Internal Combustion Engine Air-Supply Manifold Pressure Wave Interference

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Solution Overview

Problem

Internal combustion engines face efficiency deterioration due to air-supply pulsation, which existing technologies have not adequately addressed, particularly in applications with mostly rated operations like power generation engines.

Innovation Solution

An adjustment pipe with a predetermined length is integrated into the air-supply manifold, ensuring that first and second pressure waves have opposite phases, stabilizing differential pressure and increasing air supply to the cylinder, thereby enhancing engine efficiency. This configuration considers air-supply temperature and air-fuel mixture composition for optimal performance during rated operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If air is supplied to the cylinder through the air-supply manifold, then the engine operates, but air-supply pulsation causes differential pressure changes that reduce air-supply amount and deteriorate engine efficiency

Engineering Contradiction:
Improveengine efficiencyVSAvoidair-supply amount
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The adjustment pipe is designed to generate a counter-pressure wave that opposes the harmful pressure pulsation before it reaches the cylinder. By creating a pressure wave with opposite phase, the system preliminarily counteracts the pulsation effect, preventing the differential pressure from dropping and maintaining stable air supply to the cylinder.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The invention converts the harmful pressure pulsation into a beneficial effect by utilizing wave interference. The adjustment pipe generates a reflected pressure wave that, when combined with the original pulsation wave, creates destructive interference that reduces the amplitude of pressure variations. This transforms the harmful pulsation into a stabilizing effect that maintains consistent air supply.

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

2Productivity

If the differential pressure between cylinder and air-supply manifold decreases, then air-supply amount to cylinder decreases, but this causes deterioration of engine efficiency

Engineering Contradiction:
Improveengine efficiencyVSAvoiddifferential pressure
Core Design Contradiction:
ProductivityVSStress or pressure

Solution Approach 1:

The adjustment pipe preliminarily counteracts the pressure drop by generating a counter-pressure wave. This wave opposes the harmful pressure pulsation before it significantly reduces the differential pressure, thereby preventing the differential pressure from decreasing and maintaining adequate air supply pressure to the cylinder throughout the combustion cycle.

Inventive Principle:
Principle #9Preliminary anti-action

3Adaptability or versatility

If existing techniques like impulse valves are used to suppress air-supply pulsation, then following performance improves in continuous operation, but the effect is limited in rated operation applications like power generation engines

Engineering Contradiction:
Improveoperation state adaptabilityVSAvoidengine efficiency in rated operation
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The adjustment pipe is strategically positioned and dimensioned to create localized pressure wave interference specifically at the cylinder inlet. By optimizing the pipe length and placement, the system targets the specific location where pressure pulsation most adversely affects air supply, creating a localized correction that is particularly effective for rated operation conditions without requiring complex control systems.

Inventive Principle:
Principle #3Local quality

4Stability of the object's composition

If air-supply pulsation is not suppressed, then air supply varies with differential pressure changes, but suppressing it requires complex control systems

Engineering Contradiction:
Improveair-supply stabilityVSAvoidcontrol system complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The adjustment pipe creates a self-regulating system where the pressure wave interference automatically compensates for air-supply pulsation. The system uses the existing pressure waves in the manifold to generate counter-waves, eliminating the need for external sensors, actuators, or control algorithms. The geometry of the adjustment pipe itself provides the stabilizing function, making the system simple and maintenance-free.

Inventive Principle:
Principle #25Self-service

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 effectively suppresses pressure pulsation, stabilizes air supply, and improves engine efficiency, particularly during rated operations, by offsetting pressure waves and equalizing air supply among cylinders, resulting in a more compact and efficient engine design.

Implementation Method 1

a first pressure wave propagating from the air-supply manifold toward the adjustment pipe and a second pressure wave propagating from the adjustment pipe toward the air-supply manifold

Methodology Applied
Scientific EffectPressure wave propagation: Sound

Data Source

PatentEP3401523B1Internal combustion engine
Publication Date: 2021.10.20 MITSUBISHI HEAVY IND ENGINE & TURBOCHARGER LTD
  • EP3401523B1 patent drawingFigure 1~2
  • EP3401523B1 patent drawingFigure 3~4
  • EP3401523B1 patent drawingFigure 5~6

AI summary

An internal combustion engine includes: an engine body (10) having at least one cylinder; and an air-supply manifold (4) including an adjustment pipe (12). The length of the adjustment pipe is set so that a first pressure wave (14A) propagating from the air-supply manifold toward the adjustment pipe and a second pressure wave (14B) propagating from the adjustment pipe toward the air-supply manifold have opposite phases from each other at the cylinder.