Brake Booster Vacuum Estimation via Pedal Actuation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing brake systems rely on vacuum sensors for maintaining vacuum in brake boosters, which can lead to inefficiencies and increased costs due to the need for redundant sensors and continuous operation of vacuum pumps, and may not effectively detect defects or ensure minimum deceleration in fault scenarios.
Innovation Solution
A method that estimates the remaining vacuum in a brake booster independently of pressure sensors by calibrating the relationship between brake pedal actuations and vacuum levels, using available sensors like pedal travel or force sensors to control the motor-pump unit and maintain vacuum demand, reducing the need for redundant sensors and continuous operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vacuum sensors are used to detect pressure in the vacuum chamber, then the braking system can maintain vacuum levels, but the system complexity and cost increase due to redundant sensors
Solution Approach 1:
The brake booster system uses its own operational parameters (pedal travel, pedal force, brake pressure) to estimate vacuum levels through calculation rather than direct measurement. The control unit computes the vacuum state based on the relationship between pedal actuation and vacuum consumption, allowing the system to self-monitor without additional vacuum sensors.
Solution Approach 2:
The patent replaces the mechanical/vacuum sensing system with an electronic calculation system. Instead of using physical vacuum sensors to detect pressure, the system uses electronic sensors (pedal position sensors, force sensors) combined with computational algorithms to estimate vacuum levels, substituting direct vacuum measurement with indirect calculation.
2Reliability
If continuous operation of vacuum pumps is used to maintain vacuum, then vacuum levels are maintained, but energy consumption increases
Solution Approach 1:
The vacuum pump operates periodically rather than continuously. The control unit monitors the estimated vacuum level through calculation and activates the pump only when vacuum levels drop below threshold values. This periodic operation maintains vacuum effectiveness while significantly reducing energy consumption compared to continuous operation.
Solution Approach 2:
The system implements feedback control by continuously calculating vacuum levels based on pedal actuation data and using this information to control pump operation. When the calculated vacuum level falls below a threshold, the pump is activated; when sufficient vacuum is restored, the pump stops, creating a closed-loop feedback system that optimizes energy usage.
3Reliability
If vacuum sensors are used for defect detection, then fault scenarios can be detected, but the system requires additional sensors and complexity
Solution Approach 1:
The system uses its existing sensors (pedal position, pedal force, brake pressure) to detect vacuum-related defects through calculation. By analyzing the relationship between pedal actuation and expected vacuum consumption, the system can identify anomalies such as leaks or sensor failures without requiring dedicated vacuum sensors for fault detection.
Solution Approach 2:
The control unit acts as an intermediary that processes data from existing sensors and calculates vacuum levels indirectly. This intermediary calculation layer enables defect detection by comparing expected vacuum consumption (based on pedal actuation) with actual system behavior, allowing fault identification without direct vacuum measurement.
4Measurement precision
If pressure sensors are installed in the vacuum chamber, then vacuum levels can be measured directly, but the cost and system complexity increase
Solution Approach 1:
The patent substitutes direct pressure measurement with electronic calculation. Instead of installing pressure sensors in the vacuum chamber, the system uses electronic sensors to measure pedal position and force, then calculates vacuum levels based on the known relationship between pedal actuation and vacuum consumption, eliminating the need for physical pressure sensing in the vacuum environment.
Solution Approach 2:
The control unit serves as an intermediary calculation system that translates measurements from external sensors (pedal position, force) into estimates of internal vacuum conditions. This intermediary approach allows the system to infer vacuum pressure indirectly through mathematical relationships rather than direct measurement, reducing sensor installation complexity.
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 simplifies the braking system, reduces costs, and enhances reliability by using existing sensors to estimate vacuum levels, allowing for demand-controlled vacuum maintenance and improved fault detection, thereby ensuring consistent braking performance and safety.
Implementation Method 1
at least one vacuum chamber being or being able to be connected to a vacuum source to build up a vacuum
Implementation Method 2
the actuating force applied by the driver on the brake pedal is reinforced by the auxiliary power of a brake booster. Vacuum or vacuum brake boosters, which use a vacuum (or the pressure difference between a vacuum chamber and a working chamber ventilated according to the actuation of the brake pedal) as an energy source
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a method for operating a braking system, comprising a brake booster, which is divided into at least one vacuum chamber and at least one working chamber by at least one movable partition, wherein at least one vacuum chamber is connected, or can be connected, to a vacuum source for creating a vacuum, and further comprising at least one sensor, which detects at least one variable such as travel and/or angle and/or force of a brake pedal actuation and/or a brake pressure that is built up in at least one main brake cylinder connected to the brake booster in accordance with a brake pedal actuation. According to the invention, the remaining vacuum in at least one vacuum chamber is estimated on the basis of at least one of the detected variables by considering actuations already performed. The invention further relates to a braking system and to the use thereof.