Volvo Penta 750 KVA Generator mistery problem 2

[alexander coletta]

Hello,

We have a stand by 750 KVA Generator ( Marathon Electric / Volvo Penta Power ) 900 hours of use.
MTU
Model 660RVC6DT2
Engine TWD1643GE-VOLVO


The generator will run smothly when no load its applied. After a few minutes of working with load ( even 20% of the generator capacity) the engine will shut down without any warnings of alarms. ( nor the control panel or the ECU )

For some reason fuel supply its being cut , when we monitor the ECU while working we can see that all parameters are OK and suddenly the the fuel flow drops to 0 and the engine stops , no pre alarms or alarms are shown during shutdowns , later the oil press alarm will appear , but its not related to the engine shutdown

in the attachment you will see a video of the operating parameters during operation and the shutdown , we highlited the fuel consumption , so its easy to see that while RPMs are running at 1800 suddenly the fuel consumtions drops to 0

we already check all the basics with no luck solving the problem. Since we use the generator only when there is a power failure in our city, we know that we dont have any short circuits in our equipments that may trigger an emergency shutdown.

If you have problems with file you can also dowload the video here:

https://drive.google.com/file/d/1BnkBED7kG6yjUH3lqrJcXCsNW1GtfxYx/view?usp=drivesdk

any suggestions will be really apreciated!

thanks in advance,

Alexander Coletta
Maracaibo Venezuela

 

[catserveng]

According to this parts book the unit has an air to air aftercooler,

http://info.bm.ee/gene_manual/V630/DT_CPD_00048_US_0.pdf

The spec sheet I found says it can be fitted with a watercooled aftercooler, do you know which you have? The older units were air to air cooled, the newer tier 2 units had water cooled aftercoolers and a split circuit cooling system to feed colder water to the aftercooler cores.

The manual says the charge air temperature alarm should come on at 80 degrees C, shutdown is 5 degrees C higher, you should get a fault code PID 105, 6.2 when the charge air temp hits 80 degrees. What kind of display interface do yo have on the unit? The small panel or just a fault lamp?

These engines normally have a blower fan, the air cooled aftercooler cores are are on engine side of the cooler assembly, if the air side of the jacket water radiator is dirty, cooling air won't flow properly.

You also need to check what the temperature of the air coming into the cooler assembly is, you may be getting hot discharge air recirculating back into the inlet of the cooler or possibly engine exhaust, have seen both.

Have you been running the engine at low loads for extended periods of time?

Here is a spec sheet with some of the technical data,

http://www.parsian-diesel.com/Uploads/Volvo/TWD1643GE/TWD1643GE.pdf

Who packaged the unit? Volvo usually only supplies the power unit, a company like SDMO usually adds the generator and enclosure.

I have some startup data from a couple of years ago on a 60 Hz 675kW standby unit, at full load charge air temp was 310 degrees F leaving the turbo, and 168 degrees F coming out of the aftercooler at the air inlet pipe to the engine. Ambient air temp to the face of the radiator was 81 degrees F, the units were air to air aftercooled. I have no data on a water cooled aftercooled engine, don't work on these units that often.

MikeL.

 

[TugboatEng]

If there was a fuel flow restriction the fuel rate would increase to max, not drop to 0. Fuel rate out of diesel engine ECM is based strictly on injecction duration and possibly rail pressure on a common rail engine. A loss of fuel pressure would cause the duration to go to max causing the displayed fuel rate to rise.

It really looks like your engine is getting a stop signal.

 

[alexander coletta]

PROBLEM SOLVED!


We finally were able to get the generator running under load!

As mentioned before we were getting High Air Temp in the intake manifold. Today we inspected again the complete cooling system.

Our engine is equiped with a coolant overflow valve that controls the amount of flow to the engine and to the intercoolers.

We check the valve an found the plastic Disc Broken. We were able to fabricate a replacement and now everything is running perfect.

Under load the air temp its 48C / 118 F

Below you can see a picture of the broken disc and diagram of the cooling system were you can see part #17 the overflow valve.

Thank you all for your advice

 

[itsmoked]

Well done! Thanks for getting back with the final issue/solution.

Keith Cress
kcress -

http://www.flaminsystems.com