Testing the road to a CO2-free future

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MOTORSFEATURE MAZDA’S HYDROGEN POLICY: AS A motorist, who could blame you for getting a little confused by all the new technologies being presented to you? One week here at Motors , we’re all about the diesel car; the next, all the talk centres around the petrol hybrid – or, more recently, the diesel hybrid. How about electric cars and fuel cell vehicles?, asks PADDY COMYN

What we do know is that most of you want to do your bit for the environment as long as the powertrain is easy to refill, recharge or re-programme and you don’t have to plan your journey around how far you can go without conking out.

Well how about one more alternative for your consideration – one that a few manufacturers are pushing hard. Hydrogen. It is one of the most widely available fuels since it accounts for 75 per cent of the matter in the universe, but it is pretty rare in its natural state unless obtained from rivers or oceans, where water electrolysis is used to extract it. Hydrogen combustion is, in theory, pretty straightforward.

Two H2 molecules combine with an O2 molecule to form two H20 molecules in vapour form, while at the same time releasing a large quantity of energy. This reaction gives off no CO2 at all.

So if you can use hydrogen as a fuel, all our problems are solved, right? Well it’s a tricky process, but Mazda seems to have it almost cracked. In general, hydrogen isn’t suitable for a standard engine because it is so combustible and because the fuel-air mixture is injected directly into a high-temperature combustion chamber, which is sealed with very hot exhaust valves. There is a lot of waste and possibly a lot of drama.

But Mazda’s rotary engine is ideal because it has separate intake, combustion and exhaust chambers, and this means the hydrogen is injected at a low temperature and only comes into contact with the combustion chamber at the last moment.

So that is why we were in Oslo, Norway, to try not one, but two cars that are capable of running on hydrogen.

The first – the RX-8 Hydrogen RE – has been leased to Norway, which is a pioneering country in getting the fuel and infrastructure in place to make alternative-powered motoring a reality. The HyNor Project was started in Norway to promote hydrogen as an alternative fuel, and in May of this year there was the opening of the Norwegian Hydrogen Highway, which allows hydrogen-powered cars to be driven the 600km from Oslo and Stavenger.

The RX-8 features a five-speed manual transmission and a button on the dashboard allows switching between the hydrogen and petrol fuel tanks (apparently safe), with the two hydrogen fuel tanks in the boot.

So far, the car’s range is pretty limited, with 100km from hydrogen and 45km from the petrol fuel tank, but the car drives smoothly on either and sounds like an RX-8 should.

Filling the car with hydrogen, you stop at a futuristic-looking pump and slot the nozzle in place with a turn of a handle. It takes a few minutes to fill and you are ready to go again.

“A hydrogen rotary engine only emits water and, while it is not as efficient as a fuel cell, structurally it is closer to the petrol engine – hence its manufacturing cost is lower and its has fewer durability issues.

“Compared to fuel cells, hydrogen engines with the dual-fuel system are more likely to play a significant role in the initial phase of a hydrogen energy society in the future,” says Akihiro Kashiwagi, Mazda hydrogen RE programme manager.

Up second – and more impressive – was the Mazda Hydrogen Premacy RE Hybrid, which is the world’s first rotary hybrid that can run on both hydrogen and petrol. In a true display of the best of Mazda’s available technology, you are getting a hydrogen rotary engine that works as a series hybrid alongside an electric motor.

The engine output is converted to electricity, which then powers the motor that drives the wheels. Battery performance can be used to boost performance according to driving conditions and this extends the hydrogen fuel range to 200km and increases the power by 40 per cent to 147bhp. The result is zero emissions in hydrogen mode, together with driving performance that equals that of a petrol engine.

Mazda says that it could convert this car to be a full electric vehicle readily. Its driving is hugely impressive. Working on the same principle as the likes of a Toyota Prius, the battery works together with the hydrogen engine and, under deceleration, the motor acts as a generator, recovering the braking energy by converting it to electricity and charging the battery.

Mazda isn’t putting a date on this technology coming to market, simply because there isn’t anywhere near the infrastructure in place or the access to hydrogen that would be required to bring it to market.

Mazda is showing us that it can be done, though, and while it may be an immediately unrealistic target, hydrogen is often regarded as a dream fuel due to the apparent absence of emissions from the process of using it as fuel.

Until then, Mazda did tell us that it will be reducing the weight of its new vehicles by 100kg and will announce details on a range of new petrol and diesel engines in the future that will seek to reduce emissions by 23 per cent and improve fuel economy by 30 per cent.

Mazda is hoping that these measures – along with stop/start technology – will make the brand a leader in reducing CO2 emissions.

This article appears in the print edition of the Irish Times