Hydraulic Brake Pressure Control Using a Reversible Pump
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Solution Overview
Problem
Conventional hydraulic braking systems for Light Rail Vehicles face challenges in achieving precise and rapid control of braking force, particularly during wheel sliding and low traction conditions, due to complex valve technology and limited control over pressure gradients.
Innovation Solution
The system employs an electric motor-driven hydraulic pump that acts as an actuator, controlled by an electronic control unit to directly manage hydraulic pressure, eliminating the need for pressure control valves and additional accumulators, allowing for pressure increase and reduction through motor direction changes, and includes a shut-off valve and safety brake valve for safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional valve technology is used for pressure control, then pressure regulation capability is provided, but device complexity increases and control precision deteriorates
Solution Approach 1:
The patent extracts and eliminates the complex valve technology from the hydraulic braking system. Instead of using conventional pressure control valves, the system uses an electric motor-driven hydraulic pump that can directly increase or decrease pressure by changing rotation direction, thereby removing the disturbing complex valve components while maintaining pressure control capability
Solution Approach 2:
The hydraulic pump is given multiple functions: it can both increase pressure (when rotating in one direction) and decrease pressure (when rotating in the opposite direction). This multi-functionality eliminates the need for separate pressure increase valves and pressure release valves, simplifying the overall system while maintaining full pressure control capability
2Speed
If rapid pressure control is achieved, then braking response time improves, but control system complexity increases
Solution Approach 1:
The patent replaces the conventional mechanical valve-based pressure control system with an electric motor-driven hydraulic pump system. The electric motor provides rapid and precise control of the pump's rotation direction and speed, enabling fast pressure changes without the complexity of mechanical valve actuation systems
Solution Approach 2:
The system uses dynamic control of the electric motor's rotation direction to achieve rapid pressure changes. By simply reversing the motor's rotation, the pump can quickly transition from pressure increase to pressure release mode, providing fast braking response without complex mechanical switching mechanisms
3Device complexity
If pressure control valves and accumulators are eliminated, then device complexity reduces, but pressure control capability may deteriorate
Solution Approach 1:
The hydraulic pump serves itself by using its own bidirectional operation to perform both pressure increase and pressure release functions. The electric motor controls the pump's rotation direction to autonomously manage pressure regulation without requiring external valves or accumulators, maintaining reliability while reducing component count
Solution Approach 2:
The system uses dynamic reversal of the electric motor's rotation to enable the pump to switch between pressure generation and pressure release modes. This dynamic operation provides reliable pressure control throughout the braking process without needing static pressure control valves or accumulators
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 solution enables precise and rapid control of braking force with reduced technical complexity, achieving high control accuracy and reliable braking performance without overshooting, with release times as low as 180 ms and compact design, ensuring safe braking even in malfunctions.
Implementation Method 1
a hydraulic pump (2) driven by an electric motor (1) for hydraulic pressure generation
Implementation Method 2
The necessary contact forces of the lining to the brake disk are generated by a piston subjected to a hydraulic pressure
Data Source
AI summary
A Hydraulic braking system is for braking a vehicle wheel according to a braking pressure control that includes a hydraulic pump driven by an electric motor for hydraulic pressure generation, an electronic control unit for the determination of at least one control error, based on a measured actual braking pressure compared with a pressure demand setpoint, which controls at least one actuator for a pressure increase and/or a pressure reduction of the actual braking pressure to adjust to the pressure demand setpoint. Furthermore, a method is provided for braking a vehicle wheel according to this braking pressure control and a related computer program product.