Variable Valve Timing Mechanism with Control Ramp

Iikka Järvi

doi:10.4271/980768

1998-02-23

Variable Valve Timing Mechanism with Control Ramp 980768

A new fully mechanical valve timing mechanism for continuous control of valve lift, duration and phase angle has been developed. Any valve lift and duration between zero and the maximum value may be obtained by rotating an adjustable control shaft and ramp. Total valve deactivation is possible and intake valve throttling may be used.

The operation principle and several applications of the mechanism are presented. The kinematics and dynamics of the mechanism have been studied and the critical forces and stresses have been calculated. Also the tribology of the mechanism is dealt with to check possible lubrication problems. Simulation has been used to find the dynamic properties and loads of the mechanism.

The mechanism has been tested in two single cylinder intake valve prototypes using the two-lever rocker and drag lever principles. The mechanism has been functioning in the expected way but the performed durability tests indicate that certain redesign and further testing of the mechanism is necessary.

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Variable Valve Timing Mechanism with Control Ramp 980768

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