Offset Spark Electrodes in Dual Fuel Igniter Nozzle
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Solution Overview
Problem
Dual fuel engines face challenges in packaging and increased costs due to the need for both a fuel injector and a spark plug, and suffer from ignition issues with gaseous fuels like natural gas, particularly in lean burn applications where interaction between liquid fuel spray plumes and spark electrodes can lead to fouling and reduced combustion stability.
Innovation Solution
An igniter design featuring a nozzle with radially and axially outward spray orifices and offset spark electrodes, preventing interaction between fuel spray plumes and spark gaps, allowing for efficient liquid fuel injection and spark ignition of gaseous fuels without fouling the spark electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If both a fuel injector and a spark plug are used in the same dual fuel engine, then the engine can operate on both liquid and gaseous fuels, but packaging space is consumed and costs increase
Solution Approach 1:
The patent combines the fuel injector and spark plug into a single integrated igniter assembly. The injector body houses both the liquid fuel injection system and the spark electrode system, allowing both components to occupy the same packaging space and function as one unit rather than two separate parts
Solution Approach 2:
The integrated igniter assembly serves multiple functions: it can inject liquid fuel for diesel-only operation, it can provide spark ignition for natural gas operation, and it can perform both functions in dual fuel mode. This multi-functional design eliminates the need for separate fuel injector and spark plug components
2Productivity
If liquid fuel spray plumes interact with spark electrodes, then liquid fuel can be injected efficiently, but the spark electrodes become fouled and combustion stability decreases
Solution Approach 1:
The patent positions the spark electrodes in a different spatial dimension relative to the liquid fuel spray plumes. The spray orifices are arranged to direct fuel spray away from the spark electrode tips, creating spatial separation that prevents liquid fuel from contacting and fouling the electrodes while maintaining both functions within the same igniter body
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 combustion predictability and controllability by avoiding spark electrode fouling, reducing emissions, and optimizing engine performance across various fuel modes while minimizing part count and cost.
Implementation Method 1
A plurality of spark electrodes are mounted to the second igniter body end and form a plurality of spark gaps that are offset from the plurality of spray axes
Implementation Method 2
The nozzle has a plurality of spray orifices formed therein, and an outlet check movable between an open position at which the plurality of spray orifices are in fluid communication with the nozzle supply passage
Implementation Method 3
Fuel and air is combusted within an engine cylinder in a conventional operating scheme to produce a rapid rise in pressure
Data Source
AI summary
An igniter for a dual fuel engine includes a plurality of spray orifices formed in a nozzle and defining a plurality of spray axes. A plurality of spark electrodes are resident on the nozzle and form spark gaps offset from the spray axes, in a spark gap pattern that is at variance in at least one of a circumferential aspect or an axial aspect with the spray plume pattern.