Astron Aerospace has recently introduced a rotary combustion engine prototype, the H2Starfire, which achieves an impressive 60% thermal efficiency while emitting only clean water vapor and zero nitrogen oxides (NOx).
The engine is a unique take on the Wankel-rotary design but with no planetary gears or apex seals. Instead, it uses two counter-rotating shafts with incredibly tight, frictionless tolerances achieved through ceramic coatings and titanium, which help maintain pressure and mitigate heat deformation.
“The ‘H2’ in H2Starfire stands for hydrogen, a notoriously difficult gas to store and transport,” Astron Aerospace notes.
The H2Starfire engine is designed to maximize efficiency and minimize emissions. By eliminating the need for water cooling, Astron claims to have simplified the engine’s design while achieving greater than 60% thermal efficiency. This is a remarkable feat compared to typical car engines, which operate at around 20% efficiency, with the best engines reaching closer to 40%. “Sixty percent is an extraordinary claim,” Green Car Reports states.
One of the engine’s most intriguing features is its ability to run cool enough to avoid producing NOx emissions—a common issue when fuel is burned in air at high temperatures. Air and fuel are drawn into the front half of the engine, where they are compressed and mixed with hydrogen before being ignited in the rear half. The result is explosive compression that drives the engine while emitting only clean water vapor.
Astron’s design boasts a 270° rotation cycle, idling at 1,000 rpm and capable of revving up to 25,000 rpm. The engine is nearly frictionless, requiring oil only for the timing gears and bearings, thanks to the tight tolerances in its construction. The H2Starfire is also compact, measuring just 11.4 x 12.5 x 17.3 inches and weighing 120 lbs, yet it delivers an impressive 400 horsepower and 500 lb-ft of torque.
While Astron has built and run a partial prototype of the H2Starfire, the company has yet to provide extensive proof of its claims. The current demo includes a video of the engine being turned over with a power drill, which, while intriguing, leaves room for skepticism.
Source: Astron Aerospace