Indirect Injection

In an internal combustion engine, the term indirect injection refers to a fuel injection where fuel is not directly injected into the combustion chamber. Gasoline engines are usually equipped with indirect injection systems, wherein a fuel injector delivers the fuel at some point before the intake valve.

An indirect injection diesel engine delivers fuel into a chamber off the combustion chamber, called a prechamber, where combustion begins and then spreads into the main combustion chamber. The prechamber is carefully designed to ensure adequate mixing of the atomized fuel with the compression-heated air. The purpose of the divided combustion chamber is to speed up the combustion process, in order to increase the power output by increasing engine speed. The addition of a prechamber, however, increases heat loss to the cooling system and thereby lowers engine efficiency. The engine requires glow plugs for starting. In an indirect injection system the air moves fast, mixing the fuel and air. This simplifies injector design and allows the use of smaller engines and less tightly toleranced designs which are simpler to manufacture and more reliable. Direct injection, by contrast, uses slow-moving air and fast-moving fuel; both the design and manufacture of the injectors is more difficult. The optimisation of the in-cylinder air flow is much more difficult than designing a prechamber. There is much more integration between the design of the injector and the engine. It is for this reason that car diesel engines were almost all indirect injection until the ready availability of powerful CFD simulation systems made the adoption of direct injection practical.

Read more about Indirect InjectionGallery, Advantages of Indirect Injection Combustion Chambers, Disadvantages, Maintenance Hazards

Other articles related to "indirect injection, injection":

SEAT Inca - Performance
... engines, and was also available with the tried-and-tested 64 bhp (48 kW 65 PS) 1.9 (1896cc) indirect injection diesel engine from the Volkswagen Golf and Volkswagen Polo, or a 90 bhp (67 kW) Turbocharged ... A 64 bhp (48 kW 65 PS) 1.9 Suction Diesel Injection (SDI) direct injection diesel with electronic control, and improved economy over the indirect injection engine was also available from 1999. 0–80 km/h, s Acceleration 0–100 km/h, s 1.9 Indirect Injection D, 47 kW (64 PS 63 bhp) 144 km/h (89 mph) 12.4 20.6 1.9 Direct Injection SDi, 47 kW (64 PS 63 bhp) 144 km/h (8 ...
Indirect Injection - Maintenance Hazards
... Fuel injection introduces potential hazards in engine maintenance due to the high fuel pressures used ... Residual pressure can remain in the fuel lines long after an injection-equipped engine has been shut down ... its seat and operated in open air, there is a risk to the operator of injury by hypodermic jet-injection, even with only 100 psi pressure ...
SDI (engine) - SDI Vs Other VW Group Diesel Engines
... operating revs rpm dates installed 1.4 SD 1,391 cc (84.9 cu in) inline 4, indirect injection mechanical distributor injection pump 8v SOHC 35 (48) 4,500 82 (60) 2,700 - 3,500 25.2 (34.5) 5,000 Polo 2, 2F late 1980s ...

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