Charge-fed pre-chamber assembly for lean combustion
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Solution Overview
Problem
Passive pre-chamber assemblies in internal combustion engines have leaner fuel charges due to residual gas dilution, requiring more ignition energy and increasing pre-ignition tendencies, while fuel-fed pre-chambers are costly and require additional components, including an external compressor.
Innovation Solution
A charge-fed pre-chamber assembly where a portion of the air-fuel charge is directed to the pre-chamber when its pressure is lower, displacing residual gases and igniting within the pre-chamber to initiate combustion, eliminating the need for an external compressor by using the engine's pressure dynamics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a passive pre-chamber assembly is used, then the structure is simpler, but the fuel charge becomes leaner due to residual gas dilution, requiring more ignition energy and increasing pre-ignition tendencies
Solution Approach 1:
The charge flow path is segmented into multiple pathways: a first pathway directs charge to the pre-chamber, while a second pathway directs charge to the main combustion chamber. This segmentation allows the pre-chamber to receive a dedicated fuel-rich charge portion, preventing dilution from residual gases while maintaining structural simplicity.
Solution Approach 2:
Fuel is injected into the charge upstream of the pre-chamber before the charge enters the pre-chamber volume. This preliminary fuel addition ensures the charge is sufficiently rich before entering the pre-chamber, compensating for any residual gas dilution and eliminating the need for complex post-chamber fuel injection systems.
2Quantity of substance
If a fuel-fed pre-chamber is used, then the fuel content in the pre-chamber is maintained, but additional components including an external compressor are required, increasing cost and complexity
Solution Approach 1:
The pre-chamber fuel supply system is merged with the main combustion chamber fuel injection system. A single fuel injection device supplies fuel to both the pre-chamber and main chamber through integrated flow paths, eliminating the need for separate fuel injection systems and external compressors required by traditional fuel-fed pre-chambers.
Solution Approach 2:
The fuel injection system serves multiple functions: it injects fuel into the main combustion chamber and simultaneously provides fuel to the pre-chamber through the integrated first pathway. This multi-functionality eliminates the need for dedicated pre-chamber fuel injection hardware and external compression systems.
3Quantity of substance
If charge is directed to the pre-chamber when pressure is lower, then residual gases are displaced and consistent fuel content is achieved, but pressure differential control is required
Solution Approach 1:
The pre-chamber inlet valve automatically opens and closes based on the pressure differential between the charge source and pre-chamber. When charge pressure exceeds pre-chamber pressure, the valve opens to allow charge flow; when pressures equalize or reverse, the valve closes. This self-regulating mechanism achieves consistent fuel content without requiring external pressure control systems.
Solution Approach 2:
The pressure differential between the charge source and pre-chamber drives the automatic opening and closing of the pre-chamber inlet valve. This pneumatic control mechanism uses the natural pressure differences in the combustion cycle to regulate charge flow, eliminating the need for complex electronic or mechanical pressure control systems.
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 ensures consistent fuel content in the pre-chamber, reducing pre-ignition risks and eliminating the need for additional costly components, enhancing combustion efficiency without increasing engine complexity.
Implementation Method 1
supplying the second portion of the charge to the pre-chamber volume when a pressure of the pre-chamber volume is less than a pressure of the charge
Implementation Method 2
decreasing the temperature of the charge includes flowing the charge through an aftercooler
Data Source
AI summary
A method for combustion in a combustion chamber of an internal combustion engine includes mixing fuel and air to form a charge, flowing a first portion of the charge to the main chamber of an engine and a second portion of the charge to the pre-chamber volume of an engine, igniting the second portion of the charge in the pre-chamber volume, and delivering the ignited second portion of the charge to the main chamber.