Summary of the results of WP5 ‘Full scale hybrid technology demo’


The fifth work package of the CPT formed the final stage of the whole project. This stage aimed to bring together the created novel systems and engineered new solutions from the other work packages of CPT. The work package intended to demonstrate the functionality of the new RCCI combustion mode, virtual sensors, management systems and equipment for hybrid operation, and a propulsion system of multiple power sources. (RCCI: Reactivity Controlled Compression Ignition.) The VEBIC engine laboratory at the University of Vaasa (UVA) and its equipment were projected as the main centre for the demonstrations.

The hybridization of the VEBIC laboratory was a task in which the UVA aimed to extend the medium-speed Wärtsilä 4L20 engine and its alternator with hybridization equipment, such as electricity storage and inverters. The main target was to create and engineer a comprehensive energy generation system combining all developed new technologies from CPT company projects and other work packages of the public CPT project. Thus, the first internal discussions ended up with a desired hybrid system, where the batteries form an energy storage system alongside the medium-speed engine. In the next planning phase, goals were set for what kind of research should and would be desirable to do with the entire hybrid entity, to create a full-scale digitalized framework for subsequent studies. The preliminary plan covered the possible load profiles, a connection point to the existing laboratory infrastructure, high level control implementation and a suitable battery management system ensuring, e.g., safe battery operation. The hybrid system’s primary research target was set and the plan for charging the battery: it had to be possible that power can be fed into both the grid and the battery as desired. Unfortunately, the hybridization work was not finished during the CPT, but will definitely be continued.

The medium-speed engine of the VEBIC engine laboratory was to be operated in the RCCI mode to demonstrate the operation of a novel hybrid entity of power generation. The RCCI combustion technology relies on the use of two fuels during the engine operation. For the main fuel, the biomethane fuel system of the VEBIC laboratory was almost ready for commissioning during the CPT project. This fuel system will soon enable the W4L20 engine to run on both pilot diesel and biomethane fuels in the RCCI combustion mode.

For the experimental setup of the entity during the CPT, UVA researchers also developed a digital twin for real-time simulation of a combustion engine-based power plant with battery storage and grid coupling, as well as in-house control systems and data-acquisition systems. Unfortunately, the whole entity was not completed during the CPT timeline but the work continues without any interruption after the end of the project in 2023. The building of the entity is in progress.

Tampere University aimed, in turn, to create and demonstrate of a propulsion system of multiple power sources with its comprehensive management system in this work package. They were working on it around a wheel loader, sWille, where a full-scale diesel-electric-hydraulic hybrid powertrain was incorporated. The selected hybrid topology of sWille was series hybrid, i.e., the diesel engine is connected to generator, which charges batteries and provides energy to electric motors. Along with the mechanical installations, the performance and especially fuel consumption of sWille’s hybrid wheel loader was already analyzed using simulations. The simulation models contained all relevant components and their loss models for both drivetrain and working functions. This included for example the engine, battery, electric motors, and hydraulic system. The parametrization of models was based on values obtained from laboratory tests during the CPT project, from manufacturers and using values that were known from previous experience.

The simulated work task was repeated Y-cycle loading of a truck. Real measurement data from the field with standard machine was used for comparison. The simulated result for sWille with hybrid system showed a 28 % reduction in the fuel consumption. The validation of the results needs still to be tested with the real sWille machine. However, the building of sWille machine encountered several challenges, due to which it could not be operated on the field for the validation of the simulation model, as originally planned. These challenges were both technical and economical, resulting in a delayed schedule for the implementation and actual testing of the sWille machine.

Åbo Akademi University, together with Meyer Turku demonstrated virtually the functionality of the built multi-engine and energy consumer models and showed their ability to reproduce actual operation on a cruise ship. For this task, UVA supervised a master-level thesis titled as ”Utilization of batteries in the momentary load variations of a cruise ship” during the autumn 2021.

The different demonstrations, intensively pursued in this work package during the CPT project, will create together a full-scale digitized reference framework for subsequent studies as they are soon fully completed. For example, VEBIC engine laboratory will turn into a hybrid plant for energy generation with advanced combustion, management and electric systems. In the CPT project, all the work described above was closely linked to the CPT industrial projects of new forms of combustion, hybridization and control systems. The targeted hybrid power systems for the marine and off-road sectors are the main promoters of fuel flexibility at high total efficiency and with reduced greenhouse gas, particulate and NOx emissions.

Teemu Ovaska
University Teacher, University of Vaasa
WP5 leader of Clean Propulsion Technologies

WP5 research team