Rocker systems with cylinder deactivation and selective valve lift capabilities

Abstract

An internal combustion engine system includes an engine with a plurality of pistons housed in respective ones of a plurality of cylinders. A valve train is provided for opening and closing intake and exhaust valves of the cylinders during nominal engine operations. The valve train is also configured for cylinder deactivation and to provide one or more selected lift profiles for opening and closing of the intake and/or exhaust valves.

1 . A rocker system for an internal combustion engine, the rocker system comprising:
 at least one input rocker lever rotatable about an engine component in response to motion received from at least one camshaft lobe of a camshaft;   at least one output rocker lever rotatable about the engine component, wherein the at least one output rocker lever is configured to control opening and closing of at least one exhaust valve or at least one intake valve associated with a cylinder of the internal combustion engine;   at least one valve lift switch operable to:
 connect the at least one input rocker lever and the at least one output rocker lever to one another for transferring motion from the at least one camshaft lobe to the at least one exhaust valve or the at least one intake valve; and 
 disconnect the at least one input rocker lever and the at least one output rocker lever from one another; 
   at least one additional input rocker lever or output rocker lever connectable to the at least one output rocker lever with the at least one valve lift switch; and   a biasing mechanism in contact with the at least one input rocker lever and the at least one output rocker lever and configured to bias the at least one input rocker lever into direct or indirect contact with the at least one camshaft lobe,   wherein each of the at least one input rocker lever comprises a first stop member and each of the at least one output rocker lever comprises a second stop member configured to contact a corresponding first stop member to prevent over-rotation of the at least one input rocker lever under the bias of the biasing mechanism.   
     
     
         2 . The rocker system of  claim 1 , further comprising a lash adjuster that connects the at least one of the exhaust valve or the at least one intake valve to the output rocker lever. 
     
     
         3 . The rocker system of  claim 1 , wherein the at least one input rocker lever includes a first input rocker lever and a second input rocker lever that are each rotatable about the engine component in response to motion received from respective ones of a first camshaft lobe and a second camshaft lobe of the camshaft. 
     
     
         4 . The rocker system of  claim 3 , wherein the at least one valve lift switch is operable to connect each of the first and second input rocker levers to the at least one output rocker lever. 
     
     
         5 . The rocker system of  claim 3 , wherein the at least one valve lift switch includes a first valve lift switch for selectively connecting the first input rocker lever to the at least one output rocker lever and a second valve lift switch for selectively connecting the second input rocker lever to the at least one output rocker lever. 
     
     
         6 . The rocker system of  claim 5 , wherein:
 the first valve lift switch includes a first pin assembly housed in a first bore that extends between the at least one output rocker lever and the first input rocker lever, the first pin assembly including a first valve lift pin movable in the first bore from a first position in which the first valve lift pin connects the at least one output rocker lever to the first input rocker lever so that the at least one output rocker lever and the first input rocker lever rotate about the engine component together to a second position in the first bore in which the first valve lift pin is housed in one of the at least one output rocker lever and the first input rocker lever so the first input rocker lever is disconnected from the at least one output rocker lever and rotation of the first input rocker lever is not transferred to the at least one output rocker lever; and   the second valve lift switch includes a second pin assembly housed in a second bore that extends between the at least one output rocker lever and the second input rocker lever, the second pin assembly including a second valve lift pin movable in the second bore from a first position in which the second valve lift pin connects the at least one output rocker lever to the second input rocker lever so that the at least one output rocker lever and the second input rocker lever rotate about the engine component together to a second position in the second bore in which the second valve lift pin is housed in one of the at least one output rocker lever and the second input rocker lever so the second input rocker lever is disconnected from the at least one output rocker lever and rotation of the second input rocker lever about the engine component is not transferred to the at least one output rocker lever.   
     
     
         7 . The rocker system of  claim 6 , wherein, in a cylinder deactivation mode of operation, the first valve lift pin and the second valve lift pin are each placed in the second positions in the first bore and the second bore, respectively, so that rotation of the first input rocker lever and rotation of the second input rocker lever about the engine component is not transferred to the at least one output rocker lever. 
     
     
         8 . The rocker system of  claim 6 , wherein, in a standard lift mode of operation, the first valve lift pin is placed in the first position in the first bore and the second valve lift pin is placed in the second position in the second bore so that rotation of the first input rocker lever about the engine component is transferred to the at least one output rocker lever and rotation of the second input rocker lever about the engine component is not transferred to the at least one output rocker lever. 
     
     
         9 . The rocker system of  claim 6 , wherein, in an auxiliary lift mode of operation, at least the second valve lift pin is placed in the first position in the second bore so that rotation of the second input rocker lever about the engine component is transferred to the at least one output rocker lever. 
     
     
         10 . The rocker system of  claim 6 , wherein:
 the first valve lift pin includes first and second shear pin parts in the first bore that are biased away from one another to the first position, and are movable via hydraulic fluid pressure from the first position to the second position; and   the valve lift pin includes third and fourth shear pin parts in the second bore that are biased toward from one another to the second position, and are movable via hydraulic fluid pressure from the second position to the first position.   
     
