Fuel Injector Hole Geometry for Particle Emission Control
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Solution Overview
Problem
Existing fuel injection devices face challenges in reducing the emission of harmful substances (PN) due to increased penetration force and uneven fuel flow velocity, leading to attachment to engine components and increased emission of coarse particles, especially when fuel pressure is increased.
Innovation Solution
A fuel injection device with a unique configuration of injection holes, where the crossing angles and distances between the central axis and inlet surfaces of the first and second injection holes are optimized to control flow velocity and penetration, ensuring a shorter spray travel distance and reducing coarse particle generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fuel pressure is increased for atomization, then fuel particle fineness is improved, but spray penetration distance is increased causing attachment to inlet valve or cylinder wall surface
Solution Approach 1:
The patent applies local quality by varying the injection hole diameters based on their specific positions and air flow conditions. Injection holes in regions with smaller air flow have smaller diameters, while those in regions with larger air flow have larger diameters. This localized adaptation allows each injection hole to optimize its spray characteristics according to local conditions, achieving fine atomization without excessive penetration distance that would cause attachment to engine components.
2Length of moving object
If injection hole diameter is increased to reduce penetration, then spray travel distance is shortened, but fuel flow velocity becomes uneven and coarse particles are generated
Solution Approach 1:
The patent implements local quality by assigning different injection hole diameters to different positions within the injector. This spatial variation in hole diameter compensates for differences in air flow velocity and pressure distribution across the injection zone. The optimized diameter distribution ensures uniform fuel flow velocity and fine particle generation throughout the spray, even when overall penetration distance is reduced.
3Manufacturing precision
If fuel pressure is increased, then atomization is improved, but attachment to inlet valve or cylinder wall surface increases causing harmful substance emission
Solution Approach 1:
The patent applies local quality by optimizing injection hole diameters according to local air flow conditions and positions. This localized optimization enables effective atomization at moderate fuel pressures by ensuring each injection hole delivers appropriately sized particles for its specific location. The result is reduced fuel attachment to inlet valves and cylinder wall surfaces, thereby lowering harmful substance emissions while maintaining good atomization quality.
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
The optimized configuration results in superior PN performance by stabilizing fuel flow and reducing attachment to engine components, thereby minimizing harmful substance emissions.
Implementation Method 1
a method of controlling unburned gas by promoting mixture with air by increasing system fuel pressure and atomizing a particle of injected fuel
Implementation Method 2
in a case where fuel pressure is increased for atomization, penetration force of a fuel spray is increased and a spray travel distance (hereinafter, referred to as penetration) of the injected fuel spray is increased
Implementation Method 3
in a case where flow velocity of fuel is high due to a reason such as a pressure increase, there is a case where a flow of the fuel is separated from a wall surface of an injection hole
Data Source
AI summary
A fuel injection device including a valve body having an injection hole-formed part having a plurality of injection holes on the leading end side of the valve body. An injection hole comprises a crossing angle, θ1, between a central axis of the injection hole-formed part and an injection hole axis, and another injection hole comprises a crossing angle, θ2, between the central axis and another injection hole axis. θ2 is larger than θ1. The injection holes are formed such that a distance between the central axis and an inlet surface center of the injection hole is longer than a distance between the central axis and another inlet surface center of the another injection hole. A straight line beyond an outlet surface in the injection hole axis does not intersect with another straight line beyond another outlet surface in the another injection hole axis.