Dual-Stage Fuel Injection for Compression-Ignition Engine Emissions
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Solution Overview
Problem
Compression-ignition engines face challenges in reducing NOx and PM emissions, especially at higher engine loads, due to excessive combustion noise and instability in fuel/air pre-mix charge systems, which limits their operational range.
Innovation Solution
A reciprocating-piston, direct-injection compression-ignition engine with a variable-volume combustion chamber, where an initial mass of fuel is injected early in the compression stroke, and a main mass of fuel is injected coincident with the start of combustion, monitored and controlled by a sophisticated control module to optimize fuel injection timing and quantity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If fuel/air pre-mix charge systems are used to reduce NOx and PM emissions, then emissions are reduced at lower engine load operation, but combustion noise and combustion stability become excessive at higher engine load operation
Solution Approach 1:
The fuel injection process is divided into multiple distinct phases: an initial injection event that occurs early in the compression stroke to form a pre-mix charge, and a main injection event that occurs near top dead center. This segmentation allows the fuel/air mixture to be formed and stabilized before the main combustion event, enabling emission reductions while maintaining combustion stability at higher loads.
Solution Approach 2:
The initial fuel injection event occurs well in advance of the main combustion event, during the compression stroke. This preliminary action allows the fuel to mix with air and form a stable pre-mix charge before the main injection, enabling better control over combustion characteristics and reducing both emissions and combustion noise at higher engine loads.
2Object-generated harmful factors
If fuel/air pre-mix charge systems are used to reduce NOx and PM emissions, then emissions are reduced at lower engine load operation, but combustion noise becomes excessive at higher engine load operation
Solution Approach 1:
The fuel injection is segmented into an initial low-volume event and a main high-volume event. The initial event creates a controlled pre-mix charge that burns quietly, while the main event occurs when the piston is near top dead center where the controlled charge provides stable combustion. This segmentation reduces both emissions and combustion noise across the engine operating range.
Solution Approach 2:
The preliminary fuel injection during compression creates a stabilized fuel/air mixture that prepares the combustion chamber for the main injection. This preliminary action ensures that when the main fuel injection occurs, the combustion is stable and quiet, reducing combustion noise while maintaining emission benefits at higher engine loads.
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 approach allows for reduced NOx and PM emissions across a wider range of engine loads while minimizing combustion noise and improving combustion stability, as depicted in graphical and parametric data showing optimal smoke, noise, combustion efficiency, and fuel consumption.
Implementation Method 1
An initial mass of fuel is injected into the combustion chamber to form a combustion charge. Combustion is monitored and a main mass of fuel is injected into the combustion chamber
Implementation Method 2
reciprocating-piston, direct-injection, compression-ignition internal combustion engine includes a variable-volume combustion chamber defined by the piston reciprocating in a cylinder
Data Source
AI summary
A method to manage and control engine operation includes injecting an initial mass of fuel into a combustion chamber to form a combustion charge, monitoring combustion and injecting a main mass of fuel into the combustion chamber substantially coincident with a start of combustion of the combustion charge.