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Two Cycle Diesel Locomotive

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Posted by tdmidget on Tuesday, February 9, 2010 7:56 PM

 Redore appararently you haven't read this entire thread. See page 1. It should be self evident that if all these fanciful tests were done, and locomotives are still running on No.2 diesel there's a reason. IT DOES NOT WORK. period.

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Posted by Redore on Tuesday, February 9, 2010 11:26 AM

Bunker C is common on marine diesels and it actually has more heat (energy) per gallon than No. 1 or 2.  It has been used in diesel locomotives on a test basis, as well as driving the UP turbines.

 BN even ran a semi successful test using a ground coal in water slurry to operate a locomotive, as well as propane and liquified natural gas.

If it burns and you can figure a way to reliably inject it into the compression stroke of a diesel, the engine will probably run.

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Posted by broncoman on Friday, February 5, 2010 7:57 PM

 I admit that other than what I read hear I am limited to over the road diesels, but I would think that some of the items in your post would be the same no matter what size.  I don't believe that 4 stroke versus two stroke resulted in that big of a difference in component weights it would seem more a choice by designers.  While a 4 stroke may have a turbo, a 2 stroke HAS to have a turbo, or some form of forced induction.  Ford and GM both had engines without forced induction.

I wasn't able to work on as many Detroit's as I would have liked, but in driving them the power seemed way more peeky than say a Cummins or Cat like driving a small import 4 cylinder vs a v8.  I know that you also ended up with a lot of damage to a Detroit lugging it than you would with an equivalent 4 stroke.

 

 

 

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Posted by tree68 on Sunday, January 31, 2010 8:14 AM

IIRC, EMD engines and Roots blowers go (went) together like the proverbial horse and carriage.

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Posted by Cooter50 on Sunday, January 31, 2010 6:15 AM

 It has been in fact almost 15 years since I last worked a EMD so I am not up to speed on the 710 nor the late 645, I can attest to the fact all the marine 645/567 engines and stationary units I worked had conventional roots blowers with conventional gear drives, the turbo chargers were additional devices if they had them; I have never set foot into the engines of rail service so I am a bit underinformed on them.  Sorry if I offended anyone on that but I can only draw on my experiences.

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Posted by silicon212 on Saturday, January 30, 2010 7:15 PM

Cooter50

 OK, time for a old mechanic to pipe up;  I worked Detroit Diesels, EMDs, Cummins, CAT, ALCO and GE for over 25 years until I moved up to full time steam power station employee.

 

EMD is nothing more than an oversized Detroit Diesel, it uses a roots type blower to scavenge the cyls. is correct but neither has 'poppet' valves, they are conventional engine valve trains but only for exhaust.  The blower has to be connected for the engine to run and there is no over-running clutch/speed changing control on them, the turbo charger is considered the 'supercharger allowing for more air inflow so fuel can be increased.  The stroke engines respond 'quicker' unloaded but under load they tend to be sluggish unless in the power band of the engine or higher RPM, at low speeds they do not scavenge as well and loadup on fuel smoking heavily unless limited to boost air pressure until at a rating speed.

......

#1.  Poppet valves - these are the type of valve you see in car/truck engines - 4 stroke engines etc.  What you call 'regular' is in fact, a poppet valve.

#2.  EMD two stroke engines do not use a combination of Roots blowers with turbos - this is Detroit that does that.  EMD in fact does use a gear driven turbo with an overrun clutch on it, that allows it to free-spool when the exhaust drives the impeller faster than the geared input does.  This takes the place of the Roots blower, performing the same task when the engine is not running quick enough for the exhaust alone to drive the impeller.

#3.  Due to #2 above, there is no 'turbo lag'- the EMD will in fact scavenge well at low RPM and won't smoke under acceleration, unless there is a mechanical problem.

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Posted by edbenton on Saturday, January 30, 2010 12:51 PM

The will MEET it but look for Exhaust Aftertreatments on them.  Also known as DPF filters.  Those will be fun to see if they will last 90 days with no service.  Considering in the OTR service they are lucky to get 40 MTBF.

