Fuel Injector Seating Insert for Gaseous Fuel Leakage Reduction
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Solution Overview
Problem
Conventional fuel injectors are not suitable for gaseous-fuelled internal combustion engines due to the unique characteristics of gases like hydrogen, which create design challenges such as high leakage and differential wear issues.
Innovation Solution
The design includes an injection nozzle with a seating insert that reduces the differential area between upper and lower valve seats, minimizing the seating load and allowing for a smaller return spring and solenoid, while also providing two separate flow paths to reduce lift distance and energy demands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional fuel injector design is used, then the injector can deliver fuel, but the differential area between upper and lower valve seats creates high seating load requiring large return spring and solenoid
Solution Approach 1:
The valve seat is divided into two separate seating surfaces: an upper valve seat and a lower valve seat. The upper valve seat is formed on the seating insert while the lower valve seat is formed on the nozzle body. This segmentation allows the differential area between the two seats to be minimized, thereby reducing the seating load on the injection valve needle and enabling smaller return spring and solenoid components.
2Force
If larger return spring and solenoid are used to overcome high seating load, then seating force is sufficient, but energy consumption increases and device size grows
Solution Approach 1:
The upper and lower valve seats are pre-configured with optimized dimensions and positions before operation. The upper valve seat diameter is designed to be almost identical to the lower valve seat diameter, creating minimal differential area that requires only small seating force. This preliminary design configuration ensures that minimal energy is required from the return spring and solenoid to achieve proper valve seating.
3Ease of operation
If conventional single flow path is used, then fuel delivery is simple, but lift distance is large requiring more energy
Solution Approach 1:
The invention introduces a vertical dimension to the flow path by creating both upper and lower valve seats at different axial positions. This three-dimensional arrangement of seating surfaces allows the injection valve needle to achieve effective sealing at two different levels, reducing the required lift distance compared to a conventional single-plane valve seat configuration.
4Quantity of substance
If upper valve seat diameter is large, then fuel flow area is sufficient, but differential area between seats increases requiring larger seating load
Solution Approach 1:
The critical parameter changed is the diameter of the upper valve seat, which is designed to be almost identical to the lower valve seat diameter (differing by at most 20%, preferably at most 15%, more preferably at most 10%). This parameter optimization maintains sufficient fuel flow area while minimizing the differential area between seats, thereby reducing the seating load required to maintain proper valve closure.
Data Source
AI summary
An injection nozzle for an internal combustion engine, comprising a nozzle body defining a nozzle body bore, a blind end region of which defines a set of nozzle outlets. An injection valve needle is slidably received in the nozzle body bore and engageable with a seating arrangement to control fuel flow. The seating arrangement includes a seating insert received in the nozzle body bore and positioned upstream of the nozzle outlets, the seating insert defining an upper valve seat. The injection valve needle comprises a first seating portion and a second seating portion which are axially spaced along the injection valve needle. The first seating portion is engageable with the upper valve seat defined by the seating insert; and the second seating portion is engageable with a lower valve seat defined by the nozzle body bore.