Dolphin N2 ThermoPower: The hydrogen combustion engine

The ThermoPower is a radical new take on the internal combustion engine by Dolphin N2. It takes waste heat from the exhaust and puts it back into the engine – via a recuperator – increasing the engine’s efficiency by 20%.

This internal combustion engine was designed to run on diesel, but an Advanced Propulsion Centre Advanced Route to Market Demonstrator funded research project – known as RE-ARMED – determined that the same high efficiency could be achieved when using hydrogen as a combustion fuel.

The engine is currently being tested at the Millbrook Proving Ground.

“This is really exciting” says Dolphin N2 Technical Director, Nick Owen, “because this is the first new type of internal combustion engine cycle since Frank Whittle and the jet engine. Some of what we’ve learnt about conventional engines just doesn’t work on this one. So it really is a voyage of discovery.”

The engine has a split cycle, separating the ‘cold’ and ‘hot’ sections of a traditional internal combustion engine, and uses waste energy to heat air through a recuperator. By retaining and reusing the heat from the exhaust, it can achieve 55% efficiency for diesel or hydrogen combustion and produces very low NOx emissions.

The ThermoPower was designed to reduce the diesel costs and carbon emissions of logistics companies by 20% in a simple to adopt drop-in solution. The fact that the engine can now also be powered by hydrogen paves a clear pathway to a zero-emission future.

“It feels that we’ve now got a forever solution, to be honest,” says Simon Brewster, CEO of Dolphin N2, “not just for heavy freight, but also for multiple other sectors, including agriculture, construction, and marine.”

Truck manufacturer Iveco recently bought Dolphin N2, with a view to rolling out the ThermoPower to their global customer base.

This could see a British innovation delivering a short-term 20% reduction in carbon emissions even in hard to decarbonise sectors, with a pathway to a 100% reduction for some of the world’s biggest and most fuel demanding on-road and off-highway vehicles and machines.