High Exhaust Manifold Temperature on Caterpillar 3616 Diesel Engine 1

[fsxn155]

We are facing problem of High Exhaust Manifold Temperature problem on Caterpillar 3616 Diesel Engine
The Engine is rated for 5.3 MW at site Conditions (max Inlet Air temp of 49 Deg celsius. However in summer season with ambient temperature in range of 35-40 Deg celsius, the Right Exhaust Manifold (Turbo Charger Inlet) Temperature reached 639 Deg Celsius. Left Exhaust Manifold (Turbocharger) Temperature reaches 613 Deg Celsius. Alarm is at 635 Deg Celsius. The Individual Cylinder Exhaust Temperatures are b/w 458 to 502 Deg Celsius. The Inlet Manifold Pressure and Temperature were 249 KPa & 78 Deg Celsius.
Engine Jacket Water Inlet/Outlet Temperatures were 96 & 97 Deg Celsius respectively.
Engine Valve Lash, Valve Bridge, Injector Timing and Injector Synchronization have been verified/adjusted

Appreciate any advise on this issue

 

[Lou Scannon]

To start with, I suggest verification of the right exhaust manifold temp sensor.

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

 

[fsxn155]

The Sensor has been replaced.

It is a land based unit 50 hz. This is basically an Emergency Diesel Generator which is on standby during normal operation. It was commissioned in 2007. The problem is reported during last Test Run. I have been recently involved in this issue. I have come to know that the problem surfaced in 2017. I have been able to obtain Factory Test Reports which indicate that at Air inlet Temperature of 27-29 Deg Celsius, Engine was able to reach 5.9 MW with maximum 575 Deg Celsius Manifold Temperature.

When I compare parameters of Factory Test with lates test run below are some observations

At full load during factory test turbo boost pressure was 340 Kpa and Factory Test Specification requires minimum of 275 - 280 Kpa. During last test Run Inlet Manifold Pressure was 249 kp

At full load during factory test Inlet Manifold Temperature was 74 Deg celsius and specified limits are 60 - 80 Deg Celsius. During Site Test Run Inlet Manifold Temperature was 78 Deg Celsius

During Factory Test JW Pump Pressure was 363 Kpa, JW Inlet Temp was 88 Deg Celsius and Outlet was 97 Deg Celsius. Corresponding values at site test run were 270-278 Kpa (JW Pump Pressure), 96 Deg celsius (JW Inlet) & 97 Deg Celsius (JW Outlet)

The cylinder temperatures during factory test run were 448 to 471 Deg Celsius.

I am still waiting for Site Test Report from the time When Engine was OK. But based on above comparison I am not sure which can be the main contributor

Turbo boost low

JW Pump Pressure low and also little heat removed by JW as Inlet Outlet Temp rise is too low

Difference b/w Turbo charger Inlet and Individual Cylinders Exhaust during Site Test Run is greater then during factory test run. Is it possible unburnt fuel is carried to exhaust manifold and is burning there ? Injectors have not been replaced on this Engine

 

[Lou Scannon]

I'm starting to wonder about fouling in the charge cooler (pressure side), restricting the air flow. Your site intake manifold pressure is 90kPa below the factory boost pressure. Do you have site boost pressure?

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

 

[catserveng]

Can you post your serial and arrangement numbers? This helps determine exactly how your unit is configured.

Also some additional info, such as,
Hours on unit.
Is this problem existing from install or something that has happened short or long time after install?
If this problem has come up some time after install, can you describe your maintenance/testing runs? Loaded or unloaded, how do you test with load, etc.
Was a cooling system audit performed at startup and commissioning?
Can you provide more detail on site conditions? You have high ambient temp conditions, are you at altitude, near coastal conditions, etc.

Based on what you provided so far I'd think Hemi is on the right track, but need more info to make a better answer.

To your question about overfueling, is the exhaust smoke excessive?

