Irizar has unveiled its fuel cell-electric coach prototype in the form of an i6S Efficient Hydrogen integral. The Spanish manufacturer says that the vehicle could deliver a zero-emission range of up to 1,000km with a fuelling time of around 20 minutes.
The coach is a proof-of-concept vehicle, with Irizar keen to stress that production examples may not look like the seed example. It sees hydrogen power as the likely solution for many zero-emission coach applications, although Irizar Group CEO Imanol Rego says that with a common electric driveline, it would be relatively straightforward to build battery examples.
No information is yet available on the vehicle weight uplift that comes with hydrogen, and nor has Irizar identified the fuel cell manufacturer, although it says that the supplier is well-known. Early information about the i6S Efficient Hydrogen was released earlier this year.
Fuel cell combined with battery ‘boost’ in prototype driveline
The fuel cell produces a peak power of 200kW. The electric motor is rated at 400kW peak and 360kW constant, and so 60kW/h of batteries are also fitted. They can provide a boost at times of heavy power demand, and are charged from the fuel cell at other times and via regenerative braking.
ZF axles are used, with the drive unit being an A 133 model coupled to an automated three-speed gearbox. 56kg of hydrogen can be stored at 350bar, although the builder says it is exploring the use of 700bar.
Irizar adds that with such a mass of hydrogen on the i6S Efficient, 1,864kW/h of ‘raw’ energy is stored in the tanks, although some will be lost within the driveline between there and the wheels. The OEM believes that in a hypothetical tri-axle hydrogen coach, 78kg of hydrogen could be accommodated.
Various additional grilles have appeared on the i6S Efficient Hydrogen compared to a diesel example. While Mr Rego says that many safety features are incorporated, the additional ventilation is to allow the gas to dissipate quickly should a leak occur.
Irizar chief advocates hydrogen for long-distance coach use
Mr Rego is a firm advocate of hydrogen as a future coach power source. For long-distance applications, he believes that batteries are unrealistic “unless we load coaches with around five tonnes of them.”
While some other coach OEMs differ in their views on that, Mr Rego adds an expectation that hydrogen will be attractive to both scheduled service operators and retail buyers. In the latter case, he says that an entirely versatile coach will be of greatest benefit; while the vehicle could cover a low mileage one day, on the next it could be called upon for several hundred miles.
Nevertheless, the OEM will tailor its zero-emission coaches to suit buyers. The prototype 12.9m i6S Efficient is completed to a touring specification, but Mr Rego says that the product solution will be “adaptable to the customer.”
