Valve Control Electronics Adaptive Switching and PWM Modes
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Solution Overview
Problem
Existing electrically actuable valves in automotive brake systems face challenges in achieving precise pressure adjustment and noise reduction, as switching operation provides high precision but generates noise, while PWM operation offers less noise but lower precision and higher tolerances.
Innovation Solution
A control electronics system with a main switch and a freewheeling circuit including a freewheeling diode and switch, allowing optional operation in switching or PWM mode, with a voltage limiting device to manage induced voltage, enabling precise pressure adjustment and reduced noise based on operational needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If switching operation is used to control the valve, then pressure adjustment precision is improved, but noise generation increases
Solution Approach 1:
The invention applies dynamics by making the freewheeling path controllable through a freewheeling switch that can be activated or deactivated based on operating conditions. This allows the system to dynamically transition between switching operation (freewheeling path open) for precise pressure control and PWM operation (freewheeling path closed) for noise reduction, resolving the contradiction between precision and noise
Solution Approach 2:
The invention changes the operational parameters of the valve control system by introducing a controllable freewheeling path that modifies the current decay characteristics. By adjusting the state of the freewheeling switch, the system can change between rapid current decay (switching mode) and controlled current decay (PWM mode), thereby adjusting both precision and noise characteristics as needed
2Object-generated harmful factors
If PWM operation is used to control the valve, then noise generation is reduced, but pressure adjustment precision deteriorates
Solution Approach 1:
The controllable freewheeling path provides dynamic adaptability, allowing the system to switch between PWM operation (freewheeling path closed) for noise reduction and switching operation (freewheeling path open) for high precision pressure control, depending on the specific operating conditions and requirements
3Reliability
If a clamping diode is used to restrict induced voltage in switching operation, then voltage damage is prevented, but current decay time increases
Solution Approach 1:
The freewheeling diode acts as an intermediary element that provides a controlled path for current decay. When activated through the freewheeling switch, it allows the current to decay through the diode rather than generating high induced voltage, thus protecting the electronics while maintaining relatively fast current decay compared to using only a clamping diode
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
Enables precise pressure control with reduced noise, allowing for adaptive operation between switching and PWM modes to suit specific braking functions, enhancing the performance of electrically actuable valves in automotive brake systems.
Implementation Method 1
Electrically actuable valves, to which reference is made here, include a valve coil for generating a magnetic field
Implementation Method 2
the valve coil generates a relatively high induced voltage, which may impair the functioning of the electronics system
Data Source
AI summary
A device for controlling an electrically actuable valve having a valve coil, including a main switch, situated in the current circuit of the valve coil, for adjusting the current flowing through the valve coil, and a freewheeling path, which has a freewheeling diode and is switched in parallel with the valve coil. A freewheeling switch is provided, by which the freewheeling path is able to be interrupted or closed. This allows for optionally operating the valve in a PMW or in a switching operation.