Fuel Pump Impeller Counter-Pressure Chamber Design
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Solution Overview
Problem
Conventional fuel pumps experience reduced efficiency due to rotational speed drop and pulsing fuel discharge caused by pressure differences between the fuel intake and discharge sides of the impeller, leading to increased impeller resistance and reduced flow performance.
Innovation Solution
The fuel pump design features adjusted depths of concavities and grooves on the impeller and casing to balance the flow rates between the intake and discharge sides, ensuring the force acting on the impeller from swirl flow is balanced, thereby stabilizing rotational speed and improving flow performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the impeller rotates to pressurize fuel from intake to discharge side, then fuel pressure is increased, but the pressure difference creates thrust force that reduces impeller rotational speed
Solution Approach 1:
The patent introduces a counterbalancing mechanism by creating a counter-pressure chamber on the intake side of the impeller. This chamber receives excess fuel from the discharge side through a communication hole, generating counter-pressure that balances the thrust force. The balanced thrust force prevents rotational speed reduction while maintaining effective fuel pressurization.
2Stress or pressure
If the impeller is pushed against the casing by pressure difference, then fuel pressurization is enhanced, but rotational speed drops causing pulsing discharge
Solution Approach 1:
The counter-pressure chamber creates a balancing force that offsets the thrust force from pressure difference. This prevents the impeller from being pushed against the casing, maintaining stable rotational speed and eliminating pulsing discharge while preserving effective fuel pressurization.
Solution Approach 2:
The communication hole between discharge and intake sides creates a feedback mechanism where excess pressure on the discharge side is fed back to the intake side through the counter-pressure chamber. This automatic pressure balancing stabilizes rotational speed and prevents pulsing without requiring external control systems.
3Productivity
If partitioning walls are angled to improve fuel flow, then swirl flow is enhanced, but the pressure difference between sides increases causing more impeller resistance variation
Solution Approach 1:
The counter-pressure chamber compensates for the increased pressure difference caused by angled partitioning walls. By balancing the thrust force, it allows the partitioning walls to be optimized for fuel flow efficiency without suffering from excessive rotational resistance variation.
Solution Approach 2:
The patent modifies the pressure distribution parameters by introducing the counter-pressure chamber, allowing the partitioning walls to operate at optimal angles for fuel flow while the overall system maintains stable rotational characteristics through pressure balancing.
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 balances the forces acting on the impeller, stabilizing its rotation and reducing pulsing in the fuel discharge, resulting in enhanced flow performance and consistent pressure delivery.
Implementation Method 1
Swirl flow occurs between the concavities on the front surface of the impeller and the first groove and swirl flow occurs between the concavities on the back surface of the impeller and the second groove because of the effects of centrifugal force caused by the rotation of the impeller.
Data Source
AI summary
Fuel pump (10) may comprise a casing (18) and a substantially disc-shaped impeller (20) which is rotatably disposed within the casing (18). A first group of concavities (21a) may be formed in a lower face of the impeller (20). A second group of concavities (20a) may be formed in an upper face of the impeller (20). A first groove (30) may be formed in the inner face of the casing (18) opposite the upper face of the impeller (20). The first groove (30) is formed in a region opposite the first group of concavities (21a) and extending from an upstream end to a downstream end. A second groove (24) may be formed in the inner face of the casing opposite the lower face of the impeller (20). The second groove (24) is formed in a region opposite the second group of concavities (20a) and extending from an upstream end to a downstream end. Preferably, the depth of the first and second groups of concavities and the depth of the first and second grooves are adjusted such that the flow of fuel flowing through the first group of concavities (21a) and the first groove (30) is greater than the flow of fuel flowing through the second group of concavities (20a) and the second groove (24).