puristussytytksessä

Puristussytytys is a Finnish term that translates to "compression ignition" in English. It refers to an internal combustion engine in which the fuel is ignited by the high temperature generated by the compression of air within the cylinder, rather than by an external ignition source such as a spark plug. This is the fundamental principle behind diesel engines.

In a compression ignition engine, air is drawn into the cylinder and compressed to a much higher pressure and temperature than in a spark-ignition engine (like a gasoline engine). Near the end of the compression stroke, fuel is injected directly into the hot, compressed air. The fuel then ignites spontaneously due to the heat. This process allows for higher thermal efficiency compared to spark-ignition engines, leading to better fuel economy.

The development of compression ignition technology is largely credited to Rudolf Diesel, who patented his engine design in the late 19th century. Diesel engines are widely used in heavy-duty applications such as trucks, buses, trains, and ships, as well as in many agricultural and industrial machinery. Their robust construction and ability to produce high torque at low engine speeds make them suitable for demanding tasks.

The term "puristussytytys" specifically highlights the ignition mechanism that relies solely on the physical process of compression, distinguishing it from other engine types that require an active spark or other igniting agent. This emphasis on pure compression as the ignition source is central to the definition.