Toyota presents the second generation of the hydrogen car Mirai in detail

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Toyota presents the second generation of the hydrogen car Mirai in detail-presents

The car manufacturer Toyota is pursuing the vision of a sustainable, hydrogen-based society and sees hydrogen as a sensible and sufficiently available medium for storing and transporting energy. The technology has the potential to completely decarbonize traffic – automobiles and trucks as well as trains, ships and airplanes. Hydrogen is also suitable as an energy supplier for industrial plants, companies and residential buildings. Energy obtained from renewable sources can be efficiently stored with this medium and transported to where it is needed.

Toyota started developing a fuel cell vehicle back in 1992. In 2015, the first production version of the Mirai was launched in Europe. This breakthrough was based on the automaker’s world-leading expertise in hybrid systems, which are a key technology for many electrified powertrains.

Toyota has successfully implemented the basic concept of hybrid propulsion in hybrid electric vehicles (HEV), plug-in hybrids (PHEV), battery electric models (BEV) and – starting with the Mirai – also in fuel cell electric vehicles (FCEV). All drive concepts play their specific advantages in different mobility scenarios. BEV, for example, are particularly suitable for professional commuters and city traffic. HEV and Phev enable virtually any kind of rides, even longer routes are possible. FCEV are designed for long distances and mainly offer themselves for larger and heavier cars as well as for transport and public transport.

Latest Mirai generation with up to 650 kilometers range

Now a new Mirai generation goes to the start. It benefits from a consistently developed FCEV technology and convincing with an emotional appearance, so Toyota. For this purpose, the dynamic design also contributes to how the increased driving pleasure. Thanks to its completely redesigned fuel cell system, intelligent room layout and more efficient aerodynamics, the new Mirai enables a total range of around 650 kilometers – and the only thing it emits over this long distance is water in the form of steam.

In developing the new Mirai, Toyota has optimized every aspect of the vehicle to appeal to customers emotionally – in terms of power delivery and driving performance as well as the way the car drives and looks.

The declared goal was to increase the range compared to the first generation to a level that surpasses most purely battery-electric cars. For this purpose, the engine output and the capacity of the hydrogen tanks have increased, as has the aerodynamic efficiency. The result: a radius of action increased by 30 percent, which now reaches a good 650 kilometers. This means that the Mirai has finally risen to the class of long-distance vehicles.

More effective packaging for more interior space

Toyota has devoted just as much attention to the room layout. The modular GA-L platform on which the new Mirai is based allows for significantly more effective packaging. In favor of a more balanced layout of the new FCEV powertrain, the fuel cell unit is now under the hood. In doing so, it clears the way for a larger interior, which now offers space for five passengers.

The new Mirai also stands out with its more attractive proportions. While Toyota has stretched the wheelbase by 140 millimeters to 2920 millimeters, the vehicle height, which has been reduced by 65 millimeters to 1470 millimeters, now appears flatter – also thanks to the lower roof line, which, like the continuous underbody paneling, has a positive effect on aerodynamics. The rear overhang grew by 85 millimeters, bringing the overall length of the sedan to 4975 millimeters. The track, which is 75 millimeters wider, and larger wheels with 19 and 20 inch rim diameters contribute to the vehicle’s lower center of gravity and underline the dynamic appearance of the new Mirai.

Higher emotionality

When developing the new Mirai, one goal was very high in the specifications of the designers and engineers at Toyota: the latest model generation should combine the excellent environmental compatibility of the fuel cell vehicle with increased emotionality – both in terms of the lines and the driving performance. The GA-L platform and advanced FCEV technology provide the ideal basis for this.

The GA-L platform enables the fuel cell unit and the drive components to be positioned in a space-saving manner. Thus, the new Toyota Mirai now offers space for up to five passengers in the interior and convinces with a more balanced driving behavior. One of the most important further developments: The new architecture offers enough space for three instead of two high-pressure hydrogen tanks. This increases both the volume of the tank capacity and the range by 30 percent compared to the predecessor.

