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The new, second-generation Toyota Mirai hydrogen fuel cell saloon offers a driving range of 400 miles, improved styling, five seats, and no emissions other than pure water.
The new Totota Mirai will also be cheaper – around £53,000 compared to the £66,000 of the first-generation model. This will help Toyota to target a 10-fold expansion in sales of the Mirai.
The Toyota Mirai goes beyond zero emissions to “negative emissions” – the car effectively cleans the air as it moves. A catalyst-type filter is incorporated in the air intake. As air is drawn into the vehicle to supply the fuel cell, an electric charge on the non-woven fabric filter element captures microscopic particles of pollutants, including sulphur dioxide (SO2), nitrous oxides (NOx) and PM 2.5 particulates. The system is effective in removing 90 to 100 per cent of particles between 0 and 2.5 microns in diameter from the air as it passes into the fuel cell system.
A priority has been to improve the Mirai’s driving range compared to the first generation model and going beyond the distances typically achieved by battery electric vehicles.
Increased power and hydrogen fuel capacity, improved efficiency and better aerodynamics all contribute to extending the driving range by 30 per cent to around 400 miles. This gives the new Mirai a genuine long-distance driving capability.
Packaging has also been significantly improved. A more efficient and well-balanced arrangement of the new FCEV powertrain – notably with the fuel cell stack moved from beneath the cabin to the front of the car – has allowed for a more spacious, five-seat interior with improved legroom for rear seat passengers.
Adopting a new platform has allowed the fuel cell stack and drivetrain components to be repackaged in a way that makes more efficient use of space. It also enables three high-pressure hydrogen tanks to be fitted, increasing fuel capacity and the car’s driving range – by 30 per cent.
The tanks are arranged in a “T” configuration, the longest running longitudinally and centrally beneath the vehicle floor, with two smaller tanks set laterally beneath the rear seats and luggage compartment. Together they can hold 5.6kg of hydrogen, compared to 4.6kg in the current Mirai’s two tanks. Their position contributes to the car’s lower centre of gravity and avoids compromising load space.
The new architecture also allows the all-new hydrogen fuel cell to be moved from its current location beneath the floor to the front compartment (equivalent to the engine bay), while the (more compact) high-voltage battery and electric motor are positioned above the rear axle. Powertrain layout has been optimised to give new Mirai a 50:50 front:rear weight distribution.
The tanks have a stronger, multi-layer construction and are highly weight-efficient – the hydrogen accounts for 6 per cent of the combined weight of the fuel and tanks.
The fuel cell stack uses a solid polymer, as in the current Mirai, but has been made smaller and has fewer cells (330 instead of 370). Maximum power has risen from 114 kW to 128 kW. Cold weather performance has been improved with start-up now possible at temperatures from as low as -30˚C.
The new Mirai is equipped with lithium-ion high-voltage battery in place of the current model’s nickel-metal hydride unit. The battery’s smaller dimensions have allowed it to be positioned behind the rear seats, avoiding intrusion in the load compartment.
Toyota’s vision for a future sustainable hydrogen society recognises the value of hydrogen as a viable and plentiful resource for carrying and storing energy. It has the potential to deliver zero carbon mobility, not just in road vehicles but equally in trains, ships and planes, and to generate power for industry, businesses and homes. It’s also an efficient means of storing renewable energy and can be transported to where it’s needed.
Toyota began development of a hydrogen fuel cell electric vehicle in 1992, introducing the Mirai saloon to world markets in 2014.
The basic concept of hybrid power has successfully been adapted to produce Hybrid Electric (HEV), Plug-in Hybrid Electric (PHEV), Battery Electric (BEV) and – starting with the Mirai – Fuel Cell Electric Vehicles (FCEV). Each has qualities suited to different mobility requirements: for example, BEVs for shorter commutes and urban driving; HEVs and PHEVs for general and longer distance personal travel; and FCEVs for larger and heavier passenger cars, heavy-duty vehicles and public transport.
