Power Brake Cylinder Pressure Estimation Without Direct Sensors
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Solution Overview
Problem
Existing power brake systems incur high costs due to the use of pressure sensors for ascertaining power cylinder pressure, and there is a need for a more cost-efficient method.
Innovation Solution
A method that calculates power cylinder pressure using a correlation model between motor values and ESP pressure sensor readings, accounting for time delays and deviations, eliminating the need for direct pressure sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pressure sensor is disposed directly downstream of the power cylinder to ascertaining power cylinder pressure, then the power cylinder pressure can be measured accurately, but the system costs increase
Solution Approach 1:
The patent uses an ESP pressure sensor to measure brake line pressure as a proxy for power cylinder pressure. Instead of directly measuring the power cylinder pressure with a dedicated sensor, the system creates a correlated measurement through the hydraulic connection to the brake lines, thereby reducing cost while maintaining measurement capability
Solution Approach 2:
The patent replaces the direct mechanical pressure sensing at the power cylinder with an electronic control system that calculates power cylinder pressure based on motor values and ESP pressure sensor readings. This substitution of direct mechanical measurement with computational estimation reduces hardware costs
2Ease of manufacture
If a correlation model is used to calculate potential power cylinder pressure from motor values, then additional pressure sensors can be eliminated, but measurement precision may be compromised
Solution Approach 1:
The patent employs feedback by continuously comparing the potential power cylinder pressure calculated from the correlation model with the actual power cylinder pressure measured by the ESP pressure sensor. The system uses this comparison to detect deviations and correct the correlation model, thereby maintaining measurement precision over time
Solution Approach 2:
The patent performs preliminary calibration to determine the correlation between motor values and power cylinder pressure before normal operation. This preliminary action establishes the baseline correlation model that is then refined through ongoing feedback, ensuring accurate measurements from the start
Data Source
AI summary
A method for ascertaining a power cylinder pressure of a power brake system. The method includes ascertaining at least one motor value of a power cylinder motor, ascertaining a potential power cylinder pressure from the motor value using a model of the correlation between the motor value and the potential power cylinder pressure, and ascertaining a power cylinder pressure using an ESP pressure sensor in the ESP brake system. The method also includes comparing the potential power cylinder pressure with the power cylinder pressure of the ESP pressure sensor taking into account a time delay between the potential power cylinder pressure and the measured power cylinder pressure of the ESP pressure sensor and correcting the correlation model in accordance with an ascertained deviation.