Brake Actuation Recognition via Pressure Derivative Analysis
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Solution Overview
Problem
Existing brake systems struggle to reliably recognize the minimum actuation state of the brake actuating element, often leading to incorrect interpretations of pressure deviations in the brake booster's pressure chamber, which can result in unnecessary deactivation of the electric vacuum pump and false error warnings.
Innovation Solution
A brake actuation recognition device that determines the time derivative of pressure in the brake booster's pressure chamber, allowing for differentiation between actuation states below and above the minimum actuation state, and controls the pressure monitoring device to prevent incorrect error recognition, thereby optimizing vehicle functions and reducing unnecessary warnings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the brake actuation recognition device uses a brake light switch sensor to detect brake pedal actuation, then the system can recognize brake actuation states, but the device complexity increases and the reliability decreases due to potential false error warnings and unnecessary deactivations
Solution Approach 1:
The patent extracts the brake actuation detection function from the traditional brake light switch sensor and relocates it to the existing pressure monitoring system. By using the pressure sensor already present in the brake booster to detect pressure changes that correspond to brake actuation, the system eliminates the need for a separate brake light switch, thereby reducing device complexity while maintaining or improving reliability
Solution Approach 2:
The pressure sensor in the brake booster is given multiple functions: it continues to monitor brake booster pressure for its original purpose and simultaneously detects brake actuation states by monitoring pressure changes. This multi-functionality eliminates the need for dedicated brake actuation sensors, reducing overall system complexity while improving reliability through cross-validation of detection signals
2Reliability
If the pressure monitoring device continuously monitors pressure deviations in the pressure chamber, then the system can detect pressure errors, but false error warnings occur during frequent or dynamic brake actuation due to strong pressure drops being misinterpreted as errors
Solution Approach 1:
The system performs preliminary detection of brake actuation states by monitoring pressure changes before making error determination decisions. By identifying that a pressure drop is due to normal brake actuation (rather than a true error) through the brake actuation recognition logic, the system prevents false error warnings and unnecessary deactivations of the electric vacuum pump
Solution Approach 2:
The system uses feedback from the pressure monitoring data to dynamically adjust error detection thresholds or logic. When pressure changes consistent with brake actuation are detected, the error monitoring function is temporarily adjusted to prevent false positives, while still maintaining sensitivity to true pressure errors. This feedback mechanism distinguishes between normal operational pressure variations and actual error conditions
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 solution ensures accurate recognition of brake actuation states, preventing incorrect deactivation of the electric vacuum pump and reducing false error warnings, thus enhancing vehicle performance and reducing driver inconvenience.
Implementation Method 1
a pressure monitoring device which, in a first operating mode, is configured to compare an actual quantity, which relates to a pressure in a pressure chamber (16) of the brake booster, with a specified target quantity range
Implementation Method 2
a differentiation device by which a time derivative of a provided actual quantity, which relates to a pressure in a pressure chamber (16) of the brake booster, can be determined as a modification quantity
Data Source
AI summary
A brake actuation recognition device has an evaluation device by which at least one provided modification quantity relating to a temporal change in an actual quantity relating to a pressure in a pressure chamber of a brake booster of a brake system is compared with a specified comparison quantity range such that, if the at least one provided modification quantity is within the comparison value range, it is determined that a brake actuating element situated on the brake system is in an actuation state below a specified minimum actuation state, and a corresponding information is outputted.