Fuel Injector Nozzle-Check Transfer Holes for Reduced Mixing
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Solution Overview
Problem
Existing dual fuel engine systems face challenges in effectively limiting the mixing of two fuels, particularly when using a leading diesel fuel and a trailing alcohol fuel, which can reduce substitution ratios and ignitability of the combined fuel charge.
Innovation Solution
The fuel injector incorporates transfer holes with orientations including tangential and axially advancing components relative to the longitudinal axis, which minimize mixing by creating a swirl effect and limiting fuel interface mixing, enhancing fuel segregation and ignitability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transfer holes are oriented radially in existing dual fuel injectors, then fuel injection is achieved, but excessive mixing of diesel and alcohol fuels occurs which reduces substitution ratios and ignitability
Solution Approach 1:
The transfer holes are segmented into multiple orientation groups: some holes oriented axially advancing (parallel to longitudinal axis), some at oblique angles (45-60 degrees), and some radially outward. This segmentation creates distinct fuel flow paths that prevent complete mixing while maintaining injection functionality.
Solution Approach 2:
Different regions of the nozzle check have different hole orientations tailored to local requirements. Axially advancing holes in certain regions promote diesel flow and segregation, while radially oriented holes in other regions ensure proper alcohol fuel distribution. Each local region's hole orientation is optimized for its specific function.
2Productivity
If fuels are injected as a single combined charge, then injection simplicity is maintained, but fuel mixing reduces substitution ratios and combustion efficiency
Solution Approach 1:
The transfer holes introduce a dimensional variation in flow direction by orienting holes at multiple angles (axial, oblique, radial) rather than a single radial orientation. This dimensional diversity in flow paths creates natural fuel segregation through centrifugal and swirl effects, enhancing substitution ratios without adding mechanical complexity.
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 achieves improved fuel segregation and increased substitution ratios of diesel and alcohol fuels, leading to enhanced combustion efficiency and reduced emissions.
Implementation Method 1
transfer holes with orientations including tangential and axially advancing components relative to the longitudinal axis, which minimize mixing by creating a swirl effect
Data Source
AI summary
A fuel injector includes a nozzle having a combined-fuel outlet passage fluidly connected to a first fuel passage and a second fuel passage and extending to a plurality of nozzle outlets. A nozzle check movable in the nozzle includes a plurality of transfer holes fluidly connecting the first fuel passage through the nozzle check to the combined-fuel outlet passage. The plurality of transfer holes are orientated to limit mixing between two liquid fuels in a combined fuel charge in the combined-fuel outlet passage. The combined fuel charge may be formed of a leading compression-ignition liquid fuel such as diesel and a trailing liquid fuel such as methanol. Related apparatus and methodology is also disclosed.