Integrated Electro-Hydraulic Brake System with Normally Open Solenoid Valve
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Solution Overview
Problem
Existing electro-hydraulic brake systems face challenges in fuel efficiency, increased weight, and limited installation space due to separate units, and suffer from high heat generation and control characteristic deterioration in normally close type-solenoid valves.
Innovation Solution
An integrated electro-hydraulic brake system with a power source unit and integrated hydraulic control device, featuring a normally open type-solenoid out-valve for reduced heat generation, a normally close type-solenoid control valve for pressure control, and a pedal simulator with a simulation valve for stable pedal feeling, all connected via external pipes to minimize weight and optimize installation space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate units (actuator, modulator module, HPU) are used in the electro-hydraulic brake system, then the system can provide complete braking functions, but the installing space increases and weight increases
Solution Approach 1:
The patent combines the actuator, modulator module, and hydraulic power unit into a single integrated electro-hydraulic brake system. The master cylinder assembly includes the master cylinder, pedal simulator, and reservoir as one unit, while the modulator module with in-valve and out-valve is integrated with the hydraulic power unit containing motor, pump, and accumulator, eliminating the need for separate installations and reducing overall system weight.
2Reliability
If a normally close type-solenoid out-valve is used to control wheel cylinder pressure, then the valve can maintain close state for pressure control, but high current ranges are needed causing heat generation and control characteristic deterioration
Solution Approach 1:
The patent inverts the normal valve configuration by using a normally open type-solenoid out-valve instead of a normally close type. The out-valve is configured to be normally open and closes only when a close signal is received from the ECU. This inversion allows the valve to operate at low current ranges during normal operation (maintaining open state), significantly reducing heat generation and control characteristic deterioration while still providing effective pressure control when closing is required.
3Area of stationary object
If integrated hydraulic control device and power source unit are connected by external pipes, then the system can be installed in limited space, but the installation complexity increases
Solution Approach 1:
The patent divides the brake system into two main segments: the integrated hydraulic control device (master cylinder assembly with pedal simulator and reservoir) and the power source unit (hydraulic power unit with motor, pump, and accumulator). These segments can be manufactured and tested separately, then connected via external pipes during final assembly. This segmentation allows for flexible installation in limited vehicle spaces while maintaining manufacturing simplicity through modular construction.
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 enhances safety, fuel efficiency, and control characteristics by reducing weight, improving pedal feeling, and enabling easy installation, while allowing for stable hydraulic pressure control and regenerative braking in vehicles without engines.
Implementation Method 1
a power source unit including an accumulator configured to store a pressure of a predetermined level
Implementation Method 2
a pump configured to suck oil from a reservoir and discharge the oil to the accumulator in order to generate a pressure in the accumulator
Implementation Method 3
an in-valve and an out-valve configured to control a pressure delivered from the accumulator to a wheel cylinder
Data Source
AI summary
An integrated electro-hydraulic brake system includes a power source unit storing a pressure, discharging oil from a reservoir to an accumulator, and a motor driving the pump; and an integrated hydraulic control device including a master cylinder and generating a hydraulic pressure, a reservoir connected above the master cylinder and storing oil, an in-valve and an out-valve controlling pressure delivered from the accumulator to a wheel cylinder. The power source unit is provided as a separate unit to isolate operating noises, and the integrated hydraulic control device and the power source unit are connected by an external pipe, and the out-valve is provided as a normally open type-solenoid valve that is used at low current ranges, normally maintains an open state in order to reduce heat generation, but is closed when a close signal is received, compared to a normally close type-solenoid valve that normally maintains a close state.