A diesel engine is a type of internal combustion engine that converts the chemical energy of fuel into work by compressing air to a high pressure and temperature, then injecting fuel into the compressed air. The heat from the compressed air ignites the fuel, causing a controlled explosion that drives a piston down. The downward motion is mechanically converted to rotary motion by a connecting rod and crankshaft.
Diesel engines provide a rugged, efficient, versatile, self-contained source of power. These engines come in sizes ranging from a few horsepower to over 100,000. Within the limits of its range of horsepower, the diesel engine is one of the most efficient source of power available.
Diesels are widely used in a wide variety of commercial and industrial applications including electrical generation. In the field of transportation, they power locomotives, construction equipment, vehicles, and all varieties of oceangoing vessels.
Diesel engines can operate on a wide variety of liquid fuel oils. Most small and medium engines operate on petroleum diesel fuel, which is a distilled from crude oil, while large slow speed marine engines operate on Heavy Fuel Oil (HFO). There is a growing trend for engines to run on gaseous fuels such as natural gas or bio-gas. Engines which can operate on a combination of liquid and gaseous fuels are called dual-fuel.
