Internal Combustion Engine Cylinder Wall Concave Pattern
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for reducing piston ring sliding resistance in internal combustion engines, such as forming concave portions on the cylinder inner wall, can increase surface pressure and lead to excessive lubricating oil consumption as the oil is swept into the combustion chamber.
Innovation Solution
The engine design incorporates a central region on the inner wall surface with a varying number of concave portions, where the first partial region has a larger width than the second partial region, reducing the contact area and preventing lubricating oil waste by strategically placing concave portions to minimize surface pressure and oil consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If concave portions are formed on the inner wall surface of the cylinder, then sliding resistance of the piston ring is reduced, but surface pressure acting on the inner wall surface increases
Solution Approach 1:
The patent applies local quality by varying the number of concave portions in different circumferential regions of the cylinder. Specifically, the first partial region (thrust region) has a larger number of concave portions compared to the second partial region (anti-thrust region), which has a smaller number. This localized differentiation allows the thrust region to benefit from reduced sliding resistance while the anti-thrust region maintains sufficient contact area to prevent excessive surface pressure increases.
2Force
If a large number of concave portions are formed on the inner wall surface, then sliding resistance is reduced, but lubricating oil consumption increases
Solution Approach 1:
The patent implements local quality by strategically distributing concave portions only where needed for friction reduction. By having fewer concave portions in the anti-thrust region compared to the thrust region, the design minimizes the total volume available for lubricating oil accumulation and subsequent consumption, while still achieving the primary goal of reducing piston ring sliding resistance in the critical thrust region.
3Force
If concave portions are formed on the inner wall surface, then piston ring sliding resistance is reduced, but contact area between skirt portion and inner wall surface decreases
Solution Approach 1:
The patent applies local quality by creating an asymmetric distribution of concave portions where the first partial region (thrust region) has a larger number of concave portions for friction reduction, while the second partial region (anti-thrust region) has a smaller number to maintain adequate contact area. This localized approach ensures that contact area is preserved in regions where it is most critical for supporting surface pressure, while still achieving sliding resistance reduction in the thrust region.
Data Source
AI summary
An internal combustion engine includes: a cylinder including a thrust region and an anti-thrust region; and a plurality of concave portions formed in a belt-like central region including a central portion in the axial direction of the cylinder and extending along the circumferential direction on an inner wall surface. In the central region, the number of concave portions formed in a first partial region having a first predetermined width along the circumferential direction of the thrust region and the number of concave portions formed in a second partial region having a second predetermined width that is smaller than the first predetermined width along the circumferential direction of the anti-thrust region is smaller than the number of concave portions formed in other regions of the central region.