Birotary Engine –
About The Project

Throughout the history of combustion engine development, the ongoing desire to create a more capable rotary internal combustion engine has inspired various designs, generated many technological innovations and provided important learnings for engine manufacturers across the years. The constant demand driven challenge to produce ever increasingly smaller engines while delivering increased specific power output provides ongoing stimulation and opportunity for new concepts with improved designs. The successful development of a further improved high quality rotary engine has significant commercial potential in the field of lightweight aircrafts, unmanned aerial vehicles, marine applications and currently also in the field of hybrid engine solutions. In these fields, a new improved engine development with comparative advantages can provide notable and visible benefits. These benefits comprise compact dimensions, lightness, Noise Vibration Harshness (NVH) parameters and simplicity of design. An improved rotary engine, for example, would be able to make hybrid vehicles cheaper, less complex, lighter, more spacious and more powerful than they are today. This is clearly evidenced by review of several recently published car manufacturers hybrid concepts (AUDI, MAZDA, etc.).

Piston rotary aircraft engines have a long history dating back to early 1900s. Their concept was based on rotating their cylinder block around a static crankshaft. The engines had a valvetrain with poppet valves, which rotated with the cylinder block. While these engines enjoyed a considerable success in WWI, issues such as significant air resistance losses, the gyroscopic effect from the large rotating masses and total loss lubrication system led to their demise.

The Birotary concept was introduced in a 1914 patent of Ignacz Sklenar see figure below. His engine used a rotating cylinder block also as a slide valvetrain. The crankshaft rotated in the opposite direction to the cylinder bloc to reduce gyroscopic effects. However, engines based on Sklenar’s concept were large, multicylinder engines with large piston stroke and air cooling. Their design did not offer significant advantages versus traditional piston engines of their times.