GE locomotives have long been notorious for taking their good old time to load up while moving and especially when coming out of dynamic brake and going into power. A lot of this can be attributed to turbo lag and the need to match turbo boost with fuel flow in order to not create clouds of unburned fuel as the engine tries to find the correct air/fuel ratio for the requested throttle setting. In other words, the engineer wants power now, but, the engine says you are going to have to wait while I do this my way.
This makes for some no so good train handling when coming out of dips and not being able to get the power down when needed to take the slack out while going uphill. Personally, I have had light tonnage trains that while going 40 mph at the foot of the hill and then having the speed drop below 20 mph as the engine is taking its time to load. This, even though the units were more than able to pull the train uphill at more than 40 mph.
Enter Formula One
This year, F1 rules mandated the use of turbo charged V-6 engines. Along with that, there are Kinetic Energy Recovery Systems and Energy Recovery Systems Heat. The KERS uses energy stored in batteries to drive an electric motor connected in some way to the crankshaft. The batteries are charged while the car is under braking.
But wait! The ERS-H system is much more interesting and this is where GE could learn a lesson. If I may quote Mark Hughes of Motorsport Magazine:
"But these new cars have an ersH electrical turbine on the same shaft as the turbo: this can be used either to feed excess turbo energy to the battery or in the other direction to spool up the turbo to eliminate lag. (my emphasis)"
So, GE, how about embracing some new technology to make your engines load up when the engineer wants it to?
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I think I've brought up a similar idea on this forum. IIRC, it was more like having the exhaust turbine spinning an alternator, with the compressor driven by an electric motor, where both the alternator and motor were tied to the output of the main traction alternator. The idea here was that the turbine would act in the same manner as the power recovery turbines on the Wright Turbo compound Cyclone aircraft engines.
Seems like a reasonable idea to me.
- Erik
The modern AC versions of GE engines don't seem to have the lag time as the DC versions. Or maybe EMD AC versions now seem to have about the same lag time as GEs do so it isn't as noticeable as it once was.
The all time worse engine for this lag time has to be an EMD. Those SD9043 engines that UP has thankfully sidelined have to be the all time worst engines. It seemed to take them forever to start loading, worse than any GE.
Jeff
The technology being discussed here is turbo-compounding, that is using a second exhaust gas turbine (Most Diesel electrics already use an exhaust turbine-the turbocharger) to extract energy from the exhaust stream to spin a secondary alternator.
This technology is already being used on smaller diesel engines (truck engines) and much larger diesels (huge cargo ship engines) so it seems logical that it might be developed for railroad applications as well...
"I Often Dream of Trains"-From the Album of the Same Name by Robyn Hitchcock
BrendenPerkinsInstead of spending tons of money redoing the engine... change how you run. Go down the hill a few mph below track speed. BEFORE you get to the bottom, notch up. Have you engines revving at least by the time you are at the bottom.
Does not GE currently have hybrid engines running that would cover this issue? Why make the engine dance to varying loads when batteries can do that work?
Brenden no need namecalling, pretentious or anything worse, just that you are a locomotoive engineer and so is Big Jim. You can be proud that you have the skill to get the best out of GE locomotives, and I bet you can get the best out of any locomotive of any type. Big Jim prefers that the locomotive respond to his demands, that he should not have to cater to the locomotive's characteristics, but simiply run the train (Big Jim -at track speed, right?) to get over the line with good economy and minimum time. When I was on the B&M 1952-1953, I saw two different engineers handle the two GP-7's I was testing differently in several similar situations, neiher one wrong.
BrendenPerkinsI run Warren Buffets trains for a living, thank you very much. I take it you're a pretentious ****.
Different territories, different locomotives, - each requires their own train handling strategies for optimum performance.
Never too old to have a happy childhood!
Brenden and Jim,
Trainhandling, I learned and ran on California and Mexico mountain grades, and qualified and instructed engrs on them; "supervised" training and disciplined them.
What each of you are saying, works.
A train bunched on dynamic brakes at the bottom of a grade, entering another upgrade or flatter terrain, comes out of DB, puts it right into, suddenly, Run 8.... run away from the bunched slack......Benson, Az....Andesite, Ca
Hayward CA, westward (to Oakland) there's a mile long, (actually from the north part of Union City) descent at about !.5%. Suppose an occupied caboose, appropriately placed in the train, and it is climbing another 1% grade?
Cause the last, rearmost 3000' are still rising, might you decide to ride down the grade, lose speed, have to wait for turbos to do their things to get a stretch on the slack? at the grade's bottom....time? the brake release? While the train's brake release , the engines power tries to keep slack stretched.
My qualifications: Altamont, Cuesta. American Canyon, Beaumont, Bakersfield- Tehachapi-LA or -Colton, via Cajon Pass, Hipass to San Diego thru Baja California Del Norte.....Oakland to....Sparks over the Sierra Nevada...
Hello, folks:
Please remember to be respectful to one another. We are all very passionate about the topic, but we have to remember that there's no reason to insult each other. I hope you all enjoy your week and a nice three-day weekend!
Angela
Angela Pusztai-Pasternak, Production Editor, Trains Magazine
LensCapOn Does not GE currently have hybrid engines running that would cover this issue? Why make the engine dance to varying loads when batteries can do that work?
GE has been developing the hybrid version of the ES44AC for the better part of the decade but I am uncertain if they are testing the full version with the energy recovery system as of yet.
The demonstrator locomotive in the Hybrid paint scheme that GE was touring about 5 years ago did not have the batteries installed. In the development process GE determined that the existing Lithium Ion batteries available on the market (used in the majority of IC-Battery Hybrid cars and trucks)could not stand up to the shock load of a freight locomotives.
They have since developed a newer battery technology;Molten Salt batteries and have built anew manufacturing plant to make them. These are being sold to industrial and power customers so presumably the locomotive project should progress.
Molten salt batteries.....time to Google.
But first, Angela....Where were you when I couldn't wring out of "big jim'" why he thought an engr had to determine the speed, no matter what the train crew members decision was, at which speed to give the pin during a drop?
He finally, in Archie Bunker speak, stifled. Never answered.
Molten....big jim....If indications of his quirks...... were seen by me, he would not be hired by me.
Molten......a locomotive engr's strength, ego, intelligence, education, experience, guts, confidence, a lot of the valuation. But.....
Stipulating, then voluntarily stifle?
uh, NO!
the string's subject "here" was "What were poling pockets?," but differently worded.
Leaving aside the rest of the off-topic material...
efftenxrfeMolten salt batteries.....time to Google.
The COMSOL (formerly FEMLAB) multiphysics conference CD I mentioned previously, containing discussion of this battery, may no longer be available. Fortunately for those with an actual interest in the technology, the COMSOL Web site now hosts most, if not all, the conference proceedings that were on the CDs.
Vallance's paper on the GE hybrid locomotive battery is here:
http://www.comsol.com/paper/rechargeable-battery-for-hybrid-diesel-electric-locomotive-6438
There are other articles on battery chemistry and structure adaptable to hybrid locomotives, which can be relatively easily found starting from the above link. (Along with many, many other fascinating things to occupy an idle hour, or two, or more...)
Even if 'fluorescence' is misspelled (;-}), I trust this reference will be of use in understanding GE's approach to battery chemistry.
efftenxrfeHe finally, in Archie Bunker speak, stifled. Never answered.
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