Multi-cylinder Engine Cylinder Block Diagonal Rib Design
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Solution Overview
Problem
Existing multi-cylinder engine designs experience varying sealability between the cylinder block and cylinder head, with high sealability near fastener portions and low sealability far from them due to uneven compressional stress distribution.
Innovation Solution
Incorporating diagonal ribs on the side wall faces of the cylinder block that extend from connecting portions to head bolt holes, ensuring compressional stress is distributed uniformly along the circumferential direction, thereby maintaining high sealability regardless of distance from the fastener portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If recess and protrusion are formed to encircle the entire circumference of the bore opening, then sealability is improved at the contact face, but uneven compressional stress is created causing high stress near fastener portions and low stress far from fastener portions
Solution Approach 1:
The patent applies local quality by providing ribs only at specific locations where needed - namely at the connecting portions between adjacent cylinder parts - rather than uniformly around the entire circumference. This localized reinforcement creates appropriate stress distribution patterns that ensure adequate compressional stress at critical sealing regions far from head bolts, while avoiding unnecessary stress concentration near fastener portions.
Solution Approach 2:
The patent segments the circumferential reinforcement into discrete ribs positioned at specific intervals along the cylinder part, rather than providing continuous circumferential reinforcement. This segmentation allows differential stress management - providing reinforcement where needed at connecting portions while leaving regions near head bolts without additional reinforcement, thus achieving more uniform overall stress distribution.
2Reliability
If continuous circumferential reinforcement is provided, then sealability is enhanced, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent reduces structural complexity by providing reinforcement ribs only at specific locations (connecting portions between cylinder parts) rather than continuous circumferential reinforcement. This localized approach maintains sealability at critical interfaces while significantly reducing the overall complexity of the cylinder block structure.
Solution Approach 2:
The patent segments the reinforcement structure into discrete, separable ribs positioned at specific intervals, which simplifies manufacturing compared to continuous circumferential reinforcement. These segmented ribs can be more easily formed and positioned during the molding process, reducing device complexity while maintaining sealing effectiveness.
3Weight of moving object
If resin material is used for the outer cylinder block, then weight is reduced, but stress distribution and rigidity become concerns
Solution Approach 1:
The patent compensates for the lower inherent strength of resin material by providing localized rib reinforcements at critical connecting portions between cylinder parts. These strategically positioned ribs create stress distribution pathways that enhance rigidity and ensure adequate compressional stress at sealing interfaces, allowing the use of lightweight resin material while maintaining structural performance.
Solution Approach 2:
The patent effectively creates a composite structure by combining the resin outer cylinder block with integrated rib reinforcements at strategic locations. This composite approach - where the rib structures serve as embedded reinforcement elements within the resin matrix - optimizes the weight-to-strength ratio by providing rigidity and stress distribution capability where needed while maintaining the overall lightweight characteristic of the resin construction.
Data Source
AI summary
An engine includes an output shaft, a cylinder head, a cylinder block, and a plurality of head bolts. The cylinder block includes three or more cylinder parts, a plurality of connecting portions, a plurality of output shaft supporting parts, and a plurality of head bolt holes. A side wall face of at least one cylinder part includes a first rib. The first rib diagonally extends from the connecting portion toward a head bolt hole base.