Antonio Silva
Do not believe that the concept of 2-stroke engines is an invention of the last century, because it is not. It was neither more nor less in the year 1879 when Karl Benz himself, on the German side, and Dugald Clerk, on the British side, carried out the theoretical conception of these propellants. Today it is known that in those years there were two branches of research, and depending on the source consulted, the final theoretical conception is attributed to one or the other.
What is clear is that Benz built an unstable engine, which never fully worked, and abandoned this concept in 1880. The cause of the malfunction is known today: It was caused by the very low speed of engines manufactured before 1900. For its part, Dugald Clerk manufactured the first functional two-stroke engine in 1881.
Since the year 1880, numerous engineers and inventors have managed with more or less success to run artisanal or small-run engines with this cycle, initially using the engine of small motorcycles as the power plant. But it was not until 1902 that the first documented 2-stroke car appeared on the scene, a fact that we owe to Cozette.
Since then, many brands saw in this cycle an exceptional opportunity to motorize their vehicles, even for competition, being more than remarkable in this first stage the engine created by Fiat in 1926 to run. It was the Type 451, a 6-cylinder, 12-piston opposed engine, which proved to be tremendously powerful. However, Fiat's financial problems during those years made him abandon the project.
DKW, synonymous with 2 times
But if there is a brand that puts 2-stroke mechanics in the spotlight, this is undoubtedly DKW. Founded in 1916 by the Danish engineer Jørgen Skafte Rasmussen, it began manufacturing toys for children and made its first small two-stroke engine for them in 1919. This engine, with minor modifications, was later incorporated into motorcycles, which would be the basic pillar of DKW's development and which would make it, in the 30s, the world's leading motorcycle manufacturer.
As I have just remarked, DKW has been the most representative brand, for the automobile, of this type of technology. Put yourself in the Germany of the late 20s: a depressed country, economically asphyxiated by old Europe, and with a significant loss of traditional values. It is in this context that the brand decides to transform its activity and go from being a company dedicated to the manufacture of toys and motorcycles to offering a capable and economical car for the German people.
At the beginning of the happy 20s, DKW were already experts in this drive concept. During that time, they created a stroller, the "SB Wagen", with two seats in a row, on a bare wooden frame. Initially powered by electrical mechanics (1919), in 1924 it had a 2 CC 122-stroke engine. It would be manufactured more as a toy for the elderly than as a real vehicle.
With this background, they “just” had to adapt these technological principles to a lightweight and inexpensive frame to manufacture. Thus, and under those conditions, the P-1928 and the PS-15 were born in 600, with a propellant 2 cylinders in line of 600cc and 15 HP, liquid cooling, rear-wheel drive, wooden bodywork and gutta-percha; sedan, cabrio and sport roadster type. A car capable of transporting 4 passengers through the Germany of those years, with minimal consumption, correct performance and easy and cheap maintenance. It was certainly the first mass-produced 2-stroke car.
From that simple vehicle to the present day, DKW manufactured an incredible number of models and versions; first, from the 1 F1930 - the first mass-produced front-wheel drive car in Europe - to the pre-WWII F8. Later, from 3 = 6, 1000-SP, Junior, etc ... to an all-wheel drive SUV, to which Audi owes a lot, the Munga. In total 267.672 units produced by the brand before the conflict, which give an idea of the success of this scheme.
Another of the great automotive geniuses, Porsche, was attracted to this solution, which was initially chosen to power the people's car that he was designing in 1936. Ferdinand went on to manufacture several engines to test his ideas, but the more he improved them The more expensive they were to produce… Until in the end, their 4-stroke cycle parallel cylinder V2 proved more expensive than an air-cooled 4-cylinder 4-stroke engine. At that point, Porsche would end its 2T adventure.
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What does the future hold for 2T engines?
I cannot write this article without talking about what this type of driving force meant for Spain. Without a doubt, the first firm in two periods of national relevance was the Barcelona-based EUCORT (1946-1953), founded by Eusebio Cortés. Of course, the technical part falls on German personnel from DKW, who practically replicate the two-cylinder engine of the F8. Starting in 1949, they designed and manufactured a 3-cylinder. All of these cars were pretty good and advanced on paper, but with a lot of fit and definition issues in reality. The EUCORT adventure ends in 1953, with just over 1600 units manufactured. Currently one of the very few survivors, a "Victoria" model, can be seen in the Claret de Sils museum in Gerona.
Under the auspices of this type of simple and cheap engine to manufacture, in the end, various companies producing micro-cars were born in our bull skin, thanks to which the people and the Spanish market were able to start moving in the mid-50s. I am referring to brands such as Gogomobil, PTV, Biscuter ... etc. In most cases they use air-cooled two-stroke mechanics, with very simple and light bodies.
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Other international brands have been great supporters of this technology. Saab with its first two and three cylinder models -92 and 93-, whose engines were also designed by DKW staff, with Hans Muller as Chief Engineer. The incombustible brands of the eastern countries, with IFA, Wartwurg and Trabant at the top, although they were nothing more than copies with greater or worse luck of the DKW engines.
Already focused on the post-1990 stage, one of the last and most relevant attempts to resuscitate this motor conception was carried out by Ford and Orbital, during 1991-92. They developed an engine of this specific type for their small party, in which, thanks to the use of direct injection and the most advanced technologies of the moment, they reduced oil consumption to really ridiculous values, 1L / 5000 Km. Finally, even with several units produced, they paralyzed the project. The real causes of this cancellation are unknown to me, and with the information I have I could only guess about it ...
Toyota and Subaru also joined the two-stroke car bandwagon, studying this solution over the decade and manufacturing small series of engines. In both cases, with lobular type preload compressor. Toyota's hyper-evolved powerplant featured intake and exhaust valves. Both engines shared a pressure pump lubrication system, significantly extending the life of crankshafts and connecting rods. The last to sign up was Bill Gates, that since 2008 has invested about 25 million dollars in the development of this technology.
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His true Achilles heel is, today, the same as 50 years ago - a classic we go: the pollution produced. The admission through the crankshaft, the transfers and the port system, make it necessary to a greater or lesser extent to use mixtures of oils with gasoline. At this point there is more pollution in the exhaust gases, as the usual gases from the gasoline explosion (CO, CO2, NOX ...) come out through the tube, plus those produced by the combustion of the oils, and by the expulsion of a small part of it without burning.
The truth is that, to this day, it is still a scheme that attracts the attention of a large number of engineers and mechanical lovers. The application of current advances could give rise to new generations of engines, with independent lubrication of the crankshaft and connecting rods, reed or overhead valve intakes, with pre-charge compressors and stratified direct injection, exhaust valves, ignition and fuel controls. intelligent electronic curves ... Anyway, for dreaming that it is not. What I can assure you today is that driving a two-stroke vehicle is always an amazing experience.
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