Otto Engine

One thing that the development of this approx. 1,5 ton engine, producing 4 PS (3 PS*), makes quite clear, is that it is not yet intended for the installation in a vehicle. Rather, it was used in factories to drive the machines through sometimes long belts and shafts (transmissions). At the time of it's production start in 1864, the Gas Engine Factory Deutz AG, (later simply Deutz AG) was the oldest production plant producing combustion engines in the world.

In 1860, Nikolaus August Otto was a travelling salesman for a Cologne company selling groceries and colonial wares. Although not an engineer, he was very much interested in the developement work of Jean Joseph Étienne Lenoir. Using a copy of the Lenoir atmospheric engine, together with a mechanic, he developed a four-cylinder with a compression stroke, which, in the course of events, was known as the four-stroke, or Otto engine. He was granted patents by various German states, not however, by the state of Prussia. After the engine already functioned in it's first tests, he gave up his job so that he could tinker with his engine all the time.

What's important about this new invention, is the crank drive, and with it the newly introduced compression stroke. This however, made the combustion so strong that an even delivery of the torque and a regulated engine running was unthinkable. It also endangered the mechanics of the engine itself. By using a leaner mixture this became better, however, unacceptable misfiring was the result. When almost all of his financial means were used up, he got to know the energetic, successful and wealthy engineer, Eugen Langen, with whom in 1864 he founded the 'N. A. Otto & Cie' in the Servasgasse on the left bank of the Rhine in Cologne.

Instead of the four-stroke-, an improved version of the atmospheric gas engine was developed. The world exhibition in Paris turned out to be the crucial experience as far as the development of the company was concerned. The new “old” engine was not only rewarded with a gold medal (Napoleon III.), it proved itself in tests, to also be far superior to the Lenoir engine.Production und sales of this engine ensured the company, which as of 1872, was called the 'Gas Engine Factory Deutz Corporation' success and income for at least 10 years. In the course of the expansion, further qualified people, who were rare in this specialised area, came into the company.

With the war against France in 1871 over, and the increasing demand, the relocation to the other side of the Rhine, which was linked with the expansion of the company, new production methods were to be introduced. Thus, in 1872 Gottlieb Daimler joined the company as the technical director and was followed by Wilhelm Maybach as the production director. Daimler was already involved at the time of the planning of the new factory. He would be play an important part in the successful and effective manufacturing of the engines.

For many years the two families, Otto and Daimler, lived in the same house. Both principle characters have had very different concepts of life behind them. On the one hand, the worldly and eloquent engineer Daimler, who relied determinedly on his enormous experience, on the other hand, the rather reserved and pensive self taught tinkerer, Otto, who followed an idea unyieldingly and tenaciously, but seldom went beyond the borders of Cologne.Ultimately, this could not go off well, however, more about this later. The fact is, that Daimler and Maybach played a decisive role in the extending of the patents and the sales success of the atmospheric gas engine.

The question of who was responsible for which part of the development of the four-stroke engine, will probably never really be cleared up. The most important sources consider it unlikely that the ideas of Nikolaus Otto were originally responsible for the new engine. Actually, it was not all about the compression stroke, but it's teamwork with the charging and fuel-air ratio. It is extensively described how Otto came upon the deciding idea. Apparently the idea came from simple observations, and not from any existing documentation. In any event, the solution was, a sort of layer charging, a lean mixture beforehand and a rich mixture afterwards, that finally, after 14 years, brought the engine to the desired saleability.

It was high time for the new engine, because the development possibilities of the atmospheric gas engine with its 1,5 kW (2 HP) and a construction height of 3 meters, and 2,2 kW (3 HP) with a ceiling of 4 meters because of the extending gear-rod, were exhausted. It no longer came to a possible multi-cylinder engine. The new engine developed performance-wise away from the old one and was the star of the world exhibition in 1878, again in Paris. Daimler also took part in the development of a lighter variation. In Cologne-Deutz, engines for boats, on the basis of petroleum, were also being considered. There were tests to substutute the glow- with electric ignition.

Also and particularly through Gottlieb Daimler's work, the company showed a furious development. Nevertheless, it repeatedly came to differences of opinion with Otto and also Langen. After Daimler's vain trip to achieve a possible entry into Russia, he is given a stately compensation, although, actually, he would not be allowed to work on the four-stroke for five years. Wilhelm Maybach apparently, was not even asked whether he would like to remain. Thus, he went into service with Daimler and proved furthermore, his talent as a designer.

Otto considered his lifes work to be secure, however, he had to fight for a long time for his patents. After a short while, when he wanted to enforce the patents against so-called replicas, these were partly confirmed as being older than his own engine, although the introduced products were, by no means, realised and successful in their manufacture. His patent was lifted in 1886. Perhaps the development step was just too big, for one company to profit alone. In 1936 a great honour was conferred on him posthumously when the Association of German Engineers declared all engines working on the four-stroke principle (except Diesel!) to be Otto engines.

The stroke of 240 mm (300*) together with a bore of 155 mm (161*) resulted in a single/total displacement of 4,5 liters (6 liters*). The varying figures come about by the fact that the original test engine was again modified before the, much later, serial production by Wilhelm Maybach. Despite the lower cubic capacity, due to the higher revving level of 240 RPMs, the performance was increased. In the course of their development, the Deutz multi-cylinder engines would also achieve 74 kW (100 HP) and more.

The above shown engine from 1895, which was still in operation till 1953, is of course, no longer quite original. Originally, he ignition was controlled by a sliding valve which opened the space for a gas flame at the deciding moment.Later, this method of ignition was replaced by a low-voltage magneto ignition developed by Bosch. The engine was also no longer operated with illuminating gas but with petrol. A clear sign of this, is the enormous, pot-like carburettor on the left below the engine. In this case the fuel isreally gasified, in contrast to the later, also called simple carburetors. * marks the data of the first test-engine
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