Opposed-Piston Ignition Chamber for Lower-Pressure Diesel Combustion
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Solution Overview
Problem
Existing compression-ignition engines face challenges in efficiently igniting heavy fuels like diesel at lower compression ratios to reduce engine component stress and achieve improved combustion with reduced emissions.
Innovation Solution
The design features opposed piston engines with recessed and protruding portions on pistons to trap and ignite homogenous fuel, and radial channels to communicate the ignited fuel to the combustion chamber, allowing for lower overall cylinder pressures while maintaining efficient combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high compression ratios (e.g., 22:1) are used to ignite heavy fuels like diesel, then ignition reliability is improved, but engine component stress increases
Solution Approach 1:
The combustion chamber is segmented into two zones: a recessed portion that traps a specific amount of homogenous fuel mixture for controlled compression ignition, and radial channels that distribute the ignited fuel to the bulk charge. This segmentation allows localized high compression for reliable ignition while the overall engine operates at lower compression ratios, reducing component stress
Solution Approach 2:
The recessed portion creates a localized region with different compression characteristics compared to the rest of the combustion chamber. This local quality change enables precise control over the ignition zone while maintaining lower overall cylinder pressures, resolving the contradiction between ignition reliability and engine stress
2Ease of operation
If direct injection is used in compression-ignition engines, then fuel delivery control is improved, but ignition timing control remains limited
Solution Approach 1:
Homogenous fuel mixture is prepared and injected into the recessed portion before the compression stroke begins. This preliminary action allows the fuel to be positioned and pre-mixed with air, enabling better control over both fuel delivery and subsequent ignition timing through the controlled compression and ignition process in the recessed portion
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 engine stress, achieves precise ignition of homogenous fuel, and lowers emissions by allowing operation at lower compression ratios while maintaining engine performance.
Implementation Method 1
compressing and igniting a portion of homogenous fuel trapped within a recessed portion of a first opposed piston by moving the first piston and a second opposed piston comprising a protruding portion towards top dead center
Implementation Method 2
compressing and igniting a portion of homogenous fuel trapped within a recessed portion
Implementation Method 3
communicating the ignited portion of homogenous fuel through a plurality of channels in radial array within the first piston, wherein each channel begins at an interior wall of the recessed portion and extends to an ending position at a combustion chamber to ignite bulk homogenous fuel within the combustion chamber
Data Source
AI summary
Fuel is ignited in an opposed-piston engine by the mating of unique protruding and recessed portions of opposed pistons.