Vehicle Brake Booster Vacuum Pump Altitude Control
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Solution Overview
Problem
Conventional electric vacuum pumps for vehicle brake boosters face inefficiencies and reduced lifespan at high altitudes due to fixed switching thresholds, leading to continuous operation and increased energy consumption, as they fail to adjust to varying atmospheric pressures effectively.
Innovation Solution
A method that dynamically adjusts the deactivation threshold of the electric vacuum pump based on ambient atmospheric pressure, setting it as a percentage of maximum available vacuum, allowing the pump to deactivate appropriately at higher altitudes and avoiding continuous running, which is implemented through existing sensors and control systems without additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed switching thresholds are used for the vacuum pump, then the control system is simple, but the pump operates continuously at high altitude leading to increased energy consumption and reduced lifespan
Solution Approach 1:
The patent applies dynamics by making the pump control thresholds variable rather than fixed. The on/off switching values are dynamically adjusted based on ambient atmospheric pressure detected by a sensor. This allows the system to adapt to different altitudes automatically, preventing continuous pump operation at high altitude while maintaining simple control logic through pre-calibrated lookup tables.
Solution Approach 2:
The patent changes the parameters of the control system by adjusting the switching thresholds based on atmospheric pressure. Instead of using fixed pressure values, the system uses percentage-based thresholds (e.g., 65% and 80% of atmospheric pressure) that automatically scale with altitude. This parameter change resolves the contradiction by reducing energy consumption without requiring complex real-time calculations.
2Device complexity
If fixed switching thresholds are used for the vacuum pump, then the control system is simple, but the pump lifespan is reduced due to continuous operation at high altitude
Solution Approach 1:
The system dynamically adjusts the deactivation threshold based on atmospheric pressure to prevent continuous pump operation. At high altitude, the threshold is automatically raised to a level the pump can actually achieve, allowing it to cycle off properly. This extends pump lifespan by avoiding overheating and excessive wear from continuous running, while maintaining simple control through percentage-based thresholds.
Solution Approach 2:
The system uses feedback from an atmospheric pressure sensor to automatically adjust the pump control thresholds. The sensor provides continuous information about ambient pressure, and the control system uses this feedback to select appropriate switching values from lookup tables. This feedback mechanism extends pump lifespan by ensuring the pump operates within its capabilities at all altitudes without requiring complex real-time control.
3Adaptability or versatility
If atmospheric pressure compensation is implemented using a look-up table, then high altitude effects are compensated, but the device complexity increases due to additional control and memory apparatus
Solution Approach 1:
The patent uses atmospheric pressure data from an existing sensor (already present for other vehicle functions) to serve multiple purposes: both vehicle performance optimization and vacuum pump control. The same pressure sensor and processing unit are used for both functions, eliminating the need for dedicated altitude compensation hardware and reducing overall system complexity while maintaining adaptability.
Solution Approach 2:
The system performs preliminary action by pre-calculating and storing optimal pump switching thresholds in lookup tables for various atmospheric pressure conditions. These pre-computed values are stored in memory and automatically selected based on current pressure readings, eliminating the need for complex real-time calculations while providing accurate altitude compensation. This approach balances adaptability with simplicity.
4Use of energy by moving object
If the pump deactivation threshold is set close to maximum achievable vacuum, then energy consumption is reduced at sea level, but the pump cannot switch off at high altitude
Solution Approach 1:
The patent changes the deactivation threshold parameter from a fixed value to a variable that scales with atmospheric pressure. By expressing the threshold as a percentage of atmospheric pressure (e.g., 80% MAV), the system automatically adjusts the absolute threshold value based on altitude. This maintains energy efficiency at sea level while ensuring the pump can switch off at high altitude where atmospheric pressure is lower.
Solution Approach 2:
The system dynamically adjusts the deactivation threshold based on real-time atmospheric pressure measurements. At high altitude, the threshold is automatically raised to match the reduced maximum achievable vacuum, allowing the pump to cycle off properly. This dynamic adjustment maintains both energy efficiency and altitude adaptability without requiring separate control strategies for different elevations.
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
This approach ensures the vacuum pump operates within its achievable limits at all altitudes, reducing energy consumption and extending its lifespan by dynamically adjusting the deactivation threshold based on ambient pressure, thereby preventing continuous operation and maintaining efficient performance.
Implementation Method 1
vacuum exhausts a brake booster chamber which is divided by a diaphragm
Implementation Method 2
detecting ambient atmospheric pressure
Data Source
AI summary
An electric brake booster vacuum pump of a vehicle has a deactivation level determined according to a percentage of maximum available vacuum at the instant altitude of the vehicle. The activation level may be determined in the same way. The invention provides for earlier on-switching of a vacuum pump at altitude, while ensuring that the off-switching value is achievable at low atmospheric pressure.