Vacuum Brake Booster Redundancy for Electrified Vehicle Braking
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Solution Overview
Problem
Braking systems in electrified vehicles face challenges due to the lack of vacuum availability and increased costs associated with electric brake boosters and integrated simulator braking systems, necessitating a cost-effective solution that meets driver assistance and safety requirements.
Innovation Solution
An electric vacuum pump is integrated into the braking system, controlled by an ESC control device, which ensures redundancy and fail-safe operation through dual control units, allowing brake boosting via hydraulic pumps if the vacuum system fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an electric brake booster is used to replace the vacuum brake booster, then the braking system becomes independent of vacuum supply, but the cost increases considerably
Solution Approach 1:
The ESC control device is designed to perform multiple functions: it controls both the hydraulic pump for stability control and the electric vacuum pump for brake boosting. This multi-functionality allows the system to maintain vacuum brake boosting capability without requiring a separate control unit, thereby reducing overall system cost while achieving independence from traditional vacuum supply systems
Solution Approach 2:
The ESC system serves itself by using its existing control device to also control the vacuum pump. The ESC control device monitors braking conditions and automatically activates the vacuum pump when vacuum is needed, eliminating the need for separate control infrastructure and reducing system complexity and cost
2Productivity
If an integrated simulator braking system is used, then regenerative braking efficiency is improved, but the cost increases considerably
Solution Approach 1:
The ESC control device is designed to perform multiple functions: it controls both the hydraulic pump for stability control and the electric vacuum pump for brake boosting. This multi-functionality allows the system to maintain vacuum brake boosting capability without requiring a separate control unit, thereby reducing overall system cost while achieving independence from traditional vacuum supply systems
Solution Approach 2:
The system uses pneumatic principles by maintaining a vacuum chamber that can be activated to provide brake boosting force. The electric vacuum pump generates and maintains the vacuum pressure, which is then utilized by the vacuum brake booster to amplify braking force, providing a cost-effective alternative to electric brake boosters while maintaining high braking efficiency
3Reliability
If dual control units are implemented for redundancy, then fail-safety is enhanced, but the device complexity increases
Solution Approach 1:
The system implements redundancy by duplicating critical control functions within the ESC control device. The control device is designed with redundant control pathways and monitoring capabilities that can take over if a fault is detected. This beforehand cushioning ensures that potential failures are compensated for, maintaining system reliability without requiring completely separate backup systems
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
The system provides reliable brake boosting with enhanced diagnostic capabilities and redundancy, ensuring safety and efficiency in electrified vehicles without significant additional costs.
Implementation Method 1
An electric vacuum pump (3) is provided to supply the vacuum brake booster (2)
Implementation Method 2
When the brake pedal is actuated, atmospheric pressure is applied to the pedal-facing side of the diaphragm, the working chamber, via a valve, so that the pressure difference then prevailing produces a force that assists the force applied to the pedal
Implementation Method 3
the system has a hydraulic pump with which a braking pressure can be built up in the braking system independently of the driver
Data Source
AI summary
A hydraulic braking system has a vacuum brake booster, an ESC system with a hydraulic pump for generating braking force in a wheel-specific manner in a plurality of wheel brakes, an ESC control device for driving the hydraulic pump and a hydraulic pressure sensor for determining a hydraulic pressure in the hydraulic braking system. For electrified vehicles, an electric vacuum pump is provided for supplying the vacuum brake booster, wherein the ESC control device is designed to drive the electric vacuum pump logically and electrically.