Pre-combustion Chamber Hydrogen Engine Combustion Control

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Solution Overview

Problem

Existing diesel engines face challenges in operating efficiently with hydrogen gas due to inadequate mixing and distribution of fuel and air, leading to knocking problems at higher pressures common in modern diesel engines.

Innovation Solution

A method for operating an internal combustion engine system using gaseous fuel, where a first amount of fuel is injected into a pre-combustion chamber, ignited, and then a second larger amount of fuel is injected to force the burning mix into the main combustion chamber, allowing for controlled combustion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If gaseous fuel is injected directly into the main combustion chamber at high pressure, then the engine can operate at modern diesel engine pressures, but inadequate mixing and distribution of fuel and air occurs leading to knocking problems

Engineering Contradiction:
Improveengine pressureVSAvoidcombustion stability
Core Design Contradiction:
Stress or pressureVSReliability

Solution Approach 1:

The combustion chamber is segmented into two distinct chambers: a pre-combustion chamber for initial fuel injection and ignition, and a main combustion chamber for the primary combustion event. This segmentation allows controlled mixing in the pre-combustion chamber before forcing the burning mix into the main chamber, preventing knocking while maintaining high engine pressure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Fuel is injected and ignited in the pre-combustion chamber before the main combustion event. A first amount of fuel is injected, ignited by an igniter, and then a second larger amount of fuel is injected to force the burning mix through orifices into the main combustion chamber. This preliminary combustion action ensures proper mixing and controlled ignition timing.

Inventive Principle:
Principle #10Preliminary action

2Stability of the object's composition

If a first large amount of fuel is injected into the main combustion chamber at early compression stroke, then fuel distribution improves, but ignition timing becomes inadequate causing knocking

Engineering Contradiction:
Improvefuel distributionVSAvoidignition timing
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The combustion process is segmented into two stages: first, a small amount of fuel is injected and ignited in the pre-combustion chamber to establish controlled ignition timing; second, the main fuel charge is injected and forced into the main combustion chamber by the burning mix, achieving proper fuel distribution without knocking.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pre-combustion chamber acts as an intermediary space where fuel is pre-mixed and ignited before being forced into the main combustion chamber. This intermediary chamber enables precise control of ignition timing through the igniter while the subsequent forcing of fuel through orifices ensures adequate distribution in the main chamber.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If diesel engine components are modified to operate with hydrogen gas, then hydrogen combustion becomes possible, but modification complexity and cost increase

Engineering Contradiction:
Improvefuel compatibilityVSAvoidengine modification complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The pre-combustion chamber system with orifices can accommodate different gaseous fuels (hydrogen, natural gas, etc.) while maintaining the same basic engine structure. The system provides multi-fuel compatibility by using the pre-combustion chamber as a universal interface for fuel injection and ignition control, avoiding the need for extensive component modifications.

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

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

This method ensures controlled combustion and prevents knocking issues by forming an ignitable fuel-air mix in the pre-combustion chamber and allowing the majority of the fuel to burn in the main combustion chamber, even at higher pressures.

Implementation Method 1

an ignitable fuel-air mix is formed in the pre-combustion chamber

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 2

an igniter arranged to ignite a fuel-air mix present in the pre-combustion chamber

Methodology Applied
Scientific EffectElectric Spark: Electric Spark

Implementation Method 3

a piston arranged to reciprocate in a cylinder between a bottom dead center (BDC) and a top dead center (TDC), wherein a position of the piston during a compression stroke when the piston moves towards the TDC

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 4

the second injection and the second amount of gaseous fuel are adapted so that fuel is forced through the orifices into the main combustion chamber

Methodology Applied
Scientific EffectPressure Gradient: Pressure Gradient

Implementation Method 5

allowing for controlled combustion

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP4424981B1Method for operating an internal combustion engine system using hydrogen fuel
Publication Date: 2025.05.07 VOLVO TRUCK CORP
  • EP4424981B1 patent drawingFigure 1
  • EP4424981B1 patent drawingFigure 2
  • EP4424981B1 patent drawingFigure 3

AI summary

A method for operating an internal combustion engine system using gaseous fuel, the method comprising: injecting, by activating a fuel injector (14) to generate a first injection (1) in association with a compression stroke, a first amount of gaseous fuel (1A) into a pre-combustion chamber (12), wherein the first injection (1) and the first amount of gaseous fuel (1A) are adapted so that an ignitable fuel-air mix is formed in the pre-combustion chamber (12) but not in a main combustion chamber (6); igniting, by activating an igniter (15), the ignitable fuel-air mix in the pre-combustion chamber (12) formed by the first injection; and injecting, by activating the fuel injector (14) to generate a second injection (3) after ignition (2) of the first amount of fuel (1A), a second amount of gaseous fuel (3A) into the pre-combustion chamber (12), wherein the second injection (3) and the second amount of gaseous fuel (3A) are adapted so that fuel is forced through the orifices (13) into the main combustion chamber (6).