Patent ID: 6119644
Filing Date: 2000-09-19
Classification: F01L

Abstract:
A hydraulic clearance compensation element, comprising:a casing defined by an axis, said casing having an interior and being closed on one end by a bottom which bears upon one end of a gas exchange valve;a pressure piston so received in the interior of the casing that a leakage gap for hydraulic fluid is formed between an outer surface area of the pressure piston and an adjacent side wall of the casing, said pressure piston and said casing being movable relative to one another in axial direction, with a high pressure chamber being defined between the bottom and a confronting end face of the pressure piston for receiving a hydraulic fluid; anda check valve arranged on the end face of the pressure piston and opening towards the high pressure chamber, said check valve receiving hydraulic fluid from a reservoir enclosed by the pressure piston;wherein the leakage gap is dimensioned to meet a characteristic ratio (C) between 8 and 32 at a temperature of 20.degree. C. wherein ##EQU4## wherein C is the characteristic ratio number,S is the width of the leakage gap,.epsilon.' is the quotient of the thermal expansion coefficient .epsilon..sub.D of the pressure piston to the thermal expansion coefficient .epsilon..sub.G of the casing,h.sub.R is the height of a closing ramp of the cam, positioned immediately ahead of a base circle in the direction of rotation, andd.sub.m is the mean diameter of the leakage gap.