FUEL INJECTOR HAVING A COOLED LOWER NOZZLE BODY

摘要

A fuel injector is provided with a lower nozzle body which is cooled with a small amount of metered fuel. In one embodiment, a blind passage is formed to extend from the upper portion to the lower end of the injector nozzle valve element. A transverse passage is formed in the nozzle valve element connecting the blind passage and the nozzle bore. Rail pressure causes a metered amount of fuel to flow through the nozzle bore, the transverse passage and upwardly along the blind passage to the drain passage. Inward cooling occurs by providing more surface area over which the fuel flows. In another embodiment, a sleeve is formed to fit over an existing nozzle to form a passage surrounding the injector tip. An orifice is located in the nozzle housing to connect the nozzle cavity with the annular passage thereby providing a small amount of fuel to drain.