02A.8.5 First aid measures
03. Start, Stop and Operation
03.4 Normal operation supervision
If an alarm limit is reached and an alarm is activated, the engine situation is already serious. All necessary countermeasures must be taken to remove this emergency condition and return to normal operating conditions. As the abnormal operating situation may cause damages to the engine, all efforts must be put into returning to the normal operating situation instead of just waiting for an automatic shut down of the engine.
03.4.1 Every second day or after every 50 running hours
1 Read all temperatures and pressures on the WECS dis-play and at the same time, the load of the engine. All tempera-tures are more or less dependent on the load, and the lubricating oil, cooling water pressures (built-on pumps) are dependent on the speed. Therefore, always compare the values read with those at corresponding load and speed in the Accep-tance Test Records and curves. Guidance values are stated in chapter 01.
The charge air temperature should, in principle, be as low as possible, however, not so low that condensation occurs, see Fig 03-2.
2 Check pressure drop over the lubricating oil filter. Too large of a pressure drop indicates clogged candles, which re-sults in reduced oil filtration when the by-pass valve is open.
Reduced oil filtration results in increased wear. Change the candles.
3 Check the oil level in the oil sump/oil tank. Estimate the appearance and consistency of the oil. A simple control of the water content: A drop of oil on a hot surface (about 150°C), e.g.
a hot-plate. If the drop keeps “quiet”, it does not contain water;
if it “frizzles” it contains water. Compensate for oil consump-tion by adding max. 10 % fresh oil at a time.
4 Check the ventilation (de-aerating) of the engine cooling water system. Check that the leakage from the telltale hole of the HT-water- and the LT-water pump is normal (slight).
5 Check the quantity of leak-fuel from the draining pipes and from the telltale hole of the fuel feed pump.
6 Check that the drain pipes of the air coolers are open.
7 Check that the telltale holes of the oil coolers and the cooling water coolers are open.
8 Clean the compressor side of the turbocharger by in-jecting water. See the instruction manual of the turbocharger.
9 Drain the fuel day tank of water and sediments, if any, and drain the starting air receiver of water.
Condensation in charge air coolers
Example: If the ambient air temperature is 35°C and the relative humidity is 80 % the water content in the air can be read from the diagram (0.029 kg water/kg dry air). If the air manifold pressure (receiver pressure) under these conditions is 2.5 bar, i.e. absolute air pressure in the air manifold is abt. 3.5 bar (ambient pressure + air manifold pressure), the dew point will be 55°C ( from diag.).
If the air temperature in the air manifold is only 45°C, the air can only contain 0.018 kg/kg (from diag.). The difference, 0.011 kg/kg (0.029-0.018) will appear as condensed water.
60 50 40 30 20 10 0 10 20 30 40 50 60
70 .01 .02 .03 .04 .05 .06 .07 .08 .09 Water content
Water dewpoint ˚C
(kg water/kg dry air)
Amb air temperature ˚C
P=Air manifold pressure bar abs
P=4,5 P=3,5 P=2,5
P=1,5 f=40
f=60 f=80 f=100
f=Relative humidity %
Fig 03-2 3203528930
03.4.2 Every second week or after every 250 run-ning hours
1 Clean the centrifugal lubricating oil filters.
2 Keep the injection pump racks clean (free from sticky deposits), check that the parts of the fuel control shaft system move easily. Is to be done on a stopped engine. See section 22.2.
3 Clean the turbine side of the turbocharger by injecting water. See chapter 15 and the instruction book of the turbo-charger.
03.4.3 Once a month or after every 500 running hours
1 Check content of additives in the circulating water.
2 Check the cylinder pressures. At the same time, note the load of the engine (the position of the load indicator or the injection pump racks offer an accurate measure of the engine load).
Note! Measurement of cylinder pressures without simultaneous no-tation of the engine load is practically worthless.
03.4.4 In connection with maintenance work
1 Record the following steps and the running hours in the engine log:
•
lubricating oil sampling (record also operating time of oil).Lubricating oil analyses without statement of operating time is of limited value (“go - no go” only)
•
lubricating oil changes•
cleaning of centrifugal lubricating oil filter, see section 18.8•
cleaning or changing of lubricating oil automatic filter candles, see section 18.7.•
change of parts in connection with maintenance according to chapter 04.03.4.5 General
1 There is no automatic supervision or control arrangement that can replace an experienced engineer’s observations.
LOOK at and LISTEN to the engine!
2 Strong gas blow-by past the pistons is one of the most dangerous things that can occur in a diesel engine. If gas blow-by is suspected (e.g. because of a sudden increase of the lubricating oil consumption) check the crankcase pressure. If the pressure exceeds 30 mm H2O, check the crankcase venting system, if in order, pull the pistons!
3 Operation at loads below 20 % of rated output should be limited to maximum 100 hours continuously when operating on heavy fuel by loading the engine above 70 % of the rated load for one hour before continuing the low load operation or stopping the engine.
Idling (i.e. main engine declutched, generator set discon-nected) should be limited as much as possible. Warming-up of the engine for more than 3 - 5 minutes before loading, as well as idling more than 3 minutes before stopping is unnecessary and should be avoided.