EXPLAINED: Hydrogen Internal Combustion Engine

The impending switch to alternative powertrains is now clear as day. As the era of fossil fuel-dependent ICE engines draws to a close, most automakers have already dipped their toes in the pond and are working on a switch from ICE engines to lithium-ion batteries. However, as the sea of ​​electric vehicle makers fills up as we speak, a few of the companies are drifting towards other forms of power sources such as hydrogen as fuel in ICE vehicles.

Before that, we’ve seen a handful of hydrogen fuel cell electric vehicles (FCEVs) – both in concept and production form. However, for about a decade, despite several attempts, no automaker has been able to bring FCEVs into the spotlight, and as such they continue to be a rarity. Currently, the only FCEVs in production are the Hyundai Nexo crossover and the Toyota Mirai. This is after Honda recently decided to unplug its Clarity FCEV. The hydrogen engine in Hyundai and Toyota cars uses hydrogen to power the fuel cell, which converts energy into electricity through a chemical reaction and powers an electric motor to propel the vehicle.

Toyota Mirai. (Image source: Toyota)

Are FCEVs beneficial over ICEs?

The process is quite complicated and expensive. However, Toyota is now offering a more direct solution in the form of hydrogen-powered internal combustion engines. With an FCEV, there are a multitude of aspects that need to be considered. For example, the vehicle carries hydrogen tanks, the fuel cell and the electric motor(s), all married into a single cohesive unit. The system also uses platinum, a rare and quite expensive ingredient, for the oxygen reduction reaction in the fuel cell.

A hydrogen ICE is essentially a traditional combustion engine converted to run on H2. An additional point is that these existing engines can be converted by modifying certain components – such as the fuel system and the spark plugs – to use hydrogen instead of gasoline or diesel, which means automakers have a tried and tested base to build on and refine to better meet hydrogen applications, without investing heavily in electric powertrains.

The main purpose of using hydrogen would be to turn a car into a very low emission vehicle. With the combustion of hydrogen, the vehicle would mainly emit only water vapour. The reason this is not a zero emission application is that a tiny amount of carbon dioxide (CO2) is also emitted due to the combustion of engine oil, and the combustion process in an H2 ICE results in the emission of nitrogen oxides (NOx). While these emissions are significantly lower than gasoline/diesel vehicles, FCEVs are better than ICE H2s on this front, as they are true zero-emissions vehicles.

Unlike conventionally powered ICEs, hydrogen ICEs only offer 20-25% efficiency, power output varies depending on the energy density of the hydrogen/air mixture. Additionally, hydrogen ICEs are also prone to knocking, which can negatively impact engine durability as well as fuel efficiency. However, the last problem can be overcome with the help of an exhaust gas recirculation system.

Then there is the cleanliness of the hydrogen fuel itself. Currently, the process of creating hydrogen primarily involves the use of fossil fuels, which contributes heavily to CO2 emissions. This is a counter-productive solution, and the ideal and cleaner alternative, green hydrogen (produced by exploiting renewable resources), is significantly more expensive, costing between 3.5 and 6 dollars per kg. . It is unlikely that a significant drop in the price of green hydrogen will occur before the end of this decade. Until that happens, running a hydrogen vehicle — on any other form of hydrogen — may actually be worse for the environment than running a fossil fuel vehicle.

And then there’s the hydrogen fuel infrastructure itself. While battery electric vehicle charging stations are installed almost every day around the world, there are only a handful of hydrogen filling stations in major countries, which means that trips in a vehicle hydrogen are extremely limited. The cost of setting up a hydrogen station – reportedly between $2 million and $3.2 million depending on the type of station – is prohibitive in most markets, and with virtually no hydrogen vehicles on sale, investing in one doesn’t make much business sense at this point.

To complicate matters further, refilling hydrogen will result in a wait of up to 20 minutes, as the storage tank must have sufficient pressure to be able to deliver hydrogen to the car’s tank, which otherwise cannot be completely filled. . In the event of mass adoption, queues at stations would be winding and not all drivers would have time to waste.

Safety also remains a concern for hydrogen storage facilities. In the past, high-intensity explosions at hydrogen refueling and storage facilities in Norway and South Korea have raised questions about the safety of hydrogen – which is highly flammable – for mass uptake, and also led resident groups to oppose the introduction of new hydrogen refueling. stations and production facilities nearby.

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Where is India on the green hydrogen production front?

The pursuit of green hydrogen is accelerating in India. State-owned GAIL India Ltd recently announced that it will set up a 10 MW green hydrogen plant – the largest such plant in the country – over the next 12 to 14 months. Reliance Industries chief Mukesh Ambani said the company, as part of its clean energy business, is working to reduce the cost of green hydrogen to as low as $1 per kg by the end of the year. end of this decade.

The Indian government has already set safety standards for the production of green hydrogen, and Union Minister Nitin Gadkari has repeatedly advocated the use of hydrogen as an automotive and industrial fuel, including adoption would help reduce the country’s fuel import bill. substantially.

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