Kawasaki edge closer to hydrogen-powered internal combustion engine by testing prototype H2 SX

Kawasaki have taken their hydrogen internal combustion engine motorcycle project to the next stage by running a prototype machine at a test track.

We first saw renders of an H2 SX-based concept back in January but now the Japanese firm have reached the point of physical testing.

“Hydrogen engines produce power like conventional gasoline engines: air is taken in, mixed with fuel, and then combusted,” said Project Leader, Satoaki Ichi.

“When hydrogen combusts, water is produced. If you hold your hand near the tailpipe, you can feel it is moist. It is a very gentle engine – like a humidifier on wheels.”

In a video of the testing (see below), a version of the prototype can be seen filling up at a special hydrogen filling station as well as riding on track. The engine sounds very similar to what you expect from a petrol version, too, with the only real difference found in the enormous rear bodywork that houses the hydrogen fuel tanks.

The project uses not only the chassis of the Kawasaki H2 SX, but also its supercharged engine, which Kawasaki say has been adapted to allow direct injection of hydrogen. That would explain how the working prototype has been developed so quickly in automotive terms.

Watch the Kawasaki H2 SX hydrogen prototype in action in this video

Ichi continued: “Hydrogen burns more quickly and under a wider range of conditions than gasoline, making it possible to create a more responsive feeling than ever. We are still at the basic research stage.

“We have finally reached the point where we can conduct riding tests on a two-wheeled vehicle. Stay tuned for more about this environmentally friendly future motorcycle.”

Hydrogen combustion is seen by some bikers as a lifeline for internal combustion engines, and a much preferred option over battery or hydrogen fuel cell electric options. And unlike bioethanol or synthetic fuels, the hydrogen ICE puts out only water (and a tiny amount of CO2 caused by burning engine oil) so they work for clean air zones and ULEZ schemes, too.

Kawasaki are a member of HySE (Hydrogen Small mobility & Engine technology), a cross-manufacturer research project announced in May 2023 that is researching hydrogen engines, hydrogen filling systems, and fuel supply systems. HySE members also include Yamaha, Honda and Suzuki.