Ducted Fuel Injection Combustion Soot Reduction
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Solution Overview
Problem
Direct injection engines produce high levels of soot emissions due to fuel-rich mixtures, which are difficult and costly to manage with existing aftertreatment systems, and there is a need for combustion strategies that minimize soot generation.
Innovation Solution
Enhancing local mixing rates inside the combustion chamber by directing a fuel jet through a duct, which creates turbulence and draws in charge-gas to form locally premixed mixtures with lower peak fuel to charge-gas ratios, preventing soot generation during ignition and combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If direct injection is used to improve engine efficiency, then engine efficiency increases, but soot emissions increase
Solution Approach 1:
The injection system is segmented into multiple components: a fuel injector with multiple nozzles, a duct system with multiple bores, and a combustion chamber. This segmentation allows fuel to be injected through multiple separate streams, each creating its own premixed zone, thereby reducing overall soot formation while maintaining injection efficiency
Solution Approach 2:
The duct acts as an intermediary component between the fuel injector and the combustion chamber. It introduces charge-gas into the fuel stream, creating a premixed zone that mediates between direct fuel injection and combustion, thereby reducing soot formation while preserving the efficiency benefits of direct injection
2Object-generated harmful factors
If aftertreatment systems are added to reduce soot emissions, then soot removal improves, but system cost and complexity increase
Solution Approach 1:
The system performs preliminary mixing of fuel and charge-gas within the duct before combustion occurs in the chamber. This preliminary action creates premixed zones that burn more cleanly, preventing soot formation at its source rather than requiring downstream aftertreatment systems to remove it
Solution Approach 2:
The harmful soot-forming process is extracted from the main combustion chamber by creating separate premixed zones within the duct system. This isolation allows the main chamber to operate more efficiently while the premixed zones handle the fuel-air mixing, effectively removing the soot generation problem from the primary combustion process
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 solution effectively minimizes soot generation and reduces emissions of other regulated pollutants like NOx, HC, and CO, improving engine efficiency and reducing the need for costly aftertreatment systems.
Implementation Method 1
passage of the fuel causing charge-gas to be drawn into the bore such that turbulence is created within the bore
Implementation Method 2
turbulence is created within the bore to cause enhanced mixing of the fuel and the drawn charge-gas
Implementation Method 3
enhanced local mixing rates inside a combustion chamber
Implementation Method 4
combustion of the locally premixed mixtures, featuring lower peak fuel to charge-gas ratios, with the objective of enabling minimal, or zero, generation of soot
Data Source
Figure 1~3
Figure 4~5C
Figure 6A~6C
AI summary
Various technologies presented herein relate to enhancing mixing inside a combustion chamber to form one or more locally premixed mixtures comprising fuel and charge-gas with low peak fuel to charge-gas ratios to enable minimal, or no, generation of soot and other undesired emissions during ignition and subsequent combustion of the locally premixed mixtures. To enable sufficient mixing of the fuel and charge-gas, a jet of fuel can be directed to pass through a bore of a duct causing charge-gas to be drawn into the bore creating turbulence to mix the fuel and the drawn charge-gas. The duct can be located proximate to an opening in a tip of a fuel injector. The duct can comprise of one or more holes along its length to enable charge-gas to be drawn into the bore, and further, the duct can cool the fuel and/or charge-gas prior to combustion.