System and method for variable valve timing

A variable valve timing (VVT) assembly for a combustion engine, the VVT assembly comprising:

• a phaser configured to be actuated via a retarding spring, the phaser including:
• a phaser exterior body,
• a phaser interior body arranged within the phaser exterior body,
• a circumferential phaser gap between the phaser exterior body and the phaser interior body,
• a phaser exterior spline, and
• a phaser interior spline;
• a cylindrical phaser inner housing disposed in the phaser gap so as to receive a camshaft of the combustion engine, the phaser inner housing including:
• a cylindrical inner housing body, and
• an inner housing interior spline formed on an inner surface of the inner housing body so as to mate with the phaser interior spline;
• an advancing chamber including a first variable volume related to a linear position of the phaser;
• a retarding chamber including a second variable volume related to the linear position of the phaser;
• and
• a main housing that mates with the phaser.

A variable valve timing (VVT) assembly for a combustion engine, the VVT assembly comprising:

• a phaser including:
• a phaser exterior body,
• a phaser exterior helical spline formed on an outer surface of the phaser exterior body,
• a phaser interior body arranged within the phaser exterior body, and
• a phaser interior straight spline formed on an outer surface of the phaser interior body;
• a phaser inner housing disposed within the phaser, the phaser inner housing including an inner housing interior straight spline that mates with the phaser interior straight spline;
• a ring-shaped advancing chamber defined within the phaser inner housing, the advancing chamber configured to be in fluid communication with a fluid pumping assembly;
• a ring-shaped retarding chamber defined within the phaser interior body, the retarding chamber configured to be in fluid communication with the advancing chamber;
• and
• a main housing including interior helical teeth that mate with the phaser exterior helical spline, the main housing configured to receive and engage a camshaft of the combustion engine;
• wherein the advancing chamber includes an advancing variable fluid volume;
• wherein the phaser moves in a first linear direction when the advancing variable fluid volume is increased;
• wherein the retarding chamber includes a retarding variable fluid volume;
• and
• wherein the phaser moves in a second linear direction when the retarding variable fluid volume is increased.