Creating the Twentieth Century

by Vaclav Smil

  Remarkably, nearly all of the basic challenges of durable design and affordable car manufacturing were resolved in a highly effective fashion before WWI. Today’s cars do not obviously share outward features with their early 20th-century predecessors: low profile versus a tall, boxy appearance; enclosed versus open or semi-open bodies; curved versus angular body shapes; sunken versus free-standing headlights; and thick versus thin tires are just the most obvious differences. But as I show in this chapter, the evolution has been much more conservative under the hood. And while commercial long-distance flying ceased to rely on reciprocating engines during the 1960s, these efficient and highly reliable machines keep powering large numbers of smaller planes used for short-haul passenger transport, pastime flying, and tasks ranging from spraying crops to water-bombing of burning forests.

  For decades we have taken internal combustion engines for granted, but they should still be a source of admiration if only because these affordable machines, now made up of many thousands of mostly precision-machined (or cast or extruded) parts, work so reliably for such long periods of time (Taylor 1984; Heywood 1988; Stone 1993). What is even more remarkable is that they do so requiring relatively little servicing while subject not only to various environmental extremes but also to abusive handling by users most of whom know nothing about their design or operating requirements. This combination of high performance and high reliability manifests even more admirably in aircraft engines, and the very reliability, durability, and affordability of internal combustion engines are major factors that work against their rapid replacement with alternatives that may be much less noisy and much less polluting but that do not have such a remarkable record of reliable service that is provided at such an acceptable cost.

  Importance of internal combustion engines for smooth functioning of modern societies is taken entirely for granted in countries where their numbers match, and even surpass, the total numbers of population. There were about 275 million people in the United States in the late 1990s, but more than 210 million automotive and more than 100 million other internal combustion engines. The latter category includes more than 50 million engines in lawnmowers and other garden machines, about 17 million outboard and inboard engines in recreational boats, 4 million motorcycles, and nearly 2 million snowmobiles (NMMA1999). About 20 million small internal combustion engines, ranging from units for ultralight planes to emergency electricity generators, are now sold in the country every year. While the ubiquity of internal combustion engines is obvious, not too many people realize that in affluent countries their aggregate installed power is now considerably greater than that of any other prime mover.

  FIGURE 3.2. Long-term trends of the total power of main categories of the U.S. prime movers show that automotive internal combustion engines surpassed the aggregate power of both draft animals and electricity-generating equipment before 1910. Plotted from data in USBC (1975).

  Reliable U.S. data show that the total power of automotive engines had surpassed that of all prime movers used in electricity generation (steam engines, steam and water turbines) already before 1910 (USBC 1975). During the last decade of the 20th century, the total capacity of the U.S. vehicular internal combustion engines was more than 20 TW compared to less than 900 GW installed in steam and water turbines, or more than a 20-fold difference (figure 3.2). And a worldwide comparison shows that while in the year 2000 the total installed power of electricity-generating turbines was about 3.2 TW, the global fleet of road vehicles alone had installed power of at least 60 TW.

  Multiple Beginnings

  Cummins (1989:1) opens his meticulous history of internal combustion engines by noting, half seriously, that their development began with the invention of the cannon, a device whose key drawback was “that it threw away the piston on each power stroke.” But this very action clearly demonstrated the potential utility of tamed explosion, and the first sketchy suggestions of engines exploiting that principle had appeared already in the late 17th century. But the first serious attempts to abandon steam as a working medium and to use hot gas instead date to the very end of the 18th century, and many noncompression (and hence inefficient) engines that used mixture of coal-gas and air were actually built before 1860. In this respect, the development of internal combustion engine resembles the early history of incandescent light, with more than a dozen inventors—from Philippe Lebon in 1801 to Eugenio Barsanti and Felice Mateucci in 1854—patenting and demonstrating their designs.

