Abstract

The present invention increases cold temperature oil flow through the variable cam timing (VCT) phaser to reduce the amount of time it takes to replace this oil with warmer low viscosity oil and thereby improve performance. Furthermore the oil flow through the VCT phaser is reduced once the oil temperature reaches the minimum operating temperature for the VCT phaser to operate and the VCT phaser is commanded to move from the park position. Therefore, the VCT phaser is charged with hot engine oil and is commanded to move from the parked position. The VCT phaser reduces oil flow through the phaser at high oil temperatures and low oil viscosity while adding the benefit of increased oil flow through the phaser at low oil temperatures and high oil viscosity to facilitate getting warmer oil into the VCT phaser sooner for increased VCT performance.