Master Brake Cylinder Segmentation for Hybrid Braking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In hybrid brake systems combining regenerative and hydraulic braking, changes in generator torque lead to inconsistent braking effects, causing irritating pedal feedback for the driver due to decoupling of the brake pedal from the mechanical brake system, and pose risks in failure scenarios where emergency braking is hindered.
Innovation Solution
A master brake cylinder with a compensation chamber and controllable hydraulic connections between brake circuits and a volume receiving unit, allowing for adjustable volume exchange to maintain constant braking torque, thereby stabilizing pedal position and assistance force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the brake pedal is completely decoupled from the brake system and pressure build-up is created purely by external force, then braking comfort is improved, but reliability deteriorates due to loss of mechanical coupling in failure scenarios
Solution Approach 1:
The master brake cylinder is divided into two independent piston-cylinder arrangements: a first arrangement (with piston 106) that maintains mechanical coupling with the brake pedal for reliability, and a second arrangement (with piston 108) that handles hydraulic pressure control for braking comfort. This segmentation allows each subsystem to fulfill its specific function without compromising the other.
2Ease of operation
If the brake pedal is connected to a pedal travel simulator, then braking comfort is improved, but reliability deteriorates due to risk of no mechanical coupling in case of external force failure
Solution Approach 1:
The system separates the pedal travel simulation function (handled by the second piston-cylinder arrangement with volume receiving unit) from the emergency braking function (handled by the first piston-cylinder arrangement with direct mechanical coupling). This ensures that even if the external force system fails, the mechanical coupling remains intact for emergency situations.
3Force
If pressure in the hydraulic brake system is changed to compensate for generator torque, then braking effectiveness is improved, but pedal position stability deteriorates causing irritating feedback
Solution Approach 1:
The first piston-cylinder arrangement acts as an intermediary between the driver's pedal input and the hydraulic brake system. It absorbs and compensates for volume changes caused by pressure adjustments in the second arrangement, thereby isolating the driver from irritating pedal position changes while maintaining effective braking force.
Solution Approach 2:
The invention uses hydraulic fluid volume transfer between the two piston-cylinder arrangements to compensate for pressure changes. When the second arrangement adjusts pressure to maintain braking effectiveness, the first arrangement absorbs or releases corresponding fluid volume to maintain constant pedal position, eliminating irritating feedback.
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 solution ensures a consistent overall braking effect by compensating for changes in generator torque, reducing pedal feedback irritation and maintaining mechanical coupling for reliable emergency braking, even in failure scenarios.
Implementation Method 1
a brake pedal is usually actuated by the driver and, possibly with the assistance of a brake booster, mechanically moves a piston in a master brake cylinder, to whose outputs a hydraulic unit is connected. As a result, brake fluid is introduced into the hydraulic unit
Implementation Method 2
the electric motor can be used as a generator in driving situations in which the electric motor is not used as a drive, for example to charge a battery. Operating the electric motor as a generator leads to a braking effect in which the vehicle's kinetic energy is converted into electrical energy
Data Source
Figure 1
Figure 2a~2d
Figure 3a~3c
AI summary
The invention relates to a method and a device as part of a complete brake system, that is, a brake system comprising a conventional part and a further part, such as a recuperative part, by means of which volume displacements of brake fluid are possible. The method according to the invention and the device according to the invention are used particularly if the pressure conditions in the hydraulic part of the brake system are adapted by the controllable braking force amplifier to a change in the additional braking effect of the further part of the brake system. A blending of the braking effects of the different brake systems into a constant total braking effect is thus accomplished, even if the proportion of the individual brake systems in the total braking effect change. Such a pressure adaptation by the braking force amplifier is generally accompanied by a reaction on the brake pedal, particularly a displacement thereof. The pressure adaptation can take place by means of the volume displacements between at least one hydraulic braking circuit, a compensating chamber, and either an input chamber in the brake pedal or a hydraulic reservoir, without the driver realizing the same at the brake pedal due to a change in position, and thus perceiving the same as disturbing. The method can be used, for example, for vehicles wherein a delay in braking is brought about by operating an electric machine as a generator for generating electricity, and additionally comprising a conventional hydraulic brake system as a further brake system or backup brake system.