Monday, December 7, 2009

Gas Engines

The engineers quickly realized that a more suitable fuel than gun powder must be found. About one hundred years after Huygen's experiments, people believed to have found it in illuminating gas. The young Frenchman Philippe Lebon d'Humbersin (1767 - 1804) was celebrated as its discoverer. In 1801, He announced a patent on a gas engine. Due to his early death, he could not, unfortunately, realize his project.

During the next half century, many setbacks hindered a fast development of the engines. The engineers did not succeed in building a stable running piston engine with internal combustion. Partially interesting patents were announced by different engineers, but their execution failed too often. Samuel Brown, who built the first motor vehicle which was documented (1823), was an exception. He used a gas engine developed by himself.

Eugenio Barsanti (1821-1864), an Italian scientist, developed in the early 50s of the 19th century his atmospheric engine. It used a "Voltaic (from Volta) pistol" as ignition mechanism. A spark skipping between two electrodes ignited the gas mixture.
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Only in 1860, the Belgian Jean Joseph Etienne Lenoir (1822-1900) had success with his engines, which operated with illuminating gas. He did not invent any new machine, but assembled many well-known sections and built in such a way a double working engine, which was sold very well in the small trade. The engine reached just the poor efficiency of 3%.

Definitions of some words

Illuminating gas : is also known as "town gas". It was used for lighting and heating purposes. As inflammable constituents, illuminating gas contains hydrogen, methane, but also carbon monoxide, which is poisonous.


Explosion engine : In gas engines, fuel burns in a big explosion. In today's combustion engines, explosions do not occur by no means. Although the term "explosion engine" held itself still in the vernacular. An explosion of fuel in the cylinder leads to the notorious "knocking" or "pinking" of an engine.


Atmospheric engine vs. Double working engine

Atmospheric engine
In an atmospheric engine, the actual work is not carried out by the explosion of gas and the following acceleration of the piston. When the piston arrives at its highest point, the air pressure (therefore "atmospheric") and the piston's dead weight drive it into the cylinder below, which contains after the cooling of the gas an almost complete vacuum. The work is transferred to a flywheel. See sketch Otto's atmospheric engine.

Double working engine
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The double working engine has a cylinder. On the way from one extreme to the middle of the cylinder, a fuel mixture gets sucked performing work on the piston after the ignition during the other half of the way. On the other side, the discharge of the burned gas takes place at the same time. Now the engine works in the opposite direction, using the same principle. Now, fresh gas flows in from the other side. Picture shown is the lenoir engine.


At Lenoirs time, Alphonse Beau de Rochas (1815-1893) discovered the favourable effect of a compression of the gas mixture. But he could not use this important discovery in the industry. The compression stroke led later to the development of the four-stroke engine by Nikolaus Otto.

At the world exhibition of 1867 in Paris, Nikolaus August Otto's (1832-1891) and Eugen Langen's (1833-1895) success with the atmospheric engine began. The engine was working with illuminating gas, too, and achieved a better efficiency of about 30 percent than the Lenoir engines because of a better technology. During the following 10 years, Otto's atmospheric engine was sold about 5000 times and so it was the first combustion engine that was produced in big quantities. 1869, Otto and Langen founded the gas engine factory "Deutz". Many other engineers also became well-known there, e.g. Wilhelm Maybach or Gottlieb Daimler.

In the animation shown, the mode of operation of an atmospheric engine can be observed. The explosion of illuminating gas, the following acceleration of the piston, the ejection of the cooled gases and then the working stroke. Work is only performed at the flywheel when the piston goes downward, moved by its own weight and the atmospheric pressure. Down in the combustion chamber the fresh gas is ignited by a small flame.

After few years of production, the demand was already satisfied in the small trade. Attempts to replace illuminating gas for petroleum failed too. The burn was too dangerous; the enormous carburetor uneconomical. People already did not believe in a progress with that kind of engines any more, when Otto revolutionized the engine industry with his ingenious inventions.
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