Active Engine Mounts for Skip Fire NVH Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Internal combustion engines generate unwanted noise, vibration, and harshness (NVH) due to the combustion process, which are not effectively mitigated by existing technologies, particularly during skip fire or cylinder output level modulation operations.
Innovation Solution
The use of active control systems that adjust NVH characteristics based on skip fire characteristics, employing filters and actuators to synchronize with firing impulses and sequences, and incorporating active mounts, noise cancellation systems, and flow regulators to reduce acoustic and vibrational effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If skip fire or cylinder output level modulation is used to improve fuel efficiency, then fuel efficiency is improved, but noise and vibration increase
Solution Approach 1:
The active control system performs preliminary action by anticipating NVH events based on detected engine operating conditions and firing sequences. The controller predicts when noise and vibration will occur during skip fire operation and activates actuators in advance to mitigate these harmful effects before they fully manifest, thereby maintaining fuel efficiency improvements while reducing NVH.
Solution Approach 2:
The system employs feedback mechanisms where sensors continuously monitor engine operating conditions, cylinder firing sequences, and NVH levels. This feedback information is processed by the controller to dynamically adjust actuator responses, enabling real-time optimization that maintains both fuel efficiency gains and acceptable NVH levels during skip fire operation.
2Object-generated harmful factors
If active control systems are used to reduce NVH, then noise and vibration are reduced, but device complexity increases
Solution Approach 1:
The active NVH control system is designed with multi-functionality to reduce complexity. The same controller and actuators are used across different operating conditions and engine types, providing universal NVH mitigation capabilities. The system can handle various firing sequences, skip fire patterns, and operating modes through a single integrated control architecture rather than requiring separate specialized systems for each scenario.
Solution Approach 2:
The system reduces complexity by changing operational parameters rather than physical structure. The controller dynamically adjusts actuator activation timing, duration, and intensity based on detected engine conditions and predicted NVH events. This parameter-based control approach allows flexible NVH mitigation without requiring complex mechanical modifications or multiple physical control systems.
3Ease of operation
If existing engine mounts are used to absorb vibration, then vibration support is provided, but NVH reduction effectiveness is insufficient during skip fire operation
Solution Approach 1:
The invention transforms static engine mounts into dynamic active control elements. Rather than relying on passive vibration absorption, the system actively adjusts mount characteristics in real-time based on detected engine operating conditions and predicted NVH events. This dynamic adaptation enables effective NVH reduction during skip fire operation while maintaining adequate vibration support during normal operation.
Solution Approach 2:
The active control system introduces intermediary elements between the engine and vehicle chassis. These intermediaries (such as actively controlled engine mounts or isolation elements) mediate the transmission of vibrations and noise, allowing the system to selectively attenuate harmful NVH while maintaining necessary mechanical support and connection functions.
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 NVH by anticipating and mitigating the effects of firing sequences and patterns, providing a more comfortable driving experience and improved fuel efficiency by actively managing engine mounts, noise cancellation, and exhaust flow.
Implementation Method 1
vehicles utilize engine mounts that both support the engine and absorb vibration from the engine
Implementation Method 2
the active mount may become more compliant so that the vibration is better absorbed
Implementation Method 3
The noise is analyzed and used to generate canceling sounds through the speakers. The amplitude, phase, frequency and wavelength of the generated sound waves are selected to cancel the undesirable acoustic effects
Implementation Method 4
The flapper valve helps to dampen, reflect, or modulate pressure waves in the exhaust path that are generated by the engine
Implementation Method 5
The flapper valve impedes the exhaust flow from the cylinders to the tailpipe
Data Source
AI summary
Systems and methods for reducing noise or vibration generated by an internal combustion engine are described. An engine controller is arranged to operate the working chambers of the engine in a cylinder output level modulation manner A noise/vibration reduction unit actively control of a device that is not a part of the powertrain. The device is controlled in a feed forward manner to alter an NVH characteristic of the vehicle in a desired manner based at least in part on a characteristic of the cylinder output level modulation operation of the engine.