Engine Failure to Trip and Subsequent Damage

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October 12, 2020 at 1:45 pm #2255

Anonymous
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On 2020 1002 at approximately 1453 engine 5 tripped for an unknown reason. Just prior to trip the engine performed a controlled load reduction from full load to about 50% load.
Pilot LFO inlet and outlet flow went up 12 lb/min during the event.
Engine load output went up just prior to the load reduction.
Engine natural gas consumption went up significantly during the load reduction – 1959 to 2128 SCFM
All cylinder exhaust temperatures went up significantly during the load reduction.
Upon investigation it was noted that select control inputs had stopped working about 16 minutes prior to event: <!–[endif]–>Exhaust gas deviation; <!–[endif]–>Main duration offset; <!–[endif]–>Engine speed; Gas pressure; Gas control; Charge air pressure; Charge Air Temperature; Waste gate control; Knock control; <!–[endif]–>HT Water Jacket Outlet Temp A-Bank (B-Bank OK); PFI Global; <!–[endif]–>Pilot Pump Pressure; Pilot FO pressure control; Fuel Oil Pressure inlet; Main gas pressure; Main gas pressure control; Lube oil pressure inlet; Lube oil temp inlet
Upon slow roll after event loud knocking could be heard on the A-bank indicating damage of some sort. We checked the big end bearings on all cylinders but found no damage or indication of trouble. A leak down check on all cylinders could not build pressure on cylinders A2 and A3. It was discovered that the crowns had separated from the piston skirt during the event. We are in the process of removing all cylinder heads now for additional discovery.

On discussion with Wärtsilä they believe that the engine fuel mixture range went through the entire knock range and above – once the mixture went above the knock range the cylinder no longer fired. Therefore the increase in fuel flow but loss of load. The severe knock damaged A2 and A3 but all cylinders should be inspected. Wärtsilä also indicated that the engine control system should not have allowed this to occur and they are looking into the issue on their end.

Has anyone else using any other Wärtsilä product experienced similar. If you have questions or wish to discuss further please feel free to contact me at chuck.holm@pge.com


October 27, 2020 at 7:24 pm #2267

Anonymous
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What type of engine?

How many hours are on the engine and the age of the engine?

At a quick glance a control module may have failed that was common to the inputs. I would trace those points back and see if they go to a common module.

I haven’t had this problem on a Wartsila engine, but had a ABB DCS module fail and bring in stale data (flat line). Luckily the operator and supervisor noticed the problem soon enough and was able to trip the unit manually.
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