Closed Hydraulic Circuit With Accumulator-Based Fault Detection
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Solution Overview
Problem
Conventional hydraulic control systems for vehicles face inefficiencies and redundancy when fully electrified, leading to compromises in integration and performance, particularly in autonomous or semi-autonomous systems where multiple control systems need to be integrated efficiently.
Innovation Solution
A fluidic control system with a controller, pump, valve, and precharge accumulator that maintains a non-zero pressure closed circuit, allowing for the integration of brake and non-brake actuators, enabling efficient fluid distribution and fault detection, and featuring a bleed assembly for easy fluid replacement, independent of the vehicle's powertrain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional hydraulic control systems are fully electrified, then integration of multiple control systems is improved, but system complexity and redundancy increase
Solution Approach 1:
The patent merges brake control and steering control into a single integrated hydraulic system. The pump, accumulator, and valve means form a common hydraulic circuit that serves multiple actuators, eliminating the need for separate hydraulic systems for different vehicle functions. This consolidation reduces overall system complexity while maintaining the ability to independently control multiple features.
Solution Approach 2:
The valve means is designed as a multi-functional component that can direct hydraulic fluid to different actuators based on control signals. The same valve means serves both brake actuators and steering actuators, allowing a single component to perform multiple functions. The controller coordinates these functions to achieve seamless integration of different control systems.
2Reliability
If a closed pressurised circuit is used, then fault detection capability is improved, but system complexity increases
Solution Approach 1:
The sensor provides continuous feedback on the position of the movable member in the precharge accumulator, which reflects the fluid pressure and volume in the closed circuit. The controller monitors this feedback signal to detect abnormal conditions such as leaks or faults. This feedback mechanism enables fault detection without requiring additional complex sensing systems throughout the entire circuit.
Solution Approach 2:
The precharge accumulator with its movable member automatically responds to changes in circuit pressure and fluid volume. When fluid is lost or pressure drops, the movable member shifts position, providing a self-indicating mechanism for system health. This self-service approach allows the system to monitor its own condition without external intervention or additional complexity.
3Productivity
If electrification of control systems is pursued, then integration efficiency is improved, but performance compromises occur
Solution Approach 1:
The system replaces traditional mechanical linkages and cable-based control with an electrified control architecture. The controller receives electrical signals from sensors and actuators, processes them digitally, and sends control commands to the valve means. This substitution improves integration efficiency by enabling flexible electronic control while the hydraulic execution layer maintains proven mechanical reliability for force-intensive operations like braking.
Solution Approach 2:
The hydraulic fluid acts as an intermediary medium that bridges the electrified control domain and the mechanical actuation domain. Electrical signals control the valve means, which modulates hydraulic fluid flow to actuators, which then produce mechanical force. This intermediary approach allows the system to combine the advantages of electronic control flexibility with hydraulic force efficiency, avoiding performance compromises.
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 system provides improved control over braking and other vehicle functions, enhances integration of multiple control systems, and allows for autonomous operation, reducing complexity and cost while maintaining efficient pressure generation and fluid management.
Implementation Method 1
a pump having an inlet and an outlet for pressurising fluid in the circuit... a precharge accumulator fluidly connected between the valve means and the inlet of the pump... maintaining a non-zero pressure throughout the pressurised closed circuit
Implementation Method 2
a sensor for determining the position of the movable member, wherein the controller is configured to detect automatically, from a position of the movable member determined using the sensor, faults and/or leaks within the pressurised closed circuit by estimating the quantity of fluid within the circuit and/or by detecting an abnormal pressure variation within the pressurised closed circuit
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A fluidic control system (1) for controlling a vehicle, which includes a controller (2) and a closed fluidic circuit. The circuit includes a pump (3)for pressurising fluid in the circuit, valve means (40, 50, 60), an actuator (4, 5, 6) and a precharge accumulator (7). The valve means (40, 50, 60) is fluidly connected to the inlet and outlet of the pump (3) and the actuator (4,, 6) is fluidly connected to the valve means (40, 50, 60) for selectively receiving pressurised fluid therefrom. The precharge accumulator (7) includes a movable member (73, Figure 2) that describes a variable volume (71) fluidly connected to the circuit between the valve means (40, 50, 60) and the inlet of the pump (3). The system (1) also includes a sensor (70) for determining the position of the movable member (73)for estimating the quantity of fluid and/or detecting an abnormal pressure variation within the circuit.