Porsche was in the news in August with a hydrogen engine project aimed at producing the high performance needed for its cars. Most of today’s research is focused on commercial vehicles, where less than 70bhp per litre is enough, but Porsche’s interest lies at the upper end of the scale and its subject is a virtual 4.4-litre V8 petrol, which at 590bhp is making 134bhp per litre.
Although hydrogen contains nearly four times more energy by weight than petrol, it’s a gas so its volumetric efficiency is a lot less. Used in a combustion engine, which in its purest, naturally aspirated form works largely on the basis of how much gas (air) it can ingest, hydrogen doesn’t stack up so well. Even stored in liquid form, with all of the challenges that entails, it still has to return to its gaseous state inside the engine.
The way around the problem is much the same as with a…
Under the skin: Porsche’s 690bhp hydrogen V8