  Two inventors should be singled out: William Barnett for proposing, in 1838, that the charged fuel should be compressed before ignition, and Isaac de Rivaz for actually installing his engine on a small wagon in 1807 and propelling it over a short distance at a speed of less than 5 km/h (Cummins 1989). But the first engine that caused a great deal of public interest and that was actually manufactured for sale was conceived only in 1858 and patented in 1860 by Jean Joseph Etienne Lenoir (1822–1900). Like a steam engine after which it was patterned and which it outwardly resembled, it was a horizontal, double-acting machine with slide valves to admit the mixture of illuminating gas and air and to release the burnt and expanded gas. Ignition was with an electric spark without any fuel compression.

  A connecting rod joined the piston with a large flywheel to transmit the motion to its final use. This slow (about 200 rpm) engine had thermal efficiency of less than 4%, and fewer than 500 units, with typical rating of about 2 kW, were manufactured during the 1860s. They powered water pumps, printing presses, and other tasks requiring only limited amount of interruptible power. In 1862 a liquid-fuel version of the engine, mounted on a three-wheel cart and using a primitive carburetor, propelled the vehicle from Paris to Joinville-le-Point for a total distance of 18 km. This isolated trial had no follow-up, and it is not considered the real beginning of the automotive era. In fact, Lenoir did not pursue any further development of his engine after the 1860s.

  Otto and Langen

  Nicolaus August Otto (1832–1891; figure 3.3) was an unlikely candidate for revolutionizing the design of internal combustion engines (Langen 1919; Sittauer 1972). He was a traveling salesman for a wholesale food company (what Germans call Kolonialwarengrosshandlung)—but what he really wanted to do was to design a better engine. He became impressed by Lenoir’s engine during its short spell of fame, and his experiments with its copy that a skilled mechanic built for him in 1861 led to the first Otto engine fueled with alcohol-air mixture. A better machine emerged only after Otto approached Eugen Langen (1833–1895), a well-off owner of a sugar-refining business, to invest in a newly established company (N. A. Otto & Cie.) that was formed in 1864.

  FIGURE 3.3. Nicolaus Otto, the inventor of eponymous two- and four-stroke gas-fueled internal combustion engines. Reproduced from Abbott (1934).

  The new company soon produced a two-stroke engine that resembled the Barsanti-Mateucci machine, but some of whose features were sufficiently different to be patented in 1866 in Germany and a year later in the United States. Its tall cylinder surmounted by a large five-spoked flywheel was heavy and noisy, but when it was displayed in 1867 at Paris Exhibition it was found to be more than twice as efficient as other featured gas engines. This earned it a Grand Prize, and the small company, suddenly beset with orders, began serial production in 1868. Once a new substantial investor was found, the whole enterprise was expanded and then in 1872 reorganized as Gasmotorenfabrik Deutz AG, named after a Cologne suburb where it was relocated. Today’s Deutz AG remains one of the world’s leading engine makers (Deutz 2003).

  Gottlieb Daimler (1834–1900), an experienced engineer who worked previously also in France and England, was appointed as the production manager of N. A. Otto & Cie. Daimler brought along Wilhelm Maybach (1846–1929)—a draftsman whom he met for the first time in the machine workshop of Bruderhaus orphanage in Reutlingen where Maybach lived since the age of 10—as a new head of design department (LeMo 2003). The company’s improved noncompression engine launched in 1874 had efficiency of about 10%, or as much
as 75% higher than that of a comparably powerful Lenoir machine. But this performance was achieved by installing a nearly 4 m tall cylinder and letting the gas expand to 10 times its charged volume (compared to just 2.5 times in Lenoir’s engine). Moreover, at about 900 g/W, the engine was much heavier than the best steam engines of the day.

  Nevertheless, it was a commercial success, and hundreds of units were built every year during the latter half of the 1870s in Germany and under a license in France, the United Kingdom, and the United States. But as the company was engaged in numerous patent litigation trials and as many engineers, in Germany and abroad, were trying to come up with a design sufficiently different to warrant patenting, Otto felt that a much better machine was needed to preempt the competition. By the spring of 1876 he had such a design: a horizontal four-stroke compression engine that he conceived and had built not only against the prevailing wisdom of the time, but also without Daimler’s help. The main objection appeared logical enough: why have just a single power stroke for four piston strokes and two full crankshaft revolutions when every stroke was a power stroke in double-acting engines?

