Unburned Fuel Venting in Internal Combustion Engine Crevice
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Solution Overview
Problem
Internal combustion engines face inefficiencies due to unburned air/fuel-mixture being trapped in crevice volumes, which are not effectively vented and recycled for subsequent combustion cycles, leading to wasted energy and emissions.
Innovation Solution
The engine design incorporates a flow channel that connects directly to the annular crevice between the cylinder and piston, allowing unburned air/fuel-mixture to be vented and recycled during specific crank angle ranges, using a regulating valve to control the flow and direct it back into the intake channel for re-use in subsequent cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If unburned air/fuel-mixture is vented from the combustion chamber during specific crank angle ranges, then engine efficiency is improved and emissions are reduced, but the device complexity increases due to the need for flow channels and regulating valves
Solution Approach 1:
The venting system is segmented into multiple flow channels positioned at different locations around the combustion chamber, allowing selective venting of unburned mixture from different crevice volumes. This segmentation enables targeted extraction of unburned fuel without requiring a single complex venting mechanism, thereby improving engine efficiency while managing device complexity through modular design
Solution Approach 2:
The regulating valve operates periodically based on crank angle position, opening only during specific ranges (e.g., 85°-95° and 265°-275° after top dead center) to vent unburned mixture. This periodic action ensures that venting occurs only when beneficial, improving engine efficiency and reducing emissions while using a relatively simple valve mechanism rather than a continuously complex control system
2Loss of substance
If flow channels are positioned to connect directly with the annular crevice at specific crank angles, then unburned fuel recovery is maximized, but the manufacturing precision requirements increase
Solution Approach 1:
The flow channels are positioned to connect with the annular crevice at specific locations around the combustion chamber, creating local venting zones where unburned mixture accumulates. This local quality approach allows direct connection to crevice volumes without requiring precise alignment across the entire chamber, maximizing unburned fuel recovery while reducing overall manufacturing precision requirements through localized feature placement
3Productivity
If a regulating valve is used to control the flow timing, then the venting process is optimized for specific crank angle ranges, but the device complexity and ease of operation are reduced
Solution Approach 1:
The regulating valve is designed to dynamically open and close based on crank angle position, allowing the venting process to be optimized for specific ranges (such as 85°-95° and 265°-275° after top dead center). This dynamic operation maximizes unburned fuel recovery during power strokes while automatically preventing interference with compression and intake strokes, achieving process optimization through mechanical timing rather than complex electronic control
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 solution enhances engine efficiency by re-circulating unburned fuel, reducing emissions, and optimizing combustion processes by ensuring that unburned air/fuel-mixture is utilized in subsequent cycles, thereby improving overall engine performance.
Implementation Method 1
at least one flow channel fluidly connected to the combustion chamber and configured to direct unburned air/fuel-mixture out of the combustion chamber
Data Source
AI summary
An internal combustion engine is disclosed. The engine may have a cylinder that defines a combustion chamber for combusting an air/fuel mixture. The engine may also have a piston reciprocally movable within the cylinder between a top dead center (TDC) and a bottom dead center (BDC). The piston may have an uppermost piston ring configured to sealingly contact the cylinder. The engine may have an annular crevice facing the combustion chamber. The crevice may be defined by the cylinder, the piston, and the uppermost piston ring. The engine may also have a flow channel fluidly connected to the combustion chamber. The flow channel may direct unburned air/fuel-mixture out of the combustion chamber. The at least one flow channel may be fluidly connected to the annular crevice for a crank angle range of about 85° to 95° and about 265° to 275° after the top dead center (TDC).