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. F.O. return pipe joint Nozzle holder Nozzle spring Nozzle spring seat 49 MPa +1.0 (+10) Nozzle opening 21.6 (220) pressure (kgf/cm2) 0 (0) Nozzle angle deg. 162 159 No. of nozzles×dia. mm 5×0.16 5×0.17 Identification No.
162P165VAE1 159P175VAD1 (Nozzle type) Hole type fuel injection nozzle Nozzle opening pressure MPa (kgf/cm2) 21.6 +1.0 (220) (+10) 0 (0) Nozzle angle deg. 162 159 No. of nozzles×dia. mm 5×0.16 5×0.17 Identification No. (Nozzle type) 162P165VAE1 159P175VAD1