The four stroke engine was first demonstrated by Nikolaus Otto in 1876 1, hence it is also known as the Otto cycle. The technically correct term is actually four stroke cycle. The four stroke engine is probably the most common engine type nowadays. It powers almost all cars and trucks. Animated Engines - Four stroke Is this answer helpful?Thanks!Give more feedbackThanks!How can it be improved?How can the answer be improved?Tell us how Four-stroke engine - Wikipedia The resulting cycle, which closely resembles the actual operating conditions, is the Otto cycle. During normal operation of the engine, as the air/fuel mixture is being compressed, an electric spark is created to ignite the mixture. At low rpm this occurs close to TDC (Top Dead Centre).Two-Stroke Engine · History · Thermodynamic analysis · Fuel considerations 3.5 The Internal combustion engine (Otto Cycle) The Otto cycle is a set of processes used by spark ignition internal combustion engines (2-stroke or 4-stroke cycles). These engines a) ingest a mixture of fuel and air, b) compress it, c) cause it to react, thus effectively adding heat through converting chemical energy into thermal energy, d3.6 Diesel Cycle · 3.4 Refrigerators and Heat · 3. The First Law · Contents · 16ied