NOZZLE

FIT MARINE ENGINE :HANSHIN LH28(LH29RG,ARG)

MARINE NOZZLE REF NO:DLFR130T388(HAN) NP-DLF130UJ388N1

Nozzle type:uncooled marine nozzle

Hydraulically operated uncooled diesel fuel injectors are fitted in large two stroke diesel marine engines. The main characteristic feature of these types of fuel injectors used in the main engine fuel injection system of ships is that cooling effect is not provided to the injectors, by the fuel oil. In this article, we will take a look at the construction and working of such diesel injectors. Take a look at the sketch below before you read further, in order to understand it in a better manner.

Construction & Working

The design is similar for most engines and consists of a spring loaded non-return NEEDLE VALVE operated hydraulically by a fuel pressure wave from the fuel pump, to discharge fuel at high pressure through an atomizer nozzle.

A typical fuel injector consists of valve body or nozzle holder with the nozzle or atomizer being secured by a retaining nut. Needle valve is lapped into the bore of the atomizer and these must be kept as matched unit.

It has two chambers:

1. UPPER chamber being charged with fuel oil from fuel pump sealed by needle valve.
2. LOWER chamber or sac is sealed by mitre seat of the needle valve and has number of small atomiser holes of correct size and pattern to atomise and distribute the fuel spray into the combustion chamber.

The valve will open when the pressure from fuel pump acting in the shoulder of the needle valve overcomes the spring compression. As the needle valve lifts oil flows to the lower chamber in the atomiser.

Needle lifts rapidly allowing the fuel at higher pressure to pass through the atomiser holes into the combustion chamber. When the fuel pump cuts off pressure, the valve will close under spring compression.