Two Cycle Diesel Locomotive

[wabash1]

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,

[edbenton]

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.

[nfmisso]

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.

[BerkshireSteam]

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.

[Jerry Pier]

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.

[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.

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.

[BigJim]

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!

[Cooter50]

 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.

[CAZEPHYR]

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

[nedthomas]

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.

[Cooter50]

 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.

[edbenton]

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.

[silicon212]

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.

[Cooter50]

 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.

[tree68]

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

[broncoman]

 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.

 

 

 

[Redore]

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.

[tdmidget]

 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.