Nickolaus August Otto had been searching for a reliable engine to power transportation and industry for several years. In 1876, he discovered how to control the rate of burn in an engine cylinder, and apply the resulting force safely and effectively. Otto built the first four-stroke engine in 1876. After this discovery, the necessary improvements to the engine's efficiency and reliability came rapidly. The first Otto engine produced approximately 3 horsepower.
Another engineer, Wilhelm Maybach, developed the construction and manufacturing techniques that enabled the engine to be built in sufficient quantities for profitability. By the end of 1876, the engine was readily available to customers. Because the design was so simple, competitors quickly began to copy the engine. These complications caused many delays in obtaining patents to protect the work of Otto and Maybach. Before Otto died in 1891, the Otto engine reached an output of 100 horsepower.
During the intake stroke, the piston moves down, sucking the air and fuel into the combustion chamber through the intake valve. Next, the crankshaft forces the piston back up during the combustion stroke, compressing the air-fuel mixture. At this point, the spark plug ignites the mixture. The exploding mixture forces the piston back down on the power stroke, causing the crankshaft to rotate and turn the flywheel. The rotating crankshaft forces the piston back up on the exhaust stroke, forcing exhaust gases out the exhaust valve.
History is unclear about who discovered gasoline. In its early days, gasoline or petrol was used to treat lice and as a cleaning fluid. When inventors began looking for a fuel for internal combustion engines, they found that petrol could be mixed with air inside the combustion chamber and burned to run early engines. As internal combustion engine technology advanced, refining processes for gasoline improved. Eventually, lead and other chemicals were added to improve the octane rating of gasoline.
The development of the internal combustion engine dramatically changed the way people moved from one place to another. Within 20 years of Otto's discovery, several companies in Europe and the United States developed vehicles that were the predecessors of the modern automobile. Many other forms of transportation became possible because of this discovery, including motorcycles, diesel locomotives, aircraft engines and even today's buses. The internal combustion of petroleum-based fuels is also a major factor in the discussion of global warming issues.