Electro-hydraulic hybrid camshaft phaser

Abstract

A hybrid camshaft phaser comprising a conventional vane-type hydraulically-actuated phaser to which is coupled an electric motor and gear transmission. The transmission output shaft is coupled to the phaser rotor, optionally via an intermediate clutch mechanism. Under engine operating conditions in which the response of a hydraulic phaser is poor, the electric motor operates to augment the hydraulic actuation. Such conditions include at least low ambient temperatures at which oil viscosities are high, and high ambient temperatures and/or low engine speeds at which oil pressures are low. Preferably, at engine speeds above about 1500 rpm, the electric motor is de-energized.

1 . A hybrid camshaft phaser, comprising:
 a) a hydraulic camshaft phaser having a stator and a rotor disposed for rotation within said stator, said hybrid phaser being actuable by injection of a hydraulic fluid into chambers formed between said rotor and said stator; and   b) an electric motor drive operatively connected to said rotor for selectively augmenting actuating torque of said hydraulic camshaft phaser.   
   
   
       2 . A hybrid camshaft phaser in accordance with  claim 1  wherein said electric motor drive comprises an electric motor and a gear transmission. 
   
   
       3 . A hybrid camshaft phaser in accordance with  claim 2  wherein said electric motor is selected from the group consisting of axial motor, radial motor, brush, brushless, and combinations thereof. 
   
   
       4 . A hybrid camshaft phaser in accordance with  claim 2  wherein said gear transmission is selected from the group consisting of spur, helical, planetary, harmonic, and cyclical. 
   
   
       5 . A hybrid camshaft phaser in accordance with  claim 2  wherein said gear transmission is selected from the group consisting of single stage and multiple stage. 
   
   
       6 . A hybrid camshaft phaser in accordance with  claim 1  further comprising a clutch disposed between said electric motor drive and said rotor. 
   
   
       7 . A hybrid camshaft phaser in accordance with  claim 6  wherein said clutch is selected from the group consisting of friction clutch and electromagnetic clutch. 
   
   
       8 . An internal combustion engine including a camshaft and a crankshaft wherein a hybrid camshaft phaser is interposed between said crankshaft and said camshaft, wherein said hybrid camshaft phaser includes
 a hydraulic camshaft phaser having a stator driven by said crankshaft and a rotor disposed for rotation within said, stator and attached to said camshaft, said hydraulic camshaft phaser being actuable by injection of a hydraulic fluid into chambers formed between said rotor and said stator, and   an electric motor drive coupled to said rotor for selectively augmenting actuating torque of said hydraulic camshaft phaser.   
   
   
       9 . A hybrid electro-hydraulic phaser, for shifting the angular phase of a first shaft relative to a second shaft comprising:
 a) a stator rotatable by one of said first and second shafts;   b) a rotor disposed for rotation within said stator and rotatable with the other of said first and second shafts, said hybrid phaser being actuable by injection of a hydraulic fluid into chambers formed between said rotor and said stator; and   c) an electric motor drive operatively connected to one of said rotor and said stator for selectively augmenting actuating torque of said phaser.