Variable Valve Drive Damping for Oscillation Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing variable valve drives in internal combustion engines experience undesirable oscillations and noise due to rapid actuation by linear actuators, leading to erroneous switching of rocker arms and potential material failure.
Innovation Solution
Incorporating a damper mass on the elongated activation arm or leaf springs, which is oscillation-capable and configured to neutralize harmful oscillation energy by resonant frequency, reducing oscillations and noise, and allowing for space-saving synchronous activation of rocker arms without additional spring elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a linear actuator is used to rapidly actuate the elongated activation arm for synchronous switching of rocker arms, then the switching speed and synchronization are improved, but undesirable oscillations and noise are generated
Solution Approach 1:
The patent applies a damper mass that utilizes resonant frequency to convert the harmful oscillations generated by rapid actuation into beneficial damping effects. The damper mass is tuned to resonate at the same frequency as the unwanted oscillations, absorbing and dissipating the vibrational energy, thereby converting the harmful oscillations into a beneficial damping mechanism that reduces noise and prevents material failure
2Loss of time
If the movement period of the linear actuator armature is shortened for rapid actuation, then the responsiveness is improved, but the activation arm loses contact with the tappet and oscillations are created
Solution Approach 1:
The patent incorporates a damper mass that provides beforehand cushioning against the oscillations and contact losses that occur during rapid actuation. The damper mass is pre-configured with specific damping characteristics that anticipate and counteract the oscillatory movements, ensuring that the activation arm maintains reliable contact with the tappet even during very rapid actuation cycles
3Object-generated harmful factors
If a damper mass is added to reduce oscillations, then the noise and vibrations are reduced, but the device complexity increases
Solution Approach 1:
The patent merges the damper mass functionality with the existing elongated activation arm structure. The damper mass is integrated into the activation arm assembly, combining the actuation function and the damping function into a single unified component. This merging approach reduces device complexity by eliminating the need for separate damping mechanisms while still achieving effective oscillation reduction
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces or eliminates undesirable oscillations and noise, ensuring reliable operation and reducing the risk of material failure, while enabling a compact and cost-effective design for the valve drive.
Implementation Method 1
The natural frequency of the damper mass that is disposed in a oscillation-capable manner is chosen in such a manner that the harmful oscillation energy on account of said damper mass is neutralized by the resonant frequency of the valve drive and/or is converted to oscillation-related thermal energy.
Implementation Method 2
at least one damper mass is disposed or configured so as to be capable of oscillating on the elongated activation arm and/or on at least one leaf spring fastened to said elongated activation arm
Data Source
AI summary
A variable valve drive of an internal combustion engine is provided that includes at least one gas exchange valve, the valve stroke of said gas exchange valve predefined by cams of a camshaft, and by at least one switchable rocker arm. The switchable rocker arm, having a first lever and a second lever, selectively transmits cam lift to the gas exchange valve. The second lever is selectively coupled to the first lever by a coupling. The coupling is activatable by an elongated activation arm on which one leaf spring is disposed for the coupling of the switchable rocker arm. The elongated activation arm is longitudinally displaceable from a locking position to an unlocking position by a linear actuator. A damper mass is disposed or configured to be capable of oscillating on the elongated activation arm and/or on the leaf spring of the elongated activation arm.