Hydraulic Brake System Regenerative Torque Control
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Solution Overview
Problem
Conventional regenerative vehicle brake systems are complex, heavy, and require additional components, leading to increased installation space and weight, as well as complicated control systems that often result in unsatisfactory braking behavior.
Innovation Solution
A hydraulic brake system with a brake pedal, master cylinder, pump, temporary store, and pressure reduction valve, controlled by a unit that adjusts hydraulic braking torque to match the driver's input and electric machine's generating torque during regenerative braking, using pressure reduction valves and a control unit to estimate necessary braking pressure and volume flows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional components are added to enable regenerative braking, then regenerative braking capability is improved, but device complexity and weight increase
Solution Approach 1:
The existing hydraulic brake system components (master cylinder, pump, valves, hydraulic lines) are made to serve dual functions: conventional braking and regenerative braking control. The control unit coordinates these existing components to manage hydraulic pressure during regenerative braking, eliminating the need for separate dedicated components for each braking mode.
Solution Approach 2:
The control unit merges the control logic for conventional braking and regenerative braking into a single integrated system. The hydraulic brake system is unified to handle both braking modes through coordinated control of existing components, reducing overall system complexity while maintaining regenerative braking capability.
2Ease of operation
If pedal reaction-simulating apparatuses are employed to improve braking sensation, then braking behavior quality is improved, but device complexity increases
Solution Approach 1:
The existing hydraulic components (master cylinder, pump, pressure control valves) are made to serve dual purposes: providing actual braking force and simulating pedal reaction force. The control unit coordinates these components to create realistic pedal sensation during regenerative braking without requiring separate simulation apparatus.
Solution Approach 2:
The hydraulic brake system itself provides the pedal reaction simulation function through coordinated control of its existing components. The master cylinder and pump work together to generate appropriate hydraulic pressure that mimics conventional braking sensation, eliminating the need for external simulation devices.
3Speed
If the pump delivers hydraulic fluid quickly to build braking pressure, then braking response speed is improved, but pedal reaction quality deteriorates
Solution Approach 1:
The pump delivery rate is made dynamically adjustable rather than fixed. The control unit varies the pump speed and delivery quantity in real-time based on the braking phase: high delivery rate during initial pressure build-up for fast response, then reduced delivery rate for smooth pressure maintenance, optimizing both response speed and pedal reaction quality.
Solution Approach 2:
The pump operation is controlled in periodic phases: an initial high-speed delivery phase to quickly build braking pressure, followed by a maintenance phase with reduced or intermittent delivery to maintain pressure while providing smooth pedal reaction. This periodic control pattern optimizes both response speed and operation quality.
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 system provides a simple, cost-effective brake system with high control quality, mimicking conventional braking sensations without additional simulating apparatuses, minimizing valve-switching operations and maintaining a reassuring braking experience.
Implementation Method 1
a pressure reduction valve which is arranged in the return line of the wheel brake and has a throttling effect in the open state
Implementation Method 2
a pump, the output of which is connected to the wheel brake via a feed line and the input of which is connected to the wheel brake via a return line, wherein the pump is adapted to convey hydraulic fluid to the wheel brake
Implementation Method 3
a master brake cylinder which is connected to the brake pedal via a brake booster and is adapted to displace hydraulic fluid into the wheel brake when the brake pedal is actuated
Implementation Method 4
a temporary store which is connected, via the return line, to the input of the pump and to the wheel brake
Data Source
AI summary
A hydraulic brake system for a land vehicle includes a brake pedal; a wheel brake; and a master brake cylinder connected to the brake pedal by a brake booster and a pump. The outlet of the pump is connected to the wheel brake by a supply line and the inlet is connected to the wheel brake by a return line. The pump moves hydraulic fluid to the wheel brake. A temporary store is connected to the inlet of the pump and the wheel brake by the return line. A pressure reduction valve, arranged in the return line of the wheel brake, has a throttling effect in the open state. A control unit compensates for the difference between a total braking torque specified by the brake pedal and a generating braking torque provided by an electric machine by setting the hydraulic braking torque during a regenerative braking process of the vehicle.