Have you contacted your local CAT dealer, or are you in an area without good support?

MikeL

 

[fsxn155]

Engine Arrangement Number is 7E7016
Running Hours 2236
There are total 04 Engines commissioned in 2007. I have been recently involved into this problem. I have been collecting the data from past Test Runs. Uptil now the I have reviewed the Test Run results since 2015 and problem has been there since 2015 on all 04 Engines
Engines drive generators are for Emergency Power and Load Test is done once every month with Engine taken to rated load of 5.3 MW
We have high Ambient Temperatures in the range of 49 Deg Celsius and also high relative humidity as its Coastal Area. The Engines are rated for max 49 Deg Celsius Ambient and 100% Relative Humidity

I understand Turbo Boost is function of Engine Load as well as RPM not only RPM. However in current scenario I am trying to establish cause and effect i.e. reduced Turbo Boost is causing reduced Engine load/output or Reduced Output/Load is causing low Turbo Boost. Below is What is my understanding

Turbo charger Turbine Wheel output is function of Engine Exhaust Gas inlet Pressure and Temperature and Exhaust Stack Back Pressure at Turbine Wheel Outlet. Increasing Load at same Engine RPM increases Turbo Boost because inlet temperature to Turbo Charger Turbine Wheel is increased whereas Exhaust Gas Inlet Pressure to Turbo Charger as well as Stack Back Pressure remain nearly same.

In other words What I am trying to understand is comparing two cases with an Engine at 5.9 MW Load, 1000 RPM and 575 Deg Celsius Turbo Charger Inlet Temperature and same Engine at 4.6 MW, 1000 RPM and 615 Deg Celsius Turbo Charger Temperature, in which case Turbo Boost will be greater

To be honest I would like to mention that till now my experience with Engines had been with WAUKESHA L-7042 GL Lean Gas Engines and WARTSILA 18V46 Diesel Engines

 

[catserveng]

The arrangement number you provided is a basic build arrangement, so to get some more specific info I had to make some assumptions, if you can provide a serial number I don't have to guess.

Attached is what I think your performance spec is based on the info you provided so far.

A number of things are going to affect the difference in MAP vs Load, although depending on what turbo is actually installed you will find mid range power outputs will have higher exhaust manifold (turbo inlet)temperatures than at full load. These engines at higher ratings are particular about IMAT (Inlet Manifold Air Temp), a large number of smoke, low power and poor performance complaints on these engines is due to low load operation and fouled aftercooler cores.

Are Kiene (cylinder pressure indicating) valves installed?

The difference between the described exhaust port temps and the exhaust manifold temps is higher than I'd expect, normally the exhaust manifold temp runs about 50 degrees C above the average port temp. Also your port temperature deviation is a bit higher than I'd expect as well. Do you know what your exhaust back pressure is? The 3600 engines have a different exhaust backpressure spec than other CAT engines, was a pretty common issue found during commissioning.

You haven't said much about the exhaust smoke issue, does it start to clear the longer the engine runs? Overfueling could be a contributor, but usually shows up on the exhaust port temps.

These engines require a pretty comprehensive commissioning report at startup, do you have access to those, if they were actually done.

MikeL.

 

[fsxn155]

Dear Cat Serveng
Thanks for the detailed reply and providing the performance Spec. Engine Serial Number is 1PD00487
Cylinder Pressure Indicating Valves (Kiene) are not installed.
There is no abnormal observation related to Exhaust smoke though the vent is at height
I have attached the parameters from the Engine Load Test Run Data in attached Excel Sheet. It seems when Intake Manifold Temperature is below 80 Deg Celsius the Exhaust Manifold Temperature is below alarm limit of 630 Deg Celsius. Further the Cooling Water Inlet to AC/OC is many times above 63 Deg Celsius whereas as per Factory Test Specification, it should be 57 - 63 Deg Celsius
Unfortunately Exhaust Back Pressure measurements are not available. I am working on having arrangement to measure back pressure during next Load Test
Still I ma unable to access commissioning reports though I have been able to access Factory Test Reports

 

[catserveng]

Can you supply the other serial numbers? It is likely I may know who commissioned the units if they got a factory commissioning, but in later years some combined site reports only got filed under one of the serial numbers.

