said compressors is a variable geometry compressor.  
     
     
         18 . The internal combustion engine as in  claim 13 , wherein at least one of said compressors is a variable geometry compressor.