LOHC Hydrogen Feed Pressure Control for HPDI and Fuel Cells

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Solution Overview

Problem

Existing hydrogen feeding systems for vehicles face challenges in providing versatile, safe, and cost-effective hydrogen supply at varying pressures for different vehicle systems, such as HPDI and fuel cell systems, while avoiding complex and costly configurations.

Innovation Solution

A hydrogen feeding system utilizing Liquid Organic Hydrogen Carrier (LOHC) compounds that change chemical states to manage hydrogen supply pressure dynamically, combined with a gasifier system and control method to ensure pure hydrogen delivery at variable pressures based on user demand, using deformable membranes and sensors for real-time pressure regulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If high injection pressure (300-350 bar) is used for HPDI systems to enable combustion modulation, then engine efficiency is improved, but system complexity and cost increase due to the need for high-pressure pumping and storage

Engineering Contradiction:
Improveengine efficiencyVSAvoidhydrogen feeding system complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The system dynamically changes the pressure parameter of hydrogen supply based on the type of downstream system (HPDI or fuel cell). The electronic control unit regulates the pumping system to provide 300-350 bar for HPDI engines or 5 bar for fuel cells, allowing a single feeding system to optimize performance for different applications without requiring separate dedicated systems

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The hydrogen feeding system is designed to serve multiple functions: it can supply hydrogen to both HPDI engine systems requiring high pressure (300-350 bar) and fuel cell systems requiring low pressure (5 bar). This multi-functionality is achieved through a single pumping system controlled by an electronic control unit that adjusts output pressure based on downstream requirements, eliminating the need for separate feeding systems

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

2Device complexity

If medium pressure injection (60-70 bar) is used to reduce pumping complexity, then system complexity is reduced, but combustion modulation capability is lost due to premixed air-hydrogen compression

Engineering Contradiction:
Improvepumping system complexityVSAvoidcombustion modulation capability
Core Design Contradiction:
Device complexityVSPower

Solution Approach 1:

The system dynamically adjusts the injection pressure based on the operational requirements. For HPDI systems, it provides high pressure (300-350 bar) enabling late injection and combustion modulation. For fuel cell systems, it provides low pressure (5 bar). This dynamic adaptability allows the system to maintain combustion modulation capability when needed while avoiding unnecessary complexity in other operating modes

Inventive Principle:
Principle #15Dynamics

3Device complexity

If port injection is used to simplify the system, then injection complexity is reduced, but engine power is reduced and explosion risk increases due to hydrogen presence in the manifold

Engineering Contradiction:
Improveinjection system complexityVSAvoidengine safety and power
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The system applies different injection strategies to different locations and applications. For HPDI engines, it uses high-pressure direct injection into the combustion chamber where controlled combustion is desired. For fuel cells, it uses low-pressure supply to the fuel cell stack. This localized approach ensures that hydrogen is delivered to the appropriate location with the appropriate pressure, maintaining safety and performance for each specific application

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

Enables safe, efficient, and cost-effective hydrogen delivery at varying pressures, reducing risks of impurities and explosion, and maintaining hydrogen purity, while allowing common elements and components to be shared across different vehicle systems.

Implementation Method 1

utilizing Liquid Organic Hydrogen Carrier (LOHC) compounds that change chemical states to manage hydrogen supply pressure dynamically

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

a deformable membrane separating a hydrogen-rich liquid phase from a hydrogen-poor liquid phase

Methodology Applied
Scientific EffectDensity separation: Density Gradient

Data Source

PatentEP4630675B1Feeding system for a hydrogen vehicle and related control method
Publication Date: 2026.03.11 STC SRL
  • EP4630675B1 patent drawingFigure 1

AI summary

Feeding system (1) for a hydrogen user system (24), comprising a tank (2) defining a space (3) configured to house hydrogen transport means, and a gasifier system (21) configured to generate hydrogen in the gaseous state starting from the hydrogen transport means, the tank (2) defining a first outlet opening (5) and a first inlet opening (6) fluidically connected al gasifier system (21) and a membrane (8) configured to divide said space (3) into a first portion (3') and a second portion (3") respectively fluidically connected to the first outlet opening (5) and to the first inlet opening (6).