MAK M20, Operating Instructions Manual

Page: 55 / 456

Operational supervison
Exhaust system/supercharging
A3.06.06.03
M20
en / 06.03.1997 BA000672 2/4
Ĺ
The
exhaust gas temperatures after the turcbcharger
are used for the assessment of the thermody-
namic load condition of the engine, as they include the complete thermodynamic of engine and tur-
bocharger.
The temperature after the turbine should nor exceed the full-load figure on the acceptance test re-
cord
A1.10
by more than
30K
.
∆
t
Exh. gas temp. aft. turb.
≤
30 K
• Compare the exhaust gas temperature after the turbocharger with the acceptance test record
A1.10
.
If the temperature difference
∆
t > 30 K
, the cause of the temperature rise must be found, e.g.
different ambient conditions, type of fuel, fouled charger etc., see
A3.11.18.nn
.
Reduce the engine output, if the maximum permissible temperature after the turbine is
exceeding in operation:
heavy fuel t
exh. gas temp. after turb.
max. 400 °C
diesel fuel t
exh. gas temp. after turb.
max. 420 °C
• Make another check of the combustion by assessing the exhaust gas opacity. If the
combustion is good, the exhaust gas will be invisible or a light grey. For assessment of the
exhaust gas colour, see
A3.11.18.nn
.
Note for exhaust temperature monitors:
Contrary to the exhaust gas average temperature monitor, alarm is only activated when limit values
are reached (thermal) overload of a cylinder or misfiring) for monitoring the exhaust temperatures
of each cylinder. Misfiring endangers the flexible coupling!
It should be noted, that partial misfiring already subjects the flexible coupling to inadmissible loads,
see
A3.12.02.nn.