Multi-Fuel Rail Integrated Sealing for Compact Engine Packaging
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Solution Overview
Problem
Current techniques face challenges in delivering two or more fuels efficiently to direct fuel injectors in internal combustion engines, particularly due to space constraints under the valve cover and the complexity of sealing structures, which can lead to reliability and durability issues and increased deposit formation.
Innovation Solution
A multi-fuel rail apparatus featuring elongate forged members with integrated branch connecting structures and bosses that allow for efficient fluid communication and sealing of both gaseous and liquid fuels, reducing packaging constraints and assembly complexity by integrating sealing structures directly into the forged members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If cylindrical tube fuel rails with specially adapted couplings are used to deliver multiple fuels to direct fuel injectors, then fuel delivery capability is achieved, but device complexity and assembly difficulty increase significantly
Solution Approach 1:
The patent merges the fuel rail and coupling functions into a single integrated forged member. The fuel rail includes integrated boss structures that directly receive and seal the fuel line, eliminating the need for separate couplings and reducing assembly steps. This integration maintains multi-fuel delivery capability while significantly reducing device complexity.
Solution Approach 2:
The forged fuel rail member serves multiple functions simultaneously: it acts as the fuel delivery conduit, provides structural support, incorporates sealing surfaces for both gaseous and liquid fuels, and includes mounting features for fuel lines. This multi-functionality reduces the number of separate components needed while maintaining adaptability for different fuel types.
2Reliability
If specially adapted couplings with metal-to-metal sealing structures are used, then sealing capability is improved, but the coupling size becomes excessively large
Solution Approach 1:
The sealing structure is merged directly into the fuel rail body rather than being contained in a separate coupling. The boss structures on the fuel rail include integrated sealing surfaces that directly engage with the fuel line, eliminating the need for additional coupling volume while maintaining reliable metal-to-metal sealing for high-pressure gaseous fuel.
Solution Approach 2:
The sealing surfaces are concentrated at specific localized boss structures on the fuel rail rather than requiring a large overall coupling size. These localized sealing zones provide the necessary sealing capability for both gaseous and liquid fuels while keeping the overall component size compact.
3Area of stationary object
If internal fuel rails are used to deliver fuels through the cylinder head, then space constraints under the valve cover are resolved, but thermodynamic properties of the cylinder head change leading to reliability issues
Solution Approach 1:
The fuel delivery system is segmented into two separate forged members: one for gaseous fuel and one for liquid fuel. Each member is designed to deliver its specific fuel type to the appropriate fuel injector, preventing cross-contamination and thermal interference between fuel systems while maintaining compact packaging within the engine compartment.
Solution Approach 2:
The patent addresses thermal effects by providing separate fuel delivery paths for gaseous and liquid fuels, isolating the thermal environments. The forged members are designed with appropriate material selection and thermal management features to maintain cylinder head thermodynamic properties within acceptable ranges while still achieving compact space utilization.
4Ease of operation
If gaseous fuel is delivered through fuel galleries sealed with radial seals, then fuel delivery is achieved, but seal reliability is compromised during engine shut-down when pressure drops rapidly
Solution Approach 1:
The patent replaces the traditional radial seal mechanism with a metal-to-metal sealing system using boss structures that engage with the fuel line. This mechanical sealing approach maintains reliable sealing even during rapid pressure changes during engine shut-down, as the rigid metal-to-metal contact maintains seal integrity better than elastic radial seals under rapid pressure transient conditions.
Data Source
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AI summary
A multi-fuel rail apparatus for an internal combustion engine communicates fuel from 10 a first fuel source and a second fuel source to a plurality of fuel injectors. Each fuel injector receives fuel from the multi-fuel rail apparatus through a branch connection for each fuel. The multi fuel rail apparatus has a first elongate member including a first longitudinal bore spaced apart from a second longitudinal bore and first and second fuel inlets for fluidly communicating first and second fuels into the first and 15 second longitudinal bores respectively. There is a branch connecting structure for each fuel injector along the first elongate member for fluidly connecting the first and second longitudinal bores with respective branch connections from respective fuel injectors.