Dual-Fuel Supply Control Preventing Liquid LNG Engine Damage

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Solution Overview

Problem

LNG fuel components with different boiling points can cause damage to engine components and gas leakage due to liquid LNG supply at engine start.

Innovation Solution

A fuel supply control device that selectively supplies CNG fuel when the engine is not warmed up and vaporized LNG fuel when it is warmed up, using a determination unit to assess engine warmth and control valves to manage fuel supply.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If LNG fuel is supplied to the engine at start, then fuel supply is continuous, but liquid LNG damages engine components and causes gas leakage

Engineering Contradiction:
Improvefuel supply continuityVSAvoidliquid LNG damage to engine components
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The control device performs preliminary warming of the engine before allowing LNG fuel supply. The determination unit checks whether the engine temperature has reached a predetermined threshold value, and only when this condition is met does the control unit allow LNG fuel supply to begin, thereby preventing liquid LNG from damaging engine components

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system changes the fuel supply parameter based on engine temperature conditions. When the engine temperature is below the threshold, the system supplies CNG fuel instead of LNG fuel. Once the engine temperature reaches or exceeds the threshold, the system switches to supplying vaporized LNG fuel, thus adapting the fuel supply parameter to the engine's thermal state

Inventive Principle:
Principle #35Parameter changes

2Reliability

If CNG fuel is supplied when engine is not warmed up, then engine components are protected from liquid LNG damage, but fuel supply flexibility is reduced

Engineering Contradiction:
Improveengine component protectionVSAvoidfuel supply flexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The fuel supply system dynamically switches between CNG fuel and LNG fuel based on real-time engine temperature conditions. The determination unit continuously monitors engine temperature, and the control unit adjusts the fuel supply accordingly: supplying CNG fuel when the engine is cold and supplying vaporized LNG fuel when the engine is warmed up, thereby maintaining both protection and flexibility

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

Prevents damage to engine components and gas leakage by ensuring only vaporized LNG is supplied after engine warming, improving safety and preventing starting issues.

Implementation Method 1

Liquid LNG fuel stored in a tank is vaporized by a vaporizer

Methodology Applied
Scientific EffectVaporization: Evaporation

Implementation Method 2

a determination unit that determines whether the engine has been warmed up after the engine is started

Methodology Applied
Scientific EffectTemperature detection:

Data Source

PatentUS12359631B2Fuel supply control device and vehicle
Publication Date: 2025.07.15 ISUZU MOTORS LTD
  • US12359631B2 patent drawing
  • US12359631B2 patent drawing
  • US12359631B2 patent drawing

AI summary

Provided are; a fuel supply control device capable of preventing damage on components caused by LNG fuel in a liquid state; and a vehicle. The fuel supply control device is for controlling selective supply, to an engine, of either LNG fuel or CNG fuel stored in separated tanks, and is provided with: a determination unit for determining whether warming up of the engine is completed after start of the engine; and a control unit that performs CNG fuel supply control for supplying CNG fuel to the engine when the warming up of the engine is not yet completed, and performs LNG fuel supply control for supplying vaporized LNG fuel to the engine when the warming up of the engine is completed.