Hybrid cam-camless variable valve actuation system

摘要

An internal combustion engine has a cylinder head mounted to an engine block that at least partially forms a plurality of cylinder combustion chambers. The cylinder head has multiple intake ports and multiple exhaust ports. Engine valves regulate the passage of gas into and out of the combustion chamber. Cam-operated engine valves are mechanically coupled to a rotating cam directly or through one or more of a variety of components that assist in transforming the rotational kinetic energy of the cam to linear motion of the engine valves. One of the exhaust valves and one of the intake valves are mechanically coupled to the cam. Electrohydraulic actuators actuate separate intake and exhaust valves of a particular cylinder. The electrohydraulic actuators are in fluid communication with a high pressure fluid source.

主权项

1. An engine valve actuation system for an internal combustion engine that includes an engine block, a cylinder head mounted to the engine block to form at least one combustion chamber and defining a first port and a second port, a first valve arranged at least partially within the first port and movable between an opened position and a closed position to selectively open the first port, a second valve arranged at least partially within the second port and movable between an opened position and a closed position to selectively open the second port, and a rotating cam mechanically coupled to the first valve to selectively move the first valve between the open and closed positions, the engine valve actuation system comprising:
a hydraulic valve actuator coupled to the second valve to selectively move the second valve between the open and closed positions, the hydraulic valve actuator comprising: an actuator housing having a piston cavity, an inlet port, a high pressure port in fluid communication with a high pressure fluid conduit, and a low pressure port in fluid communication with a low pressure fluid conduit, a piston disposed at least partially within the piston cavity and having a first surface at a first end in fluid communication with the inlet port, the first surface and actuator housing defining a volume, and an actuator valve disposed within the actuator housing in fluid communication with the inlet port, the high pressure port, the low pressure port and the volume through the inlet port.