Hitachi ZW 550-6, Operator'S Manual

Page: 67 / 438

OPERATOR'S STATION
1-3
Aftertreatment Device
The machine is equipped with the aftertreatment system
combining Diesel Oxidation Catalyst (DOC) block (1) with
Selective Catalytic Reduction (SCR) block (2) to remove
nitrogen oxide (NOx) from the exhaust gas in order to meet
governmental emissions regulations.
The DOC reduces harmful substances in exhaust gas by
chemical reaction, then DEF is injected in dosing module
(injection chamber) (3) and mixed into the exhaust stream.
DEF decomposed to ammonia and CO
2
. SCR catalyst
converts NOx into harmless nitrogen gas and water vapor
by accelerating chemical reaction with the ammonia. The
remaining ammonia is decomposed into nitrogen and water
by DOC in SCR block (2).
Follow the instructions below to prevent the aftertreatment
device from being damaged.
IMPORTANT:

Refer to 1-35 for further information.

Exhaust gas from the aftertreatment device,
and exhaust piping becomes hotter during and
right after engine running and regeneration of
aftertreatment device. Be careful not to let your
skin contact any part of exhaust system or hot
gas from the exhaust piping. It may cause severe
burns.

If flammable objects such as dried leaves or paper
scraps are around the aftertreatment device, they
may cause a fire.

Before maintaining the machine, stop the engine
and make sure the engine has cooled down
sufficiently to prevent burns.

Be sure to use fuel that complies with JIS K-2204,
EN-590 and ASTM D-975 which contains 15 ppm or
lower sulfur. If the fuel described above is not used,
exhaust gas that exceeds the regulation values
may be discharged and serious problems may arise
on the engine.
95Z7B-SCR4
2
3
1