Operational supervison
Exhaust system/supercharging
A3.06.06.03
M20
en / 06.03.1997 BA000672 3/4
Ĺ
Indicating
For pressure measurement the following torsion bar indicators are to be employed:
• Torsion bar indicator, Type S1- 1/5 piston / S50
Tool No. 1.9410 F
Only hand-drawn indicator cards can be made with the existing instruments. Although it is im-
possible to obtain an exact relation between the pressure development in the cylinder and a
crank angle, it is nevertheless possible to see changes in the cycle of a cylinder and to find the
cause rather soon. A diagram should therefore always be drawn when the assessment of the
exhaust gas indicates a change in a cylinder. Even when watching the exhaust temperatures
does not indicate an irregularity it is recommended to check the engine by indicator cards at
regular intervals.
Only proper measuring instruments will make an exact measurement possible. The indicator must
therefore be carefully stored and the instruction of the manufacturer followed.
• Draw indicator diagrams at full load if possible.
• Blow well through the indicator valves so that no carbon particles will enter the indicator.
• Place the indicator and draw the atmospheric line.
• Open the indicator valve and rotate the recording drum accordingly in small steps to record
the firing pressure p
z
10 x separately.
• Record the entire curve pulling the recording drum through speedily.
• Note on the card: date, indicator spring scale, engine serial number, cylinder number, exhaust
gas temperature at cylinder outlet, fuel rack position, rpm, charge air pressure.
Attention:
Do not correct the firing pressure by changing a correct commencement of fuel deli-
very. This would reduce the cylinder output still further.
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