Internal Combustion Engine

 

By Rochelle Forrester

 

All Rights Reserved

 

Publication Date 2006

 

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The steam engine was an external combustion engine as the fuel was burnt outside the engine. The first internal combustion engine where fuel is burnt inside the cylinder to force a piston to move was invented in 1856 by the Italians Barsanti and Matteucci. The principle behind the internal combustion engine was the same as that behind the steam engine, namely a piston being driven by alternative phases of expanding gas and vacuums. The first internal combustion engine to be produced in substantial numbers was a gas engine built by the Belgian Lenoir in 1860. The engine lacked power and consumed a considerable amount of fuel because the fuel and air mixture was not compressed before it was ignited. In 1862 Rocas a French engineer patented a four stroke internal combustion engine which involved compression of the fuel and air mixture. The engine however was never built and in 1876 the four stroke engine was independently invented by Otto. The Otto engine produced more power and consumed considerably less fuel than the Lenoir engine.

The four stroke engine worked by the first downward stroke of the piston drawing the fuel and air mixture into the cylinder through an open inlet valve. The descending piston creates a partial vacuum in the cylinder and the valve in the cylinder closes and the piston rises compressing the fuel and air mixture. The mixture is then ignited causing the third stroke as the piston is forced downward. It is the third stroke that gives the engine its power. The fourth stroke occurs when an exhaust valve is opened and the rising piston forces the exhaust gases from the cylinder.

In 1883 Gottlieb Daimler, who had previously worked with Otto, designed a four stroke internal combustion engine that ran on petrol or gasoline. The engine ran faster than Ottos so that it produced more power for the weight of the engine. A carburetor was used to pass air over the top of petrol to mix the petrol vapor and air which was ignited to force the piston down in the third stroke. Further improvements by Karl Benz involved an electrical induction coil for ignition of the fuel mixture.

The effect of the internal combustion engine on society was immense. Its main advantage over the steam engine was its weight to power ratio. In 1880, the Otto gas internal combustion engine weighed 440 lbs per unit of horsepower produced; by 1900 a petrol driven internal combustion engine weighed only 9 lbs per unit of horsepower. The weight to power ratio allowed the engine to be used to drive motor vehicles, aircraft, tractors, submarines and tanks. During the 20th century motor vehicles were to replace railways as the principal means of land transport. The urban and rural environments of first world countries were to be criss-crossed by roads, highways and motorways built specifically for motor vehicles powered by the internal combustion engine. The ordinary citizens of first world countries enjoyed a new freedom of travel they had not previously possessed. Aircraft made considerable improvements in performance and safety during the 20th century. They became a new weapon of war but they also helped precipitate the enormous growth in international tourism that was to occur in the second half of the 20th century. Agricultural productivity improved greatly with the development of a tractor and other farm machinery powered by the internal combustion engine. The development of the engine also gave oil producing countries a wealth and an influence in world affairs that they had not previously possessed. These social and cultural consequences of the internal combustion engine were an inevitable result of the invention of the engine and the engine was only invented after certain earlier discoveries had been made.

The steps involved in the invention of the internal combustion engine followed in a logical and necessary order. The first step was the initial invention of the engine by Barsanti and Mattucci and its development by Lenoir. Only after the engine was invented was it possible to work out the best way to operate the engine which is by the four stroke cycle system that was invented by Rochas and Otto. The use of petrol in the engine was dependent upon the earlier developments of drilling for oil which began in the United States in the 1850s and by methods of refining crude oil by distilling or thermal cracking which was developed in the 1860s.

The internal combustion engine could only be invented because of certain properties of gases and vacuums. Gases expand when heated and that a piston will move to reduce a vacuum are properties of gases and vacuums which allowed the invention of the internal combustion engine. If gases and vacuums did not have these properties the internal combustion engine could not have been invented. A further requirement for an internal combustion engine is a suitable fuel which exists in nature in the form of oil deposits. This shows how the properties of the materials in nature have had a major influence on human social and cultural history.

 

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