Toyota presents the second generation of the hydrogen car Mirai in detail-toyotaToyota

The three tanks arranged in a T-shape are characterized by their stronger, multi-layer construction and their low weight. The largest of these hydrogen storage tanks is located longitudinally in the middle under the vehicle floor, the two smaller ones are located across the rear seats and the luggage compartment. Their low installation position contributes to the new Toyota Mirai’s low center of gravity and also has a positive effect on the trunk volume. The total capacity of the three tanks increased to 5.6 kilograms.

Another novelty: Thanks to the innovative architecture, the completely newly developed fuel cell has moved from the vehicle floor under the bonnet – i.e. to where conventionally powered vehicles have their engines. The even more compact high-voltage battery and the electric motor are located above the rear axle. The powertrain optimized in this way gives the rear-wheel drive Toyota Mirai a balanced weight distribution of 50 percent each on the front and rear axles.

New fuel cell stack

Toyota has designed the new fuel cell and fuel cell converter FCPC (Fuel Cell Power Converter) specifically for use in the GA-L platform. All components including water pumps, intercoolers, air conditioners, compressors and hydrogen recirculation are now part of the fuel cell network. They are characterized by a smaller and lighter design with a higher power density at the same time. With the help of the rotary welding process, Toyota was able to reduce the space between the fuel cell and the housing to such an extent that the container itself is also more compact.

As in the previous Mirai model, a solid polymer is also used in the fuel cell of the second generation. The battery pack is smaller and now consists of 330 instead of 370 cells – but with a specific power density of 5.4 kW per liter it still sets a new record. The maximum power increases from 114 to 128 kW. Toyota has also improved its behavior in the cold: the cell now even starts at temperatures as low as minus 30 degrees Celsius.

Despite a twelve percent increase in performance, the optimized components within the housing weigh a good 50 percent less. At the same time, Toyota has reduced the number and thus the amount of necessary system connections, which not only saves weight but also valuable installation space. This applies, for example, to the more compactly designed intake, which has been repositioned and thus enables the optimized shape of the gas channel separator. There are also innovative materials for the electrodes.

Toyota presents the second generation of the hydrogen car Mirai in detail-miraiToyota

The fuel cell unit also includes a DC-DC converter (direct current to direct current) and modular high-voltage components. Thanks to the latest technologies, they are 21 percent smaller than the current system, while the weight has fallen by 2.9 to 25.5 kilograms. Toyota is using the next generation of silicon carbide semiconductors for the first time in the transistors of the Intelligent Power Modules (IPM). This improves power delivery while using fewer transistors and reducing power dissipation. Conversely, this means that the entire FCPC fuel cell converter can be made smaller.

Other elements of the fuel cell stack also benefit from the minimization of size and weight. The air intake, designed for low pressure drop, contains sound-absorbing material. Just like the silencer, it prevents annoying noises from entering the passenger compartment. The outlet is made of resin tube, which can discharge a large amount of air and water. Overall, the entire air system is almost 30 percent more compact than the current Mirai and weighs over a third (34.4 percent) less.

Mirai equipped with lithium-ion battery for the first time

Instead of a nickel-metal hydride battery of Mirai predecessor generation, Toyota sets a lithium-ion high voltage battery with 84 cells at the new model. Despite their smaller dimensions, it has a greater energy density, which combines a higher power output with a better life cycle assessment. Their nominal voltage was increased from 244.8 volts to 310.8 at one of 6.5 AH to 4.0 AH reduced capacity. The weight sank from 46.9 to 44.6 kilograms and the power output rose from 25.5 kW times ten seconds to 31.5 kW times ten seconds.

Thanks to its space-saving design, the battery finds space behind the back seats without restricting the charging volume of the trunk. Discreetly attached air intakes laterally next to the back seats optimize the air flow.

Dynamic performance

As the new technical basis of the second Mirai generation, the GA-L platform lowers the center of gravity of the fuel cell vehicle. Thanks to lower mass inertia, this has an invigorating effect on driving dynamics and at the same time improves the rigidity of the reinforced body, which also benefits from strategically placed supports, additional adhesive connections and the use of laser spot welding, according to Toyota. Added to this is the ideal 50:50 weight distribution between the front and rear axles. As already described, it results from the placement of the battery and the electric motor in the rear and the relocation of the fuel cell unit from the vehicle floor under the bonnet. The result is driving stability that corresponds to the characteristics of a front-wheel drive vehicle.

