Vehicle Vacuum Pump Rotor Stopping to Prevent Abrupt Venting
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Solution Overview
Problem
Modern motor vehicle electric vacuum pumps experience damage and noise due to abrupt pressure balance and backward rotation when switched off, leading to humidity and contamination issues.
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 deceleration map for controlled motor speed reduction and a rotor-stopping control module to smoothly stop the motor, preventing abrupt venting and backward rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the electric motor is instantly switched off when the vacuum chamber pressure reaches the threshold, then the vacuum pump achieves high productivity and energy efficiency, but the pump rotor rotates backwards causing damage and noise
Solution Approach 1:
The control unit initiates a controlled deceleration process before the motor completely stops, using a deceleration map to gradually reduce motor speed and prevent the pump rotor from rotating backwards. This preliminary action of controlled stopping prevents damage to the pump components while maintaining high productivity during operation.
2Loss of energy
If the electric motor is instantly switched off, then energy consumption is minimized, but abrupt pressure balance causes high inflow velocity sucking in humidity and contaminations
Solution Approach 1:
The control unit performs a preliminary controlled deceleration using the deceleration map before complete motor shutdown, preventing abrupt pressure balance. This gradual stopping process avoids creating high inflow velocities that would suck in humidity and contaminations, while still minimizing energy consumption by shutting down the motor when vacuum threshold is reached.
Solution Approach 2:
The deceleration map provides a cushioning effect by gradually reducing motor speed before complete shutdown, preventing the abrupt pressure equalization that would cause harmful inflow. This beforehand cushioning protects the system from humidity and contamination ingress while maintaining energy efficiency.
3Device complexity
If the electric motor is instantly switched off, then the control system remains simple, but significant noise is generated due to abrupt venting
Solution Approach 1:
The control unit implements a preliminary controlled deceleration sequence using a deceleration map before complete motor shutdown. This approach reduces venting noise by preventing abrupt pressure balance, while the control complexity remains manageable through implementation in existing pump control units.
4Loss of time
If the electric motor is instantly switched off, then the response time is minimal, but the pump rotor backward rotation causes damage to the electric motor and pumping unit
Solution Approach 1:
The control unit initiates a preliminary controlled deceleration process using the deceleration map before the motor completely stops. This prevents the pump rotor from rotating backwards and causing damage to the motor and pumping unit, while minimizing the time loss through efficient deceleration control.
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 ensures reliable and low-noise operation by avoiding high inflow velocities and contamination, providing a controlled venting process that maintains pump integrity and reduces noise.
Implementation Method 1
The rotor vanes are pushed radially outwardly by the centrifugal force during pump rotor rotation
Implementation Method 2
The electric motor comprises an electromagnetic motor stator with at least one stator coil, and comprises a permanent-magnetic motor rotor
Data Source
Figure 1
Figure 2
AI summary
The invention is directed to a motor vehicle vacuum pump (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) for controlling a variable rotational motor speed (MS) of the electric motor (30), wherein the pump control unit (34) comprises - a deceleration map storage (40) storing a deceleration map (42) with at least one time-dependent and/or motor-speed-dependent motor deceleration parameter (DP1,DP2), and - a rotor-stopping control module (44) which is connected with the deceleration map storage (40) and which is configured to actively control the variable rotational motor speed (MS) based on the deceleration map (42) during a rotor stopping process (RSP). The pump control unit (34) according to the present invention provides an actively controlled rotor stopping process (RSP) which reliably avoids an abrupt venting of the motor vehicle vacuum pump (10) and thus minimizes humidity and contamination intrusion into the vacuum pump and minimizes noise. This provides a reliable and low-noise motor vehicle vacuum pump (10).