Lost motion variable valve actuation system for engine braking and early exhaust opening
First Claim
1. A system for actuating an internal combustion engine exhaust valve to provide compression release actuation during an engine braking mode of engine operation and early exhaust valve opening actuation during a positive power mode of engine operation, said system comprising:
- a first cam having a compression release lobe and an early exhaust valve opening lobe;
a hydraulic lost motion system operatively contacting said first cam, said hydraulic lost motion system including a first rocker arm;
a hydraulically actuated piston extending from said hydraulic lost motion system, said hydraulically actuated piston adapted to provide said exhaust valve with compression release actuation during an engine braking mode of engine operation and early exhaust valve opening actuation during a positive power mode of operation;
a second cam having a main exhaust lobe; and
a main exhaust rocker arm operatively contacting said second cam and adapted to provide a main exhaust actuation to said exhaust valve.
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0 Petitions
Accused Products
Abstract
A method and system for actuating an internal combustion engine exhaust valve to provide compression release actuation during an engine braking mode of engine operation and early exhaust valve opening actuation during a positive power mode of engine operation is disclosed. The system may include a first cam having a compression release lobe and an early exhaust valve opening lobe connected to a hydraulic lost motion system including a first rocker arm. A hydraulically actuated piston may be selectively extended from the hydraulic lost motion system to provide the exhaust valve with compression release actuation or early exhaust valve opening actuation. The hydraulically actuated piston may be provided as a slave piston in a master-slave piston circuit in a fixed housing, or alternatively, as a hydraulic piston slidably disposed in a rocker arm. The method and system may further provide exhaust gas recirculation and/or brake gas recirculation in combination with compression release actuation and early exhaust valve opening actuation.
46 Citations
31 Claims
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1. A system for actuating an internal combustion engine exhaust valve to provide compression release actuation during an engine braking mode of engine operation and early exhaust valve opening actuation during a positive power mode of engine operation, said system comprising:
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a first cam having a compression release lobe and an early exhaust valve opening lobe; a hydraulic lost motion system operatively contacting said first cam, said hydraulic lost motion system including a first rocker arm; a hydraulically actuated piston extending from said hydraulic lost motion system, said hydraulically actuated piston adapted to provide said exhaust valve with compression release actuation during an engine braking mode of engine operation and early exhaust valve opening actuation during a positive power mode of operation; a second cam having a main exhaust lobe; and a main exhaust rocker arm operatively contacting said second cam and adapted to provide a main exhaust actuation to said exhaust valve. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A system for actuating an internal combustion engine exhaust valve comprising:
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a first means for imparting motion for a compression release engine braking actuation and an early exhaust valve opening actuation; a hydraulic lost motion system operatively contacting said first means for imparting motion, said hydraulic lost motion system including a first rocker arm; a hydraulically actuated piston extending from said hydraulic lost motion system, said hydraulically actuated piston adapted to selectively provide said exhaust valve with compression release engine braking actuation and early exhaust valve opening actuation; a second means for imparting motion for a main exhaust actuation; a main exhaust rocker arm operatively contacting said second means for imparting motion; and means for controlling said hydraulic lost motion system to selectively provide the compression release engine braking actuation and the early exhaust valve opening actuation. - View Dependent Claims (24, 25)
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26. A method of actuating an internal combustion engine exhaust valve to alternatively provide compression release engine braking actuation and early exhaust valve opening actuation using a cam with a compression release engine braking lobe and a early exhaust valve opening lobe, said method comprising:
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imparting compression release engine braking actuation motion and early exhaust valve opening actuation motion from said cam to a hydraulic lost motion system including a first rocker arm; determining whether the internal combustion engine is in an engine braking mode of operation; selectively hydraulically locking and unlocking a hydraulically actuated piston in said hydraulic lost motion system to provide said exhaust valve with compression release engine braking actuation when the internal combustion engine is in the engine braking mode of operation; determining whether the internal combustion engine is in a positive power mode of operation and early exhaust valve opening is desired; and selectively hydraulically locking and unlocking the hydraulically actuated piston in said hydraulic lost motion system to provide said exhaust valve with early exhaust valve opening actuation when the internal combustion engine is in the positive power mode of operation and early exhaust valve opening is desired. - View Dependent Claims (27, 28, 29, 30, 31)
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Specification