Vehicle Brake Suction Valve Control Using Back-EMF Detection
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Solution Overview
Problem
Conventional vehicle brake hydraulic control systems face inefficiencies due to prolonged power connection times for suction valves, leading to increased heat generation and energy consumption, as they account for worst-case motor stop times rather than actual times, causing unnecessary heat generation in the suction valve and control unit.
Innovation Solution
A control unit with a detection module for back electromotive voltage, a voltage check module, and a time check module to accurately determine when the motor has stopped, allowing the suction valve to be closed only after the motor's inertia rotation has ceased, thereby reducing the necessary power connection time and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the suction valve is closed after a given time based on worst-case motor characteristics, then the motor inertia rotation is fully stopped and cavitation is prevented, but the power connection time to the suction valve is prolonged causing increased heat generation
Solution Approach 1:
The control unit detects the back electromotive voltage generated by the motor during inertia rotation and uses this feedback signal to determine when to close the suction valve. The detection module monitors the back EMF voltage, and when it falls below a threshold value indicating the motor has stopped, the control unit closes the suction valve, eliminating the need for prolonged power connection based on worst-case estimates.
Solution Approach 2:
The system changes the control parameter from a fixed time-based approach to a voltage-based approach. By monitoring the back electromotive voltage parameter instead of using a predetermined time delay, the system adapts to actual motor stopping conditions rather than relying on conservative worst-case parameter estimates.
2Reliability
If the suction valve remains open during the given time period, then the motor can complete its inertia rotation without causing cavitation, but the coil and ECU of the suction valve experience increased heat generation
Solution Approach 1:
The control unit uses feedback from the back electromotive voltage detection to determine the precise moment when motor inertia rotation has ceased. This feedback mechanism allows the suction valve to remain closed only for the minimum necessary duration, reducing energy loss in the coil and ECU while ensuring complete motor stop.
Solution Approach 2:
The motor's own back electromotive voltage during inertia rotation serves as the signal for controlling the suction valve closure. The system uses the motor's inherent electrical characteristic to automatically determine when closing the valve is appropriate, eliminating the need for external timing mechanisms and reducing energy consumption.
3Reliability
If a fixed given time is used for motor stop consideration, then all worst-case scenarios are covered, but the actual necessary time is often longer than required leading to inefficiency
Solution Approach 1:
Instead of using a fixed time delay that covers all worst-case scenarios, the system employs real-time feedback from back electromotive voltage detection to determine when the motor has actually stopped. This allows the suction valve closure timing to match the actual motor stopping duration, eliminating unnecessary time extension.
Solution Approach 2:
The system transitions from a static, predetermined time-based control approach to a dynamic, real-time monitoring approach. By continuously monitoring the back electromotive voltage and adapting the valve closure timing based on actual motor behavior, the system optimizes the power connection time rather than relying on fixed conservative estimates.
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 time needed to connect power to the suction valve, lowering heat generation in the suction valve and control unit by ensuring the motor has fully stopped before closing the valve, thus optimizing energy use and reducing thermal losses.
Implementation Method 1
a detection module configured to detect a back electromotive voltage generated due to an inertia rotation of the motor after disconnection of power to the motor
Data Source
AI summary
A vehicle brake hydraulic control apparatus according to one embodiment includes: a suction valve; a pump; a motor for driving the pump; and a control unit controlling the suction valve and the motor through connection/disconnection of power thereto. The control unit includes: a detection module configured to detect a back electromotive voltage generated due to an inertia rotation of the motor after disconnection of power; a voltage check module configured to check whether a voltage condition is satisfied or not that the back electromotive voltage is equal to or less than a given voltage; and a time check module configured to check whether a time condition is satisfied or not that a given time has passed after the voltage condition has been satisfied. And, the control unit closes the suction valve when the time condition is satisfied.