Porsche is committed to electric power for its future lineup, but it doesn't want to abandon the internal-combustion engine completely, especially when it comes to the 911.
That's why the company is developing solutions to help clean up emissions of internal-combustion engines, including hybrid systems and engines with improved thermal efficiency, both of which help reduce emissions. The company is also developing synthetic fuels, which could potentially mean fully carbon-neutral combustion.
Another promising solution is an engine that instead of gasoline burns hydrogen. When burning hydrogen, carbon emissions are reduced to zero. The technology isn't new. BMW in 2006, for example, presented a 7-Series with a V-12 that could run on hydrogen. The main modifications involved the fuel storage and fuel injectors.
So what's the drawback? Besides the lack of a steady supply of hydrogen, such an engine emits harmful nitrogen oxides. However, there are ways to minimize this, like using urea-based selective catalytic reduction found in modern diesel engines. Hydrogen can also be produced without emissions, by using renewable energy to split water into hydrogen and oxygen, something that Porsche is also examining in the area of synthetic fuels.
Matching the power of a gas engine is also an issue, though Porsche appears to have found a solution. Working purely in the virtual world, Porsche is testing a version of its older 4.4-liter V-8 designed to run with a higher compression ratio and a new turbocharging system. According to the automaker, for clean combustion of hydrogen, turbos need to provide around double the air mass that they do in gas engines, though this is a challenge due to the lower temperatures and pressures of the exhaust from burning hydrogen.
To make up for the lack of pressure, the engineers designed various turbo systems with electric compressors. The key is a unique arrangement for the two compressor stages, which are driven by the exhaust or a supporting electric motor. The air essentially flows through the first compressor, is cooled in the intercooler and then recompressed in the second stage.
Porsche said the hydrogen engine delivers 590 hp, which is similar to what the original gas-powered version delivered. Porsche simulated the engine in a vehicle weighing 5,842 lb (which is Cayenne territory), and for a virtual lap the Nürburgring the resulting time was approximately 8:20. Not bad for a heavy vehicle.
Don't look for a hydrogen-powered Porsche anytime soon. The automaker said the goal of the project is to examine the technical potential of the technology and expand the capabilities of existing engineering tools so a hydrogen-burning engine is ready should the need ever be required.