Always at war with those that think OTR trucking is EASY.
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Posted by Cooter50 on Saturday, January 30, 2010 12:41 PM

 I stand corrected on the 265 EMD, they are still in production but for standby systems and marine, the bugs are still being worked out.  As to the EPA cert on the 710, the 2005 limits are about to expire and the 710 may not make the next culling.

 

Evidently the GE/German GEVO engines are fairing no better.

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Posted by nedthomas on Saturday, January 30, 2010 12:08 PM

I worked on some engines in the military that started as gas engines and switched to diesel when running. A third set of valves changed the compression ratio. They had a carburetor and intake manifold. The gas was supplied from a small day tank. Lots of parts just to start the engine. Never worked that well. Your tax dollars at work.

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Posted by CAZEPHYR on Saturday, January 30, 2010 12:00 PM

Cooter50
EMD has gone to 4 stroke engines to meet emission levels as well as fuel efficiency, remember every time a 2 stroke cyl hits top dead center it fires or twice as often as a comparable 4 stroke at the same RPM and HP.

 

EMD tried the H model engine for the true SD90Mac which was a 4 stroke 6000 HP engine and cancelled it due to many problems.   The Tier II SD70Ace 710 model is a two stroke engine from all of the specifications. 

CZ

 4,300 THP and locomotive equipped with EMD's
16-710G3C-T2 engine

  • EPA Tier-2 emissions certified
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    Posted by Cooter50 on Saturday, January 30, 2010 9:55 AM

     Almost all line engines(locomotives) weigh close to the same, it is the final drive/traction motor gearing or ratings that will make them slip.  The engines run generators, now going to AC power and the transfer of power from engine hp to electrical energy is getting much better, all the new engines are doing very well as to power, speed, efficiency and productivity.

     

    I made a error in my last post, not 'The stroke but The two stroke engines'.  As to Fairbanks they also still make a opposed cylinder engine for maritime use.

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    Posted by BigJim on Saturday, January 30, 2010 9:27 AM

    monon99

    I'll take a GE every time - pulls like a bear and won't let you down - the EMDs will be a constant fight with sand and independant brake to get them to quit slipping and lose so much speed that you stall

    What a bunch of horsehocky! Guess you haven't run a GE lately!
    Those poor things will lose traction in a heart beat and stall on you just as fast!

    .

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    Posted by Cooter50 on Saturday, January 30, 2010 8:51 AM

     OK, time for a old mechanic to pipe up;  I worked Detroit Diesels, EMDs, Cummins, CAT, ALCO and GE for over 25 years until I moved up to full time steam power station employee.

     

    EMD is nothing more than an oversized Detroit Diesel, it uses a roots type blower to scavenge the cyls. is correct but neither has 'poppet' valves, they are conventional engine valve trains but only for exhaust.  The blower has to be connected for the engine to run and there is no over-running clutch/speed changing control on them, the turbo charger is considered the 'supercharger allowing for more air inflow so fuel can be increased.  The stroke engines respond 'quicker' unloaded but under load they tend to be sluggish unless in the power band of the engine or higher RPM, at low speeds they do not scavenge as well and loadup on fuel smoking heavily unless limited to boost air pressure until at a rating speed.

    GE is now using a variation of the old ALCo engines, updated, improved but just as reliable and less smokey the GE engines proved tyrannical as to internal damage for no reason.  EMD has gone to 4 stroke engines to meet emission levels as well as fuel efficiency, remember every time a 2 stroke cyl hits top dead center it fires or twice as often as a comparable 4 stroke at the same RPM and HP.  Faibanks still markets engines but from the Colt-Pielstick corporation of France, very good standby/marine engines but HUGE.  CAT is up and coming on Genset locomotives as is Cummins corporation but they are way behind on technology.

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    Posted by Jerry Pier on Friday, January 29, 2010 1:26 PM

    I hate to quibble but it's a two STROKE cycle not a two cycle engine. One of EMD engine's advantages was that the use of both a turbo supercharger and a mechanically driven supercharger improved emissions in partial throttle conditions (which is most of the time). EMD's and GE's were about the same at notch 8. Can't comment on EMD's four stroke cycle engines.

