Hi, probably a dumb question, but.
I see all the comments about the Alco engines being smoky but I have never seen anyone say why.
Top of the morning all.
Lee
not a diesel mechanic but i have a little knowledge on the subject. it is a matter of the fuel to air ratio being a little too rich. Alco's typically suffer from a condition known as turbo lag. this means that the exhaust driven turbo charger is a little late to the party and because it takes time for it to rev up and do it's job of forcing combustion air into the engine the fuel burns kind of dirty and smokes a bit until the turbo comes up to speed. Mack trucks used to suffer from the same syndrome. They always belched a lot of black smoke when their engines were first put under load. As a matter of fact, that is why coal fired steam engines could make so much smoke. when the fireman put in more coal, the air/fuel ratio was a little rich for a moment and when the engineer closed the throttle, it cut back on the draft with the same results.
Blue smoke from a diesel, on the other hand, is usually the result of one of two things. If the engine has been idling or not running at all, then it will burn off any accumulated lube oil when first fired up or worked hard. A recently started engine will also make blue smoke as a result of unburned fuel in the exhaust and lube oil getting by the rings but this occurs mostly when the engine is cold. If it is already warmed up, then the smoke tends to be more black.
perhaps someone who works on these things can better explain or elaborate on this.
Charlie
Lee,
Charlie basically nailed it. Alco and early GE's(U-Boats) use a pure turbocharger to compress/push air into the cylinders to increase HP. The 'turbo' unit is driven by the exhaust gases from the engine. When the throttle is advanced, more fuel is squirted into the cylinders by the fuel injectors. This causes the engine to run 'rich' until the increase in exhaust gases spins the turbo faster and it can get more air into the cylinder. That 'Black Smoke' is un-burned fuel.
EMD locomotives have a turbo unit that is also exhaust gas driven, but also is shaft connected via centrifugal clutch. As the throttle is increased, the rpm of the turbo also increases. At around RUN 4 of the throttle the centrifugal clutch releases and the turbo unit is exhaust driven only. This helps get rid of the 'Black Smoke' problem, but the shaft attached turbo unit is producing drag on the engine(like your air conditioner compressor in your car). Current GE's use a very sophisticated computer control to limit HP until the air input from the turbo is enough to allow more fuel to be injected. This is part of the reason you hear folks talk about GE's 'loading up' so slow compared to EMD's.
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
just my 2 cents,
Charlie and Lee hit it right on the head,having 12 of my own semi's tractors over the year's...
If you really want to see some black smoke!! Go to a farm tractor pull, a lot of smoke and loud...
Cheers,
Frank
yankee flyer Hi, probably a dumb question, but. I see all the comments about the Alco engines being smoky but I have never seen anyone say why. Top of the morning all. Lee
Alco had a history of having bad turbo chargers which also help with the smoke problem.
Overall Alco's mechanical record wasn't the best and the turbo charger problems didn't help-even when new a Alco turbo charger was subject to failure within months.
That's why railroads turned to GE and abandon Alco products.
Larry
Conductor.
Summerset Ry.
"Stay Alert, Don't get hurt Safety First!"
BRAKIE Alco had a history of having bad turbo chargers which also help with the smoke problem. Overall Alco's mechanical record wasn't the best and the turbo charger problems didn't help-even when new a Alco turbo charger was subject to failure within months. That's why railroads turned to GE and abandon Alco products.
Actually, those bad 'air cooled' turbochargers in the early Alco locomotives were made by GE! At that time, it was a joint Alco/GE marketing effort. At the end of WWII, Alco was developing their new line of locomotives, and the '244' series diesel was not producing the HP Alco felt they needed to match/exceed what the EMD 567 diesel was putting out. A GE VP told them that that GE had experts in the turbo field - They had produced hundreds of thousands of air cooled turbo units that worked in -40 degree weather at 30,000 feet(aircraft for the ware effort). GE sent some engineers to Alco and took a few measurement, then returned with a new turbocharger - lots of HP!. But there were problems:
Rather dramatic turbo failures in road service followed. GE eventually redesigned the unit to be water cooled. That and lube issues with the 244 engine soured most railroads on Alco designs. The Alco/GE partnership dissolved, and Alco eventually came out with a new power plant(251 series diesel) in 1956. Unfortunately for Alco, three other things got in the way:
Since Alco was still getting their electrical gear from GE, they were put in between a rock and a hard place. By 1967-68 Alco closed their doors.
jrbernier Since Alco was still getting their electrical gear from GE, they were put in between a rock and a hard place. By 1967-68 Alco closed their doors. Jim
Agreed..
GE had teething issues with the early GEs-yup-turbo chargers.
I always suspected the early GEs had the mechanical department heads screaming "Not again!"
Still nothing like a early GE lighting up the night sky with a fireball.
i had come off the IC which was once an all EMD railroad and the few odd balls they bought later on were not around where i was working. so, my first real exposure to GE Uboats was when i went to the Big Four.
I think the early ones had a Cooper Bessemer or perhaps a GE copy of a CB prime mover and they made a distinctive popping sound like an old John Deere tractor.
The TRRA still had some old FM power around and it just hummed. when working hard, it hummed louder.
It is fun to go on YOU TUBE and listen to all the different engines. My old man was a truck mechanic and when we traveled he could listen to the truck in front of us on the highway and tell what kind it was by the sound of the engine. after passing, i would look out the back window and he was almost always right.
Charlie, Jim and all other responders.
Thanks for the responses, I had thought it might have been the type of diesel engine.Curiosity satisfied.
Have a good evening.