Active Suspension Hydraulic Valves for Pump Failure Damping
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Solution Overview
Problem
Existing active suspension systems in vehicles face challenges in maintaining proper damping forces when the bidirectional pump fails, particularly at low rotational speeds, leading to potential short circuits and inadequate vehicle operation, which is costly and compromises occupant comfort.
Innovation Solution
Incorporation of a control valve and a restriction valve in the hydraulic lines of the suspension system to manage fluid flow, ensuring fail-safe operation by restricting flow through the pump, even when it fails, using accumulators to maintain damping forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bidirectional pump is designed to be leakage-free when failed, then reliability is improved, but device complexity and manufacturing cost increase significantly
Solution Approach 1:
A flow control valve is introduced as an intermediary component between the pump and the hydraulic system. This valve acts as a mediator that provides the necessary flow restriction and damping control when the pump fails, eliminating the need to modify the pump itself. The valve serves as a separate, dedicated component that handles the failure mode compensation, keeping the pump design simple while ensuring system reliability.
Solution Approach 2:
The system is segmented into distinct functional components: the pump, the flow control valve, and the damping controller. Instead of making the pump complex and multi-functional (including built-in failure protection), the patent separates the failure protection function into a dedicated valve component. This segmentation allows each component to remain simple while the system as a whole achieves high reliability.
2Force
If electrical phases of the motor are short-circuited to create resistance to pump rotation, then passive damping force is improved, but this only works at high rotational speeds and is inadequate at low speeds
Solution Approach 1:
The patent changes the controlling parameter from electrical resistance (which is speed-dependent) to hydraulic flow restriction through a valve. The flow control valve provides consistent flow resistance across all pump speeds, including low speeds where electrical shorting is ineffective. By changing from an electrical parameter (resistance) to a hydraulic parameter (flow restriction), the system achieves adaptability across the full speed range.
3Force
If the pump acts as high restriction element during failure, then passive damping force is improved, but a failed pump may create short circuit between rebound and compression chambers
Solution Approach 1:
The flow control valve serves as an intermediary that prevents direct communication (short circuit) between the rebound and compression chambers when the pump fails. The valve provides a controlled, restricted flow path that maintains pressure differential and damping force, preventing the harmful short-circuit effect while still allowing necessary fluid movement for passive damping.
4Device complexity
If simplified solutions are used to compensate for pump failure, then device complexity is reduced, but maintaining proper damping forces becomes challenging
Solution Approach 1:
The flow control valve acts as a simple intermediary component that maintains damping forces without adding significant system complexity. The valve provides passive flow restriction that automatically maintains proper damping forces during pump failure, eliminating the need for complex active control systems or modifications to the pump itself.
Solution Approach 2:
The flow control valve provides self-service by automatically maintaining damping forces during pump failure without requiring external control or intervention. The valve's inherent flow restriction characteristics provide the necessary damping control passively, making the system self-regulating during failure modes and reducing overall system complexity.
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
Ensures consistent damping forces and vehicle stability by providing passive resistance during pump failure, enhancing safety and reducing system complexity and cost.
Implementation Method 1
A restriction valve is positioned in the bypass line
Implementation Method 2
The control valve is positioned in one of the first and second hydraulic lines and closed when the bidirectional pump operates in a failure mode
Implementation Method 3
A bidirectional pump including a first port and a second port as well as an actuator including a first working chamber and a second working chamber
Data Source
AI summary
A suspension system comprises a bidirectional pump including a first port and a second port as well as an actuator including a first working chamber and a second working chamber. A first hydraulic line fluidically interconnects the first port and the first working chamber. A second hydraulic line fluidically interconnects the second port and the second working chamber. A first flow control valve is in fluid communication with the first working chamber. A control valve is positioned in one of the first and second hydraulic lines and closed when the bidirectional pump operates in a failure mode.