Piston Pump Plastic Seal Guide Element
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Solution Overview
Problem
Piston pumps used in internal combustion engines face challenges in achieving a sufficient delivery rate at low speeds and are costly due to the need for precise manufacturing of gap seals between the pump cylinder and piston, which are affected by thermal expansion coefficients.
Innovation Solution
A piston pump design featuring a plastic ring seal and separate guide elements replaces the traditional gap seal, allowing for improved sealing and reduced manufacturing costs, with the seal and guide elements working together to enhance the pump's efficiency and size optimization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a gap seal is used between the pump cylinder and pump piston, then the pump can be manufactured with standard materials, but the delivery rate is suboptimal at low speeds due to thermal expansion coefficients
Solution Approach 1:
The patent changes the material parameter of the seal from metal to plastic, which has a lower thermal expansion coefficient. This parameter change allows the seal to maintain effective contact with the pump piston across a wider temperature range, improving delivery rate at low speeds while maintaining reliable sealing performance.
Solution Approach 2:
The patent employs composite material construction by combining plastic seal ring with metal guide elements and fastening components. The plastic seal provides thermal stability and sealing, while the metal components provide mechanical strength and guidance, creating a composite solution that resolves the contradiction between delivery rate and sealing reliability.
2Reliability
If a gap seal with high manufacturing accuracy is used, then sealing performance is improved, but production costs increase
Solution Approach 1:
The patent replaces the expensive, precision-machined metal gap seal with a cheaper plastic seal ring that can be manufactured using simpler molding processes. The plastic seal achieves adequate sealing performance without requiring the high manufacturing accuracy of metal components, significantly reducing production costs while maintaining functional reliability.
Solution Approach 2:
By changing the seal material from metal to plastic, the patent alters the manufacturing parameters from precision machining to mold casting or injection molding. This parameter change enables mass production with lower costs while the material properties of plastic provide sufficient sealing performance for the application.
3Productivity
If the gap between seal and pump piston is reduced, then delivery rate improves, but the seal becomes vulnerable to cavitation damage
Solution Approach 1:
The patent introduces a metal guide element as an intermediary component between the plastic seal and the pump piston. This guide element maintains a minimal protective gap that prevents cavitation damage to the seal, while the plastic seal itself maintains close contact with the piston surface to ensure high delivery rate. The guide element mediates between the conflicting requirements of close sealing and cavitation protection.
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 improves the delivery rate, especially at low speeds, while reducing production costs and maintaining high-pressure sealing efficiency, with the seal's design and materials ensuring low friction and wear, and the ability to handle high system pressures.
Implementation Method 1
a seal for sealing off the pumping chamber... is designed as a plastic ring
Implementation Method 2
a separate guide element for guiding the pump piston are arranged between the pump piston and the pump housing
Implementation Method 3
a spring element presses the seal against the fastening ring
Implementation Method 4
the guide element serves as cavitation protection for the seal. The guide gap is small enough so that no vapor bubbles can reach the seal
Data Source
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AI summary
The invention relates to a piston pump (16), in particular a high-pressure fuel pump for an internal combustion engine, said piston pump comprising a pump housing (26), a pump piston (28) and a delivery chamber (38) delimited at least by the pump housing (26) and the pump piston (28). According to the invention, a seal (44) for sealing the delivery chamber (38) and a separate guide element (46) for guiding the pump piston (28) are arranged preferably between the pump piston (28) and the pump housing (26), the seal (44) being formed as a plastic ring with a substantially sleeve-shaped base portion (45).