Variable Compression Piston Engine With Rotatable Sleeve

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Solution Overview

Problem

Existing piston engine technologies with variable compression ratios face challenges such as increased emissions due to crevice volume and complex, time-consuming adjustment processes, particularly when switching between different fuels.

Innovation Solution

A piston engine design featuring a rotatable sleeve around the cylinder liner that transforms rotational movement into linear movement, allowing quick adjustment of the compression ratio through hydraulic locking means and threaded or alternating surface engagement, enabling stepless adjustment of the combustion chamber volume.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a cylinder head with additional volume is used to achieve variable compression ratio, then the compression ratio can be adjusted, but the crevice volume is increased leading to increased emissions

Engineering Contradiction:
Improvecompression ratio adjustmentVSAvoidemissions
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The invention divides the compression ratio adjustment function into separate components: a movable cylinder liner and a fixed cylinder head. This segmentation allows the combustion chamber volume to be adjusted without adding crevice volume, as the cylinder liner moves axially within the engine block rather than relying on additional volume in the cylinder head.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention extracts the volume adjustment function from the cylinder head and places it in the cylinder liner. By making the cylinder liner movable in the axial direction, the combustion chamber volume can be changed without modifying the cylinder head structure, thereby avoiding increased crevice volume and emissions.

Inventive Principle:
Principle #2Taking out (Extraction)

2Object-generated harmful factors

If a movable cylinder liner is used to adjust compression ratio, then no additional crevice volume is created, but the adjustment process becomes complicated and time-consuming

Engineering Contradiction:
Improvecrevice volumeVSAvoidadjustment time
Core Design Contradiction:
Object-generated harmful factorsVSLoss of time

Solution Approach 1:

The invention replaces complex mechanical adjustment mechanisms with a simple threaded sleeve system. The rotatable sleeve with threads engages with the cylinder liner, allowing the heavy component to be moved quickly through rotational motion that converts to linear displacement, dramatically reducing adjustment time compared to conventional mechanical systems.

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

Solution Approach 2:

The invention uses hydraulic locking means to secure the cylinder head to the engine block, enabling much quicker adjustment than conventional bolts. The hydraulic system allows for rapid release and repositioning of components, significantly reducing the time required for compression ratio adjustment.

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Strength

If conventional bolts are used to attach cylinder head, then the connection is secure, but the adjustment of compression ratio is slow

Engineering Contradiction:
Improveconnection strengthVSAvoidadjustment time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The invention replaces conventional mechanical bolts with hydraulic locking means to attach the cylinder head to the engine block. The hydraulic system provides secure connection strength while enabling rapid release and repositioning, reducing adjustment time from minutes to seconds while maintaining the necessary structural integrity.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 rapid and efficient adjustment of the compression ratio, reducing emissions and simplifying the process, allowing for quick transitions between high and low compression modes without creating additional crevice volume.

Implementation Method 1

the sleeve is provided with a thread on its inner circumference and the outer circumference of the cylinder liner is provided with a thread that is engaged with the thread of the sleeve

Methodology Applied
Scientific EffectScrew mechanism: Screw

Implementation Method 2

The cylinder head is attached to engine block by means of hydraulic locking means

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Data Source

PatentEP2841737B1Piston engine with a variable compression ratio
Publication Date: 2016.03.30 WARTSILA FINLAND OY
  • EP2841737B1 patent drawingFigure 1~6
  • EP2841737B1 patent drawingFigure 2
  • EP2841737B1 patent drawingFigure 3

AI summary

The piston engine with a variable compression ratio comprises a rotatable sleeve (6) that is arranged around the upper end of a cylinder liner (2a), and means (6a, 6b, 7, 7a, 7b, 8, 9) for transforming the rotational movement of the sleeve (6) into linear movement of the cylinder liner (2a).