Opposed-Piston Assembly With Side Injection and Integrated Wristpin Bore
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing piston constructions for opposed-piston engines with separate wristpin support structures restrict the placement of stationary oil jets and fuel injectors, limiting the design options for compact engine configurations and hindering effective piston thermal management.
Innovation Solution
The integration of a wristpin bore within the piston skirt eliminates the need for a separate wristpin support structure, allowing for more favorable positioning of stationary oil jets and fuel injectors, with diametrically opposed injection regions on the end surface enabling direct side injection and improved coolant management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate wristpin support structure is used, then the wristpin bearing can be properly supported, but the placement of stationary oil jets and fuel injectors is restricted
Solution Approach 1:
The patent merges the separate wristpin support structure with the piston skirt by forming the wristpin bore integrally within the piston skirt itself. This eliminates the need for a separate support structure and its attachment features, thereby removing the restrictions on placement of stationary oil jets and fuel injectors while maintaining proper wristpin bearing support.
Solution Approach 2:
The piston skirt is given multiple functions: it provides structural support for the piston, contains the integral wristpin bore for bearing support, and allows flexible placement of stationary oil jets and fuel injectors. This multi-functionality resolves the contradiction by making the piston skirt adaptable to various cooling and injection configurations.
2Reliability
If a separate wristpin support structure is used, then the wristpin can be properly lubricated, but the engine configuration becomes less compact
Solution Approach 1:
The patent combines the wristpin support function directly into the piston skirt by forming the wristpin bore integrally within it. This eliminates the need for separate support structures and reduces the overall engine volume while maintaining proper wristpin lubrication through the integrated design.
3Stability of the object's composition
If attachment features are added to the piston skirt, then the wristpin support structure can be secured, but the design options for injection trenches and fuel injectors are limited
Solution Approach 1:
The patent merges the wristpin support function directly into the piston skirt by forming the wristpin bore integrally within it. This eliminates the need for separate attachment features, thereby removing restrictions on injection trench placement and fuel injector design while maintaining stable wristpin support.
4Temperature
If stationary oil jets are positioned favorably, then piston thermal management is improved, but the wristpin support structure attachment is compromised
Solution Approach 1:
The patent combines the wristpin support function directly into the piston skirt, eliminating attachment features that would restrict stationary oil jet positioning. This allows stationary oil jets to be optimally positioned for piston thermal management while maintaining stable wristpin support through the integral design.
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
This configuration enables a more compact engine design with enhanced thermal management, allowing for better placement of oil jets and fuel injectors, reducing friction and assembly complexity while maintaining effective sealing and lubrication.
Implementation Method 1
stationary oil jets that deliver the streams of coolant to the annular cooling gallery
Implementation Method 2
streams of liquid coolant enter the annular coolant gallery... optimal cooling effect when the streams of coolant are aligned with injection trenches
Implementation Method 3
injection trenches and fuel injectors that limit progress toward realization of good piston thermal management... injection trenches on the piston end surface by which fuel emitted through diametrically-opposed fuel injectors enters a combustion chamber
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A piston for an opposed-piston, internal combustion engine includes a crown with an end surface having a bowl shaped to form a combustion chamber with an end surface of an opposing piston in the opposed-piston engine. A substantially circumferential top land of the crown meets the end surface at a substantially circular peripheral edge, and a skirt comprising a sidewall extends from a substantially circumferential belt region of the crown. A wristpin bore with a wristpin axis opens through the sidewall. The end surface of the piston includes a pair of injection regions across which fuel is injected into the bowl. The injection regions are disposed in substantially diametrically-opposed quadrants of the end surface which are defined by the wristpin axis and a connecting rod envelope axis substantially orthogonal to the wristpin axis. Each injection region extends along a respective arc concentric with the substantially circular peripheral edge.