VCT lock pin having a tortuous path providing a hydraulic delay

Patent No. 6,647,936

Issued: November 18, 2003
Filed: November 14, 2002

Inventor: Lewis; Jeff (Freeville, NY)
Assignee: BorgWarner Inc. (Auburn Hills, MI)


A variable cam timing phaser having a tortuous path from the supply of pressurized oil to the tapered recess into which the locking pin fits, that introduces a delay between when the engine starts and when the locking pin moves to an unlocked position. The tortuous path restricts fluid flow, preventing the locking pin from unlocking during engine start-up with the initial oil pressurization, prior to the variable cam timing phaser having sufficient oil to operate. The delay ensures that the chambers of the variable cam timing phaser have time to fill with operating fluid before the phaser is unlocked.


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