rolandsean
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Joined: September 2020
Posts: 13
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Post by rolandsean on Oct 8, 2020 8:33:44 GMT -5
Been reading this thread and I have to be honest, about brought me to tears...I mean this in the most respectful way possible. It is amazing sitting and listening to older generation people share their knowledge and memories. I am still very young and I am grateful for youth and will try not to waste it but I do have a tinge of longing listening to people reflect on a life well spent. I truly hope I can have worthwhile stories to tell and knowledge to pass on when my body starts ignoring my commands. I have been very blessed to have elderly mentors in my career as a diesel mechanic and I look forward to learning as much from this group as possible!
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Post by racket on Oct 8, 2020 15:32:00 GMT -5
Hi Sean
Yep , enjoy your youth :-)
Theres plenty of info in all the various Member's contributions , not much that hasn't been tried with varying degrees of success , so read away
Cheers
John
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rolandsean
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Joined: September 2020
Posts: 13
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Post by rolandsean on Oct 8, 2020 18:17:15 GMT -5
John, this is not a novel concept but I am curious if you know of anyone here that has tried to repurpose a compound turbo setup from the volvo d13 or the Detroit DD15 engines? Detroit has been running this setup for 10 ish years and the engineering while pretty simple was rather novel in the trucking world (although just about all the manufactures dabbled with turbine power in the 80's, i had the pleasure of seeing one of two mack superliner turbine trucks at the mack museum up in allentown and talking to the test driver who recalls the challenge of cooling the exhaust enough to stop setting trees on fire and melting telephone lines). The setup uses a normal fixed geometry turbo with a mechanical recovery turbine mounted immediately behind, scavenging any remaining heat and through a gearbox and fluid coupler directly powering the flywheel through several gearsets. I am trying to source one right now as I work in the Durability and Reliabilty dept. for volvo and it would make the power coupling much easier. I doubt the power turbine is designed for the speed or heat it will see? We also used burner chambers on the old mack spark assist DPF's for trash trucks and I am trying to get my hands on a couple of those for experimentation as well. Most of them were replaced several years ago when the tech became available for passive regenerations. Anyways, i used to work on these burner units all the time but did not appreciate the technology until a few months ago when i learned about GT and found this group. If you and others feel this may add value to this group I will try to "earn my keep" in this group and post some cutaways and tech I have acquired over my years of being a diesel mechanic. We use these devices for slightly different reasons, for example, active regenerations on burner equipped trucks was solely for the purpose of creating high enough temps to combust particulate matter. Anyways, I habe just scrated the surface of the JATO sight so please chime in if this is a well covered idea.
-Sean
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Post by racket on Oct 8, 2020 23:54:52 GMT -5
Hi Sean
The compounded turbo arrangement on the trucks are similar to our freepower turbine equiped engines , the "difference" that will make it difficult to simply use the complete truck turbo and power turbine stage is the flow matching .
From the data I've been able to collect , it would appear that the freepower power turbine stage would be "undersized" if kept downstream of its partner turbo if it was made into a gas turbine .
The truck setup uses a higher interstage pressure than what would be the case with a gas turbine , the diesel engine "exhaust manifold" is undoubtedly running a higher pressure than the inlet manifold boost pressure .
The power turbine stage from the truck could be used but it would need a smaller flow turbo upstream to better match the power turbines flow restrictions .
Cheers
John
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Post by azwood on Oct 10, 2020 5:14:40 GMT -5
John, this is not a novel concept but I am curious if you know of anyone here that has tried to repurpose a compound turbo setup from the volvo d13 or the Detroit DD15 engines? Detroit has been running this setup for 10 ish years and the engineering while pretty simple was rather novel in the trucking world (although just about all the manufactures dabbled with turbine power in the 80's, i had the pleasure of seeing one of two mack superliner turbine trucks at the mack museum up in allentown and talking to the test driver who recalls the challenge of cooling the exhaust enough to stop setting trees on fire and melting telephone lines). The setup uses a normal fixed geometry turbo with a mechanical recovery turbine mounted immediately behind, scavenging any remaining heat and through a gearbox and fluid coupler directly powering the flywheel through several gearsets. I am trying to source one right now as I work in the Durability and Reliabilty dept. for volvo and it would make the power coupling much easier. I doubt the power turbine is designed for the speed or heat it will see? We also used burner chambers on the old mack spark assist DPF's for trash trucks and I am trying to get my hands on a couple of those for experimentation as well. Most of them were replaced several years ago when the tech became available for passive regenerations. Anyways, i used to work on these burner units all the time but did not appreciate the technology until a few months ago when i learned about GT and found this group. If you and others feel this may add value to this group I will try to "earn my keep" in this group and post some cutaways and tech I have acquired over my years of being a diesel mechanic. We use these devices for slightly different reasons, for example, active regenerations on burner equipped trucks was solely for the purpose of creating high enough temps to combust particulate matter. Anyways, I habe just scrated the surface of the JATO sight so please chime in if this is a well covered idea. -Sean think this my help |
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Post by racket on Oct 10, 2020 17:12:05 GMT -5
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Post by finiteparts on Oct 11, 2020 13:44:04 GMT -5
Hi Sean, I have picked up a Cummins HP841 and you can read about it and other turbocompounding systems here: jetandturbineowners.proboards.com/post/23342/thread (corrected link - 10/13/2020) and some of the photos of the internals here: jetandturbineowners.proboards.com/post/25335I have not worked to incorporate it into an engine. I picked it up more as a curiosity to see how Cummins/Holst approached this issue. I agree with John, that the full HX55 + HP841 combo might be a challenged to run as a turbo-based engine, but I haven't run the numbers to verify that, so in reality, that is just an opinion. I also have a few staged turbochargers, such as the ACERT C-15 and the Borg Warner's R2S that I would like to try to use as a two stage gas turbine. Unfortunately, I have a pile of projects and very limited free time to work them. Hopefully, someday soon I will be able to share them on here. Good luck, Chris |
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rolandsean
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Joined: September 2020
Posts: 13
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Post by rolandsean on Oct 11, 2020 23:07:13 GMT -5
Chris, the first link you sent (jetandturbineowners.proboards.com/post/29728) just sends me to one of my posts. Is this the correct link? I am curious to see how a turbo compound setup might be superior in a GT setup. The automotive world uses turbo compounding to help with spooling a larger turbo quicker, same with split channel turbine housings; I would think that this benefit would have much less importance for the GT world. I also have a few Variable Geometry (Variable Nozzle) turbos I have toyed with the idea of seeing how they react but just like turbo compounding, VGT's shine in their uses for emission control more than outright flow. Now a turbine section of a VGT/VNT repurposed for a power take off might have benefits.
