Vehicle Vacuum Pump Speed Control for Resonance Noise Avoidance
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Solution Overview
Problem
Modern motor vehicle electric vacuum pumps can cause intense noise when operated at rotational speeds that match or are close to resonance frequencies of the vehicle or its components, leading to inefficient and unreliable braking system performance.
Innovation Solution
A motor vehicle vacuum pump with a rotatable pump rotor and an electronically commutated electric motor, featuring a pump control unit with a noise reduction control module that adjusts the rotational motor speed to avoid noise-critical frequencies by defining and operating outside noise-critical speed bands, ensuring efficient and quiet operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the electric motor is operated at efficiency-optimized rotational speeds, then energy efficiency is improved, but noise intensity increases due to resonance frequencies
Solution Approach 1:
The control unit dynamically adjusts the rotational motor speed based on operating conditions, switching between efficiency-optimized speeds and noise-reduced speeds. The system adapts the motor speed in real-time by selecting from multiple pre-defined speed levels stored in memory, allowing optimization of both energy efficiency and noise reduction depending on current operational requirements
Solution Approach 2:
The invention changes the operational parameter (rotational motor speed) to resolve the contradiction. By storing multiple pre-defined rotational speed levels in memory and selecting appropriate speeds based on noise-critical bands, the system transforms a single-parameter optimization problem into a multi-parameter solution that balances energy efficiency with noise reduction
2Productivity
If the electric motor is operated at high rotational speeds to ensure adequate vacuum supply, then vacuum provision is improved, but noise is intensified due to resonance frequencies
Solution Approach 1:
The control unit dynamically selects rotational motor speeds from multiple pre-defined levels stored in memory, adjusting the operating speed based on vacuum requirements and noise-critical band identification. This dynamic adaptation allows the system to maintain adequate vacuum provision while avoiding noise-critical speed ranges when possible
Solution Approach 2:
The system implements periodic monitoring and adjustment of rotational speeds, continuously evaluating whether current operating speeds fall within noise-critical bands and making adjustments as needed to maintain both productivity and noise reduction
3Object-generated harmful factors
If the rotational motor speed is varied to avoid noise-critical speed bands, then noise is reduced, but energy efficiency may be compromised
Solution Approach 1:
The control unit dynamically adjusts rotational motor speed based on real-time operating conditions, switching between efficiency-optimized speeds and noise-reduced speeds. The system adapts the motor speed in real-time by selecting from multiple pre-defined speed levels stored in memory, allowing optimization of both energy efficiency and noise reduction depending on current operational requirements
Solution Approach 2:
The system incorporates feedback mechanisms where the control unit monitors operating conditions and adjusts rotational speeds accordingly. By storing multiple pre-defined speed levels and selecting appropriate speeds based on feedback about current vacuum requirements and noise levels, the system optimizes the balance between noise reduction and energy efficiency
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 noise and enhances the reliability and durability of the vacuum pump by preventing operation at noise-critical speeds, thereby providing a low-noise and efficient motor vehicle vacuum pump.
Implementation Method 1
an electronically commutated electric motor which is free of mechanically abrading brush contacts and which allows an electronical control of its rotational motor speed
Implementation Method 2
the pump rotor comprises a rotor body which is eccentrically arranged in a substantially cylindrical pumping chamber and which comprises several radially slidable rotor vanes. During pump operation, the rotor vanes are in touching radial contact with a pumping chamber sidewall and define several rotating pumping-chamber compartments whose volume varies within one pump rotor revolution
Data Source
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AI summary
The present invention is directed to motor vehicle vacuum pump (10;10'), comprising a pumping unit (24) with a rotatable pump rotor (26), an electronically commutated electric motor (30) for driving the pump rotor (26), and a pump control unit (34;34') for controlling a variable rotational motor speed (MS) of the electric motor (30), the pump control unit (34;34') comprising - a standard -operation control module (40;44) which is configured to determine a standard-operation speed value (SO), and to set the variable rotational motor speed (MS) corresponding to the standard-operation speed value (SO), and - a noise reduction control module (42;44) which is configured to monitor the standard-operation speed value (SO), and to overrule the standard-operation control module (40;44) if the standard-operation speed value (SO) is within a noise-critical speed band (CB1,CB2), in that way that the variable rotational motor speed (MS) is set corresponding to a noise-optimized speed value (N01,N02) which is outside of the noise-critical speed band (CB1,CB2) in this case. The standard-operation control module (40;44) provides a reliable and efficient pump operation, wherein the noise reduction control module (42;44) according to the present invention reliably avoids that the electric motor (30) is operated with a noise-critical rotational motor speed. This provides an efficient and low-noise motor vehicle vacuum pump (10;10')·