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

 

[crshears]

Hello Alexander, the Electric Motors & Generators & Engineering forum would have been a better fit for your query...but now that it's here don't bother moving it...

Is the unit out of warranty?

When this occurs, what steps have you had to take to get it to start and run again? Or will it immediately start again following unexpected shutdown without you having to do anything extra?

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]

 

[itsmoked]

When a diesel runs out of fuel it stops really fast. Perhaps there is no monitoring of the fuel pressure so you'll never see it reported. This is because things stop so fast they don't bother to present an alarm.

I would check to see if you have a fuel delivery problem, several of which can starve the engine. If you don't have a system vent at some point the lift pump will starve.

If you have fuel contamination with water and a water separator at some point the separator can fill completely with water and deliver it to the engine.

Material contamination including biologicals which is very possible with a standby system because the fuel never gets turned over. This can blind off the fuel filter in minutes. You replace it and it runs fine for a little while until the new filter blinds off in a few more minutes. Problem is, you've just replaced the filter so think, "it can't be the filter as we just changed it and the engine ran for a bit".

Keith Cress
kcress -

http://www.flaminsystems.com

 

[noneavailable]

Is there no fault indicator causing this shutdown? I didn't see voltage on the video. I have seen a turbo not properly connected (Loose plenum for input or blocked input or bad impellers) cause undervoltage condition below 50% of rated load which is a shutdown condition which would turn off fuel.

 

[alexander coletta]

Hello All,

Thanks for your advice, I will make a list of the things we have done to the moment:

1-) Fuel System : our first Idea was to the check fuel for contamination or obstructions in the line. Everithing was checked and no problems were found . We even changed the 2 fuel filters. Old filters were cutted to inspect them and no contamination was found

2-) A local technician suggested that we monitored the the temperature of the air in the manifold . When the generator its running with no load the air Temperature its around 150 farenheit , as soon as we put load in the generator the intake air temp increases up to 183 farenheit and the engine shuts down. We tested the generator disconecting the manifold intake air temaperature sensor , we applied load and BINGO the engine did no stop

3-) the technician recomendation was to make a cleaning service to both air intercolers , we did that ( no significant contaminations was found) we put eveithing together again ( including the air temp sensor ) but the engine stoped again when we applied load.


4-) At the moment we are cheking the electronic control actuator for the wastegate turbo Valve , we dont see that valve moving at all , so we believe that we are injecting to much hot air to the intake manifold.

any suggestions or comments are greatly apreciated I will keep you posted of any progress


thanks

 

[noneavailable]

Its a long shot but we had something similar. That sensor on our CAT was causing similar issue. We inspected sensor and it was somewhat damaged. Apparently the cylinder it was next to was causing it to heat up and trip the sensor. Long shot like I said, I like the idea with waste gate. Mechanics never came back with what was wrong with cylinder but they repaired whatever it was.

 

[itsmoked]

Why is the inlet air so hot? The volume thru an engine like that should be so large that I'd expect it to be near ambient. Is the measured temp between an intercooler and the engine and not the actual inlet air temp?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[GregLocock]

Despite having changed the filters etc it still sounds like a fuel blockage to me, specifically a blocked breather on the tank or dirt in the pickup, or a filter.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[SwinnyGG]

The volume thru an engine like that should be so large that I'd expect it to be near ambient

It is turbocharged.

alexandercoletta, are you monitoring MAP or mass flow??

A wastegate fault would definitely result in excessive boost pressure under load and cause a few different ill effects.

 

[SuperSalad]

How does the ECU monitor the RPM readings?

Could it be that the RPM values being supplied to the ECU at elevated loads are incorrect due to a faulty sensor or other fault along the line, and it is incorrectly reading a decrease in RPM that would trigger a fuel cutoff?

I don't know if a generator ECU would have that same control but automotive engines cut off fuel if the throttle is released and the RPM are still above idle speed to conserve fuel. They do require the vehicle momentum to keep the engine cycling though, so that's why I'm not sure if a generator would have such a control.

