Vehicle Vacuum Pump Speed Profiling for Wear Compensation
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Solution Overview
Problem
Motor vehicle vacuum pumps experience efficiency decreases over time due to wear of components, leading to elongated evacuation processes and potential insufficient vacuum in brake booster chambers, necessitating oversized and expensive components to maintain performance.
Innovation Solution
A motor vehicle vacuum pump with a rotatable vane pump rotor and an electronically commutated electric motor, featuring a pump control unit that adapts rotational speed through a wear compensation control module, which increases evacuation cycle speed values over time to maintain performance without the need for oversized components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the pump operation time increases, then the pump components wear out, but the pump efficiency continuously decreases
Solution Approach 1:
The patent applies dynamics by making the motor speed variable rather than constant. The control unit continuously adapts the motor speed based on feedback from the pressure sensor and considerations of pump operation time. This dynamic speed adjustment compensates for wear-induced efficiency decreases, maintaining adequate vacuum levels throughout the pump's lifetime without requiring oversized components.
Solution Approach 2:
The patent implements feedback control by using a pressure sensor to continuously monitor the vacuum level in the brake booster and feeding this information back to the control unit. The control unit processes this feedback and adjusts the motor speed accordingly, ensuring that pump efficiency is maintained despite component wear over time.
2Duration of action of stationary object
If the pump operation time increases, then the evacuation process elongates, but the brake booster vacuum chamber may become insufficiently evacuated
Solution Approach 1:
The system dynamically adjusts motor speed based on pump operation time and pressure feedback. As the pump operates longer and components wear, the control unit increases motor speed to compensate for reduced pump efficiency, ensuring evacuation reliability is maintained throughout the pump's lifetime.
Solution Approach 2:
The pressure sensor provides continuous feedback on vacuum levels to the control unit, which adjusts motor speed in real-time to ensure the brake booster chamber reaches and maintains adequate vacuum levels, regardless of pump age or component wear.
3Reliability
If an oversized pumping unit is used, then the pump can provide sufficient evacuation for long pump life time, but the motor vehicle vacuum pump becomes expensive
Solution Approach 1:
The patent changes the operational parameters (motor speed) dynamically rather than using oversized hardware. By adjusting speed based on operation time and pressure feedback, the system achieves reliable vacuum provision with a standard-sized pump, avoiding the cost premium of oversized components.
Solution Approach 2:
The control system automatically compensates for wear and maintains optimal performance through adaptive speed control, eliminating the need for oversized components or frequent replacements. The system serves itself by monitoring and adjusting its own operation to maintain reliability.
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 cost-efficient vacuum pump performance by compensating for wear-induced efficiency decreases, maintaining rapid and sufficient evacuation of brake booster vacuum chambers throughout the pump's lifespan.
Implementation Method 1
During pump operation, the rotor vanes are in touching radial contact with a pumping chamber sidewall
Implementation Method 2
an electronically commutated electric motor for driving the pump rotor
Implementation Method 3
define several rotating pumping-chamber compartments whose volume varies within one pump rotor revolution
Data Source
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AI summary
The invention is directed to a 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 speed profile storage (44) which stores an evacuation cycle speed profile (46) with at least one evacuation cycle speed value (SV), - an evacuation cycle control module (42) which is configured to control the variable rotational motor speed (MS) within an evacuation cycle according to the evacuation cycle speed profile (46), - a wear compensation control module (48;48') which is configured to regularly adapt the evacuation cycle speed profile (46) by irreversibly increasing at least one evacuation cycle speed value (SV) of the evacuation cycle speed profile (46) each adapting time to thereby gradually increase an average evacuation cycle speed with increasing total pump operation time (OT). The pump control unit (34;34') according to the present invention is configured to regularly adapt the evacuation cycle speed profile (46) for increasing the pump performance with increasing total pump operation time (OT). This allows to compensate a wear-caused pump efficiency decrease without the need of "oversizing" the pumping unit (24) and thus provides a reliable and cost-efficient motor vehicle vacuum pump (10; 10').