Paper on Air Fuel Ratio and Combustion for Natural Gas Engines 2

[dwedel]

Here is a link to a paper on Air Fuel ratio for Natural Gas Engines. I have been to some of the classes offered by this company.

http://www.classactt.com/actt/actt_main/downloads/Air

Fuel Ratio Technical Paper.pdf

I was thinking that with the threads about detonation and air fuel ratio, this would be helpful.

David

 

[ElwoodGreen]

The full link didn't work for me, but I was able to get there from the company's home page. I see a couple of other potentially useful papers and an emissions calculations spreadsheet in the list of downloads.

 

[dwedel]

Kp, what is your relationship with walkesha engines? I work in the on a natural gas pipiline in the compressor dept handling maintenance issues. We have some of these engines as well as Superiors and IR.

 

[ElwoodGreen]

We have 5 Waukesha 12V-AT27GL engine-generator packages burning 100% landfill gas (about 58% methane on average). Each unit was factory rated at 2100 kW electrical output. After a series of catastrophic failures (2 connecting rods and 1 crankshaft) we tend to limit output to about 2000 kW each. Our current relationship with Waukesha is not good, as you might expect.

If you have their AT series engines (250 mm bore or 275 mm bore) then I would be interested in contacting you to discuss various items (maintenance issues, parts suppliers, etc.). That goes for anyone else reading this post. We have it on our list of things-to-do-when-time-allows to establish a users group for these engines. This might be a good year to get it done.

 

[dwedel]

contact me at david.wedel(at)wbip.com. We just installed two 8L-AT28GL drivers for pipeline compression. We also work with several 7042 & 7044 packages.

 

[mrpaul]

I maintain 2 8lat27gl cogens 1.4 kw each my employer is going to intall at least three more at27's in the near furture. I would like any info, data, problems or prayers that keep waukesha's up and running.
Thanks,
Paul

 

[ElwoodGreen]

Well, our latest failure looks to be a de-lamination of a main bearing. Bearing cavitation has been an issue in the past, and we have 2 units that haven't been "upgraded" with the later style, fully grooved, main bearings. We haven't gotten all the bearings inspected, yet, so I am not sure if we have any damage to the crank.

For all of these engines, the best thing I can say is be sure to get all the service bulletins currently in effect, and try to get all previous service bulletins. These will sometimes tell an interesting story if you can go back and see all the various "fixes" for a given problem. Exhaust, oil and coolant leaks are a problem.

On the 8-cylinder engines, they had a lot of vibration problems in the past, and aftercooler mounting problems. Could be related. I do not know if any of them had the same con rod problem. Some folks in Michigan had a broken crank that was caused by "lack of oil" or similar story. Be sure to check all the internal oil lines as Mr. dwedel can attest to.

Operationally, we have trouble keeping the air/fuel control system calibrated. Our exhaust oxygen sensors are subject to various contaminates, though. Basically, we have an extremely high amount of maintenance to do just to keep up, never mind trying to make improvements. Resources are too thin here.

 

[mrpaul]

Hey guys,
A major control systems company is in final stages of devloping a replacement fuel system for waukesha lean burn engines. The prototype is running on one of my at8's as I type this. The original waukesha fisher regulator system is complete junk by comparison. I would give you more details but they might kill me if I don't ask first.

 

[dwedel]

Is it Continental Controls/Altronic? I'm not sure on the first name here, but it was a company that developed the A/F controls for Altronic.

http://www.altroniccontrols.com/index.html

Woodward has started to get involved with the A/F controls as well. They have a product for Ajax, a company that produces integral field compressors. I hadn't heard if they were moving beyond that point.

Sounds intresting, keep us informed.

 

[ElwoodGreen]

Altronic built/builds all the electronic controls for Waukesha as far as I know--Ignition modules, Detonation sensing modules, turbo control modules, A/F modules, etc. We purchase a few items, such as ignition coils, from an Altronic dealer instead of a Waukesha dealer--saves a bunch of money that way. Our Waukesha dealer's standard practice seems to be: part maker's list price x 3 (or more) = customer's price.

We have some Fisher 1098 regulator issues, but I think it is mostly a maintenance problem caused by dirty fuel. If someone makes a fuel system that requires less maintenance with our fuel (landfill gas), then I am interested.

 

[enginesrus]

I'm curious about the bearing delamination problems.
What kind of oil and oil pump pressures are being used?
And what are the lamination layers made from and their thickness? Is the material just flaking and or pealing off, or just a pitting effect? And at how many hours?
And what kind of oil change intervals? Has it been determined if it is a manufacturing problem, a chemical or mechanical attack?
Do you keep installing bearings from the same manufacture?
And are there udates on them? What are they? Wow lots of questions. Sorry. I just have some ideas that may help.

 

[mrpaul]

The AF system is from Continental Controls contact Ted Hill 909-244-9713 and tell him Paul from IEUA sent you.

 

[dwedel]

Ha!, Continental Controls, every now and then I get lucky. We just put two on a Wauk 7042 last year (one for each bank). We have also been putting 4 on Superior 8GTL's. Of course all these are dirty burn. As far as I know the only difference with the lean burn is the O2 sensor and the O2 settings. CC has been bugging us for a couple of years to try some of these.

I imagine they work well. With the 8GTL's I think we have tried to control them ourselves, using our station PLC and have had difficulty with communication. It isn't my project, so I can only relay what I have heard.

 

[Monagas]

Hi friends,
I really need your help in this subject.

Have you heard about the NBN (n-butane number) used like a fuel gas knock index for SUPERIOR engines. If it so, could you give information about the method of calculation.

If you Know something about the HHV and LHV recommended for the normal operation of this engines, I will really appreciate it aswell.

My best regards !!!!

 

[Istanbul34]

hi,
we have the same problems with caterpillar 3516B natural gas generators related with oxygen feedback.calibration needed very often and not reliable for governing purposes.
Solution is charge density.you must cancel oxygen sensors and adjust emissions with air/fuel ratio controls,which receives feedback from kw/load sensors.

 

[Apathy2Apparent]

We have used Workhorse Power Products workhorsepower dot com for our alternative parts for the Waukesha VHP series engines....if that's any help to anyone else here. Less Expensive, with reliable parts and technical info when i need it.