Piston Pin Emergency Guiding Walls Cylinder Damage
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Solution Overview
Problem
In internal combustion engines, when a piston demotes, the connecting rod can cause significant damage to the cylinder liner due to unguided reciprocation, as existing piston pins are either axially fixed or lack emergency guidance, leading to uncontrolled movement and potential engine failure.
Innovation Solution
A piston pin with emergency guiding outer walls is designed to contact the inner cylinder wall only in case of piston demolition, featuring a fixed gap between the piston pin ends and the cylinder wall, reducing damage by providing guided movement for the connecting rod during such events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the piston pin is axially fixed in the piston using circlips or end caps, then the piston pin remains stable during normal operation, but it cannot provide emergency guidance to the connecting rod in case of piston demolition
Solution Approach 1:
The piston pin is segmented into different functional zones: a main body portion that is axially fixed during normal operation, and emergency guiding outer walls at the ends that protrude beyond the fixation points to provide guidance during piston demolition. This segmentation allows the same component to serve two opposing functions.
Solution Approach 2:
The piston pin transitions from a static, fully fixed structure to a dynamic structure where the emergency guiding outer walls can move relative to the piston body during demolition events. This dynamic capability allows the pin to adapt its function based on operational conditions.
2Object-affected harmful factors
If the piston pin is designed with emergency guiding outer walls that contact the cylinder wall, then damage during piston demolition is reduced, but the device complexity increases
Solution Approach 1:
The piston pin is designed as a multi-functional component that simultaneously serves as a connection element during normal operation and as an emergency guidance element during demolition. The emergency guiding outer walls are integrated into the piston pin structure itself, eliminating the need for separate guidance components.
Solution Approach 2:
The emergency guidance function is merged with the piston pin structure by integrating the emergency guiding outer walls directly into the pin body. This combines what could have been separate components (piston pin and emergency guide) into a single unified element, reducing overall system complexity.
3Object-affected harmful factors
If the gap between the piston pin and cylinder wall is reduced to provide better guidance, then control during demolition is improved, but friction and wear during normal operation increase
Solution Approach 1:
The piston pin features local quality variations: the main body has a larger gap from the cylinder wall to minimize friction during normal operation, while the emergency guiding outer walls at the ends have a smaller gap to provide effective guidance during demolition. This localized differentiation optimizes performance for each operational phase.
Data Source
Figure 1
Figure 2~3
AI summary
The present disclosure generally relates to piston pins connecting pistons and associated connecting rods. A piston pin (10) may be configured to connect a connecting rod (8) and a piston (6). The piston pin (10) may be integrally formed with a first emergency guiding outer wall (34) facing the inner cylinder wall (4) and a second emergency guiding outer wall (34) facing the inner cylinder wall (4). The piston pin (10) may be dimensioned to contact the inner cylinder wall (4) only in case of a demolition of the piston (6).