4 Functional Description
4.1 Diesel Engine with Exhaust Gas Aftertreatment
4.1.1 Diesel engine with EGAT – Overview
1 Exhaust pipe bellows
2 Temperature sensor
3 NOx sensor
4 Pressure sensor
5 Electrical cabling
6 Reducing agent lines
7 Engine sensors
8 Engine
ECU* Engine Control Unit
DCM* Distributed Control Module
DOC* Diesel Oxidation Catalyst
DPF* Diesel Particulate Filter
SCR* Selective Catalytic Reduc-
tion
ASC* Ammonia Slip Catalyst
PFM* Pre-Feed Module
SU* Supply Unit
DU* Dosing Unit
RA* Reducing Agent
* Abbreviations see
MTU uses a combined exhaust gas aftertreatment system (EGAT system) comprising a diesel particulate fil-
ter (DPF) with a diesel oxidation catalyst (DOC) and an SCR system (selective catalytic reduction) to moder-
ate emissions.
The use of approved fuels, lube oils and reducing agents as listed in the MTU Fluids and Lubricants Specifica-
tions prevents premature failure of the SCR catalyst and DOC as a result of contamination.
Dimensioning of the EGAT system is based on the site conditions defined for MTU 12V4000Gx5S engines. In
this application, two EGAT systems must be installed in the exhaust line of the engines to comply with these
site conditions. These MTU engines feature 2 exhaust ports so an EGAT system can be installed for each
outlet without merging the exhaust gas before.
The exhaust gas aftertreatment system is designed such as to obviate the need for a silencer in many cases.
36 | Functional Description | MS15065/01E 2019-01
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