The Szorenyi engine is a new kind of rotary engine named after its creator, Peter Szorenyi. This paper provides an explanation of its geometry, design, and operational principles. A basic mathematical simulation of this engine was performed as well as an equivalent Wankel rotary engine and reciprocating engine simulation. A comparison in pressure traces and cycle performance is made between the Szorenyi engine, the Wankel engine and a reciprocating engine. The study concludes analysing and comparing the sensitivity to the ignition advance and net work of the three engines in one working cycle. Keywords: Rotary engine; Szorenyi engine; Wankel engine; Reciprocating engine; mathematical modelling; Wiebe function; net work comparison; Szorenyi engine geometry; pressure change.