Engine Mixing Structure for Soot Reduction
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Solution Overview
Problem
Compression ignition engines face challenges in reducing soot formation due to sub-optimal fuel-and-air mix ratios and high ignition delays, which degrade engine performance and violate emissions regulations.
Innovation Solution
The introduction of mixing structures that control ignition delay by cooling hot gases with cooler air or gas streams, allowing for a leaner fuel-and-air mixture to form before combustion, using conduits and channels to direct the mixture into the combustion chamber, thereby reducing soot production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If fuel is directly injected into compressed hot gases, then the fuel mixes with in-cylinder gases and reaches ignition temperature, but the delay between injection and ignition is reduced causing sub-optimal fuel-and-air mix ratio and soot production
Solution Approach 1:
The mixing structure performs preliminary mixing of fuel and air in a dedicated chamber before injection into the combustion chamber. This preliminary action ensures optimal fuel-air ratio is achieved before combustion, preventing soot formation while maintaining appropriate ignition timing.
Solution Approach 2:
The mixing structure acts as an intermediary component between the fuel injection system and the combustion chamber. It provides a separate mixing zone where fuel and air combine properly before entering the combustion chamber, mediating the interaction between fuel injection and combustion processes.
2Temperature
If the temperature of entrained gases remains high, then the delay between injection and ignition is reduced, but the fuel-and-air mix ratio becomes sub-optimal producing soot
Solution Approach 1:
The mixing structure creates a local cooling zone within the mixing chamber where cooler air is introduced to reduce the temperature of hot gases. This local quality change allows proper mixing at lower temperatures, preventing soot formation while maintaining overall combustion efficiency.
Solution Approach 2:
The mixing structure changes the temperature parameter of the gas mixture by introducing cooler air into the mixing chamber. This parameter change from high temperature to lower temperature enables optimal fuel-air mixing ratio to be achieved, preventing soot production.
3Productivity
If fuel is injected into the other end of the spray plume while ignition occurs at the head, then combustion continues dynamically, but soot production occurs due to incomplete mixing
Solution Approach 1:
The mixing structure performs preliminary mixing of fuel and air in a controlled chamber before the mixture enters the combustion chamber. This ensures complete and homogeneous mixing occurs before combustion begins, eliminating incomplete mixing issues while maintaining dynamic combustion efficiency.
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 delays ignition and reduces soot generation, improving engine performance and compliance with emissions regulations by ensuring a more homogeneous fuel-and-air mixture is introduced into the combustion chamber.
Implementation Method 1
The body may cool the gas streams and entrain the gas streams into the liquid streams in the internal volume
Implementation Method 2
The body may thermally modify the gas streams and entrain the gas streams into the liquid streams in the internal volume
Data Source
AI summary
A mixing structure can include a body having first conduits, mixture conduits, and second conduits extending through the body to the internal volume. The first conduits may be closer to a first side of the body than the mixture conduits and the second conduits. The second conduits may closer to another side of the body than the first conduits and the mixture conduits. The internal volume may receive liquid streams from an injector. The first conduits and the second conduits may receive gas streams from outside the body. The body may thermally modify the gas streams and entrain the gas streams into the liquid streams in the internal volume. The mixture conduits may be positioned to direct the gas streams entrained into the liquid streams out of the body in directions directed toward the second side of the body and away from the first side of the body.