    JERRY PIER
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    Posted by BerkshireSteam on Thursday, January 28, 2010 4:15 PM

    Paul_D_North_Jr

    Let's review and list the functions/ events that occur during each stroke as follows, as I understand it:

    For a 4-stroke:

    Up 1 = Compress to ignite

    Down 1 = Power by expanding

    Up 2 = Exhaust push out

    Down 2 = Intake fresh air

    REPEAT . . .

    For a 2-stroke:

    Up = Exhaust push out - valves close - Compress to ignite

    Down = Power by expanding - valves open - Intake fresh air

    REPEAT . . .

    Any additions/ corrections/ clarifications ?

    - Paul North.

    Clarification. A 4-cycle engine makes power EVERY OTHER STROKE. A 2-cycle engine makes power EVERY STROKE.
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    Posted by nfmisso on Tuesday, January 26, 2010 9:53 PM

    monon99

    NYC guys swear by Baldwin S-12's being the absolute best quick-load kicking engine - don't know if the 606 or deLavergne was a two or 4 stroke.

    Baldwin offered naturally aspirated (no supercharger or turbocharger) 4 stroke diesels, and mechanically supercharged versions, inline six and inline eight cylinders.  The supercharged six matched the natural eight, at 900 to 1200 hp.  The supercharged eight was 1500 to 1600 hp.  The naturally aspirated six was in the 600 to 700 hp range.  The horsepower generally increased with newer models.  No turbos; so fast loading.

    Nigel N&W in HO scale, 1950 - 1955 (..and some a bit newer too) Now in San Jose, California
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    Posted by edbenton on Sunday, December 6, 2009 9:25 AM

    I do not know about EMD being king anymore.  Of the ones I have seen going BOOM on the former ASTF Transcon here in Streator and my Picture window is right were the Speed Resticton ends for my town going west 90% are either GP50's 60's 60M or evne SD70 aka EMD.  GE's which BNSF has alot more of make up 10% of the smokers and failures.  Also we do get PRB coal thru here loads and empties and even those are coming thru were GEVO AC's instead of SDMACs now.  Last SD70Ace I saw was on the Pasco Conway at the Connection track and it look to be DIT.

    Always at war with those that think OTR trucking is EASY.
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    Posted by wabash1 on Sunday, December 6, 2009 8:46 AM

    Monon99

      Hey wake up time to get back to reality.. sorry your stuck with GE engines some day maybe you will get the king of engines they are EMD. So take your MEDS and calm down it was only a nightmare,

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    Posted by Tugboat Tony on Sunday, December 6, 2009 4:35 AM

    Older Caterpillar and many small bore high speed engines inject the fuel into a precombustion chamber where the fuel is ingited and then the flame burns into the main cylinder. A Diesel cycle engine simply means that the fuel charge is ignited by the heat from compression only.

     

    as far as why EMD's can load faster then a GE, it's simply how the switch gear works, as stated earlier,  if you want to kick cars, grab an old FM, or alco, my in my expierance an S-2 alco will speed up before the P-contactors kick in to feed current to the motors, (the *** thing would take off like a rocket) a GE C44AC loads much faster then a SD9043MAC. its all in the wiring.

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    Posted by erikem on Wednesday, November 18, 2009 10:20 PM

    tdmidget

     Now I find that I can't edit because I use firefox. So:

     

    That's strange, I have no problem editing with firefox (version 3.5.5 running on Solaris 10u8 (SPARC)) but have had problems with paragraph formatting on Safari running on MacOS 10.5 (x86).

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    Posted by tdmidget on Tuesday, November 17, 2009 7:15 PM

     Now I find that I can't edit because I use firefox. So:

    1.If the fuel is not injected directly into the cylinder, it is not a Diesel engine

    2. IF it ran it would destroy itself due to preignition

    3.It would not produce usable power

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    Posted by tdmidget on Tuesday, November 17, 2009 6:15 PM
    monon99
    probably due to the fuel being injected ahead of the turbo instead of directly into the cylinder - which also caused our favorite ALCO smoke!
    monon99

     The EMD products are nearly all two strokes which wind up very fast on acceleration, but GE's product is a 4 stroke which is quite delayed in response. Old heads tell me that Monon RS-2's and C-420's would load up faster and kick better than an EMD by a long shot - probably due to the fuel being injected ahead of the turbo instead of directly into the cylinder - which also caused our favorite ALCO smoke! As usual the better, longer lasting product was muscled out of the market by the ones with better financial arms. Must be why they still build new ALCos in India and France.

