Detecting Gas Occlusion in Hydraulic Brake Systems
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Solution Overview
Problem
Hydraulic brake systems, including brake-by-wire systems, fail to detect gas inclusions effectively, leading to potential safety issues as the increased elasticity due to trapped gas may not be perceptible to the driver, and can exacerbate system failures if combined with other errors.
Innovation Solution
A method to detect gas inclusions by determining the pressure gradient of the hydraulic medium during braking, calculating a pressure gradient parameter from the ratio of displaced volume to pressure, and comparing it against a threshold value to assess critical gas locks, which can trigger alerts and compensatory measures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If brake-by-wire system is used to decouple brake pedal from brake system, then driver feedback about brake system state is reduced, but this also prevents driver from perceiving gas lock in the brake system
Solution Approach 1:
The patent implements an electronic feedback system that uses sensors to detect brake system parameters (pressure, temperature, fluid volume) and provides information to the driver through display units or haptic feedback mechanisms, replacing the lost mechanical feedback pathway with an electronic information channel that can convey system state without mechanical coupling
Solution Approach 2:
The patent replaces the mechanical feedback pathway (brake pedal connection) with an electronic sensing and display system that uses sensors, processors, and user interface elements to provide driver information about brake system state, substituting mechanical information transfer with electronic information processing
2Reliability
If trapped gas exceeds critical limit value, then brake system performance deteriorates, but early detection is needed to prevent dangerous situations
Solution Approach 1:
The patent replaces difficult mechanical measurement of gas presence with electronic sensing methods that measure brake fluid parameters (pressure, temperature, volume) and use these electrical/measured quantities to infer gas lock conditions, making detection easier and more reliable
Solution Approach 2:
The patent introduces intermediate measurement parameters (brake fluid pressure, temperature, volume) that serve as mediators to indirectly detect gas lock conditions, using these intermediate quantities as proxies for the difficult-to-measure presence of trapped gas
3Quantity of substance
If air is present in brake circuit, then larger volume is required to achieve specific pressure, but this increased elasticity cannot be compensated for in brake-by-wire systems
Solution Approach 1:
The patent uses sensors to continuously monitor brake system parameters and provides feedback to the control unit, which can then compensate for the effects of trapped gas by adjusting brake actuation commands or alerting the driver, creating a closed-loop system that addresses the volume-pressure anomaly
Solution Approach 2:
The patent monitors changes in brake system parameters (pressure, temperature, fluid volume) over time and uses these parameter variations to detect gas lock conditions, exploiting the fact that trapped gas causes abnormal parameter changes compared to a gas-free system
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
Enables early detection of excessive gas locks, preventing dangerous driving situations by providing feedback to the driver and allowing for automatic countermeasures to maintain brake system performance.
Implementation Method 1
the pressure gradient of the hydraulic medium is determined during a braking process from the ratio of the displaced hydraulic volume in the brake system and the associated pressure
Implementation Method 2
When the brake pedal is actuated, increased pressure is generated in the main brake cylinder and transmitted to the wheel brake cylinders
Implementation Method 3
a larger volume is required to achieve a specific pressure due to the higher compressibility of the air compared to the compressibility of the hydraulic medium
Data Source
Figure 1~2
AI summary
In a method for detecting a gas occlusion in a hydraulic brake system, when the brakes are activated the pressure gradient of the hydraulic medium is determined as a ratio of the displaced hydraulic volume and the assigned pressure, wherein a characteristic value is determined from the quotient of two different pressure gradients, and a gas occlusion is detected if the characteristic value lies outside a defined value range.