Polttomoottorit

Polttomoottorit, or combustion engines, are internal combustion engines that use the heat generated by burning fuel to create mechanical power. They are widely used in various applications, including automobiles, aircraft, ships, and stationary power generation. The basic principle of a combustion engine involves the cyclic process of intake, compression, combustion, and exhaust. In the intake stroke, a fuel-air mixture is drawn into the cylinder. During compression, the mixture is compressed to increase its pressure and temperature. Combustion occurs when the spark plug ignites the fuel-air mixture, causing a rapid expansion of gases that pushes the piston down, generating power. Finally, the exhaust stroke expels the spent gases from the cylinder.

Combustion engines can be classified into two main types: spark-ignition (SI) engines and compression-ignition (CI) engines. SI engines, such as those used in gasoline-powered cars, rely on a spark plug to ignite the fuel-air mixture. CI engines, commonly found in diesel-powered vehicles, compress the air to such a high temperature that it auto-ignites the fuel without the need for a spark plug. Both types of engines have their advantages and disadvantages, with SI engines generally offering better fuel efficiency at lower speeds and CI engines providing higher torque and better fuel efficiency at higher speeds.

The development of combustion engines has significantly impacted human history, revolutionizing transportation and industrialization. However, they also pose environmental challenges, such as air pollution and greenhouse gas emissions. As a result, there is ongoing research and development to improve the efficiency and reduce the environmental impact of combustion engines. This includes advancements in fuel injection systems, turbocharging, and the use of alternative fuels. Despite these challenges, combustion engines remain a vital technology in modern society.