Fuel Pump Discharge Passage Throttle Design
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Solution Overview
Problem
Existing fuel pumps experience stagnant flow and energy loss due to centrifugal force causing fuel to separate from the inner wall of the discharge passage, leading to a reduced effective sectional area and decreased efficiency.
Innovation Solution
A fuel pump design with a throttle part connecting the pressurizing passage to the discharge passage, where the discharge passage is narrower and positioned towards the radially outer wall, and the throttle part is angled to maintain a similar cross-sectional area, reducing stagnant flow and energy loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the discharge passage is made wider to increase effective discharge area, then the discharge capacity is improved, but centrifugal force causes fuel to separate from the inner wall creating stagnant flow and reducing effective area
Solution Approach 1:
The discharge passage is designed with a gradual expansion angle (5-15 degrees) rather than a sudden expansion, creating a dynamic transition that maintains flow attachment to the inner wall while increasing discharge area. This gradual expansion prevents flow separation and stagnant flow formation that would occur with abrupt expansions.
Solution Approach 2:
The passage width is gradually increased along the flow direction with a controlled expansion angle, changing the geometric parameter progressively rather than abruptly. This gradual parameter change allows the fuel to adapt to the expanding passage without separating from the inner wall, maintaining effective flow area while increasing discharge capacity.
2Loss of energy
If the discharge passage is made narrower to prevent stagnant flow, then energy loss is reduced, but the effective discharge area is decreased
Solution Approach 1:
The discharge passage transitions from a narrower section to a wider discharge section through a gradual expansion with a controlled angle. This dynamic geometric transition allows the passage to maintain narrow dimensions where needed while expanding to provide sufficient discharge area, preventing stagnant flow in the transition zone.
Solution Approach 2:
The discharge passage utilizes three-dimensional spatial arrangement with gradual expansion in the radial direction. By controlling the expansion angle and positioning the discharge passage appropriately, the design achieves both compact dimensions and sufficient discharge area without creating stagnant flow regions.
3Area of stationary object
If the discharge passage outlet is made equal to or wider than the pressurizing passage, then discharge area is maximized, but stagnant flow occurs near the inner wall reducing effective area
Solution Approach 1:
The discharge passage employs a gradual expansion design where the outlet width is increased relative to the pressurizing passage through a controlled expansion angle. This dynamic geometric transition ensures that the fuel flow remains attached to the inner wall throughout the expansion, preventing stagnant flow and maintaining flow stability despite the increased outlet area.
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 design enhances fuel flow efficiency by preventing fuel stagnation and reducing energy loss, while maintaining effective discharge area utilization.
Implementation Method 1
the impeller can be rotated to suction fuel from the outside of the casing into the pump passage, pressurize the suctioned fuel, and discharge the pressurized fuel out of the casing
Implementation Method 2
Because centrifugal force acts on the fuel flowing through the discharge passage, the fuel is out of contact with the radially inner wall of the discharge passage
Data Source
AI summary
A fuel pump includes an impeller and a casing member. The impeller defines a plurality of vane grooves arranged in a circumferential direction. The casing member receives the impeller, and the casing member defines therein a pump passage configured to have an arcuate shape along the vane grooves. The discharge passage is provided downstream of the pressurizing passage. The discharge passage has a width narrower than a width of the pressurizing passage, and the discharge passage is positioned toward a radially outer wall of the pressurizing passage. The pressurizing passage includes a throttle part that extends from a starting point to an inlet of the discharge passage. The throttle part has a first width at the starting point, which corresponds to the width of the pressurizing passage, and a second width at the inlet, which corresponds to the width of the discharge passage.