Motorcycle Brake-by-Wire Backup Using Split Master Cylinder Pistons
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Solution Overview
Problem
Existing brake-by-wire systems in motorcycles lack hydraulic backup functionality in case of E/E system failure or power loss, and do not allow for partially fluid-free actuation of braking systems, especially in electric vehicles with regenerative braking.
Innovation Solution
A braking system with a first and second hydraulic supply circuit, each connected to a manually actuated piston and an electrically or electro-mechanically actuated piston, featuring a by-pass duct and a processing and control unit that switches between standard and backup modes to ensure hydraulic backup and direct actuation, even in the absence of power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If brake-by-wire system is used with electric actuators, then automation and control precision are improved, but reliability deteriorates due to lack of hydraulic backup in case of system failure
Solution Approach 1:
The manually actuated piston is segmented into two independent parts: a first piston directly connected to the manual brake control, and a second piston connected through a by-pass duct. This segmentation allows the manual braking function to be preserved independently of the electric actuator system, ensuring reliability even when the automated system fails.
Solution Approach 2:
The system incorporates a by-pass duct and second piston that are pre-configured to provide hydraulic backup before any failure occurs. The processing and control unit is programmed to automatically switch to this backup pathway when sensor signals indicate system failure, ensuring continuous braking capability without interruption.
2Ease of operation
If electric actuators are used for braking, then ease of operation is improved, but adaptability deteriorates for electric vehicles requiring fluid-free actuation
Solution Approach 1:
The system dynamically adapts its actuation mode based on vehicle type and operating conditions. For electric vehicles, the processing and control unit can command the electric actuator to operate in a fluid-free manner by controlling the by-pass duct closure, while maintaining the same manual interface for the rider. This dynamic adaptability allows a single system design to serve both traditional and electric motorcycles.
Solution Approach 2:
The braking system is designed with universal functionality to serve multiple purposes: it can operate as a traditional hydraulic system, as a brake-by-wire system with fluid backup, and as a fluid-free actuated system for electric vehicles. The by-pass duct and second piston provide the flexibility to accommodate different actuation modes without requiring separate systems.
3Reliability
If by-pass duct is added for hydraulic backup, then reliability is improved, but device complexity increases
Solution Approach 1:
The by-pass duct and second piston are integrated into the existing hydraulic circuit architecture rather than being added as completely separate systems. The by-pass duct connects to the existing hydraulic supply circuit, and the second piston shares the same hydraulic fluid and chamber structure as the first piston, thereby reducing overall system complexity while maintaining backup functionality.
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 hydraulic backup from both controls (lever and pedal) in system failures and power loss, ensuring braking functionality and compatibility with electric vehicles, including regenerative braking.
Implementation Method 1
a first indirect piston, in series with the first direct piston and connected thereto by the interposition of a first return spring
Implementation Method 2
a first hydraulic supply circuit, a first electric actuator having first electrical or electro-mechanical motor means operatively connected to a first electrically or electro-mechanically actuated piston fluidically connected to said first hydraulic supply circuit
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A braking system (4) for a motorcycle (8) comprising at least a first braking device (12) operatively connected to a first wheel (16) of the motorcycle (8), and provided with a first hydraulic supply circuit (20), a first electric actuator (24) having first electrical or electro-mechanical motor means, operatively connected to a first electrically or electro-mechanically actuated piston (28) fluidically connected to said first hydraulic supply circuit (20), at least one first interface or input port (32) operatively connected to a first hydraulic device (36) provided with a first manually actuated piston (40), wherein the first manually actuated piston (40) is subdivided into a first direct piston (41), directly connected to the first interface port (32), and a first indirect piston (42), in series with the first direct piston (41), connected thereto by the interposition of a first return spring (43), the first indirect piston (42) being hydraulically connected to said first hydraulic supply circuit (20) through a first by-pass duct (44), and arranged in series, upstream, with the first electrically or electro-mechanically actuated piston (28). The braking system (4) comprises a hydraulic fluid reservoir (52) fluidically connected to the first hydraulic device (36) by a connection duct (56) upstream of the first indirect piston (42) and a connection duct (60) downstream of the first indirect piston (42), wherein the braking system (8) is provided with a processing and control unit (68), operatively connected to said first electric actuator (24), programmed so that : in standard operation, upon actuation of the first interface port (32), the first electrically or electro- mechanically actuated piston (28) translates so as to occlude the first by-pass duct (44), fluidically disconnect the first manually actuated piston (40) from the first hydraulic supply circuit (20), and simultaneously actuate the at least one first braking device (12).