Vacuum Pump Control via Indirect Pressure Calculation
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Solution Overview
Problem
Conventional electric vacuum pump systems in vehicles operate inefficiently as they constantly run to maintain negative pressure in brake boosters, leading to reduced pump service life and unnecessary power consumption, and the use of pressure sensors increases vehicle weight and complexity.
Innovation Solution
A method to indirectly ascertain the negative pressure in the brake booster by calculating the difference between negative pressure loss and gain using hydraulic pressure and ambient pressure, allowing the vacuum pump to activate only when necessary, eliminating the need for a dedicated pressure sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vacuum pump operates constantly to maintain negative pressure in the brake booster, then the negative pressure is maintained, but the pump service life is reduced and power is consumed unnecessarily
Solution Approach 1:
The vacuum pump operates periodically rather than continuously. The control device monitors negative pressure and activates the pump only when the pressure drops below a threshold value, allowing the pump to remain idle when sufficient vacuum is already present, thereby extending service life and reducing power consumption.
Solution Approach 2:
The system uses feedback from negative pressure monitoring to control pump operation. When the negative pressure in the brake booster falls below a predetermined threshold, the control device receives a signal and activates the vacuum pump to restore the required pressure level, creating a closed-loop control system that prevents unnecessary operation.
2Productivity
If a pressure sensor is used to monitor negative pressure and control pump activation, then pump operation is optimized, but vehicle cost, weight, and complexity increase
Solution Approach 1:
The control device performs multiple functions: it monitors negative pressure, determines pump activation requirements, controls pump operation, and adapts to varying pump characteristics. By consolidating these functions into an existing control unit rather than adding dedicated sensor and control hardware, the system achieves optimized pump operation without increasing overall system complexity.
Solution Approach 2:
The system uses readily available data from the vehicle's existing sensors and control systems to determine negative pressure conditions and control pump operation. Rather than requiring a dedicated pressure sensor, the control device utilizes information already present in the vehicle's electronic architecture, allowing the system to self-regulate without additional components.
3Reliability
If the vacuum pump operates constantly, then negative pressure is maintained, but energy consumption increases
Solution Approach 1:
The vacuum pump operates periodically based on actual need rather than continuously. The control device activates the pump only when negative pressure drops below the threshold, allowing energy-saving idle periods when sufficient vacuum is already maintained, thereby significantly reducing overall power consumption while ensuring reliability when needed.
Solution Approach 2:
The system dynamically adjusts pump operation parameters based on actual negative pressure conditions. By monitoring pressure levels and activating the pump only when thresholds are breached, the system changes its operational state from constant to conditional operation, optimizing the balance between reliability and energy consumption.
Data Source
AI summary
A method for actuating an electric vacuum pump of a brake booster including indirectly ascertaining a negative pressure in the brake booster. Depending on the indirectly ascertained negative pressure, and on a pumping capacity of the vacuum pump, ascertaining at least one activation parameter for the vacuum pump. Activating the vacuum pump in accordance with the activation parameter, when the indirectly ascertained negative pressure drops below a predefined minimum value.