Patent ID: 7007644
Filing Date: 2006-03-07
Classification: F01L

Abstract:
1. A valve actuation system for use in an internal combustion engine comprising at least one combustion cylinder having a piston and an engine valve, said valve actuation system comprising: a hydraulic pump configured to produce a hydraulic output based on a valve-piston clearance profile of at least one cylinder of said combustion engine; a high-pressure reservoir coupled with said hydraulic pump; and an electro-hydraulic valve actuator coupled with said high-pressure reservoir and configured to actuate at least one engine valve of said combustion engine according to an output of said hydraulic pump; wherein said electro-hydraulic valve actuator includes a control chamber coupled with said high-pressure reservoir and at least one plunger fluidly connected with said control chamber and mechanically connected to said at least one engine valve, and said valve actuation system further comprising at least one feedback loop from said control chamber to said high-pressure reservoir; and wherein said at least one feedback loop comprises a first feedback loop having a first check valve disposed therein, said first check valve configured to allow hydraulic fluid to flow from said control chamber to said high-pressure reservoir when the pressure in said control chamber exceeds the pressure in said high-pressure reservoir.