DETROIT DIESEL 53
2.1.1
FUEL INJECTOR (NEEDLE VALVE)
The fuel injector (Figs. 1 and 2) is a lightweight compact unit which enables quick, easy starting directly on diesel fuel
and permits the use of a simple open type combustion chamber. The simplicity of design and operation provides for
simplified controls and easy adjustment. No high pressure fuel lines or complicated air-fuel mixing or vaporizing devices
are required.
The fuel injector performs four functions:
1. Creates the .high fuel pressure required for efficient injection.
2. Meters and injects the exact amount of fuel required to handle the load.
3. Atomizes the fuel for mixing with the air in the combustion chamber.
4. Permits continuous fuel flow.
Combustion required for satisfactory engine operation is obtained by injecting, under pressure, a small quantity of
accurately metered and finely atomized fuel oil into the cylinder.
Metering of the fuel is accomplished by an upper and lower helix machined in the lower end of the injector plunger.
Figure 3 illustrates the fuel metering from no-load to full-load by rotation of the plunger in the bushing.
Fig. 1 Fuel Injector Assembly
Fig. 2 Cutaway View of Fuel Injector
March, 1973
SEC. 2.1.1
Page 1