Piston Cover Plate Resilient Attachment and Cooling
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Solution Overview
Problem
Existing pistons in internal combustion engines face challenges in securely attaching cover plates, requiring complex fastening methods like screwing, soldering, or welding, and lack effective cooling mechanisms for the skirt walls and pin bores.
Innovation Solution
A cover plate with grooves in the lower area of the piston skirt, featuring spring-elastic indentations and latching elements, is securely attached under resilient pretension, capturing and redistributing cooling oil to enhance cooling efficiency through the shaker effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex fastening measures (screwing, soldering, riveting, welding, or pressing) are used to attach the cover plate, then the attachment security is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The cover plate is designed with resilient biases that enable it to automatically attach to and remain secured on the piston without requiring external fastening operations. The resilient biases create a self-retaining mechanism where the cover plate maintains its position through elastic deformation and geometric interlocking, eliminating the need for screwing, soldering, riveting, welding, or pressing operations
Solution Approach 2:
The invention replaces complex mechanical fastening systems (screws, welds, rivets) with a simplified resilient bias mechanism. The cover plate utilizes elastic deformation and geometric constraints to achieve secure attachment, substituting multiple complex mechanical joining operations with a single resilient retention system that simplifies both manufacturing and assembly
2Temperature
If cooling oil is allowed to flow freely through the piston, then the cooling efficiency is improved, but the oil outflow in the direction of the crankshaft increases causing heat loss
Solution Approach 1:
The invention extracts or removes the harmful outflow of cooling oil toward the crankshaft by designing the cover plate with resilient biases that redirect the oil flow. The cover plate structure captures the cooling oil within the piston interior and prevents its unwanted discharge in the direction of the crankshaft, thereby eliminating the energy loss associated with premature oil outflow while maintaining effective cooling
Solution Approach 2:
The cover plate acts as an intermediary element between the cooling oil and the crankshaft direction. It intercepts the cooling oil flow and redirects it to remain within the piston interior, mediating the interaction between the cooling system and the crankshaft area to prevent harmful heat loss while maintaining cooling effectiveness
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 solution reduces operating temperatures of the piston head, ring grooves, and pin bores by up to 30% and improves cooling of the skirt walls, eliminating the need for complex fastening and enhancing the overall cooling effect.
Implementation Method 1
between the recess and at least one of the free ends there is a spring-elastic indentation with a U-shaped or V-shaped cross section
Implementation Method 2
Due to the shaker effect that occurs during engine operation, the cooling oil caught by the cover plate is moved back and forth at high frequency in the direction of the pin bores and the piston head
Implementation Method 3
The cooling oil can be introduced directly into the interior of the piston above the cover plate by means of an oil injection nozzle, or it can flow out of a cooling channel
Data Source
Figure 1a~1b
Figure 1c
Figure 2
AI summary
A piston for an internal combustion engine may include a piston head and a piston skirt. The piston skirt may include piston bosses disposed opposite one another having a boss bore and at least two shank walls disposed opposite one another having a running surface. A cover plate including a recess for receiving a connecting rod may be secured in a lower region of the piston skirt. The cover plate may have at least two longitudinal sides disposed opposite one another and at least two free ends disposed opposite one another. At least two grooves may be arranged in the lower region of the piston skirt on the at least two shank walls. The at least two free ends of the cover plate may be accommodated resiliently prestressed in the at least two grooves.