Piston Nozzle Arrangement for Cooling and Connecting Rod Lubrication

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Solution Overview

Problem

Internal combustion engines face challenges in achieving adequate lubrication and cooling of piston components, leading to increased friction, wear, and potential engine failure, particularly due to the inefficiencies in oil distribution and lubrication at the piston-connecting rod interface.

Innovation Solution

The implementation of two separate oil feeds, one for the piston cooling channel and another for lubricating the piston-connecting rod assembly, utilizing nozzles directly connected to a common oil reservoir to ensure consistent oil supply and minimize lubricant turnover.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If engine oil is injected directly into the piston cooling channel for effective cooling, then cooling efficiency is improved, but adequate lubrication of the piston-connecting rod joint cannot be assured

Engineering Contradiction:
Improvepiston cooling efficiencyVSAvoidlubrication adequacy
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The single oil feed is segmented into two separate oil feeds: one dedicated to the piston cooling channel and another dedicated to the piston-connecting rod joint. This segmentation allows each system to receive optimized oil supply independently, resolving the conflict between cooling efficiency and lubrication adequacy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different oil supply qualities are provided to different locations: the piston cooling channel receives oil optimized for cooling, while the piston-connecting rod joint receives oil optimized for lubrication. This local differentiation ensures each component receives the appropriate oil characteristics for its specific function.

Inventive Principle:
Principle #3Local quality

2Device complexity

If a single oil feed is used for both piston cooling and lubrication, then device complexity is reduced, but both cooling and lubrication functions cannot be adequately performed simultaneously

Engineering Contradiction:
Improveoil feed system complexityVSAvoidfunctional performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The oil feed system is divided into two independent feeds with separate control and distribution paths. This segmentation enables each feed to be optimized for its specific function while maintaining overall system manageability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The oil feed system maintains universality by using the same lubricant (engine oil) for both cooling and lubrication functions, just through separate delivery paths. This allows a single lubricant type to serve multiple purposes without requiring different fluid systems.

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

3Reliability

If engine oil is sprayed onto the piston crown for lubrication, then lubrication is adequate, but cooling efficiency is reduced

Engineering Contradiction:
Improvelubrication adequacyVSAvoidpiston cooling efficiency
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The oil application is segmented into two distinct streams: one directed at the piston crown for lubrication and another injected into the cooling channel for cooling. This eliminates the compromise required when using a single spray method for both purposes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The piston cooling channel acts as an intermediary structure that captures the cooling oil jet and directs it along the piston underside, separating the cooling function from the lubrication spray on the crown. This intermediary mechanism allows both functions to occur simultaneously without interference.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 ensures effective lubrication and cooling of critical engine components, reducing friction, wear, and the risk of engine failure by maintaining a consistent oil supply to both the piston cooling channel and the piston-connecting rod interface, thereby enhancing engine efficiency and longevity.

Implementation Method 1

engine oil flows as a cooling medium through the cooling channel below the piston bowl

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

The smoothness of the pivoting motion between the piston and the connecting rod is crucial, because the friction that occurs not only leads to a certain reduction in efficiency but also represents a critical starting point for increased wear

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP4026990A1Combustion engine with a nozzle arrangement for cooling and lubricating the piston-connecting rod assembly
Publication Date: 2022.07.13 LIEBHERR MACHINES BULLE
  • EP4026990A1 patent drawingFigure 1a~1b
  • EP4026990A1 patent drawingFigure 2~3
  • EP4026990A1 patent drawingFigure 4a~4b

AI summary

The invention relates to an internal combustion engine with at least one combustion chamber and a piston movably mounted therein, which is pivotally connected to one end of a connecting rod, and has a piston base with a recess, wherein a cavity runs through the piston base below the recess, and wherein at least two separate oil supply lines are provided to supply the oil on the one hand to the cavity of the piston and on the other hand to the connection point between the piston and the connecting rod.