Patent number: 6748912

Method to vent air from a cam phaser with a center mounted spool valve

Original Assignee: BorgWarner Inc.

Field of technology: Vehicles, Engines and Transportation

Patent granted on: Tue, 15 Jun 2004

Patent drawing

Abstract

A variable camshaft phase adjustment device (phaser) for an internal combustion engine having at least one camshaft. The phaser has a housing having an outer circumference for accepting a drive force, and a rotor connected to a camshaft coaxially located within the housing. The housing and the rotor are capable of rotation to shift the relative angular position of the camshaft and the crankshaft. The spool valve comprising a spool slidably mounted within a bore in the rotor. In the spool a chamber is present that has an input communicating with the bore the spool is mounted in, an output communicating with the outside, and an air flow restriction. Hydraulic fluid from the input communicating with the bore is prevented from communicating with the outside by the air flow restriction. The air flow restriction is either in the input communicating with the bore or the output communicating with the outside.