  Four-stroke operation was not the only innovation: Otto’s first patents for the engine actually stressed more the novelty of stratified combustion, whereby gas and air mixture is preceded by air alone to create a lean charge near the piston and to produce a smoother, gradual burning of the fuel. Nothing came out of this proposition during Otto’s time and for decades afterward, but the concept was revived during the 1970s as one of the means to lower emissions of combustion gases that act as precursors of photochemical smog. Otto’s distrust of electric ignition led him to retain a small continuous ignition flame that was controlled by a sliding valve (figure 3.4).

  This is how Otto’s U.S. patent summarized the engine’s key feature (Otto 1877:1):

  According to my present invention an intimate mixture of combustible gas or vapor and air is introduced into the cylinder, together with a separate charge of air or other gas, that may or may not support combustion, in such a manner and in such proportions that the particles of the combustible gaseous mixture are more or less dispersed in an isolated condition in the air or other gas, so that on ignition, instead of an explosion ensuing, the flame will be communicated gradually from one combustible particle to another, thereby effecting a gradual development of heat and a corresponding gradual expansion of the gases, which will enable the motive power so produced to be utilized in the most effective manner.

  FIGURE 3.4. Cross section of a cylinder (with continuous ignition flame on the lower right) and overall arrangement of Otto’s gas-fueled four-stroke engine patented in the United States in 1877. This illustration accompanies U.S. Patent 194,047.

  Under Maybach’s direction the new design was improved and turned rapidly into a series of production models as both the company’s tests and independent appraisals confirmed the engine’s superior performance. Although its overall thermal efficiency was basically the same as for the noncompressing engine (about 17%), the new design reduced the piston displacement by 94% and mass/power ratio by nearly 70%. And although the engines were still quite heavy (at best, 200 g/W), they were now lighter than comparably sized small steam engines. Moreover, they could be built with much higher maximum capacities than the original Otto & Langen machines, and they were also much quieter and vibrated much less. Otto’s horizontal four-stroke engines were targeted for workshops too small for installing their own steam engine, and about 8,000 of these machines, with ratings ranging from 375 W to 12 kW, were sold by the end of the 1880s. Eventually, nearly 50,000 units with a combined capacity of about 150 MW (i.e., about 3 kW per engine) were made over the period of 17 years.

  Specifications for Otto’s typical early four-stroke machine were compression ratio about 2.6, air-to-fuel ratio 9:i, bore 210 mm, and stroke length 350 mm for a 6-kW engine running at 160 rpm, and they were still quite heavy at more than 250 g/W (Clerk 1909). The fundamental operating principle of Otto’s invention has not changed, but the inventor would be impressed by much improved performance of today’s identically powerful engines. A horizontal Honda, model GX240K1, commonly used as portable generator of electricity, provides an excellent example (Honda Engines 2003). This engine runs much faster (3,900 rpm), has a much higher compression ratio of 8.2:i (hence a much smaller bore and stroke, 73 mm and 58 mm), and is much lighter (slightly more than 4 g/W). And, of course, it is fueled by gasoline and not by illuminating gas made from coal. But before I describe the rapid improvements of gasoline engines after their public demonstration on first clumsy carriages in 1886, I must take a short detour and clarify the origins of the four-stroke engine by looking at the role of Beau de Rochas.

  Beau de Rochas and Otto: Ideas and Machines

  Success of Otto’s four-stroke engine led to many attempts to challenge its patent rights, but all of them were unsuccessful until a chance discovery of a forgotten patent. This claim was filed by a French engineer Alphonse Eugène Beau (1815–1893, who later in life styled himself Beau de Rochas) with the Société de Protection Industrielle on January 16, 1862 (No. 52,593) under an expansive title Nouvelles recherches et perfectionnements sur les conditions pratiques de la plus grande utilisation de la chaleur et en général de la force motrice, avec application aux chemins de fer et à la navigation (Payen 1993). The patent contained no drawings, and it was not based on any experimental model— but, undeniably, it detailed the principle of a four-stroke engine powered by a gas-air mixture that is compressed before its combustion.

