Hydraulic Distributor for Cryogenic Pump Efficiency
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Solution Overview
Problem
Existing cryogenic fuel pumps for mobile applications, such as mining trucks and locomotives, face inefficiencies in delivering cryogenically stored fuels like LNG and CNG due to their low densities and the need for efficient pressure management, which current piston-based pumps struggle to address effectively.
Innovation Solution
A hydraulically driven cryogenic pump with multiple pumping elements, each sequentially actuated by a hydraulic distributor, which includes a rotor that rotates to align passages for efficient fluid communication and pressure management, allowing for the efficient delivery of cryogenically stored fuels by varying the pressure and phase of the fuel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single piston pump is used to deliver cryogenic fuel, then the pump structure is simple, but the pumping efficiency and pressure delivery capability are insufficient
Solution Approach 1:
The pump is divided into multiple independent pumping elements (at least two), each with its own piston, cylinder, and valve assembly. This segmentation allows parallel pumping action to improve productivity while maintaining modular simplicity in each individual element's design.
Solution Approach 2:
Multiple pumping elements are combined within a single pump body, sharing common components such as the drive mechanism, valve system, and fluid pathways. This merging approach achieves high productivity through parallel operation while avoiding the complexity of completely separate pump units.
2Reliability
If cryogenic fuel is stored at low pressure (300 psi), then storage safety is improved, but the pressure differential required for efficient pumping to high pressure (20.7 MPa) increases energy consumption
Solution Approach 1:
The pump employs periodic reciprocating motion of multiple pistons, with at least one piston in each phase of the cycle (intake, compression, discharge, exhaust). This periodic action with multiple elements creates continuous pressure waves that improve energy efficiency while maintaining the safety of low-pressure storage.
Solution Approach 2:
The system changes pressure parameters dynamically through the pumping cycle, using the mechanical advantage of the reciprocating piston mechanism to efficiently transform low-pressure storage conditions into high-pressure delivery, minimizing energy loss during the pressure differential transition.
3Productivity
If multiple pumping elements are used to improve pumping efficiency, then productivity increases, but the device complexity and hydraulic distribution system become more complex
Solution Approach 1:
The hydraulic distributor is designed as a universal component that simultaneously controls multiple pumping elements through a single rotation mechanism. Each rotor position activates a specific piston while deactivating others, allowing one distributor structure to perform the function of multiple valve assemblies and reducing overall system complexity.
4Productivity
If a rotor with multiple orientations is used to sequentially actuate pumping elements, then fluid communication efficiency is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The rotor and pump body feature asymmetric passage designs where the rotor passages are deliberately misaligned with the pump body passages in certain orientations. This asymmetry creates natural flow directionality that guides fluid communication efficiently between elements while reducing the need for ultra-precise rotational alignment, as the asymmetric geometry provides mechanical guidance for proper positioning.
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 solution enables efficient pumping and phase transition of cryogenic fuels, improving the delivery of gaseous fuels to engines by managing pressure differentials and fluid flow effectively, enhancing the operational efficiency and reliability of mobile fuel systems.
Implementation Method 1
A first orientation, the fill opening is aligned with the first head-end passage to place the first head-end passage in fluid communication with the high-pressure inlet opening, and the radially extending passage overlaps the first rod-end passage to place the first rod-end passage in fluid communication with the drain opening
Data Source
AI summary
A pump has a pump body and at least first and second pumping elements, each pumping element including a piston defining a head-end and a rod-end. The pump receives a pressurized fluid at an inlet, and returns fluid through a drain outlet. A hydraulic distributor operates to fluidly connect the head end of an extending piston to the pressurized fluid, and the rod end of the extending piston to the drain outlet. The hydraulic distributor further connects the rod-end of a retracting piston to the drain outlet, and the rod-end of one or more retracting pistons to the drain or to a return pressure, which is lower than an extending pressure.