Engine Compression Ratio Adjustment via Reaction Force Pumping

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Solution Overview

Problem

Existing engines face challenges in varying compression ratios without requiring high-power hydraulic pumps, as the compressive load from combustion pressure exceeds the hydraulic oil pressure in hydraulic pressure chambers.

Innovation Solution

An engine design featuring a hydraulic pressure adjustment mechanism with a plunger pump and spill valve, where the plunger pump supplies hydraulic oil to the hydraulic pressure chamber using a reaction force and the spill valve adjusts pressure by circulating hydraulic oil, allowing for varying the piston or power transmission section's length to change the compression ratio without a high-power hydraulic pump.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a hydraulic pump is used to vary the compression ratio by pressing hydraulic oil into the hydraulic pressure chamber, then the compression ratio can be changed, but a high-power hydraulic pump is required to overcome the compressive load from combustion pressure

Engineering Contradiction:
Improvecompression ratio variationVSAvoidhydraulic pump power
Core Design Contradiction:
Adaptability or versatilityVSPower

Solution Approach 1:

The invention converts the harmful compressive load from combustion pressure into a beneficial force by using it to drive the plunger pump. The compressive load pushes the plunger into the pump cylinder, which in turn presses hydraulic oil into the hydraulic pressure chamber to vary the compression ratio, thus transforming the problem of high compressive load into the solution for hydraulic pressure generation

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The system uses its own compressive load from combustion pressure to power the hydraulic pump, making the engine self-sufficient for compression ratio variation without requiring an external high-power hydraulic pump. The engine's operational force becomes its own power source for control

Inventive Principle:
Principle #25Self-service

2Stress or pressure

If a high-power hydraulic pump is used to increase hydraulic oil pressure for compression ratio variation, then the desired pressure can be achieved, but the device complexity and cost increase

Engineering Contradiction:
Improvehydraulic oil pressureVSAvoidhydraulic pump system complexity
Core Design Contradiction:
Stress or pressureVSDevice complexity

Solution Approach 1:

The compressive load that was previously a burden requiring high-power pumps to overcome is now converted into the driving force for the plunger pump, naturally generating the required hydraulic pressure without complex high-power pumping systems

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The invention uses hydraulic principles where the plunger mechanically presses hydraulic oil into the pressure chamber, utilizing fluid transmission to achieve compression ratio variation with simpler components compared to traditional high-power hydraulic pumps

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

This design effectively increases hydraulic oil pressure to change the compression ratio without the need for a high-power hydraulic pump, reducing costs and maintaining engine stability.

Implementation Method 1

a plunger pump that has a pump cylinder into which the hydraulic oil is guided and a plunger which moves in the pump cylinder in the stroke direction and has one end protruding from the pump cylinder, and that supplies the hydraulic oil in the pump cylinder to the hydraulic pressure chamber by pushing the plunger into the pump cylinder

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 2

When hydraulic pressure is applied to one of the hydraulic pressure chambers, a connecting portion between the piston head and a piston rod is extended. When hydraulic pressure is applied to the other of the hydraulic pressure chambers, the connecting portion is shortened

Methodology Applied
Scientific EffectHydraulic force transmission: Pascal's Law

Data Source

PatentEP3098417B1engine
Publication Date: 2018.10.10 IHI CORP
  • EP3098417B1 patent drawingFigure 1
  • EP3098417B1 patent drawingFigure 2A~2B
  • EP3098417B1 patent drawingFigure 3A~3B

AI summary

Provided is an engine that includes a first member (piston rod (112a)), a second member (crosshead pin (114a)), a first hydraulic pressure chamber (168a) formed between facing parts of the first and second members, and a hydraulic pressure adjustment mechanism (196). The hydraulic pressure adjustment mechanism has a plunger pump (182) having a pump cylinder (182a) and a plunger (182b) and configured to supply hydraulic oil in the pump cylinder to the first hydraulic pressure chamber by pushing the plunger into the pump cylinder. The plunger pump moves in a stroke direction along with a piston and a power transmission section, and the plunger is pushed into the pump cylinder by receiving a reaction force opposite to reciprocating forces of the piston and the power transmission section.