Electric Vacuum Pump Control Device for Thermal Overload Prevention
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Solution Overview
Problem
Electric vacuum pumps in motor vehicles are prone to thermal overload due to increased operating temperature, leading to potential defects and necessitate periodic shutdowns, which can occur at critical driving situations.
Innovation Solution
A control device dynamically adjusts the operating parameters of the electric vacuum pump by modifying the target values for the controlled variable based on cumulative operating time or temperature, preventing excessive stress and ensuring the pump operates within a non-critical range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electric vacuum pump operates continuously to maintain vacuum pressure, then the vacuum supply reliability is improved, but the pump temperature increases leading to thermal overload and potential defects
Solution Approach 1:
The patent implements dynamic control of the upper threshold value based on cumulative operating time. As the pump operates longer, the upper threshold is reduced, causing the pump to cycle off earlier. This dynamic adjustment prevents thermal overload while maintaining adequate vacuum supply through adaptive operation patterns.
Solution Approach 2:
The patent introduces periodic cycling of the vacuum pump by comparing operating time against a threshold. When the cumulative operating time exceeds the threshold, the pump is switched off; when it falls below, the pump restarts. This periodic action prevents continuous operation and associated thermal overload while maintaining vacuum pressure within acceptable ranges.
2Temperature
If the electric vacuum pump is switched off periodically to prevent thermal overload, then the pump temperature is controlled, but the vacuum pressure may drop below required levels during critical driving situations
Solution Approach 1:
The upper threshold value is dynamically reduced based on cumulative operating time rather than using a fixed threshold. This ensures the pump cycles off before reaching critical temperature while adapting to different operating conditions, maintaining vacuum pressure stability without causing thermal overload.
Solution Approach 2:
The system continuously monitors cumulative operating time and uses this feedback to adjust the upper threshold value. This closed-loop control ensures the pump operates within safe temperature limits while maintaining adequate vacuum pressure by adapting the cycling pattern to actual operating conditions.
3Device complexity
If a fixed upper threshold value is used for controlling the vacuum pump, then the control system is simple, but the pump cannot adapt to varying operating conditions and may be subjected to excessive stress
Solution Approach 1:
The patent transforms the fixed upper threshold into a dynamic threshold that varies with cumulative operating time. This simple yet effective adaptation mechanism allows the system to respond to varying operating conditions without requiring complex control algorithms or additional sensors.
Solution Approach 2:
The system changes the threshold parameter based on operating time accumulation. By modifying the threshold value according to how long the pump has been running, the system adapts to different operating conditions and prevents excessive stress without adding significant complexity to the control logic.
Data Source
Figure 1~2
Figure 3a~3b
Figure 4
AI summary
The invention relates to a control device (12) for an electric vacuum pump (13), having a determining device (12a) which is designed to measure an operating parameter of the electric vacuum pump, which is dependent on an operating duration of the electric vacuum pump, and a regulating variable for the electric vacuum pump, having a switching device (12d) which is designed to activate or deactivate the vacuum pump as a function of a comparison of the regulating variable with at least one setpoint value, and having a regulating device (12c) which is designed to vary the at least one setpoint value of the regulating variable as a function of the operating parameter.