Active Vibration Damping Device for Engine Mounts
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Solution Overview
Problem
Existing active vibration damping devices are ineffective in suppressing low-frequency noise and booming noise in vehicles, as they rely on active noise control methods that are not suitable for reducing these types of noise, and can generate excessive sound pressure at varying engine rotational speeds and torques.
Innovation Solution
An active vibration damping device with a vibration control unit that detects rotational speed and torque of the internal combustion engine, executing amplitude and phase variable control for the engine mount actuators, prohibiting these controls at low rotational speeds or torques to prevent low-frequency noise generation, and enabling them at higher speeds or torques to achieve effective vibration damping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If amplitude variable-phase variable control is executed at low rotational speeds, then vibration damping effect is improved, but low-frequency noise and booming noise increase excessively
Solution Approach 1:
The patent applies parameter changes by switching between two different control modes (amplitude variable-phase fixed control and amplitude variable-phase variable control) based on engine rotational speed. At low rotational speeds, the system uses amplitude variable-phase fixed control to avoid excessive low-frequency noise, while at high rotational speeds, it switches to amplitude variable-phase variable control to achieve effective vibration damping. This dynamic parameter switching resolves the contradiction between vibration damping effectiveness and noise generation.
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 device effectively suppresses low-frequency noise and achieves suitable vibration damping by controlling the active vibrations of the engine mount actuators based on engine conditions, ensuring that noise levels remain within acceptable limits across different operational states.
Implementation Method 1
suppress vibrations transmitted from a side of the internal combustion engine to a side of the vehicle body, by active vibrations generated by actuators of the engine mount
Implementation Method 2
the vibration control unit executes an amplitude variable-phase variable control for variably controlling the amplitude and phase of the active vibrations generated by the actuator according to the rotational speed detected by the rotational speed detection unit
Implementation Method 3
the vibration control unit prohibits the amplitude variable-phase variable control, in the case that the rotational speed detected by the rotational speed detection unit is less than a predetermined rotational speed
Data Source
AI summary
A phase variable control is prohibited in the case that a rotational speed NE of the engine is less than a first predetermined rotational speed NE_th1.