New Wankel rotary engine design from America gives ridiculous power-to-weight ratio, could revolutionise motorcycle design.

New Wankel Engine Design Gives 160bhp from 33lb

The death of the Wankel rotary engine has been predicted many, many times over the years but it seems it is the concept that will just not die. It's easy to see why: one moving part means it is cheap to build, physically small and smooth running and it gives good power for its size. Negatives are bad emissions and, at the beginning, at least, trouble with the rotor sealing blades. That latter has largely been solved thanks to advances in metallurgy, although the emissions problem still remains.

As for the power output, well that has been convincingly demonstrated by American start-up firm Astron, that has developed a modular system Wankel-type rotary-pistoned engine that gives a frankly unbelievable 160bhp from an engine weighing in at only 15kg (33lb).

For comparison, a typical turbocharged V8 diesel engine might have an engine power of 340 hp and a mass of 840 lb, giving it a power-to-weight ratio of 0.40 hp/lb. The Astron Wankel design gives 4.84hp/lb!

Astron claims it has overcome the rotor sealing problem and reiterates the claims that the design is hugely more efficient than a conventional reciprocating internal combustion engine, largely due to a massive reduction in frictional losses.

Previous Wankel designs traditionally had one or two rotors. The Astron engine takes the concept further, with four rotors running in two separate chambers. The 'front' two rotors take care of intake and compression while the rear two rotors look after combustion and exhaust. A rotary disc valve sits between the two halves.

This arrangement allegedly increases the efficiency of the engine, something that is helped by a new feature that allows the engine to fire once every five or ten rotations once cruising speed has been attained. On acceleration or when the throttle is depressed when a burst of speed is needed, the computer increases the firing rate giving instant power with no throttle lag.

For now, the motor is being aimed at the automotive and aerospace sectors but surely it is a shoe-in for the motorcycle industry? Only time will tell.