Cam phaser for engines having two check valves in rotor between chambers and spool valve

Patent No. 6,763,791

Issued: July 20, 2004
Filed: July 18, 2002

Inventor: Gardner; Marty (Ithaca, NY); Duffield; Michael (Medina, NY)

Assignee:BorgWarner Inc. (Auburn Hills, MI)

An infinitely variable camshaft timing device (phaser) has a control valve located in the rotor. Since the control valve is in the rotor, the camshaft need only provide a single passage for supplying engine oil or hydraulic fluid, and does not need multiple passageways for controlling the phaser, as in the prior art. Two check valves, an advance chamber check valve and a retard chamber check valve, are also located in the rotor. The check valves are located in the control passages for each chamber. The main advantage of putting the check valves in the advance and retard chambers instead of having a single check valve in the supply is to reduce leakage. This design also eliminates high pressure oil flow across the spool valve and improves the response time of the check valve to the torque reversals due to a shorter oil path. In addition, the phaser of the present invention outperforms an oil pressure actuated device and consumes less oil.

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