Dual-Piston Pump Switching for Fast Vehicle Ride Height Adjustment
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Solution Overview
Problem
Existing vehicle suspension systems with gas springs require pumps that can rapidly adjust ride height by varying gas volume, necessitating high flow rates to facilitate quick adjustments.
Innovation Solution
A reciprocating piston pump system with dual pistons and a directional control valve (DCV) that alternately supplies fluid to chambers, combined with relief valves and orifices to manage pressure differentials, enhancing the pump's output pressure and flow rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single piston pump is used, then the device complexity is low, but the flow rate and adjustment speed are insufficient for rapid ride height adjustment
Solution Approach 1:
The pump is divided into two separate piston chambers (first and second chambers) that operate independently but are coupled through a common rod. Each chamber has its own piston (first piston and second piston) that can move in opposite directions, effectively doubling the flow rate compared to a single piston while maintaining a relatively simple overall structure.
Solution Approach 2:
The first piston and second piston are coupled together through a common rod, allowing them to move in a coordinated manner. This merging of two piston mechanisms into a single integrated unit achieves high flow rate performance while avoiding the complexity of two completely separate pump systems.
2Stress or pressure
If high pressure is generated in one chamber, then the output pressure is high, but the pressure differential causes slow response and reduced flow rate
Solution Approach 1:
The pump operates by periodically alternating the pressure generation between the first chamber and second chamber. During each cycle, one chamber generates high pressure while the other chamber maintains lower pressure, allowing fluid to flow into the lower pressure chamber. This periodic alternation ensures continuous high flow rate while maintaining high output pressure capability.
Solution Approach 2:
By coupling the two pistons together, the system ensures that while one chamber is pressurizing, the other chamber is simultaneously receiving fluid. This continuous alternation eliminates idle time and maintains continuous useful action, ensuring both high pressure and high flow rate are achieved simultaneously throughout the operating cycle.
3Speed
If the DCV shifts quickly in response to pressure, then the response time is fast, but the pressure differential causes premature shifting and reduced maximum pressure
Solution Approach 1:
The system changes the pressure parameters in the two chambers periodically, allowing one chamber to reach high pressure while the other remains at lower pressure. This parameter change strategy enables the DCV to respond quickly to pressure differentials without causing premature shifting, as the high pressure is maintained in one chamber while the other chamber is being filled, creating a controlled pressure differential that drives rapid DCV response without limiting maximum pressure.
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 achieves increased maximum output pressure and flow rate, enabling rapid adjustment of vehicle ride height by efficiently managing fluid flow and pressure within the gas springs.
Implementation Method 1
The relief valve is configured to supply the second fluid to the DCV in response to a pressure within the sensing line exceeding a shift pressure to move the DCV from the first position to the second position
Implementation Method 2
The DCV is configured to alternately supply a second fluid to the second chamber and the fourth chamber such that the first fluid is forced out of one of the first chamber or the third chamber
Implementation Method 3
The first inlet check valve is positioned to permit a first fluid received from the reservoir to enter the first chamber. The second inlet check valve is positioned to permit the first fluid received from the reservoir to enter the third chamber
Data Source
AI summary
A pump system includes a housing defining a first internal volume and a second internal volume, a first piston positioned to separate the first internal volume into a first chamber and a second chamber, a second piston positioned to separate the second internal volume into a third chamber and a fourth chamber, a first inlet check valve configured to permit fluid flow into the first chamber, a second inlet check valve configured to permit fluid flow into the third chamber, a directional control valve (DCV) repositionable between (a) a first position where the DCV is configured to fluidly couple the second chamber to a high pressure fluid source and (b) a second position where the DCV is configured to fluidly couple the fourth chamber to the high pressure fluid source, and a relief valve configured to supply a fluid to the DCV through an orifice to move the DCV.