Komatsu HM400-1, Manual

Page: 131 / 258

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OPERATION
OPERATION
OPERATION
OPERATION
5. When the engine starts, release the key in starting switch (1).
The key will return automatically to the ON position.
REMARK
If the engine does not start, turn the key in starting switch (1) to the
OFF position, then turn it back to the ON position. The preheating
will automatically start again according to the engine water
temperature.
6. Immediately after starting the engine, run at idling continuously for 15 seconds. Do not operate the accelerator
pedal during this time.
Guideline for idling time
Cold temperature: 15 seconds or more
When first starting engine after changing engine oil and replacing engine oil filter: 20 seconds
REMARK
Immediately after the engine is started, the turbo protect function is actuated. Even if the accelerator pedal is
depressed, the engine speed will not rise above 1000 rpm.
Engine water temperature Turbo protect time
above 10
°
C (50
°
F) 0 sec
-10
°
C to 10
°
C (14
°
F to 50
°
F) 0 to 5 sec
below -10
°
C (14
°
F) 5 sec
The turbocharger rotates at extremely high speed. Immediately after the engine is started, the pressure of the
lubricating oil has not risen sufficiently, so if the engine speed is suddenly raised, it may lead to damage or seizure
of the turbocharger bearing. The turbo protect function acts to prevent this problem. It uses electronic control
to prevent the engine speed from rising above a certain speed for the first few seconds after the engine started.
To improve the ease of starting in cold weather, the low idling speed becomes slightly higher for the time given
below and the engine sound is different. In addition, it functions to make the acceleration gradual during this time.
Engine water temperature
Injection characteristics
change time
above 20
°
C (68
°
F) 0 sec
0
°
C to 20
°
C (32
°
F to 68
°
F) 0 to 6 sec
-20
°
C to 0
°
C (-4
°
F to 32
°
F) 6 to 12 sec
-30
°
C to -20
°
C (-22
°
F to -4
°
F) 12 to 15 sec
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