9 Commissioning
KRONOS 20 47
4.
Count the number of counter-clockwise revolutions required to achieve gas output
pressure drop. The mixture change resulting from this forced disturbance should lead
to a leaner operation and the closed loop should then correct this effect.
5.
Go back to the starting point.
6.
Turn a few clockwise revolutions to repeat the test for a richer mixture.
7.
Go back to the original position of the zero governor adjustment spindle.
8.
A further disturbance can be brought about by opening the compensating line.
9.
Working with a biogas plant or landfill gas plant, ask the plant operator to change gas
composition in order to check the dimensioning of the fuel system (control reserve)
and the control system (correction quality).
9.5 Further commissioning for CLOSED LOOP with λ1 control
(KRONOS 20 version with λ1 sensor)
General:
Commissioning of λ1 control is carried out in two steps:
-
adjustments for open loop
-
adjustments for closed loop
Open loop operation is active when the engine starts, as long as the lambda sensor is not
ready for operation yet, when the sensor has failed or if closed loop operation has not been
activated yet (5400
ClosedOrOpenLoop). During calibration of the open loop, closed loop
operation may not be active.
Correct calibration in open loop guarantees that closed loop operation achieves an ap-
proximate
λ1 ratio straight away and the corrections for closed loop remain small under all
operating conditions. This allows a good starting behaviour and, due to the relatively small
lambda trim values (3464
LambdaTrim Value), also a good dynamic behaviour in closed
loop. In addition, the trim value range may be limited to a small range (1464
LambdaT-
rimValueLimit). This avoids major variations in case the sensor fails.
In closed loop, fine tuning is done by a pre-setting a default control voltage for the λ sensor
within the voltage jump range. For
λ1 this value is usually set between 0.1 and 0.7 Volt.
This procedure allows a very precise lambda control
Settings for open loop:
1. First, disable (5400 ClosedOrOpenLoop). Verify the load and speed dependent
λ adjustment values (7400-7599 LambdaMap). To begin with, all map values should
be set to 1 (this table serves only for later correction purposes here).
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