Exhaust Tuning Valve Imbalance Control
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Solution Overview
Problem
Existing exhaust noise reduction methods, such as active exhaust valve systems, fail to effectively address sub-firing order vibrations, leading to undesirable sounds and vibrations in separate tail-pipe outlets, which can result in customer complaints.
Innovation Solution
The system differentially adjusts exhaust tuning valves in separate exhaust passages to address combustion torque imbalances between cylinder groups, using a vibration dose value and driving behavior classification to optimize valve positions and reduce sub-firing order disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a muffler is used to dampen engine noise, then exhaust noise is reduced, but undesirable sounds and insufficient desirable sound generation remain
Solution Approach 1:
The exhaust valve position is dynamically adjusted based on real-time driving conditions and detected vibration patterns. The system transitions from a static muffler approach to a dynamic control system that can open or close the exhaust valve to either dampen noise or allow desirable exhaust notes to pass through, depending on the driving situation.
Solution Approach 2:
The system changes the exhaust flow parameters by adjusting the exhaust valve position. By varying the valve opening degree, the system can alter exhaust gas flow rate, backpressure, and acoustic characteristics to eliminate undesirable sounds while preserving desirable engine notes.
2Object-affected harmful factors
If active exhaust valve systems adjust valve position based on driving conditions, then exhaust noise control is improved, but sub-firing order vibrations cause undesirable sounds in separate tail-pipe outlets
Solution Approach 1:
The system incorporates vibration sensors that continuously monitor exhaust system vibrations, particularly sub-firing order vibrations. This feedback is processed by the control unit, which then adjusts the exhaust valve position to counteract detected vibration patterns, eliminating undesirable sounds from separate tail-pipe outlets.
Solution Approach 2:
The exhaust valve position is dynamically adjusted based on real-time driving conditions and detected vibration patterns. The system transitions from a static muffler approach to a dynamic control system that can open or close the exhaust valve to either dampen noise or allow desirable exhaust notes to pass through, depending on the driving situation.
3Object-generated harmful factors
If differential control of exhaust valves is implemented to address cylinder imbalance, then suborder vibrations are reduced, but system complexity increases
Solution Approach 1:
The exhaust system is segmented into separate exhaust passages for different cylinder groups, each with its own independently controlled exhaust valve. This segmentation allows differential control of exhaust flow from different cylinder banks, enabling targeted suppression of suborder vibrations generated by combustion torque imbalances.
Solution Approach 2:
Each exhaust valve is controlled independently based on the specific characteristics of its associated cylinder group. The control system applies local quality by adjusting each valve's opening degree according to the local vibration and torque characteristics, rather than applying a uniform control strategy to all exhaust valves.
Data Source
AI summary
Methods and systems are provided for controlling imbalance with an exhaust tuning valve. In one example, a method may include adjusting a first exhaust tuning valve in response to combustion torque imbalance in a first and second group of cylinders. Additionally or alternatively, the position of the second exhaust tuning valve may be adjusted in response to an imbalance generated by the same group of cylinders.