Otto Engine - The Otto Cycle

The Otto Cycle

The Otto Engine of 1876

An Otto engine with slide valve ignition

After 14 years of research and development Otto succeeded in creating the compressed charge internal combustion engine May 9, 1876. Otto found a way to layer the fuel mixture into the cylinder to cause the fuel to burn in a progressive, as opposed to explosive fashion. He referred to this as being a layered or stratified charge. This resulted in controlled combustion and a longer push of the piston in the cylinder rather than the explosion which destroyed all the engines attempted previously. The fuel was still Illuminating Gas just as Lenoir's and his own atmospheric engines had used.

This engine that uses four cycles in its creation of power. It is known now as the Otto Cycle engine. This is the same engine that was first attempted in 1862.

Otto turned his attention to the 4-stroke cycle largely due to the efforts of Franz Rings and Herman Schumm, brought into the company by Gottlieb Daimler. It is this engine (the Otto Silent Engine), and not the Otto & Langen engine, to which the Otto cycle refers. This was the first commercially successful engine to use in-cylinder compression (as patented by William Barnett in 1838). The Rings-Schumm engine appeared in autumn 1876 and was immediately successful.

The cylinder arrangement of the compression engine was horizontal. It featured a slider valve control with gas flame ignition, which overcame the problems that Lenoir could not overcome with electric ignition which was unreliable at that time. In the 15 years prior to the development of the Otto engine power output never exceeded 3 hp. In a few years after the Otto engine was developed engine power rose until it reached 1000 hp.

The Otto Cycle engine was eventually adopted to run on Ligroin and eventually gasoline, and many gases. During WWII Otto engines were run on more than 62 different fuels, such as wood gas, coal gas, propane, hydrogen, benzene, and many more. The engine is limited to light fuels. A later development of this engine, known as the Diesel engine can burn heavy fuels and oils.