C3 H5 N3 O9 – Nitroglycerine C3 H5 N3 O9 – Nitroglycerine

Wankel Engine

Experiment ZR012 indications were inspired by the Wankel engine.

In 1919, a 17-year-old German boy called Felix Wankel dreamt of a new type of engine. Despite no formal training, Wankel believed that he could design an engine in which the four stages of intake, compression, combustion and exhaust-took place in one rotation, rather than four separate reciprocations of a piston as in a normal engine. 

It was an ambitious goal, which others had been unsuccessfully attempting since the 16th century.  In 1924 Wankel created a small laboratory to develop his rotary engine and eventually tested the first prototype in 1957, over three decades later.

The Wankel motor cycleThe Wankel motor cycle

One of the main reasons development took so long is that Wankel’s orbital engine was based on a convex-triangle rotor rotating inside a epitrochoid combustion chamber. An epitrochoid is a very complex shape traced by a point on a small circle rotating around the perimeter of a larger circle and plotting that shape involves seriously complex mathematics.


x = cos(w1*t) + (R/L)*cos[(w1+w2)*t]
y = sin(w1*t) + (R/L)*sin[(w1+w2)*t]

Epitrochoids

From over 800 shapes considered, Wankel investigated nearly 150 configurations and variations – this was before computers  – before settling on a fat figure-eight form.  


In standard internal-combustion engines, pistons reciprocate four times for every cycle of power; in the Wankel engine, power is smoothly generated each rotation with fewer moving parts enabling the motor to be lighter, more compact and more reliable than reciprocating engines.

The epicycloid curve has been of special interest to astronomers over the centuries as the shapes are often found in the coronas of stars. Wankel was the first to use an epicyloid in an internal combustion engine; Experiment ZR012 is the first to use an epicyloid indications in a wristwatch.