  Beau de Rochas did so by prescribing first the four parameters “for perfectly utilising the elastic gas in an engine” (citing from Donkin’s [1896:432–433] translation):

  1. The largest possible cylinder volume with the minimum boundary surface.

  2. The greatest possible working speed.

  3. Greatest possible number of expansions.

  4. Greatest possible pressure at the beginning of expansion.

  As for the sequence (shown in figure 3.5 by both piston movement and pressure-volume diagram), “the following operations must then take place on one side of the cylinder, during one period of four consecutive strokes:

  1. Drawing in the charge during one whole piston stroke

  2. Compression during the following stroke.

  3. Inflammation at the dead point, and expansion during the third stroke.

  4. Discharge of the burnt gases from the cylinder during the fourth and last stroke.”

  FIGURE 3.5. Idealized Otto cycle (with heat supplied and exhausted at constant volume) and piston movements corresponding to the four phases of the pressure-volume diagram.

  Because Beau de Rochas failed to pay the requisite fee, the patent was never published, and it circulated in just a few hundred copies distributed by the inventor. He also did not try to assert his rights when Otto’s engine first appeared on the market, or for many years afterward. Only in 1884, after a patent attorney called attention to Beau’s old private pamphlet did the Körting brothers, builders of large gas engines in Hannover, contest the originality of Otto’s idea. Although it was obvious that Otto’s engine was designed without any reference to Beau’s obscure description, he eventually lost the legal fight in Germany in 1886, but his rights were upheld in the United Kingdom. More than a century later, the split persists: Deutz AG and German engineers, as well as most British and American automakers, talk about the Otto cycle, but in France it is cycle de Beau de Rochas. Whatever the name, the four strokes—aspiration, compression, inflammation, refoulement in Beau’s language, Ansaugen, Verdichten, Arbeiten, Ausschieben in Otto’s tongue—have become one of the ruling rhythms of modern civilization.

  But the Beau-Otto affair goes far beyond the common patent interferences and usual complications and revisions in dating inventions, in this case pushing back the beginnings of four-stroke internal combustion engine to 1862 from 1876. Indeed, it goes to the very core of the concept of the Age of Synergy I advocate in this book. Beau de R
ochas was content to set down his ideas on paper and then walk away from them, although he had opportunities to do otherwise: he was Lenoir’s friend, since 1852 he lived and worked in Paris in the government’s transportation department, and he was engaged in many projects that involved propulsion machinery.

  I would argue that if Beau de Rochas were to get this priority, then Leonardo da Vinci might as well be regarded as the creator of helicopter on the basis of his famous sketch in Manuscript B. That brilliant Florentine did not have technical means (materials, prime mover) to convert this, and many other of his bold ideas, even into simple models, much less into real and practical machines. In contrast, Beau could have called on many technical advances available by the 1860s in order to construct at least a working prototype—but he simply chose not to do so. He made designs for railways and ship docks and planned the use of Lake Geneva for hydroelectric generation, but he did not try to convert his 1862 idea of a four-stroke engine even into a toylike model.

  In contrast, Otto’s approach was the very quintessence of the Age of Synergy. First, he developed a noncompression engine better than Lenoir’s inefficient machine; then, working against the dominant consensus, and even against the judgment of his experienced production manager, he went on, entirely independently, to develop a much better four-stroke compression engine, patented it properly and promptly, and then committed resources to its further improvement, started its manufacturing in large series, and licensed it widely in his country and abroad. This is the very procedure whose numerous repetitions eventually created the civilization of the 20th century. Not surprisingly, Otto’s inventive élan was sapped by the German denial of his four-stroke patent. His last innovation was the first low-voltage magneto ignition he designed in 1884, two years after the University of Wurzburg awarded him, together with Alexander Graham Bell, an honorary doctorate. He died before his 59th birthday in Cologne, the town where he spent nearly all his adult life.