    NYC guys swear by Baldwin S-12's being the absolute best quick-load kicking engine - don't know if the 606 or deLavergne was a two or 4 stroke.

    On a practical level in todays railroading a two stroke is the best  on a light intermodal train for maintaining a schedule but on a heavy drag freight in hilly terrain with tough grades I'll take a GE every time - pulls like a bear and won't let you down - the EMDs will be a constant fight with sand and independant brake to get them to quit slipping and lose so much speed that you stall.

     

    monon99

     The EMD products are nearly all two strokes which wind up very fast on acceleration, but GE's product is a 4 stroke which is quite delayed in response. Old heads tell me that Monon RS-2's and C-420's would load up faster and kick better than an EMD by a long shot - probably due to the fuel being injected ahead of the turbo instead of directly into the cylinder - which also caused our favorite ALCO smoke! As usual the better, longer lasting product was muscled out of the market by the ones with better financial arms. Must be why they still build new ALCos in India and France.

    NYC guys swear by Baldwin S-12's being the absolute best quick-load kicking engine - don't know if the 606 or deLavergne was a two or 4 stroke.

    On a practical level in todays railroading a two stroke is the best  on a light intermodal train for maintaining a schedule but on a heavy drag freight in hilly terrain with tough grades I'll take a GE every time - pulls like a bear and won't let you down - the EMDs will be a constant fight with sand and independant brake to get them to quit slipping and lose so much speed that you stall.

     

    monon99

      - probably due to the fuel being injected ahead of the turbo instead of directly into the cylinder - which also caused our favorite ALCO smoke!

     WHAT have you been smoking?

     

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    Posted by monon99 on Monday, November 16, 2009 10:05 PM

     The EMD products are nearly all two strokes which wind up very fast on acceleration, but GE's product is a 4 stroke which is quite delayed in response. Old heads tell me that Monon RS-2's and C-420's would load up faster and kick better than an EMD by a long shot - probably due to the fuel being injected ahead of the turbo instead of directly into the cylinder - which also caused our favorite ALCO smoke! As usual the better, longer lasting product was muscled out of the market by the ones with better financial arms. Must be why they still build new ALCos in India and France.

    NYC guys swear by Baldwin S-12's being the absolute best quick-load kicking engine - don't know if the 606 or deLavergne was a two or 4 stroke.

    On a practical level in todays railroading a two stroke is the best  on a light intermodal train for maintaining a schedule but on a heavy drag freight in hilly terrain with tough grades I'll take a GE every time - pulls like a bear and won't let you down - the EMDs will be a constant fight with sand and independant brake to get them to quit slipping and lose so much speed that you stall.

     

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    Posted by creepycrank on Wednesday, November 11, 2009 9:32 AM
    Yes, thank you. I discovered that I can edit after the fact. I think the point I wanted to make was that revising the design to get to Tier 2 isn't all that difficult and but you can rapidly get bogged done in the details, the reports on this subject can run to 50 pages. Of the other 2 stroke manufactures only Fairbanks Morse seems to be building for the new engine market as they announced that they sold some fast start emergency generators to a customer in Australia. Without researching, Bergen Diesel, owned by Rolls Royce, still makes 2 stroke engines.
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    Posted by M636C on Wednesday, November 11, 2009 7:31 AM

    Creepycrank I'm sure you didn't mean:

    "The first thing was to develop new piston rings which at this point reduce lube oil consumption by about 50airbox temperature at about 120deg."

    There must be something missing between "50" and "airbox".

    Also

    " It made T2 but with a penalty of raising the bnsf from 0.325 to about 0.350."

    Did you mean BSFC (Brake Specific Fuel Consumption) in pounds per horsepower hour?

