Reduced-Length Master Cylinder Pressure Chamber for Short Pedal Travel
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Solution Overview
Problem
Conventional braking systems require a longer brake pedal stroke and more space in the engine compartment, which is undesirable for modern vehicles aiming to maximize habitability and reduce pedal travel.
Innovation Solution
The braking system incorporates a reduced-length pressure chamber with a pressure sensor and proximity detection means, allowing the electronic stability control device to manage braking pressure in two phases, enabling a shorter master cylinder stroke and reduced space requirements while maintaining effective braking performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the master cylinder uses a conventional length pressure chamber, then the braking stroke is sufficient to establish adequate braking pressure, but the pedal travel becomes excessively long and the space required in the engine compartment increases
Solution Approach 1:
The braking process is divided into two distinct phases: a first phase where the master cylinder piston establishes initial braking pressure through conventional mechanical action, and a second phase where the electronic stability control device takes over to increase braking pressure. This segmentation allows the master cylinder to have a reduced stroke while maintaining adequate braking capability through electronic supplementation.
Solution Approach 2:
The master cylinder piston performs a preliminary action by establishing initial braking pressure during the first phase before the electronic stability control device intervenes. The proximity detection means detect when the piston approaches the end of its reduced stroke, triggering the electronic system to complete the braking pressure establishment, thus preparing the system for effective braking with limited mechanical travel.
2Area of stationary object
If the pressure chamber length is reduced to decrease pedal travel, then habitability and space utilization improve, but the ability to generate sufficient braking pressure through mechanical means alone is compromised
Solution Approach 1:
The electronic stability control device acts as an intermediary between the driver's pedal input and the final braking pressure output. When the master cylinder piston reaches proximity to the end of its reduced stroke, the electronic system intervenes to supplement and increase the braking pressure, ensuring sufficient stopping force is achieved despite the reduced mechanical travel distance.
Solution Approach 2:
The system replaces part of the mechanical pressure generation function with an electronic control system. Instead of relying solely on the mechanical advantage of a long master cylinder stroke, the electronic stability control device uses sensors and control algorithms to manage and increase braking pressure electronically, substituting mechanical leverage with electronic control capability.
3Ease of operation
If the master cylinder is designed with reduced stroke for improved habitability, then pedal travel is minimized, but the system requires additional sensing and control mechanisms to maintain braking effectiveness
Solution Approach 1:
The system incorporates proximity detection means that continuously monitor the position of the master cylinder piston. When the piston approaches the end of its reduced stroke, the detection means provide feedback to the electronic stability control device, triggering the second phase of braking. This feedback mechanism enables the system to automatically adjust from mechanical to electronic pressure control, maintaining braking effectiveness while minimizing pedal travel.
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 configuration allows for a reduced master cylinder stroke and space usage while maintaining similar braking characteristics to conventional systems, with the electronic stability control device managing pressure effectively across different phases to ensure stable vehicle control and additional braking pressure when needed.
Implementation Method 1
at least the pressure chamber which is associated with the secondary braking circuit comprises a pressure sensor
Implementation Method 2
two radial supply ducts which connect an external reservoir of hydraulic fluid to each supply chamber
Implementation Method 3
bore comprising two front and rear seals which are interposed between each primary/secondary piston and the bore
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The system (10) has a master brake cylinder (12), a primary braking circuit (34), and a secondary front pressure chamber (24) that is of reduced length to provide reduced braking stroke to a piston (20). A displacement sensor (48) detects a proximity end of travel position of the piston and transmits a braking set point to an electronic stability control device (46). The piston is moved to establish braking pressure in the chamber and a secondary braking circuit (36) in a braking phase. The device controls the pressure in the circuit (36) in another phase when the piston is in the position.