Electrohydraulic Brake Simulator Circuit Venting
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Solution Overview
Problem
The maintenance of electrohydraulic motor vehicle brake systems is costly due to the complexity of bleeding and troubleshooting, as they require separate bleeding of the wheel brakes, simulator circuit, and hydraulic control unit, and detecting leaks or defective valves is time-consuming.
Innovation Solution
An electrohydraulic motor vehicle brake system with a hydraulic simulator circuit that includes a first cylinder-piston device, an electromechanical actuator, and fluid paths with valve devices for selective coupling to the simulator circuit and a hydraulic fluid reservoir, allowing for efficient bleeding and testing of brake system components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate bleeding procedures are used for wheel brakes, simulator circuit, and hydraulic control unit, then each component can be bled individually, but the total maintenance time becomes considerable
Solution Approach 1:
The patent merges the bleeding procedures for the wheel brakes, simulator circuit, and hydraulic control unit into a single integrated process. By establishing fluidic coupling between all these components through controlled valve operations, hydraulic fluid can be moved simultaneously through all circuits from a central reservoir, eliminating the need for separate bleeding operations and significantly reducing total maintenance time.
Solution Approach 2:
The hydraulic control unit is designed with multi-functionality, serving both as a control element for brake pressure regulation and as a reservoir for hydraulic fluid during bleeding operations. The same valve assemblies and fluid pathways used for normal brake operation are utilized during bleeding, allowing the system to serve multiple purposes without requiring additional dedicated bleeding equipment or procedures.
2Adaptability or versatility
If multiple valves and fluid pathways are used for brake control, then pressure regulation and vehicle dynamics control are improved, but the complexity of detecting leaks and defective valves increases
Solution Approach 1:
The patent combines multiple diagnostic functions into a single integrated testing procedure. By establishing fluidic coupling between the hydraulic control unit and simulator circuit and then moving hydraulic fluid through this coupled system, the procedure simultaneously tests for leaks, detects defective valves, and verifies proper operation of multiple components in one operation, rather than requiring separate diagnostic steps for each component.
Solution Approach 2:
The braking system performs self-diagnosis through the fluid movement procedure. The actuation of valves and movement of hydraulic fluid through the coupled circuits automatically reveals system conditions - leaks are detected by pressure changes, defective valves are identified by abnormal flow patterns - without requiring external diagnostic equipment or complex troubleshooting procedures.
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
Facilitates easier bleeding and testing of the brake system, reducing maintenance time and costs by enabling simultaneous fluidic coupling and decoupling of components, thus improving diagnostic efficiency.
Implementation Method 1
an electromechanical actuator (160) acting on the first cylinder-piston assembly (100, 701) for generating hydraulic pressure
Implementation Method 2
hydraulic pressure at the wheel brakes is generated independently of foot force via a hydraulic pressure generator
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A method for venting a hydraulic simulator circuit (145) of an electro-hydraulic motor vehicle braking system (1000, 1000a) is described. The electro-hydraulic motor vehicle braking system (1000, 1000a) comprises the hydraulic simulator circuit (145) for generating a pedal return force, a first cylinder-piston assembly (110, 112, 114, 701, 702), an electromechanical actuator (160) acting on the first cylinder-piston assembly (110, 112, 114) for generating hydraulic pressure in at least one brake circuit (10, 20), a first fluid path (340) with a first valve assembly (330) arranged therein for selectively coupling the first cylinder-piston assembly (110, 112, 114, 701, 702) with the simulator circuit (145), and a second fluid path (140) with a second valve assembly (130) arranged therein for selectively coupling of the hydraulic simulator circuit (145) with a pressureless hydraulic fluid reservoir (170).The venting procedure comprises the following steps: - Opening the first valve assembly (340) to fluidically couple the first cylinder-piston assembly (110, 112, 114) to the simulator circuit (145); - Opening the second valve assembly (340) to fluidically couple the simulator circuit (145) to the hydraulic fluid reservoir (170), provided the second valve assembly (340) was in a closed state; and - Actuating the electromechanical actuator (160) to displace hydraulic fluid from the first cylinder-piston assembly (110, 112, 114) via the simulator circuit (145) into the hydraulic fluid reservoir (170).