2.2. The principle of operation of the thermal engine.

The most widely used internal combustion engines. Internal combustion engine - a heat engine in which fuel is burned in the cylinder below the piston. The heat of combustion thus converted into work by the piston and crank mechanism. The cylinder has two openings with valves, through which there is one working fluid injection (air or mixture of air and gasoline vapor) and by the other output of the combustion products after completion of the cycle. A piston in the engine cylinder during one cycle four stroke Otto commits or stroke: suction, compression, expansion after combustion mixture. The efficiency of the engine is equal to:

Where - the degree of compression.

According to the formula, engine efficiency depends upon the degree of compression, which in turn depends on the fuel quality, the adiabatic index. Increasing the compression action is limited to self-ignition of the fuel, which dramatically reduces the efficiency of the engine. The degree of compression in conventional gasoline engines does not exceed 7 - 12.

The development of the automotive industry required new materials, fuels, alloys. All of these materials produces chemical industry.

2.3 The development of tires (tires).

For the operation of cars need a large number of rubber, a lot of it is used for making tires, but not least, it is important in the manufacture of various materials for the fuel system.

Nevertheless, the lion's share goes to the manufacture of rubber tires. For the manufacture of synthetic rubber tires are used, which improve its properties for carbon black was added, a metal wire, antioxidants, dyes.

At the beginning of the XX century for the manufacture of tires using natural rubber, but the amount was limited, so it is necessary to adjust the production of synthetic rubber. Its production in the Soviet Union established in 1932 under the guidance of Academician SV Lebedev of ethyl alcohol, which is chemically converted to the 1,3 butadiene and polymerized in the rubber:

   

Thus we obtained butadiene rubber. Now for tire production using better types of rubber: styrene-butadiene, which is prepared by co polymerization of styrene and butadiene, it differs from butadiene more resistant to abrasion, more frost.

2.4 Petrol (new fuels).

For car engines must be fuel. In the type of fuel used oil products, they are called gasoline. For refining is customary to use the distillation and cracking. Distillation separates only oil in several fractions with different boiling points, and provides a cracked gasoline by cleavage of complex oil substances.

The gasoline composition comprises hydrocarbons having a carbon number in a molecule from 4 to 7. The temperature of the boiling is in the range 30 - 200 ° C. In addition to hydrocarbons in the gasoline also includes various additives designed to improve its quality. Antioxidants used as additives which enhance the chemical stability of gasoline, antiknock that increase the octane number.

Now that the problem of air pollution has become very important, especially in large cities, cars began to translate the use of alternative fuels: gas, biofuel, such as E85 fuel (85% ethanol and 15% gasoline), the cost of which is 25% cheaper than traditional fuels already used in many European countries.