Pre-Chamber Hydrogen Injection for Homogeneous Piston Engine Combustion

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Solution Overview

Problem

Existing piston engines, particularly those using hydrogen as fuel, suffer from low efficiency due to inhomogeneous fuel distribution in the combustion chamber, leading to unwanted pre-ignition and inefficient combustion, which is exacerbated by direct injection methods that cause fuel to vaporize prematurely and create rich and lean regions.

Innovation Solution

The method introduces fuel into a pre-chamber at high pressure, allowing it to spread via flow paths to multiple positions in the combustion chamber, mixing with oxygen-containing gas to form a homogeneous mixture, and igniting the mixture at multiple points to achieve rapid and efficient combustion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If fuel is injected directly into the combustion chamber, then injection simplicity is improved, but fuel distribution homogeneity deteriorates

Engineering Contradiction:
Improveinjection system complexityVSAvoidfuel distribution homogeneity
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The combustion chamber is segmented into a pre-chamber and a main combustion chamber. Fuel is injected into the pre-chamber first, then distributed to multiple positions in the main combustion chamber through flow paths, achieving homogeneous fuel distribution without requiring a complex multi-point direct injection system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pre-chamber acts as an intermediary between the fuel injector and the main combustion chamber. It receives fuel from the injector and distributes it to multiple positions in the main combustion chamber, ensuring homogeneous mixing while simplifying the injection system architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Speed

If cryogenic hydrogen is injected directly into the combustion chamber, then injection speed is improved, but fuel vaporization control deteriorates

Engineering Contradiction:
Improveinjection speedVSAvoidfuel vaporization control
Core Design Contradiction:
SpeedVSTemperature

Solution Approach 1:

Hydrogen is injected into the pre-chamber before entering the main combustion chamber. This preliminary injection allows the cryogenic hydrogen to begin vaporizing and mixing in the pre-chamber environment, improving temperature control and preventing premature vaporization issues that would occur with direct injection into the hot combustion chamber.

Inventive Principle:
Principle #10Preliminary action

3Power

If direct injection into combustion chamber is used, then power density is improved, but pre-ignition control deteriorates

Engineering Contradiction:
Improvepower densityVSAvoidpre-ignition control
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The pre-chamber provides a localized environment with different temperature and pressure characteristics compared to the main combustion chamber. Fuel injection and initial mixing occur in this controlled local environment, preventing premature ignition while maintaining high power density through subsequent combustion in the main chamber.

Inventive Principle:
Principle #3Local quality

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 approach results in a highly efficient combustion process with a very high power density, preventing unwanted pre-ignition and enabling complete combustion by ensuring a uniform fuel distribution, even with cryogenic hydrogen injection.

Implementation Method 1

fuel, in particular hydrogen, is introduced into a pre-chamber by means of an injector at high pressure

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 2

fuel then spreads from the pre-chamber into the combustion chamber via flow paths which connect the pre-chamber with several positions in the combustion chamber

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

fuel mixes with an oxygen-containing gas, in particular air, in the combustion chamber and the ignitable mixture is formed

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 4

the ignitable mixture is ignited in the combustion chamber

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP4653678A1Method for operating a piston engine and piston engine
Publication Date: 2025.11.26 PANKL RACING SYST AG
  • EP4653678A1 patent drawingFigure 1
  • EP4653678A1 patent drawingFigure 2
  • EP4653678A1 patent drawingFigure 3

AI summary

The invention relates to a method for operating a piston engine, in particular a reciprocating piston engine, wherein an ignitable mixture is ignited in a combustion chamber (19) adjacent to a piston (18), which piston (18) is connected to a shaft (20) rotating about an engine axis. To achieve particularly high efficiency, the invention provides that fuel, in particular hydrogen, is introduced into a pre-chamber (1) by means of an injector (13), and that this fuel then spreads from the pre-chamber (1) into the combustion chamber (19) via flow paths (2) connecting the pre-chamber (1) to several positions (5a, 5b) in the combustion chamber (19), after which the fuel mixes with an oxygen-containing gas, in particular air, in the combustion chamber (19) and the ignitable mixture is formed, after which the mixture is ignited in the combustion chamber.The invention further relates to a fuel, in particular hydrogen, which is introduced into a pre-chamber (1) by means of an injector (13) and which subsequently spreads from the pre-chamber (1) into the combustion chamber (19) via flow paths (2) which connect the pre-chamber (1) with several positions (5a, 5b) in the combustion chamber (19), after which the fuel mixes with an oxygen-containing gas, in particular air, in the combustion chamber (19) and the ignitable mixture is formed, after which the mixture is ignited in the combustion chamber.