[[Image:diesel pump icon.png|right|80px]][[Image:dieselGenerator.jpg|thumb|right|300px200px|Diesel engine and centrifugal pump. Drawing: WHO.]]__NOTOC__<small-title />Diesel generators are frequently used as a stationary power source. The main parts of the engine are the cylinders, pistons, valves and crankshaft. Air is compressedby a piston inside a cylinder and diesel fuel is injected into it by a high pressure pump, which results in an explosion that moves the piston. In turn, the piston turns a crankshaft, which can be put to use, for example, by driving a pump or electricity generator. Valves in the cylinder regulate the inflow of fuel and air, and the outflow of exhaust gases.
Diesel engines differ from petrol engines in that they do not have spark-plugs to ignite the fuel mixture, and work at much higher pressures. Diesel engines need less maintenance that petrol engines, and they are more efficient. Diesel engines can differ in size (from 1–6 cylinders or more) and speed (revolutions per minute), and by the number of engine cycles (2-stroke, or 4-stroke). In general, low-speed four-stroke engines last longer, and high-speed two-stroke engines produce more power per kg of engine weight. Water-cooled engines generally need less maintenance than air-cooled engines.
* it is important to select a brand that has a good reputation, and for which servicing and spare parts are locally available.
===Suitable conditions===
Globally used, especially for high-power needs and where no grid electricity is available.
===Construction, operations and maintenance===
'''Life cycle''': A diesel generator can operate for between 5000–50 000 hours (average 20,000 hours), depending on the quality of the engine, whether it has been installed correctly, and whether O&M has been properly carried out.
— from time to time, a specialist mechanic will be needed to service and repair the generator.
===Costs===
Initial cost: From US$ 200 per kW for 25 kW engines to US$ 600 per kW for 2 kW engines.
==Field experiences=Acknowledgements= ==Manuals, videos, and links== ==Acknowledgements==* Brikke, François, and Bredero, Maarten. [http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CC0QFjAB&url=http%3A%2F%2Fwww.who.int%2Fwater_sanitation_health%2Fhygiene%2Fom%2Flinkingintro/water_sanitation_health/hygiene/om/linkingintro.pdf&ei=cwJpT-zaO-OiiQKCst2rBw&usg=AFQjCNEWOQhTgF3a7lzhuw5OA2KmbVGxcA&sig2=Rt2EURUyGVqDcwFg6p0xAw Linking technology choice with operation and maintenance in the context of community water supply and sanitation: A reference document for planners and project staff]. World Health Organization and IRC Water and Sanitation Centre. Geneva, Switzerland 2003.