Fuel Injector For Marine Engines With Simple Diagram

  • The two main basic parts are its  nozzle and nozzle holder or body.
  • The high-pressure fuel enters and travels down a passage in the body and then into a passage in the nozzle, ending finally in a chamber surrounding the needle valve.
              Must Read:> Fuel Injector Leaking Causes, Indication, Action  
  • The needle valve is held closed on a mitred seat by an intermediate spindle and a spring in the injector body.
  • The spring pressure, and hence the injector opening pressure, can be set by a compression nut which acts on the spring.
  • The nozzle and injector body are manufactured as a matching pair and are accurately ground to give a good oil seal.
  • The two are joined by a nozzle nut.
  • The needle valve will open when the fuel pressure acting on the needle valve tapered face exerts a sufficient force to overcome the spring compression.
  • The fuel then flows into a lower chamber and is forced out through a series of tiny holes.
  • The small holes are sized and arranged to atomise, or break into tiny drops, all of the fuel oil, which will then readily burn.
  • Once the injector pump or timing valve cuts off the high pressure fuel supply the needle valve will shut quickly under the spring compression force.
  • All slow-speed two-stroke engines and many medium-speed four-stroke engines are now operated almost continuously on heavy fuel.
  • A fuel circulating system is therefore necessary and this is usually arranged within the fuel injector. During injection the high-pressure fuel will open the circulation valve for injection to take place.
  • When the engine is stopped the fuel booster pump supplies fuel which the circulation valve directs around the injector body.
  • Older engine designs may have fuel injectors which are circulated with cooling water.

A simple Diagram of Fuel Injector

ref: introduction to marine engineering by D A Talyor

Post a Comment

>> Your Comments are always appreciated...
>> Discussion is an exchange of knowledge It Make the Mariner Perfect.... Please Discuss below...

Previous Post Next Post