| 摘要 |
The invention concerns a method of actuating a device for varying the valve timing of an internal combustion engine, said device comprising an element fixed to the camshaft and an element fixed to the crankshaft, which elements are in power-transmitting relationship with each other through at least one hydraulic working chamber formed within the device. When the internal combustion engine has been switched off, the element fixed to the camshaft can be mechanically coupled by a locking element to the element fixed to the crankshaft in a preferred basic position for starting the internal combustion engine. According to the invention, to avoid a jamming of the locking element during starting of the internal combustion engine, the solenoid of the hydraulic valve is at first subjected to a sudden energization with a current of an intensity lower that that required for the central position of the valve piston of the hydraulic valve. Following this, the energization is gradually increased to a current intensity higher than that required for the central position of the valve piston. If the microprocessor now determines that the element fixed to the camshaft is still in its basic position, the first two phases are repeated, and when the microprocessor determines an angular displacement of the element fixed to the camshaft out of its basic position, the solenoid is again subjected to a sudden energization with a current defined by the microprocessor and corresponding to an adjusted angular position of the camshaft relative to the crankshaft.
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