Kubota M7131, Operator'S Manual

Page: 114 / 298

OPERATING THE ENGINE 82
B
Tips on Diesel Particulate Filter (DPF)
Regeneration
A
Operation
The higher in speed or load the engine operates, the
higher the exhaust temperature rises. As a result,
particulate matter (PM) inside the DPF is consumed,
therefore the regeneration process is required less
frequently over time.
The lower in speed or load the engine operates, the
lower the exhaust temperature. Accordingly, less
particulate matter (PM) inside the DPF is consumed,
therefore more accumulation of PM will occur, which
requires frequent regeneration, therefore avoid
prolonged idling if possible.
A
Necessary conditions for "Regeneration"
When conditions below are all satisfied, regeneration
will start. However, if even one condition is deviated
during the process, the regeneration will be
interrupted.
(1) The engine coolant temperature.
(2) The DPF temperature.
(3) The engine speed is 1200 rpm or higher.
A Usually it takes 15-20 minutes to complete the
regeneration cycle.
Actual regeneration time may depend on ambient
temperature, exhaust temperature and engine speed.
A
It is recommended to do the regenerating while the
engine is warm.
A Do not unnecessarily start and interrupt the
regeneration process. Otherwise, a small amount of
fuel becomes mixed with the engine oil, which
degrades the oil quality.
A
While the DPF is being regenerated, the engine air
flow rate is automatically limited to keep up the
exhaust temperature. Because of this the engine may
sound differently, this is normal for this engine.
A
Just after the regeneration has ended, the DPF muffler
remains hot. It is advisable to keep the engine running
for about 5 minutes to allow cooling of the exhaust
components.
SELECTIVE CATALYTIC REDUCTION
(SCR) MUFFLER
B
Outline of the SCR
The injector jets urea aqueous solution (DEF/AdBlue®)
into the muffler, and the solution is hydrolyzed with the
heat of exhaust gas to generate ammonia (NH3).
The ammonia generated thus is mixed with exhaust gas
by the SCR muffler. In this way, nitrogen oxides (NOx)
contained in exhaust gases are reduced by ammonia and
decomposed into nitrogen and water vapor.
B DEF/AdBlue®
To avoid personal injury:
A The urea aqueous solution (DEF/AdBlue®) is
colorless, odorless and harmless.
If the solution gets on your skin, immediately
wash it away with water.
The DEF/AdBlue®, used as reducing agent of SCR, is a
32.5% urea aqueous solution.
No qualification for handling the urea aqueous solution is
needed. As well, the solution is not designated as a
hazardous material.
The product is available at gas stations, truck stops and
specialty shops. Be sure to use the genuine product only.
Do not use any poor-quality products, or the engine may
have trouble and be damaged.
Generally speaking, the consumption of DEF/AdBlue® is
about 5% of the fuel. Add this solution every two refueling
occasions.
(1) SCR muffler