Electric CVVT and CVVD Engine Valve Timing Control

The patent implements dynamic adjustability of valve timing and duration through continuously variable mechanisms. The CVVT apparatus allows continuous adjustment of intake valve timing by varying the phase angle between intake camshaft and crankshaft, while the CVVD apparatus enables continuous adjustment of exhaust valve duration by varying the phase angle between exhaust camshaft and crankshaft. This dynamic capability replaces fixed timing systems, achieving optimal valve operation across different engine speeds without requiring multiple discrete cam profiles.

The patent divides the valve control system into independent segments: intake valve timing control (CVVT) and exhaust valve duration control (CVVD) are implemented as separate apparatuses. Each apparatus independently adjusts its respective parameter, allowing optimized control of intake and exhaust processes without interfering with each other. This segmentation enables targeted optimization of each valve train while maintaining overall system manageability.

The patent achieves optimal valve operation across different engine speeds by continuously changing the timing parameter (phase angle) rather than changing the valve lift profile. The CVVT and CVVD apparatuses adjust the phase angles between camshafts and crankshaft continuously, allowing a single cam profile to operate optimally across the entire engine speed range. This eliminates the need for multiple discrete cam profiles with different lift characteristics.

The patent replaces complex mechanical systems (multiple cams, CVVL mechanisms) with a simpler phase-angle adjustment mechanism. Instead of physically changing cam profiles or valve lift characteristics through multiple mechanical components, the system achieves optimal valve operation by simply varying the timing phase angle, which is mechanically simpler and more cost-effective to implement.