Pilot Subchamber Fuel Segmentation for Partial Load Combustion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Internal combustion engines with large pilot subchambers and injectors create a rich fuel mixture, leading to inefficient operation, particularly at partial load conditions, where fuel consumption is high and lean air-to-fuel mixtures are difficult to maintain.
Innovation Solution
A method for operating internal combustion engines, including rotary engines, that utilizes a pilot subchamber with a pilot fuel injector and ignition element to create a hot wall, restricting the ignited fuel flow to the main combustion chamber, allowing for reduced main fuel injection and maintaining efficient combustion at partial load conditions, thereby reducing fuel consumption and enabling lean air-to-fuel mixtures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large pilot subchamber and large pilot injector are used, then the pilot fuel flow is sufficient to maintain combustion, but the overall fuel mixture becomes too rich leading to high fuel consumption at partial load conditions
Solution Approach 1:
The combustion chamber is segmented into a pilot subchamber and a main combustion chamber. The pilot subchamber receives a controlled portion of fuel (at most 10% of maximum fuel quantity) to initiate combustion, while the main chamber receives the remaining fuel. This segmentation allows precise control of the pilot fuel amount to prevent excessive richness while ensuring reliable combustion initiation.
Solution Approach 2:
The patent dynamically adjusts the pilot fuel injection quantity based on engine operating conditions. At partial load conditions, the pilot fuel quantity is limited to at most 10% of the maximum fuel quantity injected at full load. This parameter change optimizes the air-to-fuel mixture ratio, enabling lean operation and reducing fuel consumption while maintaining combustion stability.
2Reliability
If a large portion of fuel is injected as pilot injection, then combustion can be maintained, but lean air-to-fuel mixtures cannot be achieved at partial load conditions
Solution Approach 1:
By dividing the fuel injection into pilot and main portions delivered to separate chambers, the system can precisely control the pilot fuel amount to be at most 10% of maximum fuel quantity. This enables the main combustion chamber to receive a much larger portion of air relative to fuel, achieving lean air-to-fuel mixtures that would be impossible with a single large pilot injection.
Solution Approach 2:
The pilot fuel quantity parameter is changed based on load conditions. At partial load, limiting pilot fuel to at most 10% of maximum fuel quantity allows the overall air-to-fuel mixture to become lean (excess air ratio lambda > 1), improving combustion efficiency and reducing emissions while maintaining continuous combustion through the pilot chamber's controlled fuel supply.
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 reduces fuel consumption at idle and partial load conditions, allowing the engine to operate efficiently with lean air-to-fuel mixtures, achieving lower fuel usage and maintaining suitable temperatures for quick relighting to full combustion.
Implementation Method 1
An ignition element (54) is received in communication with the pilot subchamber (32)
Implementation Method 2
create a hot wall, restricting the ignited fuel flow to the main combustion chamber
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method of operating an internal combustion engine (100) having pilot subchambers (142) communicating with main combustion chambers (122), the internal combustion engine (100) configured in use to deliver a main fuel injection of a maximum quantity of fuel to the main combustion chambers (122) when the internal combustion engine (100) is operated at maximum load. The method includes delivering a pilot fuel injection of at most 10% of the maximum quantity to the pilot subchambers (142), igniting the pilot fuel injection within the pilot subchambers (142), directing the ignited fuel from the pilot subchambers (142) to the main combustion chambers (122), and delivering a main fuel injection of a main quantity of fuel to at least one of the main combustion chambers (122) receiving the ignited fuel, with the main quantity being at most 10% of the maximum quantity.