Hy2Rail: Retrofitting older vehicles with hydrogen battery hybrid drive

Rail technology Hy2Rail: Retrofitting older vehicles with hydrogen battery hybrid drive

2024-05-31 From Richard Oed * | Translated by AI 4 min Reading Time

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The Austrian Hy2Rail project is investigating whether existing rail vehicles can become more environmentally friendly with a hydrogen battery hybrid drive as a replacement for the diesel engine. A demonstrator has now been put into operation.

The technology demonstrator, converted from a motor tower car, in front of the on-site generator. Both are based on fuel cell technology.(Image: Hy2Rail project | ÖBB Train Tech | Special Vehicles Franz Simonitsch) — The technology demonstrator, converted from a motor tower car, in front of the on-site generator. Both are based on fuel cell technology.
(Image: Hy2Rail project | ÖBB Train Tech | Special Vehicles Franz Simonitsch)

Richard Oed is a freelance contributor to ELEKTRONIKPRAXIS, a brand from Vogel Communciations Group.

Sustainability and emission-free operation are also current topics in rail transport. But what to do with existing diesel-powered vehicles when the diesel engine is due for maintenance or replacement? Simply scrapping the vehicles is not a solution due to their long lifespan; replacing the diesel engine with a new one is often even less so. In Austria, the Hy2Rail project, as part of the "Mobility of the Future" program, investigated whether diesel-powered vehicles could be converted to a hybrid drive using fuel cells and batteries.

The project goals included a feasibility study for the conversion of diesel-hydraulic universal locomotives of the 2068 series of the Austrian Federal Railways (ÖBB) and the development and construction of a technology demonstrator based on a diesel-electric motor tower car of the X534 series. This also included the construction of a hydrogen system for rail operations and an external hydrogen filling container. Additional tasks included the production of a mobile emission-free on-site generator and a simulation suite for the battery and fuel cell hybrid system. The technological development of the conversion was carried out by the Austrian engineering office m.ZERO, which also held the technical leadership of the overall project. The vehicle conversion was realized by project partner ÖBB Technical Services (TS).

The range is 450 km (approx. 280 miles)

For the central fuel cell system, m.ZERO developed the H120. It consists of three series-connected, rail-suitable H2 stacks of the PEM FC HD40 type from Accelera, a business unit of Cummings and includes the balance-of-point components.

The H120 fuel cell system from m.ZERO installed in the demonstrator vehicle.
(Image:Project Hy2Rail | ÖBB Train Tech | Special vehicles Franz Simonitsch)

The 120 kW system is supplied from four Type 4 hydrogen tanks with 35 MPa pressure, which together provide a capacity of 22 kg of hydrogen. This gives the X534 a range of approximately 450 km (approx. 280 miles) . Also present are two lithium-nickel-manganese-cobalt batteries, each with 35 kWh, combined in a ternary battery system and housed in a special fire protection case. Both the fuel cell and the battery system feed into the 620 V to 750 V DC intermediate circuit. In addition, the H120 is equipped with a DC/DC converter with a power of 120 kW.

For the operation of the direct current motor with 95 kW, which was retained from the original vehicle, a DC/AC traction inverter fed from the intermediate circuit and an AC/DC rectifier with 3x 530 A at 500 V are provided. Additionally, there is a DC/DC converter to supply the 24-V consumers and a DC/AC inverter for auxiliary operations such as the newly installed electric brake air compressor, the cooling pump, and the fans.

Also new to develop were the driver's desk and the human-machine interface (MMI) as well as the entire vehicle control system, to which the systems are connected via a CAN bus. The executing project partner here was the Technisches Büro Wiener together with m.ZERO and ÖBB-TS.

The demonstrator is a true hybrid vehicle. This means that both the fuel cell system and the battery can be used for traction, and can also be used together if necessary. The operating program provides for supply from both energy sources when starting up. During the journey to the place of use, the battery is used and the fuel cell system charges the battery. At the workplace, the H2 system is switched off if the battery is fully charged, as only short driving movements in the range of a few meters usually take place there.

Block diagram of the technology demonstrator
(Image:Image:)

Complete ecosystem

The mobile, emission-free, modular on-site generator based on fuel cell technology, which was also developed as part of the project, provides between 8 kW and 40 kW with a 3-phase alternating voltage of 400 V and a direct voltage programmable in the range of 600 V and 800 V. The tanks used have a capacity of 1.5 to 8 kg of hydrogen at pressures of 20 MPa to 35 MPa and 17 kg at 70 MPa.

Worthington Industries constructed the associated hydrogen refueling system and was also responsible for the on-board hydrogen system. The tank system allows a filling pressure of up to 40 MPa and is operated with compressed air, not electrically. The dispenser nozzle and the 15 m long hose have a breakaway protection.

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The University of Rome, Tor Vergata programmed the simulation suite for the battery and fuel cell hybrid system, which was also part of the project. The MATLAB and SimScape based system includes simulations for a given route, a speed profile, or a schedule and outputs values for tractive force, power, and energy. In addition, the suite calculates models of the drivetrain, such as the strategy for using the battery and fuel cell (or both), as well as the balance-of-plant components.

Other project participants were RCC Railway Competence and Certification as project coordinator as well as PJ Messtechnik, TEMO, and the University of Leoben (Austria) as supporting partners. After the tests are completed, the demonstrator will be converted back to its original configuration. (se)