Fuel System Return Line Phase Separation for Gas Fuel Utilization

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Solution Overview

Problem

Current fuel systems for internal combustion piston engines are inefficient in utilizing liquid gas fuels, as they typically combust gaseous fuels in their gaseous form, failing to effectively utilize hydrocarbon compounds that could otherwise be wasted, especially due to stringent emission requirements.

Innovation Solution

A fuel system comprising fuel injectors, a high-pressure pump, and a fuel return line with a separation unit to separate gaseous and liquid portions of the return fuel, where the liquid portion is recycled and the gaseous portion is directed to the air intake system, allowing for efficient combustion of liquid gas fuels by controlling pressure and admission of the gaseous portion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If liquid gas fuel is injected directly into the engine without separation, then the fuel system is simple, but the gaseous portion is wasted and cannot be utilized

Engineering Contradiction:
Improvewaste of hydrocarbon compoundsVSAvoidfuel system complexity
Core Design Contradiction:
Loss of substanceVSDevice complexity

Solution Approach 1:

The fuel system is segmented into separate handling paths for liquid and gaseous fuel portions. The separation unit divides the return fuel into liquid and gaseous streams, with the liquid portion being recycled through the high-pressure pump and the gaseous portion being directed to the air intake system for utilization in combustion.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of discarding the gaseous portion of the return fuel, the system recovers it by directing it to the air intake system where it can be utilized for combustion. The liquid portion is recovered and recycled back through the fuel injection system.

Inventive Principle:
Principle #34Discarding and recovering

2Loss of substance

If the gaseous portion of return fuel is discarded, then the fuel system operation is simple, but hydrocarbon compounds are wasted

Engineering Contradiction:
Improvehydrocarbon compound utilizationVSAvoidfuel system operation simplicity
Core Design Contradiction:
Loss of substanceVSEase of operation

Solution Approach 1:

The return fuel, which would normally be considered waste or a problem to be disposed of, is converted into a beneficial resource. The gaseous portion is redirected to the air intake system to be used as fuel, transforming what would be waste into a useful combustion resource.

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

3Productivity

If return fuel is recycled without separation, then the system is simple to operate, but the gaseous portion cannot be effectively utilized

Engineering Contradiction:
Improvefuel utilization efficiencyVSAvoidfuel system structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The fuel system is segmented into separate handling paths for liquid and gaseous fuel portions. The separation unit divides the return fuel into liquid and gaseous streams, with the liquid portion being recycled through the high-pressure pump and the gaseous portion being directed to the air intake system for utilization in combustion.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The fuel system achieves multi-functionality by handling both liquid and gaseous fuel portions through different paths. The system can simultaneously recycle liquid fuel and utilize gaseous fuel, making the fuel system more versatile and efficient in terms of fuel utilization.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Object-affected harmful factors

If liquid gas fuel is combusted without separating phases, then the fuel system is simpler, but emission requirements cannot be met

Engineering Contradiction:
Improveemission complianceVSAvoidfuel system configuration
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The fuel system is segmented into separate handling paths for liquid and gaseous fuel portions. The separation unit divides the return fuel into liquid and gaseous streams, with the liquid portion being recycled through the high-pressure pump and the gaseous portion being directed to the air intake system for utilization in combustion.

Inventive Principle:
Principle #1Segmentation

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 system enables efficient utilization of liquid gas fuels, with the gaseous portion being reused in the air intake, reducing waste and improving engine efficiency, and allowing for adjustable fuel ratios, enhancing operational flexibility and environmental sustainability.

Implementation Method 1

a separation unit configured to separate gaseous and liquid portions of the return fuel

Methodology Applied
Scientific EffectPhase separation: Phase Change

Implementation Method 2

the fuel is given enough pressure increase inside the fuel tank by the high pressure pump to remain in the liquid form after passing by the injector

Methodology Applied
Scientific EffectPressure increase: Pressure Increase

Data Source

PatentEP3510271B1A fuel system for feeding gas fuel to an internal combustion piston engine and a method of operating an internal combustion piston engine
Publication Date: 2020.06.17 WARTSILA FINLAND OY
  • EP3510271B1 patent drawingFigure 1

AI summary

Invention relates to a fuel system (10) for feeding gas fuel to an internal combustion piston engine the system comprising one or more fuel injectors configured to inject liquid gas fuel into the engine, a fuel inlet line (26) extending from a fuel tank (18) via a high pressure pump (28) to the one or more injectors (20), and a fuel return line (30) for handling a so called return fuel from the one or more injectors, characterized in that the fuel return line (30) comprises - a separation unit configured to separate gaseous and liquid portions of the return fuel, - a first return line section (30.1) configured to return liquid portion of the return fuel from the separation unit for use in the high pressure pump (28), - a second return line section (30.2) configured to direct the gaseous portion of the return fuel to an air intake system (12) of the engine to be fed to the engine with the charge air.