Seat Ventilation Fan Speed Control via Acoustic Characteristic Map
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Solution Overview
Problem
Existing seat ventilation devices with fans, especially those using brushless DC motors, face challenges in maintaining optimal ventilation performance while minimizing noise emissions, as the speed of the fan increases with back pressure changes due to occupancy, leading to increased noise and reduced comfort.
Innovation Solution
A method and device that map-control the fan speed based on a characteristic map created by measuring noise emissions under varying back pressures, ensuring the speed is adjusted to maintain a predefined acoustic limit value, allowing for optimal noise management and maximum volume flow regardless of counter-pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the fan speed is increased to maintain volume flow when back pressure increases due to occupancy, then the ventilation performance is maintained, but the noise emissions increase
Solution Approach 1:
The patent applies dynamics by making the fan speed adjustable and adaptive rather than fixed. The control unit dynamically adjusts the rotational speed of the fan based on detected back pressure conditions, allowing the system to optimize between volume flow and noise emissions in real-time. This is achieved through a control method that modifies operational parameters according to actual operating conditions.
Solution Approach 2:
The patent implements parameter changes by varying the rotational speed parameter of the fan motor in response to changing back pressure conditions. The control unit changes the speed parameter to maintain optimal performance, using a characteristic map that correlates back pressure values with appropriate speed settings to balance ventilation effectiveness and acoustic performance.
2Object-generated harmful factors
If the fan speed is reduced to decrease noise emissions, then the acoustic comfort is improved, but the volume flow and ventilation performance decrease
Solution Approach 1:
The patent applies feedback by using a control unit that detects back pressure conditions and uses this information to adjust fan speed accordingly. The system continuously monitors operating conditions and provides feedback to the control unit, which then modifies the fan speed to maintain optimal performance while minimizing noise, creating a closed-loop control system.
Solution Approach 2:
The system dynamically adjusts fan speed based on real-time back pressure detection, allowing the ventilation system to adapt its performance characteristics to match actual occupancy and environmental conditions, thereby optimizing the balance between noise emissions and volume flow delivery.
3Productivity
If the fan speed is continuously adjusted to adapt to back pressure changes, then the ventilation performance is optimized, but the control system complexity increases
Solution Approach 1:
The patent applies self-service by implementing a control system that automatically detects back pressure conditions and adjusts fan speed without requiring manual intervention or complex external control mechanisms. The control unit autonomously manages the optimization process using pre-stored characteristic maps, allowing the system to self-regulate based on its own operational parameters.
Solution Approach 2:
The patent implements preliminary action by pre-storing characteristic maps that contain optimized speed recommendations for various back pressure conditions. This preparatory work allows the control unit to quickly determine appropriate speed adjustments without performing complex real-time calculations, thereby simplifying the control system while maintaining optimized ventilation performance.
4Measurement precision
If the characteristic map is created with precise acoustic measurements under varying back pressures, then the noise control accuracy is improved, but the measurement and calibration time increase
Solution Approach 1:
The patent applies preliminary action by performing acoustic measurements and creating the characteristic map during the manufacturing or setup phase, before the vehicle is delivered to the customer. This pre-calibration process establishes accurate speed recommendations for various back pressure conditions, allowing for precise noise control during actual operation without requiring time-consuming calibration in the field.
Data Source
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AI summary
The invention relates to a method for operating a seat ventilation device (5) which has at least one blower (6) and at least one ventilation opening (7) which is arranged in a seat surface (4) and has an air-ventilation connection to the blower (6), wherein the blower (6) is actuated in order to set a setpoint rotational speed, and wherein the setpoint rotational speed is adapted as a function of a current state value (i) of the blower (6) which depends on a volume flow (V) conveyed by the blower (6). It is provided that the adapted rotational speed is selected from a characteristic diagram (KF) as a function of the current state value (i), wherein the characteristic diagram (KF) is/has been produced as a function of a predefined acoustic limiting value.