Brake System Pump Calibration via Power Consumption Correction
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Solution Overview
Problem
The functional relationship between pressure difference and electrical control in electrically controllable brake systems is subject to significant scattering due to manufacturing tolerances and aging/wear of system components, leading to inaccurate brake pressure generation.
Innovation Solution
Determine a predetermined first and second pressure difference and their associated power consumptions, calculate a correction value, and use this value to set a target pressure difference, allowing for continuous calibration and error detection in the brake system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electrically controlled valve arrangements are used to set pressure difference, then brake pressure control is achieved, but manufacturing tolerances and aging cause significant scattering in the functional relationship
Solution Approach 1:
The patent applies preliminary action by performing calibration measurements before normal operation to establish correction values. The system determines the actual functional relationship between electrical control signals and pressure difference through measured values from sensors, then stores correction values that compensate for manufacturing tolerances and aging effects. This preliminary characterization eliminates the need for repeated complex measurements during operation.
Solution Approach 2:
The patent implements feedback by using measured values from pressure sensors to determine the actual pressure difference and compare it with the target value. Based on this feedback, the control unit adjusts the electrical control signals using stored correction values to compensate for deviations caused by manufacturing tolerances and aging, ensuring accurate pressure control throughout the system's operational life.
2Measurement precision
If calibration measurements are performed frequently to maintain accuracy, then pressure control precision is improved, but system complexity and measurement time increase
Solution Approach 1:
The patent performs calibration measurements as a preliminary action during system setup or maintenance periods, storing the results as correction values in memory. This eliminates the need for frequent complex calibration measurements during normal operation, reducing system complexity while maintaining accuracy through the use of pre-determined correction factors.
Solution Approach 2:
The system uses its own operational data and sensor measurements to automatically determine correction values without requiring external calibration equipment or complex intervention. The control unit processes measured values and generates correction values autonomously, simplifying the calibration process and reducing system complexity.
3Measurement precision
If correction values are determined through multiple measurements, then accuracy is improved, but calibration time and energy consumption increase
Solution Approach 1:
The patent determines correction values based on a sufficient number of measurements that achieve the required accuracy without performing excessive measurements. The system identifies when adequate correction data has been obtained and proceeds to normal operation, optimizing the balance between calibration time and accuracy by avoiding unnecessary extended measurement periods.
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
Ensures accurate brake pressure generation by compensating for changes in power consumption, enabling recalibration during operation and detecting potential system errors, thus maintaining system performance and safety.
Implementation Method 1
The power consumption of the pump is determined by means of the electric motor driving the pump, which acts as a converter of electrical energy into mechanical energy
Data Source
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AI summary
A method for operating an electrically controllable brake system for a motor vehicle having at least one electrically actuated valve arrangement (71; 51",1") for setting a pressure difference (Δρ) between a second brake pressure (Pcircuit) and a first brake pressure (PHZ; Pwheel), wherein in a first time interval (Δt1) a predetermined first pressure difference (Δρ1) is set and an associated first power consumption value (P1) of the pump (31) is identified; in a second time interval (Δt2) a predetermined second pressure difference (Δρ2) is set and an associated second power consumption value (P2) of the pump (31) is identified; a correction value (K) is obtained from the first power consumption value (P1) and the second power consumption value (P2); the correction value (K) is taken into account for setting a setpoint value (S) for the pressure difference (Δρ).