Pre-Chamber Piston Engine Ignition Timing via Intermediate Chambers
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Solution Overview
Problem
Existing piston engines achieve thermodynamically non-ideal combustion due to varying ignition times of flame fronts across different transfer ports, leading to inefficiencies.
Innovation Solution
Incorporating intermediate chambers in selected flow paths with larger cross-sections to delay flame propagation, ensuring nearly simultaneous ignition across the combustion chamber despite varying port lengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If multiple transfer ports with different lengths are used to ignite mixture at different positions, then combustion time is reduced, but flame fronts reach combustion chamber at different times causing thermodynamically non-ideal combustion
Solution Approach 1:
An intermediate chamber is introduced as a mediator between the pre-chamber and the combustion chamber. This intermediate chamber receives the flame front from the pre-chamber and redistributes it through multiple overflow channels to different transfer ports, ensuring that flame fronts reach all combustion chamber positions simultaneously despite varying path lengths.
Solution Approach 2:
The flow path from pre-chamber to combustion chamber is segmented into multiple stages: the pre-chamber, the intermediate chamber with multiple overflow channels, and the final transfer ports. This segmentation allows the flame front to be distributed and synchronized across multiple pathways, resolving the timing discrepancy caused by different path lengths.
2Adaptability or versatility
If transfer ports have different lengths to reach different combustion positions, then ignition coverage is improved, but flame propagation velocity varies causing non-simultaneous ignition
Solution Approach 1:
The intermediate chamber creates an equipotential condition for flame propagation by providing a common origin point for multiple overflow channels. Although the subsequent transfer ports have different lengths to reach different positions, the flame front starts from the same potential level in the intermediate chamber, allowing simultaneous arrival at all destinations.
Solution Approach 2:
Different overflow channels in the intermediate chamber are configured with different characteristics to match the specific requirements of each transfer port. This local adaptation ensures that flame propagation velocity is optimized for each specific path while maintaining overall synchronization.
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 design allows for nearly simultaneous ignition at multiple positions, reducing time differences between first and last flame front arrivals, enhancing combustion efficiency and achieving thermodynamically favorable constant-volume combustion.
Implementation Method 1
flame fronts propagate from the pre-chamber via the flow paths into the combustion chamber
Implementation Method 2
The intermediate chamber causes a delay in flame propagation in this shorter flow path, so that a lower average flame propagation velocity is achieved in the flow path containing the intermediate chamber
Data Source
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AI summary
The invention relates to a piston engine, in particular a reciprocating piston engine, with a combustion chamber (19) into which an ignitable mixture can be introduced in order to set a shaft (22) into a rotary motion about an engine axis (21) by means of a movable piston (18) adjacent to the combustion chamber (19) by means of ignition of the mixture in the combustion chamber (19), and with a pre-chamber (1) which is fluidically connected to the combustion chamber (19) via several flow paths (2), wherein the flow paths (2) are each at least partially formed by transfer channels (3) so that the mixture in the combustion chamber (19) can be ignited by ignition of an ignitable mixture in the pre-chamber (1), wherein the flow paths (2) have different lengths.In order to achieve simultaneous initiation of combustion in the combustion chamber (19) at different positions (5) despite flow paths (2) of different lengths, the invention provides that at least one flow path (2), which differs from a flow path (2) with a maximum length, has an intermediate chamber (4) into which a transfer channel (3) opens, which connects the intermediate chamber (4) with the pre-chamber (1), wherein the intermediate chamber (4) has a cross-section which is larger than a cross-section of the transfer channel (3) opening into the intermediate chamber (4).The invention further relates to a method for operating a piston engine wherein an ignitable mixture is ignited in a combustion chamber (19) which borders a piston (18) which piston (18) is connected to a shaft (22) rotating about an engine axis (21) by igniting an ignitable mixture in a pre-chamber (1) which is connected to the combustion chamber (19) via several flow paths (2), after which flame fronts propagate from the pre-chamber (1) via the flow paths (2) into the combustion chamber (19) and ignite the mixture located in the combustion chamber (19), so that the shaft (22) is moved by means of the piston (18) due to a pressure increase in the combustion chamber (19).