Piston Ring Assembly Layout for Low Blow-By Diesel Engines
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Solution Overview
Problem
In compression ignition engines, particularly diesel engines, reducing blow-by gas while minimizing piston weight and friction is challenging, especially in small engines where increasing the number of compression rings is difficult due to weight and friction concerns.
Innovation Solution
A configuration of three compression rings and one oil ring is used, with specific axial widths and tensions, and a tapered shape for the third compression ring, along with strategic land space volume distribution to reduce blow-by gas and piston weight, while maintaining ring strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If three or more compression rings are used to reduce blow-by gas, then gas seal performance is improved, but piston weight increases
Solution Approach 1:
The patent applies different axial widths to different compression rings based on their specific positions and functions. The first compression ring has width B1, the second has width B2, and the third has width B3, where B1 ≥ B2 and B1 ≥ B3. This local differentiation allows each ring to be optimized for its specific sealing requirements while minimizing total piston weight.
Solution Approach 2:
The patent changes the parameter of ring axial width to optimize the balance between sealing performance and weight. By setting specific width relationships (B1 ≥ B2 and B1 ≥ B3) and controlling the total width sum (B1+B2+B3 ≥ 3.9mm), the invention achieves effective blow-by gas reduction while suppressing piston weight increase.
2Reliability
If three or more compression rings are used to reduce blow-by gas, then gas seal performance is improved, but friction increases
Solution Approach 1:
The patent applies different axial widths to different compression rings based on their specific positions and functions. The first compression ring has width B1, the second has width B2, and the third has width B3, where B1 ≥ B2 and B1 ≥ B3. This local differentiation allows each ring to be optimized for its specific sealing requirements while minimizing total piston weight.
Solution Approach 2:
The patent changes the parameter of ring axial width to optimize the balance between sealing performance and weight. By setting specific width relationships (B1 ≥ B2 and B1 ≥ B3) and controlling the total width sum (B1+B2+B3 ≥ 3.9mm), the invention achieves effective blow-by gas reduction while suppressing piston weight increase.
3Reliability
If the axial length of piston is increased to accommodate three or more compression rings, then gas seal performance is improved, but piston weight increases
Solution Approach 1:
The patent applies different axial widths to different compression rings based on their specific positions and functions. The first compression ring has width B1, the second has width B2, and the third has width B3, where B1 ≥ B2 and B1 ≥ B3. This local differentiation allows each ring to be optimized for its specific sealing requirements while minimizing total piston weight.
Solution Approach 2:
The patent changes the parameter of ring axial width to optimize the balance between sealing performance and weight. By setting specific width relationships (B1 ≥ B2 and B1 ≥ B3) and controlling the total width sum (B1+B2+B3 ≥ 3.9mm), the invention achieves effective blow-by gas reduction while suppressing piston weight increase.
Data Source
AI summary
A combination of piston rings assembled to a piston includes a first compression ring, a second compression ring, a third compression ring and an oil ring. When an axial width of the first compression ring is h1(1), an axial width of the second compression ring is h1(2), an axial width of the third compression ring is h1(3) and an axial width of the oil ring is h1(4), h1(1)≥h1(2) and h1(1)≥h1(3), and when h1(TOTAL)=h1(1)+h1(2)+h1(3)+h1(4), h1(TOTAL)≥3.9 mm.