     
         11 . The rocker system of  claim 6 , wherein:
 the first valve lift pin includes first and second shear pin parts in abutting engagement with one another in the first bore that are biased to the first position, and are movable via hydraulic fluid pressure from the first position to the second position; and   the second valve lift pin in the second bore is biased to the second position, and is movable via hydraulic fluid pressure from the second position to the first position.   
     
     
         12 . The rocker system of  claim 1 , wherein the at least one input rocker lever includes:
 a standard lift input rocker lever rotatable about the engine component in response to motion received from a first camshaft lobe of the camshaft;   a first auxiliary lift input rocker lever rotatable about the engine component in response to motion received from a second camshaft lobe of the camshaft; and   a second auxiliary lift input rocker lever rotatable about the engine component in response to motion received from a third camshaft lobe of the camshaft.   
     
     
         13 . The rocker system of  claim 12 , wherein the at least one output rocker lever includes a rocker body with a first arm spaced from a second arm, the first and second arms being configured for placement around the engine component and forming a space therebetween for receipt of the standard lift input rocker lever, the first auxiliary lift input rocker lever being positioned on the engine component on a side of the first arm opposite the standard lift input rocker lever, and the second auxiliary lift input rocker lever being positioned on the engine component on a side of the second arm opposite the standard lift input rocker lever. 
     
     
         14 . The rocker system of  claim 13 , wherein each of the standard lift input rocker lever, the first auxiliary lift input rocker lever, and the second auxiliary lift input rocker levers includes a roller in direct or indirect contact with the respective ones of the first, second and third camshaft lobes of the camshaft. 
     
     
         15 . The rocker system of  claim 14 , wherein each of the standard lift input rocker lever, the first auxiliary lift input rocker lever, and the second auxiliary lift input rocker lever is engaged to respective ones of first, second and third biasing springs forming the biasing mechanism and that contact the output rocker lever and bias the rollers into direct or indirect contact with the respective ones of the first, second and third camshaft lobes of the camshaft. 
     
     
         16 . A rocker system for an internal combustion engine, the rocker system comprising:
 a first input rocker lever rotatable about an engine component in response to motion received from a first camshaft lobe of a camshaft;   a second input rocker lever rotatable about an engine component in response to motion received from a second camshaft lobe of the camshaft;   at least one output rocker lever rotatable about the engine component, the at least one output rocker lever being configured to control opening and closing of at least one exhaust valve or at least one intake valve associated with a cylinder of the internal combustion engine;   a first valve lift switch and a second valve lift switch, wherein:
 the first valve lift switch is operable to connect the first input rocker lever to the at least one output rocker lever to transfer motion from the first camshaft lobe to the at least one exhaust valve or the at least one intake valve; 
 the second valve lift switch is operable to connect the second input rocker lever to the at least one output rocker lever to transfer motion from the second camshaft lobe to the at least one exhaust valve or the at least one intake valve; and 
 the first and second valve lift switches are operable to disconnect the respective first and second input rocker levers from the at least one output rocker lever so that motion from the first and second camshaft lobes is not transferred to the at least one output rocker lever; and 
   a biasing mechanism in contact with the first input rocker lever, the second input rocker and the at least one output rocker lever and configured to bias the first input rocker lever and the second input rocker lever into direct or indirect contact with the first camshaft lobe and the second camshaft lobe, respectively,   wherein each of the first input rocker lever and the second input rocker lever comprises a first stop member and each of the at least one output rocker lever comprises a second stop member configured to contact a corresponding first stop member to prevent over-rotation of the first input rocker lever and the second input rocker lever under the bias of the biasing mechanism.   
     
     
         17 . The rocker system of  claim 16 , wherein:
 the first valve lift switch is housed in a first bore extending between the at least one output rocker lever and the first input rocker lever; and   the second valve lift switch is housed in a second bore extending between the at least one output rocker lever and the second input rocker lever.   
     
     
         18 . The rocker system of  claim 16 , wherein the first valve lift switch and the second valve lift switch are each hydraulically controlled to connect and disconnect the corresponding one of the first input rocker lever and the second input rocker lever to the at least one output rocker lever. 
     
     
         19 . The rocker system of  claim 16 , further comprising a third input rocker lever rotatable about the engine component in response to motion received from a third camshaft lobe of the camshaft, wherein:
 the third input rocker lever is connectable to the at least one output rocker lever with the second switch to transfer motion from the third camshaft lobe to the at least one exhaust valve or the at least one intake valve; and   the third rocker lever is disconnectable from the at least one output rocker lever so that motion from the third camshaft lobe is not transferred to the at least one output rocker lever.   
     
     
         20 . The rocker system of  claim 16 , further comprising:
 a second output rocker lever rotatable about the engine component, the second output rocker lever being configured to control opening and closing of at least one other exhaust valve or at least one other intake valve associated with a cylinder of the internal combustion engine; and   wherein the first switch is operable to connect and disconnect the second output rocker lever from the at least one output rocker lever.   
     
     
         21 . The rocker system of  claim 1 , wherein each of the first stop members comprises a stop pin. 
     
     
         22 . The rocker system of  claim 1 , wherein each of the second stop members comprises a stop member projection. 
     
     
         23 . The rocker system of  claim 16 , wherein each of the first stop members comprises a stop pin. 
     
     
         24 . The rocker system of  claim 16 , wherein each of the second stop members comprises a stop member projection.