Fuel Injection Circuit for Multi-Fuel Engine Mode Switching

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Solution Overview

Problem

Multi-fuel engines face challenges in making an instant switch from gaseous fuel to residual liquid fuel due to the high viscosity of residual fuels, requiring an intermediate phase with distillate grade liquid fuel, which increases operational costs and emission control complexities.

Innovation Solution

A fuel injection circuit with a fuel circulation duct and solenoid valves for each cylinder, allowing selective fuel circulation and temperature monitoring, enabling quick mode changes from gaseous to residual fuel operation by maintaining fuel injector temperatures and optimizing fuel flow control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If the engine operates on gaseous fuel, then emission limits are met and operating costs are reduced, but the fuel injectors cool down and cannot immediately switch to residual fuel due to high viscosity

Engineering Contradiction:
ImproveemissionsVSAvoidfuel mode switching capability
Core Design Contradiction:
Object-generated harmful factorsVSAdaptability or versatility

Solution Approach 1:

The system performs preliminary heating of the fuel injectors by circulating hot liquid fuel through them during gas mode operation. This preliminary action ensures that when switching to residual fuel is required, the injectors are already at the necessary temperature to handle the high viscosity fuel immediately, eliminating the need for an intermediate LFO phase.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces liquid fuel circulation as an intermediary mechanism between gas mode and residual fuel mode. By circulating liquid fuel through the injectors during gas operation, it serves as a thermal mediator that maintains injector temperature without requiring actual residual fuel injection, enabling direct mode switching.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the engine switches from gaseous fuel to residual fuel directly, then operational flexibility is improved, but the high viscosity of residual fuel prevents proper injection without intermediate heating

Engineering Contradiction:
Improvefuel mode switching capabilityVSAvoidfuel injection reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The system performs preliminary heating of the fuel injectors by circulating hot liquid fuel through them during gas mode operation. This preliminary action ensures that when switching to residual fuel is required, the injectors are already at the necessary temperature to handle the high viscosity fuel immediately, eliminating the need for an intermediate LFO phase.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system changes the temperature parameter of the fuel injectors by circulating heated liquid fuel through them during gas mode. This parameter change (temperature increase) prepares the injectors to handle residual fuel's high viscosity characteristics, enabling reliable direct switching between fuel modes.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If an intermediate phase with LFO operation is used between gas and HFO, then reliable fuel injection is ensured, but the transition time increases to half an hour and operational costs increase

Engineering Contradiction:
Improvefuel injection reliabilityVSAvoidfuel mode transition time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary heating of the fuel injectors by circulating hot liquid fuel through them during gas mode operation. This preliminary action ensures that when switching to residual fuel is required, the injectors are already at the necessary temperature to handle the high viscosity fuel immediately, eliminating the need for an intermediate LFO phase.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system maintains continuous heating of the fuel injectors by circulating liquid fuel through them during gas mode operation. This continuous useful action ensures that the injectors remain ready for residual fuel injection at any time, eliminating the need for intermediate phases and enabling instantaneous mode switching.

Inventive Principle:
Principle #20Continuity of useful action

4Adaptability or versatility

If liquid fuel is circulated through fuel injectors during gas mode, then injector temperature is maintained for quick switching, but fuel consumption increases

Engineering Contradiction:
Improvefuel mode switching capabilityVSAvoidfuel consumption
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The system uses the engine's own liquid fuel supply to heat and maintain the temperature of the fuel injectors during gas mode operation. The liquid fuel serves a dual purpose: as a heating medium for the injectors and as the actual fuel for combustion when needed, eliminating the need for separate heating systems or additional fuel consumption.

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

Enables immediate switching from gaseous to residual fuel operation without an intermediate phase, reducing operational costs and enhancing emission control by maintaining fuel injector temperatures and optimizing fuel circulation.

Implementation Method 1

a fuel circulation valve for each cylinder of the engine for selectively preventing and allowing fuel circulation through the fuel injectors and the fuel circulation duct

Methodology Applied
Scientific EffectValve control: Valve

Implementation Method 2

at least one fuel injection pump and at least one fuel injector for injecting liquid fuel into the cylinders

Methodology Applied
Scientific EffectFuel injection: Injector

Data Source

PatentEP3036426B1Fuel injection circuit and method for operating a multi-fuel piston engine
Publication Date: 2017.08.02 WARTSILA FINLAND OY
  • EP3036426B1 patent drawingFigure 1~2

AI summary

The fuel injection circuit for a piston engine comprises at least one fuel injection pump (7) and at least one fuel injector (12) for each cylinder (14) of the engine. Each fuel injector (12) is connected to a fuel circulation duct (16) and the fuel injection circuit is provided with a fuel circulation valve (17) for each cylinder (14) for selectively preventing and allowing fuel circulation through the fuel injectors (12) and the fuel circulation duct (16).