Nitrided Fuel Pump Valve Seat for Low-Cost GDI Sealing
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Solution Overview
Problem
The existing fuel pump systems for gasoline direct injection engines face challenges in manufacturing costs due to the expensive materials and processes required for the outlet valve seat, which also necessitate tight size and surface finish tolerances for proper sealing.
Innovation Solution
A fuel pump design featuring a stainless steel housing with a nitrided outlet valve seating surface integrated into the fuel pump housing, reducing the number of components and manufacturing costs by eliminating the need for a separate valve seat, and utilizing a nitrided layer to enhance the sealing and durability of the outlet valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate valve seat is used with a press fit interface, then sealing can be achieved, but manufacturing cost increases and tight size tolerances are required
Solution Approach 1:
The outlet valve seating surface is integrated directly into the fuel pump housing, eliminating the separate valve seat component and its press fit interface. This merging of functions reduces component count while maintaining sealing capability through the nitrided layer on the housing surface.
Solution Approach 2:
A nitrided layer is applied to the outlet valve seating surface area of the fuel pump housing, providing localized enhanced sealing properties and durability only where needed, rather than requiring the entire valve seat to be made of expensive hardened material.
2Reliability
If a separate valve seat with press fit interface is used, then sealing can be achieved, but manufacturing cost increases
Solution Approach 1:
The outlet valve seating surface is integrated directly into the fuel pump housing, eliminating the separate valve seat component and its press fit interface. This merging of functions reduces component count while maintaining sealing capability through the nitrided layer on the housing surface.
Solution Approach 2:
The nitrided layer modifies the surface properties of the housing material at the seating area, providing enhanced sealing characteristics and durability without requiring the entire component to be made of expensive hardened material, thus reducing overall manufacturing cost.
3Reliability
If tight size tolerances and surface finish tolerances are required for the press fit interface, then proper sealing is achieved, but manufacturing complexity increases
Solution Approach 1:
A nitrided layer is applied to the outlet valve seating surface area of the fuel pump housing, providing localized enhanced sealing properties and durability only where needed, rather than requiring the entire valve seat to be made of expensive hardened material.
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 reduces manufacturing costs and improves the sealing efficiency of the outlet valve, preventing fuel backflow while maintaining the necessary performance and durability for high-pressure fuel injection systems.
Implementation Method 1
a nitrided layer extends from the outlet valve seating surface (28b) into the fuel pump housing (28)
Data Source
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AI summary
A fuel pump (20) includes a fuel pump housing (28) made of stainless steel and having a pumping chamber (38) therewithin, a plunger bore (30) extending thereinto, an inlet passage (41) extending thereinto, and an outlet passage (43) extending thereinto. A pumping plunger (34) reciprocates within the plunger bore (30) such that an intake stroke of the pumping plunger (34) increases volume of the pumping chamber (38) and a compression stroke of the pumping plunger (34) decreases volume of the pumping chamber (38). An outlet valve (42) controls fuel flow from the pumping chamber (38) out of the fuel pump housing (28). The outlet valve (42) includes an outlet valve seating surface (28b) formed by the fuel pump housing (28) within the outlet passage (43) such that a nitrided layer (110) extends from the outlet valve seating surface (28b) into the fuel pump housing (28). The outlet valve (42) also includes an outlet valve member (104) within the outlet passage (43) which is moveable between a seated position and an unseated position.