Porsche is leaving no stone unturned as it looks ahead to an era of cleaner mobility. Already working on electric cars and e-fuels, the brand revealed today that its engineering department was also considering converting one of its V8 engines to run on hydrogen.
The company “developed hydrogen combustion engine which aims to match the power and torque of today’s high-performance petrol engines as a concept study,” said Vincenzo Bevilacqua, senior engine simulation expert at Porsche Engineering. “At the same time, we also aimed to achieve low fuel consumption and keep emissions at the same level as ambient air.”
Although this was just a virtual study rather than a physical one, the team started with a 4.4 liter Porsche V8 engine and modified it to run on hydrogen. The biggest problem was the adaptation of the turbochargers to work with the new fuel.
“For clean combustion hydrogen, turbochargers must, on the one hand, deliver about twice the mass of air that they do in gasoline engines,” said Bevilacqua. “On the other hand, however, the lower temperature of the exhaust gases results in a lack of energy to move them on the exhaust side.”
The team, therefore, had to turn around to electric compressors to create the necessary pressure, and after several trials eventually landed on a back-to-back turbocharged system. Using a common shaft driven by a turbine or electric motor, the air passes through the first compressor, is cooled in an intercooler, and then recompressed in the second stage.
The result was an engine that, when modeled, can produce about 590 hp. (440 kW/598 hp). The Porsche Cayenne Turbo S E-HybridThe 4.0-liter V8, for comparison, produces 541 hp. (403 kW/548 hp). However, in combination with electric motors, the system can generate 670 hp. (500 kW/680 hp).
To find out how this performance would translate into a vehicle, the team used a “digital twin”, a simulation of a vehicle with an engine inside it, to gauge how fast it could go Nürburgring. Housed in a “luxury reference vehicle with a relatively high GVW of 2,650 kg” (5,842 lb), which is about 220 lb (100 kg) more than the Cayenne Hybrid, the vehicle was able to lap the famous circuit in 8:20. For reference, that’s exactly the same time as the 2008 Chevrolet Camaro SS.
According to Porsche, CO2 emissions aside, the exhaust from the hydrogen engine is as clean as the air around it, albeit with a small amount of nitrogen oxide, which The Volkswagen Group has struggled since before. However, it says that it can easily reduce the concentration of this gas to Euro-7 standards.
Although Porsche claims that the cost of production hydrogen engine would be comparable to production gasoline engines, this concept engine is unlikely to reach that stage. However, this does not mean that we will never see a Porsche with a hydrogen engine.
“The study allowed us to gain valuable insights into the development of high-performance hydrogen engines and add hydrogen-specific models and techniques to our virtual simulation methodology,” explains Bevilacqua. “With this know-how, we are ready to efficiently handle future customer projects.”