Fuel Injection Nozzle; Functioning Of Fuel Injection Nozzle; Type/Construction Of Fuel Injection Nozzle - Takeuchi TB 175 Handbuch

5. Fuel injection Nozzle

When fuel 0il pumped by the fuel injection pump reaches the injection nozzle， it pushes up the nozzle valve （held down by
spring） ，and is injected into the combustion chamber at high pressure．
The fuel is atomized by the nozzle to mix uniformly with the air in the combustion chamber. How well the fuel is mixed with
high temperature air directly affects combustion efficiency，engine Performance and fuel economy．
Accordingly, the fuel injection nozzles must be kept in top condition to maintain performance and operating efficiency.

5.1. Functioning of fuel injection nozzle

Fuel from the fuel injection pump passes through the oil port in the nozzle holder and enters the nozzle body reservoir.
When oil reaches the specified pressure，it pushes up the nozzle valve（held by the nozzle spring） ，and is injected
through the small hole on the tip of the nozzle body．
The nozzle valve is automatically pushed down by the nozzle spring and closed after fuel is injected.
Oil that leaks from between the nozzle valve and nozzle body goes from the hole on top of the nozzle spring through the oil
leakage fitting and back into the fuel tank.
Adjustment of injection starting pressure is effected with the adjusting shims.

5.2. Type/construction of fuel injection nozzle

There are two types of fuel injection nozzles. Direct injection engines are equipped with the hole type, and indirect injection
engines with the pintle type.
The YPD-MP fuel injection pump is designed for use with both direct and indirect injection engines. The hole type/pintle
type of fuel injection nozzle are used according to the engine type.
Hole type fuel injection nozzle
Nozzle opening
pressure
Nozzle angle
No. of nozzles×dia.
Identification No.
(Nozzle type)
F.O. return pipe joint
Nozzle holder
Nozzle spring
Nozzle spring seat
49
MPa
21.6
2
(kgf/cm )
deg. 162
mm
5×0.16
162P165VAE1
+1.0 (+10)
(220)
0 (0)
159
5×0.17
159P175VAD1