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Optimisation of a Hydrogen Powered Internal Combustion Engine

The internal combustion engine is ideally suited for hydrogen application since it offers high-power density at relatively low cost. HyICE is an initiative for automotive hydrogen engine development, which will provide economically feasible and environmentally friendly solutions for the increasing mobility demand.

Tags: Road


To usher in a new era in global energy production, hydrogen can be produced using many kinds of renewable energy sources, including solar or geothermal power. As the only carbon-free fuel no CO2 is released during combustion and it can also be applied for various drivetrain systems.

Increasing interest to accelerate the introduction of hydrogen gave space for using existing technologies such as the internal combustion engine (ICE), which is the most feasible approach considering time, cost and available knowledge. Due to the possibility of bi-fuel operation, the ICE has the potential to stimulate the mid-term transition into a hydrogen-based mobility.


The goal of the project is to create the knowledge for building a highly efficient hydrogen engine with a better specific power than gasoline and diesel at competitive costs.

One key component is the system applied for mixture formation. For the two most promising concepts, direct injection (DI) and cryogenic port injection (CPI), the necessary knowledge concerning design and application has to be created.

As the first logical step, dedicated injectors capable of handling the new fuel with its specific characteristic have to be developed. The processes of mixture formation and combustion will be studied and optimised by the use of test engines as well as CFD calculations.

A third subproject is delivering the supporting technologies, necessary for both engine concepts. These are an ignition system, able to deal with the broad flammability limits of hydrogen, and CFD-models adapted to hydrogen application.

Within the fourth subproject, International Co-operation, an information exchange between automobile industry and researchers from Europe and the USA will extract the maximum benefit out of all efforts and investments made on both sides of the Atlantic Ocean.

BMW Forschung und Technik GmbH

Description of work

Subproject 1 – Direct Injection (DI):

Injectors for low-pressure as well as for high-pressure DI are developed by Hoerbiger Valve Tec.

The DI combustion system is developed at Graz Technical University (TUG).

The subproject Direct Injection, aims at a multi-cylinder engine, optimised by MAN and the simulation of a free piston energy converter, operated by Volvo Technology.

Subproject 2 – Cryogenic Port Injection (CPI):

The highest vehicle range can be achieved with liquid hydrogen. The properties of this cryogenic fuel fit very well to the requirements of the engine.

The related injectors have been developed and tested.

The optimisation of mixture formation and combustion takes place at BMW.

Subproject 3 – Supporting technologies:

Dedicated ignition system

Several generations of power modules (which integrate both ignition coil and electronics) have been developed by Mecel in Sweden.

CFD adaptation

CFD models have to be adapted to account for properties of hydrogen in both mixture formation and combustion. A URANS (Unsteady Reynolds Averaged Navier-Stokes) approach is the methodology adopted in the simulation work of HyICE. For calculating the combustion process, two models have been investigated. The first one is the ECFM (extended coherent flame model) developed by IFP, France and the second is a Flamelet-based model co-developed by the University of Armed Forces in Munich (UBW) and Ansys Germany.

Validation takes place at an optical chamber, built and operated by UBW, and at an optical engine of TUG.

Both combustion models will be integrated by Ansys Germany into the commercial flow solver CFX.

Subproject 4 – International Co-operation:

This subproject puts its emphasis on the technical co-operation in research activities between the European Community and the USA. The research work of Ford is conducted in Dearborn, Michigan. Additionally, Ford is also the US interface for work that is being carried out at the Sandia National Laboratories, Livermore, California and at the Argonne National Laboratory, Chicago. Furthermore, Ford is supporting H2DI spray penetration and mixing model development, and bench validation work at the ERC of the University of Wisconsin-Madison.


The results of the project HyICE are the prerequisites for the further development of an optimised propulsion system including components and supporting technologies:

Subproject 1 – Direct Injection:

The feasibility of hydrogen DI injectors has been shown and the necessary design knowledge has been created.

Mixture formation and combustion are being optimised individually in several engines.

The H2 operation of a free piston energy converter has been simulated and relating design changes have been carried out.

Subproject 2 – Cryogenic Port Injection:

The injectors are working satisfactorily.

The engine tests show remarkable results in power as well as efficiency within the whole work envelope.

With the help of a specially developed simulation model, icing effects within the inlet manifold can be avoided.

Subproject 3 – Supporting technologies:

Dedicated ignition system

The work has been focused on a system that can provide a spark burning mainly in breakdown discharge mode, resulting in higher transfer efficiency to the gas and less electrode heating.

CFD Adaptation

Combustion models for diffusion flames as well as premixed and partially premixed combustion have been adapted to the special properties of hydrogen, validated by experiments on optical devices and engines. After approval, they will be inserted into the commercially available solver CFX provided by Ansys Germany.

Subproject 4 – International Co-operation:

An exchange between European and US research activities has been established, which has proved to be very fruitful for all involved parties.