Maintenance manual for sunray hfc4da1-2c china-IV diesel engines
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closes the fuel drainage hole. The armature is of two-part design. Though the armature block is guided by the pressure
shoulder during the downward movement, it can bounce back following the return spring and thus will not apply
downward force onto the armature and the ball valve.
The close of fuel drainage hole enables the entry of fuel via fuel inlet hole into the control chamber for pressure
establishment. This pressure is equivalent to the rail pressure and applies additional force onto the end face of the
control plunger. The resultant force from this force and spring force overcomes the pressure in the injector nozzle
chamber to close the injector nozzle needle valve.
The close speed of the injector nozzle needle valve depends on the flow passing through the fuel inlet hole. Once the
injector nozzle needle valve hits its lower seat again, the fuel injection stops.
3) Measurement analysis
4) Matching of fuel injector
The matching of fuel injector must be performed in event of any
of the following conditions:
z Replacement of fuel injector.
z Replacement of ECU
z Confusion of installation serial number before and after the
maintenance.
While performing the matching, input the matching code on the
fuel injector (as shown in the figure) in order into the diagnosis
instrument for matching.
2. EGR valve control system
1) Overview
z The electronically controlled EGR valve controls the
open extent of the valve by means of the positive and
reverse rotation of the DC motor and performs the
close-loop control as per the feedback signal of the
position sensor.
z To guarantee the NOx emission of the engine, the ECU
measures and calculates the EGR percentage as per the
input parameters of the engine (such as speed and intake
pressure) and the calibrated MAPs), issues control
signal to the EGR valve, and performs the close-loop
control via the position sensor.
z The EGR valve is installed on the intake manifold. The constant temperature of the EGR valve inlet emission
Fuel injector 1 “high”
Fuel injector 1 "Low”
Fuel injector 4 “high”
Fuel injector 4 "Low”
Fuel injector 2 "Low”
Fuel injector 3 "Low”
Fuel injector 3 “high”
Fuel injector 2 “high”
Cylinder 1
Cylinder 4
Cylinder 3
Cylinder 2
EGR valve
Intake manifold
assembly