Opposed-Piston Engine Combustion Chamber Segmentation
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Solution Overview
Problem
Conventional opposed-piston engines face challenges in achieving high thermal efficiency, compact structure, and low vibrations due to limitations in compression ratio and heat insulation, particularly in 2-stroke cycle engines and horizontal opposed-piston designs.
Innovation Solution
The opposed-piston engine design features a combustion chamber formed outside the cylinder with joint and capacity spaces, air intake and exhaust valves, and a spark plug, where the piston heads face each other within a split cylinder structure, enhancing heat insulation and allowing for a high compression ratio and efficient combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the combustion chamber is disposed outside the cylinder, then the structure is simplified and manufacturing is easier, but the compression ratio cannot be sufficiently increased thus lowering thermal efficiency
Solution Approach 1:
The combustion chamber is segmented into two distinct spaces: a joint space formed by recessed portions on the end surfaces of both piston heads, and a capacity space formed by bulging the cylinder wall. These spaces are communicated with each other and together constitute the complete combustion chamber, allowing the chamber to be formed outside the main cylinder body while maintaining high compression ratio
Solution Approach 2:
The combustion chamber is positioned in a spatial arrangement outside the main cylinder axis, utilizing the end spaces of the cylinder. The joint space is formed at the piston head interfaces while the capacity space extends along the cylinder end, creating a three-dimensional combustion chamber configuration that achieves high compression ratio without interfering with the main cylinder structure
2Reliability
If piston rings are arranged on the lower end of the piston to prevent lubricant from entering the combustion chamber, then oil control is improved, but the piston must be elongated thus increasing engine size
Solution Approach 1:
The lubricant sealing function is extracted from the piston structure itself and transferred to a dedicated piston ring arranged on the lower end of the piston. This separate piston ring specifically prevents lubricant from entering the combustion chamber through the scavenging and exhaust ports, allowing the main piston body to be shortened while maintaining effective oil control
3Device complexity
If the cylinder is formed as a single horizontal cylinder, then the structure is simple, but heat insulation of the combustion chamber becomes difficult thus lowering thermal efficiency
Solution Approach 1:
The cylinder is segmented into left and right cylinder unit bodies that are joined together to form the complete horizontal cylinder. This segmentation allows the combustion chamber, which is formed outside the cylinder at the joint of the two unit bodies, to be thermally insulated by positioning it away from the cooled inner cylinder wall, thereby improving thermal efficiency while maintaining a relatively simple overall cylinder structure
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 configuration enables improved thermal efficiency, reduced engine size, and lower vibrations by increasing the compression ratio and enhancing combustion efficiency, while facilitating easier assembly and cooling efficiency.
Implementation Method 1
ignition explosion of a fuel/air mixed gas
Implementation Method 2
realizing a high compression ratio of a fuel/air mixed gas in a cylinder
Implementation Method 3
enhance thermal efficiency of an engine due to a high heat insulation function
Data Source
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AI summary
Provided is an opposed-piston engine which enhances thermal efficiency by improving heat insulation efficiency of constitutional members of the engine as much as possible, realizing a high compression ratio in a combustion chamber and lowers vibrations. Left and right pistons which are movable independently from each other are housed in the inside of a horizontal cylinder in a state where heads of the respective left and right pistons face each other in an opposed manner, one combustion chamber is formed outside the horizontal cylinder in a state where the combustion chamber is communicated with a space defined between the left and right piston heads whereby an output is taken out by making use of approaching each other or moving away from each other of the left and right pistons caused by ignition explosion in the inside of the combustion chamber.