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 drive train systems.
Increasing interest to accelerate the introduction of hydrogen created room for using existing technologies such as the internal combustion engine (ICE), which is the most feasible approach considering time, cost and available knowledge.
According to the statements of the European Commission's strategic research agenda hydrogen can be introduced by use of the internal combustion engine already in the near future, provided the hydrogen fuel is available. Specialist vehicles will be established by 2010, mass market transport applications by around 2020.
Due to the possibility of bi-fuel operation, the ICE has the potential to stimulate this short-term transition into a hydrogen-based mobility.
For acceptance by the customer any alternative propulsion system has to fulfil the requirements set by today's gasoline and diesel engines.
The ultimate goal of the project 'HyICE' is to work out engine concepts which have the potential to beat both gasoline and diesel engines with respect to power density and efficiency at competitive costs. As a result, HyICE technologies may present not just an intermediate, but also a long-term solution.
HyICE was structured in five sub projects. It targeted the two promising concepts for mixture formation: direct injection and cryogenic port injection. The relating components have been developed and the combustion processes have been optimised to a certain extent. This work was complemented by the development of supporting technologies for both approaches like a dedicated ignition system and new software tools for CFD (Computational Fluid Dynamics)-simulation of the combustion process of Hydrogen. A Technological exchange of information with corresponding efforts made in the USA turned out very fruitful. The assessment of deliveries was organised by 'Supplier-Customer' principle.
Sub project 0 – Project management
All administrative issues were concentrated here and performed by dedicated experts.
Sub project 1 - Direct Injection (DI).
Injectors for low-pressure as well as for high-pressure DI have been developed. The DI combustion system has been developed at Graz Technical University (TUG). With the help of the developed components and the know-how acquired at a single cylinder research engine, a multi-cylinder engine has been optimised and the operation of a free piston energy converter has been simulated.
Sub project 2 – Cryogenic Port Injection (CPI).
Individual mobility needs highest energy density of the fuel stored on-board. With hydrogen this can be achieved in liquid stage. The properties of this cryogenic fuel fit very well to the requirements of the engine. The related injectors have been developed and tested. As to the engine remarkable winnings in power density and efficiency have been demonstrated. Icing effects inside the inlet manifold now reliably can be avoided thanks to a special simulation model developed within subproject 3.
Sub project 3 – Supporting technologies.
Very important was the delivery of supporting technologies, necessary for both engine concepts. These were an ignition system, able to deal with the broad flammability limits of hydrogen, and CFD-models adapted to Hydrogen application.
Dedicated ignition system. Several generations of power modules (which integrate both ignition coil and electronics) have been developed by Hoerbiger Control Systems (former Mecel AB) in Sweden.
CFD adaptation for Hydrogen ICEs. CFD models have been adapted to account for properties of hydrogen in both mixture formation and combustion. A URANS (Unsteady Reyno
All key components for building high efficient internal combustion engines as well as the necessary know-how have been created. Therefore, the projects results represent a major step in the use of hydrogen as an alternative fuel.
T1: The demonstrated power density of 100 kW/litre displacement exceeds by far the level of current production engines. This gives space for improvements in fuel economy by downsizing and reducing internal friction losses.
T2: An indicated efficiency of 46 % has been achieved with a HD truck engine and 44% with a single cylinder engine of dimensions suitable for passenger cars. It has been shown that these figures don't represent a technical limit, because further enhancements are possible.
T3: The fuel injectors for both types of mixture formation have been developed. (direct injection at 10 – 250 bar and cryogenic port injection at – 250 °C).
T4: A commercial CFD-solver has been adapted and validated for Hydrogen combustion and now is ready to use for the development of series Hydrogen engines.
T5: An exchange of knowledge with US national labs and automotive industry has been established and turned out very fruitful.
P1: By supporting Hydrogen technologies, there is a real chance to take over the leadership in production and marketing of sustainable energy systems. Also the automotive industry will contribute significantly towards the transition to a hydrogen economy.
The internal combustion engine is ideally suited for this transition since it offers high power density at relatively low cost and therefore represents an economic energy converter for mobile applications.
All hitherto existing developments and investments for Otto- and Diesel engines may be used as a basis for further development.
As a result of its possibility for bi-fuel operation, the ICE effectively bridges the gap between today's hydrocarbon based and tomorrows Hydrogen based energy economy. Optimised monofuel engines also can offer a long-term economic solution for Hydrogen based mobility.