Komatsu 4D98 Series Shop Manual page 103

8. Turbocharger (for 4TNE106T)
(3.1) Method for checking the waste gate valve opening pressure and lift
@ Equipment
Prepare the equipment shown in the figure below.
@ Measuring instruments and devices
Dial gage Capable of measuring 0 to 10 mm (A flat head type is recommendable.)
Manometer Mercury column or electrical type (capable of measuring 0 to 1500 mmHg)
Pressure regulating valve Allowing gradual adjustment in a range between 0 and 2 kgf/cm2 (0.196 Mpa)
Pressure reducing valve Used for suppressing the air supply pressure at 5 kgf /cm* (0.49 Mpa) or less.
1 Pressure gage 1 Bourdon tube pressure gage (0 to 10 kgf/cm* (0.98 Mpa))
I
Waste gate actuator
0
a.
b.
C.
0
.
.
.
.
.
.
.
\
Waste gate valve
pre,?;. redz;;vegulating valve
Manometer
[Note] PC (controller pressure) varies with the set
output in a range between 600 and 750 mmHg.
Check method
Set the manometer control pressure (PC) applied to the waste gate actuator to 0 and set
the dial gage to the zero point.
Gradually open the pressure regulating valve and measure the PC value when the actua-
tor rod is operated by 2 mm.
For the hysteresis, let the rod move to 3 mm first. The gradually close the pressure
regulating valve, measure the pressure when the rod is moved to 2 mm and obtain the
difference from the pressure measured in b. above.
Precautions
Set the dial gage on the extension line of the actuator rod.
The piping and joints shall completely be free from leak.
Fix the turbocharger and dial gage securely.
If an electric manometer is used, it shall have sufficient precision.
Even when an electric manometer is used, use of a mercury column type manometer in
combination is recommended for calibration and daily check.
The speed for increasing/decreasing PC by means of the pressure regulating valve shall
be very slow near the measuring point. If the 2 mm position is exceeded, restart from the
beginning.
Do not apply over 5 kgf/cm2 (0.49 MPa) to the actuator.
(3.2) Waste gate actuator leak test
Apply 1.2 kgf/cm2 (0.12 Mpa) to the actuator and hold the state for 1 minute. The actuator is
good if the pressure then is 1 .l kgf/cm2 (0.11 MPa) or above.
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