Pinless Connecting Rod Lubrication for Piston Pivot Cooling

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Solution Overview

Problem

Existing reciprocating engines, such as diesel and gasoline engines, face inefficiencies and high emissions due to the high mass of moving parts, particularly in the piston and connecting rod design, which lacks effective lubrication and cooling, leading to overheating and assembly reliability issues.

Innovation Solution

A connecting rod design with a lubricant guide that channels lubricant from the crankshaft to the pivot connection between the piston and connecting rod, incorporating a lubricant reservoir and valve assembly to control lubricant flow based on the angular position, ensuring reliable lubrication and cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a piston pin connection is used between piston and connecting rod, then the connection is simple and reliable, but the mass of moving parts increases significantly

Engineering Contradiction:
Improveconnection reliabilityVSAvoidmass of moving parts
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The invention extracts and eliminates the piston pin from the connection system. Instead of using a separate piston pin component, the connecting rod head is directly inserted into the piston's connecting rod receptacle with an undercut, creating a pinless connection that reduces moving mass while maintaining reliability through the undercut retention mechanism

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The connection is segmented into the thickening of the connecting rod head and the undercut in the piston receptacle. This segmentation allows the connecting rod to be inserted and retained without a continuous piston pin, reducing overall mass while maintaining connection integrity through the undercut geometry

Inventive Principle:
Principle #1Segmentation

2Weight of moving object

If a pinless connecting rod design is used, then the mass of moving parts is reduced, but the lubrication and cooling of the pivot connection cannot be ensured

Engineering Contradiction:
Improvemass of moving partsVSAvoidlubrication and cooling reliability
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The invention implements preliminary action by providing oil supply channels in the piston that deliver lubricant to the connecting rod pivot connection before the connecting rod head is fully inserted into the receptacle. This preliminary lubrication ensures that the pivot connection is protected from the start, preventing overheating and seizing issues

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention introduces an intermediary lubrication system with oil supply channels and oil spray nozzles that mediate between the main oil supply and the pivot connection. This intermediary system delivers lubricant directly to the critical pivot area, ensuring reliable cooling and lubrication without requiring a traditional piston pin

Inventive Principle:
Principle #24Intermediary (Mediator)

3Weight of moving object

If a thickening with undercut connection is used, then the mass is reduced, but assembly reliability and manufacturing complexity become problematic

Engineering Contradiction:
Improvemass of moving partsVSAvoidmanufacturing and assembly ease
Core Design Contradiction:
Weight of moving objectVSEase of manufacture

Solution Approach 1:

The invention makes the piston serve multiple functions: it acts as both the piston component and as the retaining structure for the connecting rod through the undercut in the connecting rod receptacle. This multi-functionality eliminates the need for a separate piston pin while simplifying the overall assembly process

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The oil supply channels are preliminarily formed in the piston structure during manufacturing, and the undercut geometry is pre-configured in the connecting rod receptacle. This preliminary preparation of features simplifies the final assembly process, as the connecting rod can be directly inserted and retained without additional fastening operations

Inventive Principle:
Principle #10Preliminary action

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 design enhances engine efficiency by actively lubricating and cooling the pivot connection, reducing thermal stress and improving assembly reliability, thereby optimizing heat dissipation and reducing emissions.

Implementation Method 1

a lubricant introduced into the lubricant guide at the second connection in the area of the crankshaft is guided through the lubricant guide to the first connection and the lubricant is available for lubricating and/or cooling the first connection

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 2

the lubricant is available for lubricating and/or cooling the first connection

Methodology Applied
Scientific EffectCooling: Cooling

Data Source

PatentEP4453391B1Connecting rod, piston, crank drive, and reciprocating internal combustion engine
Publication Date: 2026.04.15 NEWGREEN AG
  • EP4453391B1 patent drawingFigure 1
  • EP4453391B1 patent drawingFigure 2a~2b
  • EP4453391B1 patent drawingFigure 2c~2d

AI summary

The invention relates to a connecting rod, in particular for an engine, comprising a head region, a central region (305), and a foot region. The head region has a first connection with a thickened section for connecting a piston to a connecting rod receiving area of the piston in a rotatable manner about a pivot axis, said connecting rod receiving area having an undercut which corresponds to the thickened section. The foot region has a second connection for receiving a crankshaft, and the head region is connected to the foot region via the central region. The invention additionally relates to a piston, a crank drive, and an internal combustion engine.