Could hydrogen keep the internal combustion engine alive?


Increasingly stringent emission rules make it difficult for automakers to continue offering cars powered by internal combustion engines, with some countries like the UK even taking steps to ban the engines altogether.

Interestingly, hydrogen, of all things, could prove to be the savior of the internal combustion engine.

Several automakers have proposed converting hydrogen produced from renewable sources into carbon-neutral synthetic fuel. Porsche and its partners have even built a pilot plant capable of producing synthetic fuel on an industrial scale.

Toyota is now testing another much older solution involving hydrogen: burning the substance directly in an internal combustion engine.

The automaker last week unveiled a racing car with an inline 3-cylinder engine designed to run on pure hydrogen. The race car is still in testing, but will compete in a round of the 2021 Super Taikyu Series racing series in Japan in May.

As mentioned, this solution is not new. BMW presented a prototype of the 7 Series whose V-12 engine could run on hydrogen. This was in 2006. The main modifications needed relate to the fuel storage and the fuel injectors.

During the combustion of hydrogen, there are no CO2 emissions. However, the technology is not without its drawbacks. The combustion of hydrogen in an internal combustion engine produces harmful nitrogen oxides. However, there are ways to minimize this, such as using urea-based selective catalytic reduction as in modern diesel engines.

The biggest problem, as we have already explored, is the low efficiency. Energy is already wasted in producing hydrogen from renewable energies, and by the time the hydrogen is burned in an engine and the power transferred to a transmission and ultimately to the wheels, only about 25% of the value hydrogen’s energy is actually transferred.

This is why fuel cell electric cars like the Toyota Mirai make more sense when they use hydrogen for fuel. Here, hydrogen is combined with oxygen in the air to create electricity which then powers an electric motor that can directly power the wheels. Here the yield is closer to 50%. And there are no harmful emissions either. Just water.

Another disadvantage of hydrogen? There is no infrastructure in place to properly source and deliver it to customers. That’s why battery-electric cars, which can use the existing power grid, are likely to be the main source of personal transportation in the future, although hydrogen may still have a place in long-distance transportation.


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