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rolandsean
Member
Joined: September 2020
Posts: 13
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Post by rolandsean on Oct 11, 2020 23:20:44 GMT -5
HAHA I was just thinking about this but I wanted to search for it to see if it had already been done before I asked you fine folk! For kicks and giggles I was staring at the ol 12v today contemplating throwing a GT in the bed and seeing how she would respond. Anyways, dumb idea I just thought it would be interesting to replace the turbo with a GT and see how throttle response and soot might clear up a little. |
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Post by racket on Oct 11, 2020 23:57:30 GMT -5
Hi Sean
More info please , expand the concept :-)
Cheers
John
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rolandsean
Member
Joined: September 2020
Posts: 13
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Post by rolandsean on Oct 12, 2020 8:44:55 GMT -5
I probably shouldn't have used that nomad/napier engine as a segway; poor comparison! THAT was an enjoyable read, John! What a cool engine!
It is merely a pipe dream right now but I was curious if you had a high CPR (I believe this is the characteristic you would want) turbocharger if you could divert a part of the compressed air to the engine, literally as redneck and barebones as connecting that outlet directly where the normal turbocharger compressor outlet would be (a way to modulate air would be mandatory so the GT could be optimized to run on the reduced air flow, a blow off valve would suit this purpose), through the CAC and intake and the rest is suck squeeze bang blow history...
Besides heat concerns I would imagine you would also have to consider the richness of the engine since simply calculating the amount of air leaving the compressor would no longer be accurate for knowing fuel demands. Aviation jet engines bleed a good amount of compressed air for cooling, AC, hydraulics and other PTO. Of course it would be terribly inefficient but thought it would be cool to see how it would compare to compounds or VGT's. Plus you could probably make a case as a hybrid and get them gov'ment tax credits to add a spare bed onto the doublewide!
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jetric
Veteran Member
Joined: December 2014
Posts: 149 
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Post by jetric on Oct 12, 2020 10:04:02 GMT -5
Hi, It has already been done and it is called 'Hypercharging' large tank engines used to use it in order to have huge amounts of torque at low RPM, It is discussed in thomas kamps book, picture below;  Also look at this, Enjoy, Richard S. I probably shouldn't have used that nomad/napier engine as a segway; poor comparison! THAT was an enjoyable read, John! What a cool engine! It is merely a pipe dream right now but I was curious if you had a high CPR (I believe this is the characteristic you would want) turbocharger if you could divert a part of the compressed air to the engine, literally as redneck and barebones as connecting that outlet directly where the normal turbocharger compressor outlet would be (a way to modulate air would be mandatory so the GT could be optimized to run on the reduced air flow, a blow off valve would suit this purpose), through the CAC and intake and the rest is suck squeeze bang blow history... Besides heat concerns I would imagine you would also have to consider the richness of the engine since simply calculating the amount of air leaving the compressor would no longer be accurate for knowing fuel demands. Aviation jet engines bleed a good amount of compressed air for cooling, AC, hydraulics and other PTO. Of course it would be terribly inefficient but thought it would be cool to see how it would compare to compounds or VGT's. Plus you could probably make a case as a hybrid and get them gov'ment tax credits to add a spare bed onto the doublewide! |
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rolandsean
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Joined: September 2020
Posts: 13
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Post by rolandsean on Oct 12, 2020 10:30:55 GMT -5
Appreciate it, Richard! I will check this out tonight
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rolandsean
Member
Joined: September 2020
Posts: 13
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Post by rolandsean on Oct 12, 2020 13:33:07 GMT -5
I really appreciate that link, Richard. That was an amazing video! Literally exactly what I was thinking of...of course it has already been done! Thanks again!
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Post by wannabebuilderuk on Oct 12, 2020 14:57:17 GMT -5
So that's basically a race car with an air starter gas turbine providing a constant 30psi to the intake.... Jesus that's gotta be fun!
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