Active Engine Mount Diagnostics via Induced Vibration
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Solution Overview
Problem
Active engine mounts in vehicles degrade over time, leading to reduced effectiveness in absorbing engine vibrations, which can result in increased noise, vibration, and harshness (NVH) issues, affecting engine performance and fuel efficiency.
Innovation Solution
A method involving the controlled adjustment of active engine mounts to dampening and stiffening modes through induced vehicle vibrations, monitored by vibrational sensors, to diagnose and address degradation by determining if the mounts are functioning correctly or stuck in a specific mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If active engine mounts are used to absorb engine vibrations at idle, then NVH performance is improved, but the mounts degrade over time and may stick in dampening mode
Solution Approach 1:
The system performs preliminary diagnostic actions by inducing vibrations in specific patterns before normal operation to proactively detect mount degradation. The controller induces vibrations at frequencies that would excite the mount if it were stuck in dampening mode, allowing early detection before failure occurs.
Solution Approach 2:
The system uses mechanical vibration induction as a diagnostic tool. By controlling the engine to vibrate at specific frequencies and observing the response, the system can determine if the active mount is properly transitioning between modes or if it is stuck in dampening mode.
2Object-affected harmful factors
If active engine mounts are controlled to change dampening characteristics, then vibration absorption is improved, but degradation detection becomes more complex
Solution Approach 1:
The existing active engine mount control system is made multi-functional by adding diagnostic capabilities. The same actuators and sensors used for vibration control are also used for degradation detection, eliminating the need for separate diagnostic hardware and reducing overall system complexity.
Solution Approach 2:
The active engine mount system performs self-diagnosis by monitoring its own response to induced vibrations. The controller analyzes vibration data from existing sensors to determine if the mount is degrading, allowing the system to self-assess its health without external intervention.
3Measurement precision
If engine vibrations are induced to diagnose active engine mounts, then degradation identification is improved, but engine operation is disrupted
Solution Approach 1:
The diagnostic vibration induction is performed periodically rather than continuously. The controller induces vibrations at scheduled intervals when the vehicle is already idle or during normal operation, allowing brief diagnostic windows without requiring extended engine shutdowns or continuous disruption.
Solution Approach 2:
The system maintains continuous vibration monitoring and control capabilities while performing diagnostics. The induced vibrations are brief and integrated into normal engine operation, allowing the engine to remain operational throughout the diagnostic process without significant interruption to useful work.
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
This approach allows for timely identification and improvement of active engine mount health, reducing NVH-related issues and enhancing engine performance by ensuring the mounts operate as intended.
Implementation Method 1
the rubber naturally absorbed vibrations from the engine
Implementation Method 2
rubber naturally absorbed vibrations
Implementation Method 3
the active engine mounts may be configured to stiffen (e.g. stiffening mode), to limit undesired engine motion
Implementation Method 4
engine vibrations may be monitored via one or more vibrational sensors
Data Source
AI summary
Methods and systems are provided for identifying degradation of active engine mounts coupled to a vehicle engine. By correlating the monitored vibrational pattern to a selected active mounts operating mode, the conditions of active engine mounts may be distinguished. Timely diagnosis of active engine mounts may improve active engine mount health and prevent noise, vibration, and harshness (NVH) issues.