Brake Hold Control Using Electric Boosting in Non-Driving Mode
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Solution Overview
Problem
Vehicle brake systems using a brake hold function can disconcert drivers due to the brake pedal being drawn towards the floor when increasing brake fluid pressure to prevent sudden movement from creep phenomena, especially when shifting from a non-driving to a driving mode.
Innovation Solution
A vehicle brake system with a processor-controlled electric brake booster that uses a pressurizing motor to increase braking force when the brake pedal is released, maintaining a stationary state by monitoring shift position and brake operation, ensuring the braking force is sufficient to prevent creep-induced movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If brake fluid pressure is increased using a pressure intensifier connected directly to the brake pedal to prevent sudden vehicle movement from creep phenomenon, then vehicle stability is improved, but the brake pedal moves towards the floor panel which disconcerts the driver
Solution Approach 1:
The patent introduces a brake hold control unit as an intermediary between the driver's brake pedal operation and the pressure intensifier. This control unit monitors brake pedal operation status and shift position, and only activates the pressure intensifier when the brake pedal is released and the transmission is in non-driving mode. This intermediary control prevents direct pressure increase while the driver's foot is on the pedal, eliminating the pedal movement that disconcerts drivers while maintaining vehicle stability when needed.
Solution Approach 2:
The system implements feedback by continuously monitoring the operation status of the brake pedal and the shift position of the automatic transmission. The brake hold control unit uses this feedback information to determine the appropriate timing for activating the pressure intensifier, ensuring that pressure increase occurs only when the brake pedal is released and the vehicle is in non-driving mode, thereby preventing both sudden movement and driver disconcertion.
2Reliability
If brake fluid pressure is increased to maintain stationary state during mode transition, then prevention of sudden vehicle movement is improved, but continuous brake pedal pressure is required which reduces ease of operation
Solution Approach 1:
The patent applies preliminary action by having the brake hold control unit detect when the brake pedal is released and the transmission is in non-driving mode before the mode transition occurs. The pressure intensifier is activated in advance to increase brake fluid pressure and maintain stationary state, so that when the transmission shifts to driving mode, the vehicle is already prepared and will not experience sudden movement. This eliminates the need for continuous brake pedal pressure while ensuring reliability.
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 effectively prevents vehicle movement during mode transitions, eliminating driver disconcertion by maintaining a stable braking force without requiring continuous brake pedal pressure, thus enhancing safety and comfort.
Implementation Method 1
a pressurizing motor 53 that increases a braking force generated by operating the brake pedal 26
Data Source
AI summary
A vehicle brake system including: a pressurizing motor that is connected to a brake pedal and configured to increase a braking force that is generated; and a processor. The processor is configured with a program to perform operations including: operation as an information acquisition part to obtain information on whether a shift position of an automatic transmission is in a non-driving mode and information on operation on the brake pedal; and operation as a braking force controller to perform, when a predetermined retention condition is met, control of braking force so that a stationary state of a host vehicle is maintained. When the predetermined retention condition is met and the shift position is in the non-driving mode, the braking force controller is configured to perform control to increase the braking force that is generated using the pressurizing motor once the brake pedal is in a non-operated state.