Andrew H.

http://www.mototribology.com

 

[davidbeach]

Perhaps out in left field, but what's happening with your fuel temperature? If the engine is using return fuel as coolant for the injection system, some do and some don't, and your fuel source is getting too hot that would cause trouble.

 

[Lou Scannon]

I assume there is a fuel cutoff solenoid or device. Did you monitor that to see exactly when it is being cut off, relative to the engine stoppage?

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

 

[FreddyNurk]

I've not seen it personally, but I've heard of issues with Detroit Series 60 units being rather sensitive to intake air temperature, and from your testing it wouldn't surprise me if you're experiencing something similar.
I don't recall whether it was identified through an engine fault code or not but from what I understand it was quite repeatable.

At a guess if its a fuel blockage, sometimes the engine will need to be reprimed, although the absence of that aspect for you doesn't necessarily rule it out. I'd also experienced issues with a fuel filter / flow meter arrangement that would starve the engine of fuel, in my case as far as I can recall the engine needed to be reprimed, it also damaged the injector tips after it happened a few times.

EDMS Australia

 

[catserveng]

Here is a link to an online manual if you don't have one,

http://library.parsianind.com/heading-7746032_view-2.htm

These engines are normally pretty well protected, and my experience with them has been that if anything is being monitored by the ECM causing a problem, it will log a code. Only two exceptions I know of is a problem with battery power, if the battery power drops below the minimum level the engine will stop and the codes will clear, it sees it as a RESET, at least in the versions I'm familiar with. Or a CANBUS fault.

In the genset applications fuel restriction usually shows up first as speed instability, not a sudden stop of the engine. If it runs out of fuel, on restart they usually run pretty rough after finally getting them started, then should smooth out once they purge the air. These engines don't have a very large fuel return rate as I remember, at least compared to other engines I work around.

The fact the low oil pressure alarm comes on after it stops usually indicates the ECM did not call for the shutdown, otherwise it would block that fault from coming in afterward.

If you have a wiring diagram, take a close look at the CANBUS wiring, some of these engines had issues with poor connections and bad or loose terminations resistors causing unexplained shutdowns. The workshop manual in the link above has the generic on engine wiring diagram, may not have the specific accessory wiring depending on your actual arrangement.

How long has this problem been occurring?
How old is the unit?
Did the problem start after a repair or service?
Is the problem getting worse?

Hope that helps, MikeL.

 

[dgallup]

2-) A local technician suggested that we monitored the the temperature of the air in the manifold . When the generator its running with no load the air Temperature its around 150 farenheit , as soon as we put load in the generator the intake air temp increases up to 183 farenheit and the engine shuts down. We tested the generator disconecting the manifold intake air temaperature sensor , we applied load and BINGO the engine did no stop

So you have already isolated the fault. Either the intake manifold air is getting too hot or the sensor is bad.

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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

 

[itsmoked]

I suggest the intercooler is not doing its job for some reason.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[alexander coletta]

Hello all and thanks for your posts

Today we did two new tests:

we used an old school pressure gauge to compare the readings of the control panel , conclusion manifold pressure sensor its OK

Later during the day we found a new Air Temp/ Air pressure sensor and run a test. Result was the same, as soon as we applied load to generator the air temperature in the manifold started to rise until the engine shut off at 185 F ( air temp)

All other parameters were running OK.

Intercoolers were allready properly cleaned , we dont know what other thing to test.

any suggestions? thanks


Alexander Coletta

 

[EdStainless]

You need to measure the inlet and outlet temps at the intercooler, on both sides.
You should be able to do a heat balance and see where the issue is.
It sounds like your 'clean' intercooler isn't actually cooling.
Either the cool side is actually fouled, or the flows are too low.


= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[FreddyNurk]

If its actually hitting 185F (85C) intake temperature then its not surprising that its shutting down.

From memory, the DDC Series 60 units would shut down under 70C, so its doing well to keep running at that temperature. EdStainless is correct, it seems that your intercooler isn't doing what its supposed to.

EDMS Australia

 

[FreddyNurk]

Actually, what kind of cooler is used for the intake air?

I've only ever dealt with air / air arrangements, but I'm aware of air / water, no chance its an air / water and the coolant pump isn't working?

EDMS Australia