Supplementary Liquid Injection System for Piston Engine

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Solution Overview

Problem

Existing supplementary liquid injection systems for piston engines face challenges with hot and cold corrosion of water injectors due to temperature fluctuations, and existing solutions do not effectively manage corrosion while achieving efficient NOx emission reduction and fuel efficiency.

Innovation Solution

A supplementary liquid injection system with a high-pressure pump, accumulators integrated with flow fuses near each injector, and temperature control to prevent corrosion, allowing for precise injection timing and pressure management to reduce NOx emissions and improve fuel efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If water injection is used to reduce NOx emissions, then temperature in combustion chamber is reduced and NOx emissions decrease, but water injectors are subject to hot corrosion when injection is not in use and cold corrosion when injection is in use

Engineering Contradiction:
ImproveNOx emissionsVSAvoidwater injector corrosion resistance
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The system separates the water injection function into two independent systems: a high-pressure injection system for NOx reduction and a low-pressure cooling system for temperature control. This segmentation allows each system to optimize its function without compromising the other, preventing both hot and cold corrosion while maintaining NOx reduction capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A temperature control system acts as an intermediary between the high-pressure injection system and the water injectors. This intermediary continuously supplies low-pressure water to maintain injector temperature within safe operating ranges, preventing corrosion during both injection and non-injection periods.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If direct water injection into cylinders is used, then smaller amount of water is needed compared to intake manifold injection, but water injector must be placed in harsh cylinder conditions

Engineering Contradiction:
Improvewater quantityVSAvoidcylinder environment harshness
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The system divides water injection into two pressure levels: high-pressure injection for efficient NOx reduction and low-pressure continuous cooling for temperature management. This segmentation enables direct cylinder injection with reduced water quantity while protecting injectors from harsh thermal conditions through the secondary cooling system.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If high-pressure injection is used for efficient NOx reduction, then injection precision is improved, but pressure management complexity increases

Engineering Contradiction:
Improveinjection timing precisionVSAvoidpressure management system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The pressure management system is segmented into two independent pressure levels: a high-pressure system (500-2000 bar) for precise injection timing and a low-pressure system for temperature control. Each pressure system operates independently with its own pump and control logic, simplifying overall pressure management while maintaining high injection precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically switches between high-pressure injection mode and low-pressure cooling mode, and can operate both simultaneously. The control unit adjusts pressure levels and flow rates dynamically based on engine operating conditions, optimizing both injection precision and temperature management efficiency.

Inventive Principle:
Principle #15Dynamics

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 system effectively prevents corrosion, ensures efficient NOx reduction, and enhances fuel efficiency by using high-pressure injection and temperature control, while the flow fuses ensure reliable operation and pressure management.

Implementation Method 1

a pump (7) for pressurizing the liquid to a pressure level of at least 500 bar

Methodology Applied
Scientific EffectPressurisation: Pressurisation

Implementation Method 2

an accumulator (5) for receiving pressurized liquid from the pump

Methodology Applied
Scientific EffectHydraulic Accumulator: Hydraulic Accumulator

Implementation Method 3

an injector (3) connected to the accumulator (5) and configured to inject the liquid into a cylinder (2) of the engine

Methodology Applied
Scientific EffectFluid Spray: Fluid Spray

Data Source

PatentEP3440338B1Injection system and method for injecting supplementary liquid into cylinders of piston engine
Publication Date: 2021.03.17 WARTSILA FINLAND OY
  • EP3440338B1 patent drawingFigure 1~2

AI summary

The supplementary liquid injection system for injecting non-combustible liquid into cylinders (2) of a multi-cylinder piston engine (1) comprises a pump (7) for pressurizing the liquid, an accumulator (5) for receiving pressurized liquid from the pump (7), and an injector (3) that is connected to the accumulator (5) and configured to inject the liquid into a cylinder (2) of the engine (1).