I will take a look a your data when I get home this weekend.

My biggest red flag is the difference in your average exhaust port temps and the turbo inlet temps. The most common cause of this is excessive exhaust back pressure, the ABB turbo's are pretty picky about that. Other possible causes are a dragging turbo, and have found in some cases incorrect fuel injector timing (too retarded) causing a similar issue. And that problem is more common that expected since the correct timing should be on the nameplate and is in the performance spec, but the service manual uses the "standard" timing. You appear to have a "high output" engine, so likely you timing is something pretty different than the standard setting.

Hope that helps, MikeL

 

[fsxn155]

Dear Mikel
Many thanks for useful information provided
The Engine Serial Numbers are
1PD00484
1PD00486
1PD00487

Valve Lash and Fuel Injector Timing has been adjusted/verified by Cat Dealer. I have come across the term "High Out put" in O&M Manual. As per O&M Manual the high exhaust manifold temperature alarm for high High Out Put Rating should be 650 Deg Celsius whereas for standard engines it is 630 Deg Celsius. Our documents show alarm set point of 630 Deg Celsius.
Can you advise what is criteria to determine if the Engine is High Output Rating Engine

Thanks Again for sparing time and reviewing our problem.

 

[catserveng]

So this is your actual performance spec for your engines, 0K8359

Yes, your engines as standby rated at that power level would be considered "High Output".

Just taking a quick look at your numbers I suspect that the bank to bank injector sync may be off a bit, and with that engine not hard to do. How much experience does the local dealer have with 3600 engines?

Are the engines installed in Kuwait? Or somewhere else?

So when you used to test run in the summer to ACOC inlet temps were above spec max of 60C, but it looks like sometimes of the year you were at or below spec. Now your your IMAT temps are going up even when the inlet water is at or below spec, your increase in exhaust temps coincides with your increase in IMAT temps. So based on that info I'd check the water side of your aftercooler core and see how it looks. Have you been using proper coolant and corrosion inhibitor? Actually in standby units we can tend to have more cooling system problems because the coolant doesn't circulate well enough. Also in your part of the world getting cooling water that meets the CAT spec is a challenge, I dealt with many engines in the region and found that scale and deposit buildup was a fairly common problem in cooling systems in that area.

In reality those engines should have been CCAC, Combined Circuit AfterCooling, letting the jacket water system strip off most of the heat and using the separate circuit to take it down the rest of the way. Based on your as shipped consist it looks like CAT shipped a bare genset engine with rails and locally a generator was installed.

Those engines also shipped with the GMS PLC based monitoring system, early on we had several problem with electrical noise affecting the thermocouple input modules. Have you followed the factory procedures to verify that the TC's are reading correctly? We used to recommend that the GMS system be calibrated and tested at a minimum of every two years.

A final thought, you have a couple of outstanding service letters on those units, one for inspecting the turbos due to a possible improper assembly of some bolt locks, and more importantly, there was a safety program that according to the record was never done for a rod bolt inspection. I would appreciate it if you would diplomatically ask your dealer about those and any other possible service letters that apply to you engines. I'm not technically in the CAT "family" anymore and CAT tends to be protective of the dealers. You might just ask the dealer if you can see a SIMS report for each of your serial numbers to make sure nothing has been missed. Some of the programs may be expired, but yuo should review what they are and the possible impacts to your equipment.

Hope that helps, MikeL

 

[catserveng]

You may find this helpful as well, it is a bit before your engines time but most of the info applies to your engines.

 

[fsxn155]

Hi catserveng
A lot of thanks for providing much useful information. I really appreciate your kind support on this issue