Engine Cylinder Ring Abradable Layer for Thermal Efficiency
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Solution Overview
Problem
Existing diesel engine structures have room for improvement in thermal efficiency due to unnecessary volume communication with the combustion chamber.
Innovation Solution
An engine structure with a ring having a first abradable layer on its inner peripheral surface, which is worn down by contact with the piston, reducing the gap between the piston and the ring and minimizing unnecessary volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a standard cylinder bore is used without additional components, then the structure is simple, but unnecessary volume communicates with the combustion chamber reducing thermal efficiency
Solution Approach 1:
The invention divides the sealing function into two parts: the piston rings seal the lower portion of the cylinder bore, while the separate annular ring seals the upper end portion. This segmentation allows the upper ring to reduce unnecessary volume near the combustion chamber without requiring the entire cylinder bore to be modified, thus improving thermal efficiency while maintaining relatively simple structure.
Solution Approach 2:
The abradable layer on the annular ring acts as an intermediary that facilitates controlled wear to achieve precise sealing. As the piston moves upward, the abradable layer is worn away to create an optimal gap between the piston and the annular ring, ensuring complete sealing of the combustion chamber and eliminating unnecessary volume communication, thereby improving thermal efficiency.
2Manufacturing precision
If the gap between piston and ring is large, then manufacturing is easier, but unnecessary volume increases reducing compression ratio
Solution Approach 1:
The abradable layer is pre-applied to the annular ring before assembly, creating a controlled mechanism for gap adjustment. During initial operation, this layer wears down systematically to achieve the precise target gap between the piston and ring, eliminating the need for complex post-assembly adjustments and ensuring accurate compression ratio without requiring extremely tight manufacturing tolerances.
Solution Approach 2:
The invention changes the hardness parameter of the ring material by applying a softer abradable layer on the inner peripheral surface. This parameter change allows the ring to wear down controllably during initial operation, automatically adjusting the gap size to the optimal value for sealing the combustion chamber, thus achieving precise gap control while simplifying manufacturing requirements.
3Reliability
If abradable thermal spray is applied to the entire cylinder bore, then sealing is improved, but manufacturing complexity and cost increase
Solution Approach 1:
Instead of applying abradable thermal spray to the entire cylinder bore, the invention applies it only to the inner peripheral surface of the annular ring at the upper end portion. This localized application provides sealing where it is most critical (near the combustion chamber) while avoiding unnecessary manufacturing complexity and cost associated with treating the entire cylinder bore surface.
Solution Approach 2:
The invention extracts the abradable layer application from the cylinder bore and concentrates it on the annular ring component. This extraction allows the sealing function to be achieved through a smaller, more manageable surface area, reducing manufacturing complexity while maintaining reliable sealing performance in the critical combustion chamber region.
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
The configuration improves the compression ratio in the combustion chamber, enhancing thermal efficiency and reducing manufacturing complexity by eliminating the need for abradable thermal spray on the cylinder bore.
Implementation Method 1
a first abradable layer that is worn down by contact with an outer peripheral surface of the piston is formed on an inner peripheral surface of the ring
Implementation Method 2
a first abradable layer that is worn down by contact with an outer peripheral surface of the piston is formed on an inner peripheral surface of the ring
Data Source
AI summary
This engine structure includes: a cylinder block in which a cylinder bore is formed; a piston provided in the cylinder bore; a cylinder head provided to an upper portion of the cylinder block in a manner to seal the cylinder bore; and a ring that is inserted in the upper end portion of the cylinder bore and has an inner diameter that is smaller than the diameter of the cylinder. A first abradable layer that is worn down by contact with an outer peripheral surface of the piston is formed on an inner peripheral surface of the ring.