Induction-Actuated Connecting Rod for Variable Compression Ratio

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Solution Overview

Problem

Existing reciprocating piston machines lack a simple, space-saving, and reliable method to flexibly adjust the compression ratio of individual cylinders, which limits emission and consumption efficiency.

Innovation Solution

An electrically connected induction device is integrated with the connecting rod, using a magnet device to induce current for controlling the compression ratio, allowing for quick and low-wear switching independent of operating conditions, with a compact design featuring an induction loop and adjustable magnetic polarity, and contactless signal transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a control valve with axial displacement closure element actuated by return spring and oil pressure is used, then the connecting rod length can be adjusted, but the structure becomes complex and space-consuming

Engineering Contradiction:
Improvecompression ratio adjustmentVSAvoidcontrol valve structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces the traditional mechanical control valve actuation system (return spring, oil pressure) with an electromagnetic induction system. The induction device with magnet and conductor generates electrical current through relative motion, which directly actuates the control valve, eliminating the need for complex mechanical components and reducing structural complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the actuation parameter from mechanical (spring force, oil pressure) to electromagnetic (induced current). By varying the relative speed between the magnet and conductor, the induced current changes, providing a direct and simple means to control the valve position and adjust the compression ratio.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If traditional control valve actuation methods are used, then the connecting rod length can be changed, but wear increases and reliability decreases

Engineering Contradiction:
Improvecompression ratio switchingVSAvoidswitching durability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces mechanical actuation mechanisms with an electromagnetic induction system. The induction device generates current through relative motion between magnet and conductor, providing contactless actuation that eliminates wear and significantly improves reliability and durability of the compression ratio switching mechanism.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The induction device utilizes the existing relative motion between the connecting rod and crankshaft to generate the electrical current needed for actuation. The system serves itself by converting the mechanical energy already present in the engine into the electrical energy required for control, without requiring additional power sources or complex actuation mechanisms.

Inventive Principle:
Principle #25Self-service

3Extent of automation

If complex wiring and electrical connections are made in the connecting rod area, then electrical control can be achieved, but the structure becomes complicated and manufacturing difficult

Engineering Contradiction:
Improveelectrical control of compression ratioVSAvoidwiring complexity
Core Design Contradiction:
Extent of automationVSEase of manufacture

Solution Approach 1:

The patent replaces complex wiring systems with an electromagnetic induction system. The induction device generates current through relative motion, eliminating the need for complex electrical connections and wiring in the connecting rod area, thereby simplifying manufacturing while achieving automated electrical control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The induction device acts as an intermediary that converts mechanical motion into electrical current locally within the connecting rod assembly. This eliminates the need for long electrical leads and complex wiring harnesses, as the current is generated right where it is needed, simplifying the overall electrical architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Productivity

If compression ratio adjustment is made independent of operating point, then emission and consumption advantages are achieved, but the actuation system becomes more complex

Engineering Contradiction:
Improveemission and consumption efficiencyVSAvoidactuation system
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces complex actuation systems with a simple electromagnetic induction system that can be independently controlled regardless of operating conditions. The induction device generates current based on relative motion, providing a simple and reliable means to achieve compression ratio adjustment independent of the operating point, thereby improving emission and consumption efficiency.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

Enables continuous, low-wear switching of the compression ratio with emission and consumption advantages, minimizing wear and ensuring reliable operation by allowing independent adjustment of the compression ratio without complex wiring.

Implementation Method 1

an electric current can be induced by means of at least one - preferably - crankcase-fixed or crankshaft-fixed magnet device

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3334915B1Reciprocating piston engine, in particular internal combustion engine
Publication Date: 2020.06.03 AVL LIST GMBH
  • EP3334915B1 patent drawingFigure 1~4
  • EP3334915B1 patent drawingFigure 5~6
  • EP3334915B1 patent drawingFigure 7~8

AI summary

The invention relates to a reciprocating piston engine, in particular an internal combustion engine, comprising at least one length-adjustable connecting rod (1) connected to a crankshaft (26), which connecting rod (1) comprises at least one first rod part (2) having a small connecting-rod eye (3) and at least one second rod part (4) having a large connecting-rod eye (5), which two rod parts (2, 4) can be displaced telescopically with respect to and/or into each other by means of a length adjustment device (100), wherein the length adjustment device (100) can be fluidically connected in at least one position of a control valve (15) to at least one oil pressure line (14, 6), and can be separated from the oil pressure line (16) in at least one second position of the control valve (15), wherein the control valve (15) can be electrically switched and inductively actuated. In order to allow the compression ratio to be flexibly changed in a way that is as simple, space-saving and reliable as possible, the control valve (15) can be electrically connected to at least one induction device (21) fixed to the connecting rod, in which an electrical current can be induced in at least one position of the connecting rod (1) by means of at least one magnet device (24) fixed to the crank housing or crankshaft.