    Detroit Diesel's problem was that with the blowers running at full power, they couldn't get anywhere near the fuel consumption of the competing four strokes, which EMD achieved with the overrunning clutch on their turbo and blower. That was too expensive for the small engines, so they just changed over to four strokes.

    M636C

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    Posted by creepycrank on Tuesday, November 10, 2009 12:54 PM
    aut1rml

    When I was a kid the Detroit truck engine used both a blower and a turbo. Scavenging of a cylinders exhaust was not good from an emissions point of view. How did they clean up the 710.

    Although EMD and Detroit Diesel Allision were part of GM together the engineer departments never coordinated on anything. The only exception is that Allison made all the engine bearings and I suppose had a lot to do with the turbo design. I know EMD started using CAD fairly early and had enough computer capacity to run prototype designs on the computer rather than build the parts and run the equivalent of several years in the field on test engines. Possibly all this was done on a GM mainframe. I don't know what happened to DDA but I think they just went along with the conventional wisdom rather than have any confidence in there own abilities. Somehow they still offer 2 stroke engines probably for the export market. Everybody and their brother has a different scheme to improve the basic 710. The first thing was to develop new piston rings which at this point reduce lube oil consumption by about 50%. You can get away with this because of the very great improvement in oil additive packages in the last 30 years. For locomotive EMD has electronic unit fuel injectors, 18:1 compression pistons, and a separate cooling system for the after coolers to control the temperature at 120 deg F. There was an experiment done at Southwest Research on a Ingram Barge 12-710-GA engine that include an injector of a patented design o an f after treatment catalyst. It made T2 but with a penalty of raising the bnsf from 0.325lb/hp-hr to about 0.350lb-lb-hr. They didn't replace the original 2 pass aftercoolers or the original 16:1 pistons.
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    Posted by oltmannd on Tuesday, November 10, 2009 7:09 AM
    creepycrank
    All the other locomotive builders except Fairanks Morse, lacked the imagination to build anuthing but 4 stroke engines.
    You win! That's my laugh for the day! (EMD people were always some of my favorites....)

    -Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/

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    Posted by aut1rml on Tuesday, November 10, 2009 3:42 AM

    When I was a kid the Detroit truck engine used both a blower and a turbo. Scavenging of a cylinders exhaust was not good from an emissions point of view. How did they clean up the 710.

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    Posted by creepycrank on Monday, November 9, 2009 3:37 PM
    chutton01

    Since we are discussing 2cycle vs 4cycle, I have read that the 4cycle engined locomotives don't 'load' as fast as an equivalent 2cycled one, so that acceleration is consequently poorer.
    Is this, as a rule, true (or was it at one time)?

    Its called turbo lag. EMD unique scavenging system uses an over running clutch and an 18 to step up gear train to turn the impeller at start up and lower speeds an loads where there isn't enough exhaust flow and energy to turn the turbine fast enough to give enough combustion air. Both 4 stroke and 2 stroke diesel are more properly called compression ignition engine where a charge of air is compressed enough to heat it to the point where diesel fuel at the top dead center is sprayed in and ignites. The resultant increase in pressure on the piston is extracted a torque by the crankshaft as the piston descends. Getting air and exhaust out of the cylinder is called scavenging. The piston on the 4 stroke substitutes as an part time air pump where as 2 strokes use a separate blower or the gear drive turbo combination that EMD uses. Positive displacement blowers like root blowers are more efficient at moving air in high volumes and low pressure than centrical blowers and both are better than piston pumps. Thats the reason just about every 4 stroke engine above 40 hp size uses a turbo to get a decent specific horsepower. Now back to turbo lag. EMD generators running at synchronous speed no load have the turbo at 16200 rpm an closing the breaker it quickly goes to full power with the turbo off the gear train at about 18000 rpm for full air box pressure. A 4 stroke at synchronous speed no load has a turbo being dragged around by to low energy exhaust flow and has to gain a great more rotational speed to pick up the full load. Typically 4 stroke can only manage to pick up 35% load without stalling but the EMD can pickup 100%. For locomotives as well as generators the load has to be fed in slowly to avoid smoking which makes them even slower.
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