Hydraulic Brake Control for Accumulator Drainage Without Return Pump
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Solution Overview
Problem
Hydraulic brake systems in vehicles, particularly eBikes and Pedelecs, require additional components in the secondary circuit to return brake fluid to the master cylinder, increasing installation space, weight, and cost when ABS is activated.
Innovation Solution
A method that allows brake fluid to be reliably returned to the master cylinder reservoir through the primary circuit without a secondary circuit return pump or check valve, using a controllable inlet valve and outlet valve to manage the fluid flow based on predetermined conditions such as pressure and vehicle speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a secondary circuit with return pump and check valve is used to return brake fluid to the master cylinder, then reliable brake fluid return is achieved, but installation space, weight, and cost increase
Solution Approach 1:
The patent merges the brake fluid return function into the existing primary circuit by utilizing the inlet valve's partial closing capability. Instead of requiring a separate secondary circuit with return pump and check valve, the system uses the primary circuit's existing components (inlet valve, accumulator outlet valve) to achieve both brake application and fluid return functions through coordinated valve control sequences.
Solution Approach 2:
The inlet valve in the primary circuit is given multiple functions: it controls brake fluid flow to the wheel cylinder during normal braking, and when partially closed during specific sequences, it enables accumulator drainage back to the master cylinder. This multi-functionality eliminates the need for dedicated return pump and check valve components.
2Reliability
If additional components (return pump, check valve) are added to the secondary circuit, then brake fluid return is enabled, but installation space and weight increase
Solution Approach 1:
The system combines the brake fluid return function with the existing primary circuit components. The inlet valve and accumulator outlet valve work together in a coordinated sequence to drain the accumulator back to the master cylinder through the primary circuit, eliminating the need for separate return pump and check valve hardware that would add weight.
3Reliability
If additional components (return pump, check valve) are added to the secondary circuit, then brake fluid return is enabled, but system cost increases
Solution Approach 1:
The patent merges the brake fluid return functionality into the existing primary circuit control logic. By using the inlet valve's partial closing capability and coordinating it with the accumulator outlet valve opening, the system achieves fluid return without requiring additional return pump, check valve, or associated piping components, thereby reducing manufacturing cost.
4Reliability
If the inlet valve is opened via predetermined duty cycle and outlet valve is opened for predetermined time periods, then brake fluid is drained through the primary circuit, but control complexity increases
Solution Approach 1:
The system uses periodic action through predetermined duty cycle control of the inlet valve and timed opening sequences of the outlet valve. The control unit executes specific time-based sequences where the inlet valve is opened for predetermined duty cycles and the outlet valve is opened for predetermined time periods, creating a rhythmic drainage pattern that reliably empties the accumulator through the primary circuit.
Solution Approach 2:
The control unit monitors system conditions (such as brake fluid pressure, valve positions, and drainage progress) and adjusts the valve control sequences accordingly. This feedback mechanism ensures that the predetermined duty cycles and time periods are optimized in real-time to achieve complete accumulator drainage while maintaining system safety and performance.
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 approach reduces the need for additional components, minimizing installation space, weight, and costs while ensuring reliable brake fluid return, thus enhancing the efficiency and cost-effectiveness of the brake system.
Implementation Method 1
it is checked whether a drain condition for draining an accumulator of the brake system is met, and - if the drain condition is met - firstly a controllable inlet valve in a primary circuit of the brake system is opened via a predetermined duty cycle
Implementation Method 2
so that brake fluid is drained from the accumulator via the outlet valve, the inlet valve, and the primary circuit into a reservoir of a master cylinder
Data Source
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AI summary
The present invention relates to a method for controlling the operation of a hydraulic brake system (1) of a vehicle, and in particular of a vehicle powered by muscle power and/or – especially additionally – by motor power, an electric bicycle, e-bike, pedelec or the like, in which it is checked whether a draining condition for draining an accumulator (22) of the brake system (1) is met, and – if the draining condition is met – first a controllable inlet valve (14) in a primary circuit (10) of the brake system (1) is set to a partially closed state via a predetermined duty cycle, in particular of 10%, and/or for a predetermined period of time, and then an outlet valve (24) of the accumulator (22) is opened – continuously or intermittently – for a predetermined period of time, so that brake fluid from the accumulator (22) is discharged via the outlet valve (24),the primary circuit (10) and the inlet valve (14) are emptied into a reservoir (13') of a master cylinder (13) of the primary circuit (10).