Hydraulic Pump Control for Brake Pedal Counterforce Stability
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Solution Overview
Problem
In hydraulic brake systems, when the hydraulic pump is activated, there is a risk of hydraulic pressure dropping in the master brake cylinder, leading to a decrease in brake pedal counterforce, which can result in an inconsistent and irritating driving experience due to the disconnect between brake pedal actuation and braking effect.
Innovation Solution
A method is implemented to control the hydraulic pump to maintain a minimum pressure in the master brake cylinder by monitoring hydraulic pressure with a pressure sensor, ensuring the brake pedal counterforce remains consistent by adjusting the hydraulic pump's activity based on brake pedal speed and pressure levels, using a control unit to regulate the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the hydraulic pump is activated to provide brake force amplification, then the braking effect is improved, but the hydraulic pressure in the master cylinder drops causing brake pedal counterforce to decrease
Solution Approach 1:
The control unit continuously monitors the hydraulic pressure in the master brake cylinder and uses this feedback information to regulate the hydraulic pump's operation. When pressure drops below a threshold, the control unit adjusts pump activation to maintain pressure, creating a closed-loop control system that balances braking effect with pedal counterforce stability
Solution Approach 2:
The system dynamically adjusts the hydraulic pump's activation state based on real-time driving conditions and pressure requirements. The control unit modulates pump operation between active and inactive states, and between different activation frequencies, to optimize the balance between providing brake force amplification and maintaining adequate pedal counterforce
2Use of energy by moving object
If the hydraulic pump is activated slowly, then energy consumption is reduced, but the hydraulic pressure drops significantly causing inconsistent pedal resistance
Solution Approach 1:
The control unit implements periodic activation of the hydraulic pump rather than continuous operation. The pump is activated in controlled cycles with specific duty cycles and frequencies, allowing the system to maintain adequate hydraulic pressure and pedal resistance consistency while minimizing overall energy consumption through intermittent operation
3Reliability
If the hydraulic pump operates continuously, then adequate brake pressure is maintained, but energy consumption increases
Solution Approach 1:
The system transitions from static continuous pump operation to dynamic intermittent operation. The control unit continuously evaluates system state and adjusts pump activation accordingly, maintaining adequate brake pressure only when necessary while reducing energy consumption during periods when existing pressure suffices
Solution Approach 2:
The hydraulic pump operates in periodic cycles rather than continuously. The control unit manages activation duration and frequency based on pressure requirements, implementing duty cycles that maintain reliable brake pressure while minimizing energy consumption through strategic intermittent operation
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 method maintains a consistent brake pedal counterforce, providing a predictable and reassuring driving experience by ensuring the hydraulic pressure in the master brake cylinder remains above a minimum level, even when the hydraulic pump is active, thus maintaining a plausible connection between brake pedal actuation and braking force.
Implementation Method 1
The hydraulic pressure in the master cylinder is monitored, in particular by means of a pressure sensor that is part of the brake system
Implementation Method 2
when the hydraulic pump in the brake circuit is activated, brake fluid is pumped from the master cylinder into the brake circuit
Implementation Method 3
When the brake pedal, which is also part of the braking system, is pressed, brake fluid is pumped from the master cylinder into the brake circuit
Data Source
Figure 1
Figure 2~3
AI summary
In a method for adjusting the brake pedal counterforce in a hydraulic braking system, a hydraulic pump (18, 19) is controlled in such a way that the hydraulic pressure in the master cylinder (4) does not drop below a minimum pressure (pHZ,min) when the brake pedal is actuated.