What the gasoline engine is
A gasoline engine is a type of internal combustion engine: it burns a fuel and air mixture inside a cylinder, and the expanding gas pushes a piston. A spark ignites the mixture, which separates it from the diesel engine that relies on compression to ignite fuel. The history of this engine involves many people over about two centuries. Because inventors often worked in parallel, and because patents sometimes overlapped, assigning credit to a single person is difficult.
Early experiments
The idea of burning something inside a cylinder is old. In the 1670s and 1680s, Christiaan Huygens proposed a design using black powder to push a piston, and Denis Papin took the concept further. These designs were not practical, but they posed the key question of how to turn a quick burst of burning into useful work.
Steam engines, such as the atmospheric engine of Newcomen and later machines by Watt, dominated the eighteenth century. In the early nineteenth century, inventors tried engines that burned gas, hydrogen or turpentine vapor. Samuel Brown in England built a gas-vacuum engine in the 1820s, and in 1860 the Belgian engineer Étienne Lenoir produced a double-acting gas engine that ran on lighting gas with an electric spark. Several hundred were sold, mainly for small workshops, although they were noisy, inefficient and consumed a lot of gas.
The four-stroke cycle
In 1862, a French engineer, Alphonse Beau de Rochas, described a four-stage cycle of intake, compression, power and exhaust in a patent, but he did not build a working engine. In Germany, Nikolaus Otto and Eugen Langen developed an atmospheric gas engine that was exhibited in 1867 and was more efficient than Lenoir’s. In 1876, Otto built an engine that used the four-stroke cycle, compressing the mixture before ignition, which improved efficiency considerably. The “Otto cycle” is still the name for how a gasoline engine works. Otto’s patent was later challenged in Germany on the grounds that Beau de Rochas had described the cycle earlier, and the patent was ruled invalid in the 1880s, opening the way for others to use the design.
These engines ran on gas supplied through pipes, so they were stationary machines. They powered workshops and small factories, competing with steam and later with electric motors.
Liquid fuel and the road engine
To power a vehicle, an engine needed to be lighter and run on a portable liquid fuel. Gasoline, a light fraction of crude oil, had been a by-product of making kerosene, and as petroleum refining grew it became easier to obtain. Gottlieb Daimler and Wilhelm Maybach, who had both worked with Otto’s company in Deutz, left to build a small, fast engine in Stuttgart. Their 1885 engine ran at much higher speeds than Otto’s, and a form of hot-tube ignition kept it simple. Maybach’s carburetor in the 1890s improved fuel mixing by spraying gasoline into the airstream. Karl Benz, working separately, built a lightweight four-stroke engine with electric ignition for his Motorwagen in 1885 and 1886.
Because both groups made decisive contributions, many historians credit Benz, Daimler and Maybach jointly with creating the gasoline engine as a vehicle power source, while Otto is credited with the practical four-stroke cycle. Others, including Siegfried Marcus, are cited in some sources, though evidence for their claims is weaker.
Making the engine reliable
The first vehicle engines were fragile. Ignition was a major trouble spot, and the high-voltage magneto by Bosch in the early 1900s helped make firing more dependable, while the electric starter of 1912 on Cadillac cars replaced the hand crank. Engines were also improved by water cooling, better lubrication and stronger materials. A lead-acid battery supplied power to the starter and lights.
In the 1920s, designers faced the problem of knocking, an uncontrolled burning of the fuel that limited how much the mixture could be compressed. Adding tetraethyl lead to gasoline raised the octane rating and let engines run at higher compression. The additive was later phased out in most countries because of lead pollution and health concerns. Octane ratings, catalytic converters and unleaded fuel became part of the story from the 1970s on.
Aircraft and other uses
Gasoline engines were adopted widely outside cars. The Wright brothers’ engine was a gasoline design, and the demands of flight pushed engineers to produce lighter, more powerful aircraft engines through the 1910s and 1930s. Small gasoline engines powered motorboats, motorcycles, lawn equipment and, in time, farm tractors that replaced draft animals.
From workshop to mass production
Early gasoline engines were hand-built. Ford’s Model T engine of 1908 was designed for easy manufacture, with cylinders cast in a single block, and the moving assembly line helped produce engines in large numbers. In 1932, Ford introduced a V8 engine cast as a single block, bringing eight cylinders to a low-priced car. The scale of manufacturing in the 1920s and 1930s cut costs and made reliable engines available to millions of drivers.
The gasoline engine is still found in most cars, though it faces competition from hybrids and electric motors. Its history shows how a technology depends on many pieces: fuel supply, ignition, materials, manufacturing methods and the skill of many engineers, not on any single flash of invention.