GDI Fuel Pump Outlet Seat Nitriding to Cut Valve Seat Complexity
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Solution Overview
Problem
The high cost and complexity of manufacturing hardened stainless steel valve seats for high-pressure fuel pumps in gasoline direct injection systems, due to their corrosive environment and wear resistance requirements, lead to increased production costs and component count.
Innovation Solution
A fuel pump design with a nitrided layer extending from the outlet valve seating surface into the fuel pump housing, eliminating the need for a separate hardened stainless steel valve seat, and incorporating a moveable outlet valve member within the outlet passage to control fuel flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate hardened stainless steel valve seat is used, then wear resistance and corrosion resistance are improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines the valve seat and fuel pump housing into a single integrated component. The valve seat is formed as an integral part of the housing through a nitrided layer applied to the housing material, eliminating the need for a separate valve seat component while maintaining wear and corrosion resistance properties.
Solution Approach 2:
The patent uses a composite material approach by applying a nitrided layer to the stainless steel housing material. This creates a composite structure where the base material provides structural integrity and the nitrided surface layer provides enhanced wear and corrosion resistance, replacing the need for separate hardened stainless steel valve seat components.
2Reliability
If a separate hardened stainless steel valve seat is used, then corrosion resistance is improved, but manufacturing cost increases
Solution Approach 1:
The patent combines the valve seat and fuel pump housing into a single integrated component. The valve seat is formed as an integral part of the housing through a nitrided layer applied to the housing material, eliminating the need for a separate valve seat component while maintaining wear and corrosion resistance properties.
Solution Approach 2:
The patent changes the material parameter by applying a nitrided layer to the stainless steel housing, which modifies the surface properties to provide enhanced corrosion and wear resistance. This parameter change allows the base housing material to serve dual functions as both structural component and corrosion-resistant valve seat.
3Reliability
If a press fit interface is used to seal the valve seat, then sealing function is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The patent combines the valve seat and fuel pump housing into a single integrated component. The valve seat is formed as an integral part of the housing through a nitrided layer applied to the housing material, eliminating the need for a separate valve seat component while maintaining wear and corrosion resistance properties.
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 the number of components and manufacturing costs while maintaining the necessary wear resistance and corrosion resistance, enhancing the operational efficiency and reliability of the fuel pump.
Implementation Method 1
a nitrided layer extends from the outlet valve seating surface into the fuel pump housing
Data Source
AI summary
A fuel pump includes a fuel pump housing made of stainless steel and having a pumping chamber therewithin, a plunger bore extending thereinto, an inlet passage extending thereinto, and an outlet passage extending thereinto. A pumping plunger reciprocates within the plunger bore such that an intake stroke of the pumping plunger increases volume of the pumping chamber and a compression stroke of the pumping plunger decreases volume of the pumping chamber. An outlet valve controls fuel flow from the pumping chamber out of the fuel pump housing. The outlet valve includes an outlet valve seating surface formed by the fuel pump housing within the outlet passage such that a nitrided layer extends from the outlet valve seating surface into the fuel pump housing. The outlet valve also includes an outlet valve member within the outlet passage which is moveable between a seated position and an unseated position.