Vehicle Brake Device Backup Mode Control via Fallback Valve
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional brake devices with integrated electric boosters face challenges in performing stable electric parking braking cooperative control during backup modes due to malfunctions like low voltage or circuit burnout, leading to insufficient braking deceleration and potential vehicle instability.
Innovation Solution
Incorporating a master cylinder, liquid pressure supply device, hydraulic pressure supply lines, a cut valve, and a fallback valve to selectively shut off brake liquid pressure, allowing the brake device to enter a backup mode and perform dynamic parking brake control by controlling the fallback valve to prevent rear wheel lock and ensure stable braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the electric booster is used to increase braking force, then braking performance is improved, but the system reliability deteriorates due to high possibility of switching to backup mode from electric malfunctions
Solution Approach 1:
The brake system is divided into two independent subsystems: the electric booster system for normal operation and the electronic parking brake system for backup mode. This segmentation allows the electronic parking brake to take over when the electric booster fails, maintaining reliability while preserving the high braking force capability of the electric booster during normal operation.
Solution Approach 2:
The electronic parking brake is pre-configured as a backup system that can immediately take over when the electric booster fails. By preparing this redundant system in advance, the patent ensures that braking reliability is maintained without compromising the high-performance electric booster operation during normal conditions.
2Reliability
If the electric booster switches to backup mode, then system reliability is maintained, but braking deceleration performance deteriorates due to lack of braking assist force
Solution Approach 1:
The patent replaces the mechanical/electric booster system with an electronic parking brake system during backup mode. By using the electronic parking brake actuator to apply braking force through the hydraulic system, the patent maintains adequate braking deceleration performance even when the primary electric booster system fails.
3Speed
If the electric parking brake is used for dynamic parking braking in backup mode, then braking deceleration is improved, but rear wheel lock occurs due to liquid pressure already being transmitted to the caliper
Solution Approach 1:
Before applying dynamic parking braking in backup mode, the patent first closes the cut valve to shut off the liquid pressure supply from the master cylinder to the wheel brakes. This preliminary action prevents liquid pressure from being present in the caliper, allowing the electronic parking brake to apply braking force without causing rear wheel lock and maintaining vehicle stability.
Solution Approach 2:
The patent implements control logic that monitors the operational mode (normal or backup) and adjusts the cut valve state accordingly. In backup mode, the system detects the failure condition and automatically closes the cut valve to enable safe electronic parking brake operation, providing feedback-based control that prevents rear wheel lock and maintains vehicle stability.
4Ease of operation
If the cut valve is in open state during backup mode, then ease of operation is improved, but device complexity increases due to need for additional fallback valve
Solution Approach 1:
The patent extracts the pressure control function from the cut valve by introducing a dedicated fallback valve that specifically manages the liquid pressure supply to the wheel brakes in backup mode. This separation of functions allows the cut valve to remain simple while the fallback valve handles the complex pressure management needed for electronic parking brake operation during failures.
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 stable electric parking brake cooperative control during backup modes, preventing rear wheel lock and enhancing vehicle braking performance and stability by selectively shutting off brake liquid pressure to the rear wheels, thus avoiding collisions and improving braking deceleration.
Implementation Method 1
a master cylinder configured to receive pedaling force outputted from the electric booster and generate brake liquid pressure
Implementation Method 2
a cut valve disposed on the backup line and configured to selectively shut off the brake liquid pressure; and a fallback valve disposed on the hydraulic pressure supply line connected to the wheel brake
Implementation Method 3
performing dynamic parking brake control in which braking force for vehicle deceleration is generated by using the electronic parking brake
Data Source
AI summary
The present disclosure relates to a brake device for a vehicle, and a main object of the present disclosure is to provide a brake device for a vehicle which can stably perform an electric parking braking cooperative control process for dynamic parking braking in a state in which the brake device enters a backup mode due to an abnormality or a malfunction generated in a device related to an electric booster in a vehicle equipped the electric booster. In order to achieve the above object, a brake device including a fallback valve which is provided on a hydraulic pressure supply line connected to a wheel brake of a wheel on which an electronic parking brake is installed, and which is configured to selectively shut off brake liquid pressure supplied to the wheel brake, and a method for controlling the same are disclosed.