Fuel Injector Feed Bore Segmentation for Deposit Prevention
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Solution Overview
Problem
Conventional side feed systems in modular common rail injectors for internal combustion engines lead to inadequate fuel exchange in high-pressure accumulators, resulting in deposit formation and residue issues, especially with high viscosity fuels, and exacerbate pressure pulsations and wear due to direct fuel flow to the injection nozzle.
Innovation Solution
Designing a separate feed bore that connects the lance connection directly to the high-pressure accumulator, promoting fuel turbulence and air removal, and integrating a resonator line with a restrictor to mitigate pressure pulsations, while ensuring efficient fuel circulation and reducing wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the feed bore opens into the high-pressure bore connecting the high-pressure accumulator to the nozzle chamber, then the fuel path is shortened and injection pressure is maintained, but fuel exchange in the high-pressure accumulator becomes inadequate leading to deposit formation
Solution Approach 1:
The feed bore is segmented into two separate sections: one section feeds fuel to the injection nozzle through the high-pressure bore, while another section feeds fuel directly to the high-pressure accumulator. This segmentation allows independent optimization of both fuel delivery speed and accumulator fuel exchange, resolving the contradiction between maintaining injection pressure and preventing deposit formation.
2Device complexity
If the feed bore is integrated with the high-pressure bore, then the device structure is simplified, but the outlet location embodied as a T joint is disadvantageous in terms of strength
Solution Approach 1:
Instead of integrating the feed bore with the high-pressure bore as a single T-jointed structure, the invention segments them into separate bores. The feed bore runs independently from the lance connection to the accumulator, while the high-pressure bore connects the accumulator to the injection nozzle. This eliminates the weak T-joint while maintaining structural simplicity through separate, straightforward bore paths.
3Stress or pressure
If high-pressure fuel flows directly from the lance connection to the injection nozzle, then injection pressure is maintained, but pressure pulsations increase leading to severe wear at the nozzle seat
Solution Approach 1:
The high-pressure accumulator serves as an intermediary between the lance connection and the injection nozzle. Fuel flows from the lance connection to the accumulator, and then from the accumulator to the nozzle. This intermediary role of the accumulator dampens pressure pulsations that would otherwise travel directly from the nozzle closure back to the lance connection, reducing wear at the nozzle seat while maintaining injection pressure.
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 enhances fuel exchange and turbulence in the accumulator, effectively prevents deposit formation, reduces pressure pulsations, and minimizes wear by ensuring efficient fuel circulation and resonance-based pressure wave cancellation.
Implementation Method 1
integrating a resonator line with a restrictor to mitigate pressure pulsations, while ensuring efficient fuel circulation and reducing wear by ensuring efficient fuel circulation and resonance-based pressure wave cancellation
Implementation Method 2
This routing of the fuel furthermore promotes the formation of turbulence, thereby ensuring better removal of air from the high-pressure accumulator
Data Source
AI summary
A device for injecting fuel into the combustion chamber of an internal combustion engine comprising at least one injector. The injector includes an injector body, a high-pressure accumulator integrated into the injector body, an injection nozzle, a high-pressure bore, and a feed bore. The injection nozzle defines a nozzle chamber and has a nozzle needle configured to be guided in an axially movable manner and that is surrounded by the nozzle chamber. The high-pressure bore is connected to the high-pressure accumulator and the nozzle chamber. The feed bore is configured to feed high-pressure fuel to the high-pressure accumulator. Additionally, the feed bore has a lance connection positioned laterally on the injector body, is formed as a bore separate from the high-pressure bore, and connects the lance connection directly to the high-pressure accumulator.