Hydrogen Combustion Engines: What are the opportunities and challenges?

In this article, we’ll take a look at the opportunities and challenges of using hydrogen converted combustion engines.

Video: Engineering Explained

Solving global reliance on fossil fuels in order to reduce carbon emissions is a huge challenge for engineers and manufacturers. Any answer must also successfully balance sustainability with the commercial drivers of cost and performance.

The automotive engineering industry has long led this innovative approach. One of the key ways is the wider adoption of electric vehicles, and they’re certainly set to play a vital role in a low carbon transport future.

But what if there’s another (or additional) solution? Instead of building millions of brand new electric cars, what if automotive manufacturers could utilise existing car technology to convert modern combustion engines into more environmentally friendly, hydrogen fuelled engines which reduce carbon emissions?

You can watch this great video from Engineering Explained which covers the topic in more detail.

What are the advantages of a hydrogen fuelled combustion engine?

The key argument for using hydrogen fuelled converted combustion engines is that instead of carbon, the main emission from the engine is water. Although there are still some Co2 emissions from the engine oil required, carbon emissions are significantly reduced compared to a traditional carbon-fuelled combustion engine.

The advantages of using a hydrogen fuelled engine include:

• Significantly reduced carbon emissions.
• Hydrogen is a readily available and renewable potential energy source.
• Hydrogen fuelled engines can utilise existing vehicles, supply chains and automotive technologies to reduce carbon emissions in combustion engines.

The possibility to reduce carbon emissions with a hydrogen powered engine has been referred to as a ‘powerful weapon in the quest for carbon neutrality’. And on paper, the premise seems extremely promising. But how realistic is a hydrogen fuelled engine?

Toyota Corolla Sport: Proving the concept of a hydrogen powered engine

Toyota took on finding an answer to this question by creating a hydrogen fuelled three-cylinder HCCI engine in their Toyota Corolla Sport, entering the car in the Fuji24 Hours race. The aim was to test speed, endurance and proof of concept. Impressively, the car did manage to finish the 24 hour race, requiring 4 hours of refuelling.

What are the disadvantages of a hydrogen fuelled combustion engine?

The race also highlighted some of the key challenges in using hydrogen fuelled combustion engines, including:

• The low density of hydrogen means that huge storage tanks are required.
• The production of hydrogen fuel generates harmful emissions itself.
• It is currently extremely expensive to produce hydrogen using renewable energy sources.
• Currently, a hydrogen fuel cell is more cost efficient, as well as enabling greater range than a hydrogen fuelled engine. This makes a fuel cell a more consumer-friendly choice.
• There are still NOx emissions with hydrogen fuelled engines.
• Knocking is a potential issue with hydrogen engines. This is because the ignition energy required for hydrogen is very low, making it extremely easy to ignite a hydrogen/ oxygen mixture.

Read more: Surviving the engineering valley of death with sand casting

Read more: Are ICE parts harder to produce than EV powertrain parts?

Read more: 4 ways sand casting is supporting electric vehicle manufacturing

Sand castings and hydrogen fuelled combustion engines: What is the future?

Although challenges remain, the possibility of hydrogen fuelled combustion engines is still a potentially exciting development in automotive technology. The concept of a hydrogen combustion engine highlights huge potential within the automotive industry to utilise technological capabilities and engineering expertise to work to create a carbon neutral future. 

Sand castings are set to play a huge role in contributing to lower carbon emissions by developing lighter, part-count reduced prototype engines. As an industry, sand casting is well-placed to support the development of hydrogen-fuelled engines, once automotive engineers and technology can make wider adoption of HCCI more realistic. 

To wrap up

Creating a carbon-neutral transport future is complicated, requiring engineering expertise and innovation. The concept of hydrogen fuelled combustion engines represents the possibility and challenge of this huge task, as well as highlighting the role of sand casting in supporting future prototyping of these engines.

To find out more about the role of sand casting in electric vehicle manufacture, download our free eBook, Making EV Components with Sand Casting.