Brake-By-Wire Solenoid Valve Control for Noise-Response Balance
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Solution Overview
Problem
The existing by-wire vehicle brake systems experience a trade-off between reducing collision noise and maintaining responsiveness, leading to potential erroneous evaluations of braking performance by evaluation systems, especially under heavy braking loads.
Innovation Solution
A vehicle braking system that employs a determination unit to assess the braking load and adjusts the solenoid valve closing transient characteristic based on the load conditions, using a steeper characteristic when the load is in a caution range to prevent erroneous performance evaluations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If silent control is used to suppress plunger speed when reaching the valve closed position, then collision noise is reduced, but responsiveness of the solenoid valve deteriorates
Solution Approach 1:
The solenoid valve control system dynamically adjusts the supply current based on operating conditions. The controller increases supply current when rapid valve closing is required (for responsiveness) and reduces supply current when noise suppression is prioritized (silent control mode), making the system adaptable to different operational requirements
Solution Approach 2:
The system changes the electrical parameters (supply current magnitude) to the solenoid valve depending on the operational context. By varying the current supply rate, the system achieves different valve closing speeds, thereby balancing between noise reduction and responsiveness based on real-time conditions
2Object-affected harmful factors
If silent control suppresses plunger speed to reduce noise, then collision noise is reduced, but time delay in shutting off hydraulic passage increases
Solution Approach 1:
The control system dynamically switches between silent control mode (reduced current, noise suppression) and rapid response mode (increased current, minimal delay) based on the operational requirements, ensuring optimal performance for each situation
3Object-affected harmful factors
If silent control is used to reduce noise, then collision noise is reduced, but degree of consistency between braking operation amount and generated braking force deteriorates
Solution Approach 1:
The system adjusts the electrical parameters (supply current) to the solenoid valve based on braking conditions. By changing the current supply characteristics, the system maintains consistent correlation between brake pedal operation and generated braking force when required, while suppressing noise when appropriate
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 enhances the system's responsiveness while minimizing the risk of poor braking performance evaluations, even under heavy braking loads, by optimizing the solenoid valve control.
Implementation Method 1
a solenoid valve of a type that drives a plunger connected to a valve toward a valve closed position against spring force of a return spring
Implementation Method 2
against spring force of a return spring
Implementation Method 3
The brake fluid pressure thus generated activates wheel cylinders, thereby applying braking force to a vehicle
Data Source
AI summary
Vehicle braking system includes controller that performs driving control to close a normally-open solenoid valve based on required boosting request, and determination unit that determines whether a braking load upon boosting request is in a steady range. When the braking load upon the boosting request exceeds a predetermined first load threshold, the determination unit determines that the braking load is in a caution range above the steady range. When the braking load upon the boosting request is in the caution range, the controller executes braking control using a first valve closing transient characteristic to close the solenoid valve from the point of occurrence of the boosting request. The first valve closing transient characteristic is set steeper than a second valve closing transient characteristic to close the solenoid valve from the point of occurrence of the boosting request when the braking load upon the boosting request is in the steady range.