76
Q&A
Why the “click” sounds are heard from the engine for a
while during cold start? ?
Leaving valve clearance in the valve train will cause the valve train to make
impact and noise while the engine is operating. To eliminate such a defect,
some engines adopt a hydraulic tappet mechanism to realize zero valve
clearance.
There is an oil cavity in the hydraulic tappet. When the valve is closed,
the oil cavity will be lled with oil, making the tappet touch the cam all the
time; when the cam opens the valve, the oil will be squeezed out again (the
amount of the squeezed oil is controlled by the clearance) to ensure that
the tappet keeps touching the cam.
However, when the engine is cold, running noise may occur for a short time
because the oil pressure in the hydraulic rod cannot reach the prescribed
value immediately. This is a normal phenomenon and requires no worry.
How to avoid a trac accident?
Keep sober﹣minded and step up vigilance when following other vehicles.
Never get distracted during driving. Clearly and effectively communicate
with other drivers by turning on the signal lamp in advance to inform them
of your driving intention. Adopt a preventive driving method, predict the
driving intention of the users on other roads, and keep an elliptical space
around this vehicle. Stay focused and do not pay any attention to other
matters that have nothing to do with driving.
Why should the engine be kept idling for a period of
time (3~5 minutes) after cold start?
If the engine accelerates immediately after start, the turbocharger will
work at the maximum speed before its bearing is lubricated fully, which will
damage its bearing and reduce its service life.
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