On the other hand the rotary engine doesn't have any hot exhaust valves and the combustion chamber walls might also be somewhat cooler. So considering this, the rotary engine has actually some advantages compared to the piston engine.

 

this is why it can run hydrogen.

 

Piston engines run on hydrogen as well.
http://www.bmwworld.com/models/750hl.htm

 

globi, the renesis needed very little work to convert it, while piston engines take more work to convert to hydrogen... which I think is his point.

 

Labop, keep in mind that the BMW engine is capable to switch from gasoline to hydrogen as well. It appears as it is mainly a question of having 2 different fuel induction systems. Or can you be a somewhat more precise why exactly the rotary engine conversion should be easier?

 

The rotary engine is ideally suited to burn hydrogen without inviting the backfiring that can occur when hydrogen is burned in a traditional piston engine.

The separate induction chamber also provides a safer temperature for fitting the dual hydrogen injectors with their rubber seals, which are susceptible to the high temperatures encountered in a conventional reciprocating engine.

Twin hydrogen injectors Because hydrogen has an extremely low density, a much greater injection volume is required compared with gasoline. This demands the use of more than one injector, which can be difficult to achieve with a conventional reciprocating engine because of the structural constraints that prevent directly mounting injectors in the combustion chamber. In contrast, the rotary engine provides adequate space for installation of two injectors per induction chamber. With its twin hydrogen injectors, Mazda?s hydrogen rotary engine is both practicable and able to deliver sufficient power.

Excellent mixing of hydrogen intake charge In a reciprocating engine, the output shaft turns through 180 degrees in one cycle, whereas the rotary engine's output shaft covers a greater angle of 270 degrees, enabling a more vigorous intake flow for ample mixing of the hydrogen-air intake charge. This promotes production of a uniform mixture, which is critical for hydrogen combustion.

http://rotarynews.com/?q=node/view/216

 

this is from an article I read, don't remember where I saw it, I'll try to find it.

certain parts need to be changed out right? less parts need to be changed out with a rotary. I'll find the article, it explains it pretty well.