Hydraulic lock for electrically-actuated camshaft phasers

Abstract

A variable camshaft timing device that adjusts phase between a camshaft and a crankshaft includes a planetary gear assembly that changes an angular position of the camshaft relative to an angular position of the crankshaft; a sun gear configured to receive an output shaft of an electric motor that rotates at least a portion of the planetary gear assembly and controls phase adjustment between the camshaft and crankshaft by angularly displacing the camshaft with respect to the crankshaft; and a hydraulic lock (82) that releasably engages a portion of the variable camshaft timing device (10) in response to force applied by pressurized fluid thereby selectively preventing rotation of the camshaft relative to the crankshaft.

Description

technical field [0001] The present application relates to electrically actuated camshaft phasers, and more particularly, to hydraulic lockers for selectively controlling camshaft phasing by electrically actuated camshaft phasers. Background technique [0002] An internal combustion engine includes a camshaft that opens and closes valves to regulate the combustion of fuel and air within the engine's combustion chambers. The opening and closing of the valves are precisely timed with respect to various events, such as injection of fuel into the combustion chamber for combustion, position of the piston relative to top dead center (TDC), and rotational speed of the crankshaft, to name a few. The camshaft is driven by the rotation of the crankshaft through a drive member connecting these elements, such as a belt or chain. [0003] In the past, there was a fixed relationship between the rotation of the crankshaft and the rotation of the camshaft. Increasingly, however, internal c...

AI Technical Summary

Problems solved by technology

[0004] However, maintaining the phase relationship between the camshaft and crankshaft using electrically actuated camshaft phasers can be challenging

Images