Low-Aromatic Fuel Composition for Expanded Lean-Burn Limits

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Solution Overview

Problem

Existing lean burn engines face limitations in expanding the lean limit, which hinders improvements in fuel efficiency and combustion stability.

Innovation Solution

A fuel composition comprising hydrocarbons with 4 to 6 carbon atoms as the main component, with specific ratios of normal paraffins, isoparaffins, and olefins, and controlled aromatic content, along with optional oxygen-containing compounds and additives, is developed to enhance the lean limit of lean burn engines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional gasoline compositions are used in lean burn engines, then the engine can operate with air-fuel mixtures leaner than theoretical ratio, but the lean limit cannot be sufficiently expanded

Engineering Contradiction:
Improvecombustion stabilityVSAvoidlean limit expansion
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies parameter changes by precisely controlling the composition parameters of hydrocarbons with 4-6 carbon atoms (85-95 vol%), normal paraffins (10-15 vol%), isoparaffins (35-45 vol%), and limiting aromatic content (0.5-2 vol%). This compositional parameter optimization enables the fuel to achieve both expanded lean limit and maintained combustion stability, resolving the technical contradiction between lean limit expansion and combustion reliability.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the air-fuel ratio is reduced below theoretical ratio to improve fuel efficiency, then fuel consumption decreases, but combustion stability deteriorates

Engineering Contradiction:
Improvefuel efficiencyVSAvoidcombustion stability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent employs composite material principles by creating a sophisticated fuel composition that combines multiple hydrocarbon types (normal paraffins, isoparaffins, olefins) with specific ratios. This composite fuel structure synergistically improves combustion characteristics, allowing the engine to operate stably at ultra-lean conditions (air-fuel ratio ≥ 2.0) while maintaining high fuel efficiency, thus resolving the contradiction between fuel efficiency improvement and combustion stability.

Inventive Principle:
Principle #40Composite materials

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 fuel composition effectively expands the lean limit of lean burn engines, improving fuel efficiency and combustion stability.

Implementation Method 1

a lean burn engine that burns fuel in an air-fuel mixture leaner than the theoretical air-fuel ratio

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP3957707B1Lean burn engine-use fuel composition
Publication Date: 2025.10.08 ENEOS CORP

AI summary

A fuel composition for a lean burn engine comprising hydrocarbons having 4 to 6 carbon atoms as main component, with an aromatic content of 25 vol% or less.