The chassis of the new Mirai includes new multi-link wheel suspensions front and rear. They replace the previous MacPherson struts at the front and the twist-beam construction of the rear axle. This layout ensures great driving stability, safe handling and pronounced suspension comfort. Details such as reinforced anti-roll bars, the optimized arrangement of the upper and lower ball joints and an overall high rigidity of the suspension components contribute to the agile response of the chassis.

Toyota presents the second generation of the hydrogen car Mirai in detail-toyotaToyota

Larger wheels and wider tires also make an important contribution to the improved driving characteristics. The 19 and 20-inch rims with tires in the dimensions 235/55 R19 and 245/45 R20 are characterized by reduced rolling resistance and lower rolling noise. As a result, they contribute to fuel efficiency and a quieter vehicle interior and benefit handling as well as directional stability. The larger diameter of the rims and tires also creates space for the now three hydrogen tanks.

All in all, the additional power of the new fuel cell unit gives the Mirai a smooth, linear start-up and powerful acceleration that corresponds harmoniously and willingly with the movement of the accelerator pedal. Motorway journeys are relaxed and stress-free. On country road tours, the new model conveys a lot of sovereignty and shows an agile temperament.

The Mirai cleans the air while driving

The environmental benefit of the Toyota Mirai goes far beyond the claim of enabling mobility without local emissions: In fact, it leaves the ambient air that it takes in while driving cleaner than it found it. This cleaning effect is based on an innovative filter developed by Toyota that works according to the catalyst principle.

An electrically charged fleece element captures microscopic particles from the air that is drawn in to supply the fuel cell, including sulfur dioxide (SO2), nitrogen oxides (NOx) and PM-2.5 nanoparticles. Expressed in figures: Effectively, 90 to 100 percent of all particles with a diameter between zero and 2.5 microns that flow through the intake tract get caught.

Extravors of the deliveries

The new Mirai should penetrate the market deeper than before: Toyota expects a paragraph that exceeds the predecessor generation by a factor of ten. Columns of this growth are in addition to the improved performance and the larger attractiveness of the new model, which is more than 20 percent more favorable selling price, which enable the development jumps of the hydrogen vehicle.

In addition, this is generally the greater attractiveness of fuel cell technology through their everyday use – many markets build their hydrogen infrastructure, the number of gas stations increases and more and more public funding programs are launched to strengthen the change towards a cleaner mobility.

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4 thoughts on “Toyota presents the second generation of the hydrogen car Mirai in detail”

  1. It’s a pity that there aren’t many users of these vehicles, I would be interested to know how the batteries last for the small size, if an electric car with a large battery has a 20% loss after 10 years, a battery that is permanently loaded will last even less..

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  2. Unlike Germany, the Japanese are on the one hand “green” hydrogen, which, like now in Fukushima, is generated with electricity from renewable sources such as wind and sun. This stream is however, relatively expensive due to the expensive soil and deep seabed in Japan – and thus also drives up the costs of “green” hydrogen.

    The Asians’ second approach could be cheaper: “blue” hydrogen, which is produced using fossil fuels.. (Source: wiwo.de – June 2020)

    If the ground is so expensive, why not provide all roofs with PV systems and use them to charge e-cars directly. Better than producing hydrogen from fossil fuels, which may have originated in the 6th century.000km distant Australia comes by ship (diesel engine, heavy oil combustion, dirty air).

    Hydrogen cars should (e.g.B. in the EU) only if the green electricity cannot be used sensibly elsewhere – it is better to convert electricity into hydrogen than to switch off wind turbines.

    But do not build additional wind turbines just to produce hydrogen for hydrogen cars, that would be a waste of resources and money.

    Reply

  3. Hydrogen is needed for blast furnaces, ships, airplanes. Maybe also for trucks but not for cars. Hydrogen by electrolysis is very, very ineffective. only approx. 20% arrive at the B-cell at the rear wheel. With a battery car it is at least approx. 70%.

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  4. The Japanese government has just increased subsidies for e-cars by half. So I wonder what motivates Toyota to put so much energy into the inefficient hydrogen technology of hydrogen cars. Hydrogen is good for large vehicles, airplanes, ships and to generate electricity from stored hydrogen that was previously generated by regenerative energies. But each of you must know for yourself what you are wasting your money on.

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