Pre-Chamber Fuel Vaporization for Low-Energy Active Flushing

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Solution Overview

Problem

Existing fuel supply systems for pre-chambers in spark-ignition engines are inefficient in actively purging them with gaseous fuel, requiring significant drive energy and lacking flexibility in fuel mixture control.

Innovation Solution

A fuel supply system with an evaporator upstream of the pre-chamber, utilizing a high-pressure pump for both pre-chamber and main combustion chamber, allows for the evaporation of liquid fuel into gaseous fuel or fuel-air mixtures, controlled by a regulating mixing valve, and is integrated with a heating device for efficient purging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If liquid fuel is supplied directly to the pre-chamber without evaporation, then drive energy requirements are reduced, but the fuel cannot be effectively ignited and mixed with air in the pre-chamber

Engineering Contradiction:
Improvedrive energy requirementsVSAvoidfuel ignition and mixing effectiveness
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies phase transition by evaporating liquid fuel into gaseous fuel vapor before supplying it to the pre-chamber. The evaporator converts liquid fuel to gaseous state, enabling effective mixing with air and reliable ignition in the pre-chamber, while the system recycles the evaporated fuel vapor to maintain efficient combustion.

Inventive Principle:
Principle #36Phase transitions

2Ease of operation

If a separate high-pressure pump is used for pre-chamber fuel supply, then fuel delivery control is improved, but device complexity increases

Engineering Contradiction:
Improvefuel delivery controlVSAvoidpump system configuration
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent implements multi-functionality by designing the high-pressure pump to serve dual purposes: supplying liquid fuel to the evaporator for pre-chamber operation and supplying liquid fuel directly to the main combustion chamber. This eliminates the need for separate pump systems while maintaining precise fuel delivery control for both combustion zones.

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

3Device complexity

If fuel is supplied as liquid directly to the pre-chamber, then system simplicity is maintained, but fuel vaporization and mixing with air is insufficient

Engineering Contradiction:
Improvesystem structureVSAvoidfuel mixture control flexibility
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent applies parameter changes by controlling the evaporation process to adjust the fuel vapor concentration and mixing ratio with air. The system can operate with varying degrees of mixing by controlling the evaporator performance and air-fuel mixture ratio, enabling flexible adaptation to different combustion conditions and engine operating points.

Inventive Principle:
Principle #35Parameter changes

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

Reduces drive energy requirements and enhances flexibility in fuel mixture control, enabling efficient purging of pre-chambers with gaseous fuel or fuel-air mixtures, improving engine performance.

Implementation Method 1

liquid fuel is evaporated in an evaporator before being supplied to the at least one pre-chamber

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

the evaporator for evaporating the liquid fuel is equipped with a heating device or is connected to a heating device for supplying heat

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 3

the evaporator is equipped with a heating device or is connected to a heating device for supplying heat

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 4

the evaporator is designed in a heat exchanger configuration, wherein the heat is extracted from the cooling water of the internal combustion engine and supplied to the evaporator

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP3841292B1Fuel supply system for active flushing of an antechamber of an internal combustion engine operated by gasoline with fuel vapor or a fuel vapor-air mixture by means of a fuel vaporizer upstream of the antechamber
Publication Date: 2026.01.07 VOLKSWAGEN AG
  • EP3841292B1 patent drawingFigure 1

AI summary

The invention relates to a fuel supply system (100) for active flushing of at least one antechamber (32) of an internal combustion engine (30) operated by gasoline with a gaseous fuel (K), the internal combustion engine (30) comprising at least one main combustion chamber (31), which is connected to the at least one antechamber (32) at least on the fuel side. According to the invention, a vaporizer (11) is arranged upstream of the at least one antechamber (32).