N. Otto four-stroke engine invention.

Combustion engine history: A. Otto 4-stroke engine invention and his coal gas engine model.
An outstanding role in developing combustion engine belongs to German inventor Nikolai-August Otto (1832-1891) from Köln. Working together with rich engineer Eugeniy Langen (1833-1895) Otto managed to improve the idea of E.Lenouar coal engine model.

Examining Lanouar’s engine Otto came to the conclusion that its output could be increased if to spark the gas mixture at pistons highest position not at its middle as Lenouar had made. But there was an obstacle – how to fill the cylinder chamber with fuel mixture before a piston starts its stroke down? Otto inflated the chamber with gas, rotating the shaft and switched on the ignition right at the moment when the piston came back to the highest position! The result was surprising – the shaft sharply grown in speed while using the initial way of sparking at the middle had produced fewer rotations. That was the birth of 4-cycle engine. Though Otto assumed the shaft speed increase was the result of gas mixture prolonged expansion while burning. But indeed it was mainly caused by gas mixture more compressed state after the piston made its two strokes down and up before sparking. Nevertheless this does not diminish the importance of the invention and Otto’s deserve.

In 1864 August Otto took out the patent for his first coal gas engine and together with Langen created a company - “Otto and Company”. It took them 15 years to construct his main invention – 4-cycle engine. In 1877 Otto got the patent for this invention. The engine was named “4-stroke engine” as the working process in it included 4 piston strokes and 2 crankshaft rotations accordingly. Otto and Langen were not well adept at electrical engineering so their 4-cycle engine’s ignition was carried out by constantly burning gas jet. At the proper moment a slide enabled the access between sparking chamber and the cylinder and the gas jet sparked the gas mixture in a cylinder chamber. Currently slide distribution and burner ignition are out of use though the 4-cycle engine working process preserved all its features. Almost every modern combustion engine uses this working principle.

The main achievement of Otto’s engine is its increased coefficient of efficiency that came up to 15% while Lenouar’s engine has just 4% ratio. Otto’s 4-cycle engine was superb in this relation to steam engines as well. The only disadvantages of Otto’s engine were its big mass and small speed. With crankshaft 180 revo the engine often stuck in stoppages and quick deterioration. More over coal gas reserve demanded spacious tankage given coal gas factories were rather few. Considering this the application range of the invention was limited therefore Otto’s engine succeeded mainly for stationary industrial purposes not in automobile field.

Though the public demand for Otto engine was ...