Kubota M4N-071, Operator'S Manual

Page: 46 / 152

6. Tips on diesel particulate filter
(DPF) regeneration
• 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 and 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
and more accumulation of PM will occur, which
requires frequent regeneration. Therefore, avoid
prolonged idling if possible.
• Necessary conditions for “Regeneration”
When the conditions below are all satisfied,
regeneration will start. However, if even one
condition is deviated from during the process, the
regeneration will be interrupted.
– The engine coolant temperature.
– The DPF temperature.
– The engine speed is 1200 rpm or higher.
• Usually, it takes 15-20 minutes to complete the
regeneration cycle.
Actual regeneration time may depend on ambient
temperature, exhaust temperature and engine
speed.
• It is recommended to do the regenerating while the
engine is warm.
• 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.
• 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, but this is normal for this
engine.
• 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
1. 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 (NH
3
).
The ammonia generated thus is mixed with exhaust
gas by the SCR muffler. In this way, nitrogen oxides
(NO
x
) contained in exhaust gases are reduced by
ammonia and decomposed into nitrogen and water
vapor.
(1) SCR muffler
2. DEF/AdBlue
®
CAUTION
To avoid personal injury:
• 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.
(1) DEF/AdBlue
®
tank (blue
cap)
NOTE :
• On the North American market, the high-grade
NOx reducing agent called urea aqueous
solution is sold in the name of diesel exhaust
fluid (DEF).
OPERATING THE ENGINE DIESEL PARTICULATE FILTER (DPF) MUFFLER
40
M4N-071, M5N-091, M5N-111