Flexible Connection Rod for Stable Combustion Pressure

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Solution Overview

Problem

Internal combustion engines lack control over combustion energy, leading to variations in combustion pressure, which affects engine performance.

Innovation Solution

An energy storage device with a flexible connection rod that stores and releases energy during the combustion process, using elastic buckling to maintain constant combustion pressure by converting peak cylinder pressure into strain energy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a conventional stiff connection rod is used, then high compression ratios are maintained, but combustion pressure varies significantly during the combustion process

Engineering Contradiction:
Improvecombustion pressure stabilityVSAvoidconnection rod structure
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The connection rod transitions from a static rigid structure to a dynamic flexible structure that can change its stiffness characteristics during operation. The rod is designed to undergo elastic buckling at specific pressure thresholds, dynamically adjusting its mechanical properties to stabilize combustion pressure while maintaining structural integrity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The connection rod's structural parameters are designed to change under different loading conditions. By controlling the rod's flexibility and buckling characteristics, the system changes its effective stiffness parameter in response to combustion pressure variations, thereby stabilizing the pressure without requiring a completely different structural design.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If a flexible connection rod is used to store energy, then combustion pressure is stabilized, but the rod must undergo elastic buckling which reduces initial stiffness

Engineering Contradiction:
Improvecombustion pressure stabilityVSAvoidconnection rod stiffness
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The connection rod is pre-configured with specific geometric and material properties that determine its buckling behavior. The rod is designed in advance to buckle elastically at predetermined pressure thresholds, allowing it to store energy and stabilize combustion pressure while maintaining sufficient initial stiffness for normal operation.

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

The solution provides improved engine performance by maintaining high compression ratios, increasing torque and power, enhancing fuel economy, and improving cold start and emissions control.

Implementation Method 1

the connection rod portion is configured to provide a high initial stiffness that replicates existing stiff connection rods to maintain high compression ratios, but is configured to undergo elastic buckling at peak cylinder pressures above a cylinder pressure threshold to store energy and provide a more constant combustion process

Methodology Applied
Scientific EffectElastic buckling: Elasticity

Data Source

PatentEP3308059B1Combustion chamber elasticity device
Publication Date: 2021.05.26 CUMMINS INC
  • EP3308059B1 patent drawingFigure 1~2
  • EP3308059B1 patent drawingFigure 3~5
  • EP3308059B1 patent drawingFigure 4~4A

AI summary

An energy storage device is provided for a combustion chamber of an internal combustion engine. The energy storage device includes first and second end connectors connected to respective ones of a piston and crankshaft, and a flexible connection rod portion rotatably connected with the first and second end connectors. The flexible connection rod portion elastically buckles above a predetermined cylinder pressure threshold to store combustion energy and provide a more constant pressure combustion process.