Systems and methods for hydraulic lash adjustment in an internal combustion engine

摘要

Systems and methods for actuating engine valves for positive power and engine braking operation are disclosed. The systems may include a self-lashing hydraulic piston slidably disposed in a fixed or rocker arm housing. The hydraulic piston may have an internal cavity in which a motion absorbing piston is disposed. A hydraulic fluid source may communicate with the hydraulic piston bore. A check valve which may be incorporated in a control valve may controls hydraulic fluid supply from the hydraulic fluid source to the hydraulic piston to provide self-lashing operation of the valve actuation system.

主权项

1. A system for hydraulic lash adjustment and engine valve actuation comprising:
a housing disposed above an engine valve train element, said housing having a piston bore and a hydraulic fluid supply passage communicating with the piston bore; a hydraulic piston slidably disposed in the piston bore, said hydraulic piston having an internal cavity; a motion absorbing piston slidably disposed in the hydraulic piston internal cavity; a hydraulic fluid source communicating with the hydraulic fluid supply passage; a check valve in the hydraulic fluid supply passage between the hydraulic fluid source and the piston bore; a first spring disposed between the motion absorbing piston and the hydraulic piston; and a second spring biasing the hydraulic piston into the piston bore, wherein the hydraulic piston and the motion absorbing piston are configured such that a volume of hydraulic fluid in the piston bore and checked by the check valve causes the motion absorbing piston to engage the hydraulic piston within the internal cavity, thereby permitting conveyance of auxiliary valve actuation motions to the engine valve train element.