I have heard that EMD’s engines(except for the SD90MAC) use 2 stroke engines, but I am in a class at school where we work on lawn mowere and other small engines and a 2 stroke engine has holes in the side of the cylinder where the gas comes in and exhaust gose out but your sposed to mix the oil with the gas because where the air/fuel mixture comes in is where the oil would be on a 4 stroke. So unless they do mix their gas and oil together then how do these engines differ from a chain saw or weed wacker in terms of where the oil goes and where the holes are in the cylinder and where they come from and go out, but if there is oil then it couldnt go throug the crank case where the oil would be??? I am really confused
EMD prime movers are 2 cycle in operation but they operate as a 4 cycle…I.E. they have intake and exhaust valves…the pressures in the combustion chamber in a diesel are to high to operate with reed valves like a dirtbike or chainsaw…
This is a EMD power assembly from the outside. The piston is inside.
The holes in the side are where the air/fuel mixture come in to the cylinder. EMDs force the air/fuel mix into the cylinder, by a supercharger or a turbocharger.
The valves on top are exhaust valves.
Some EMDs do blow a lot of oil out, especially the SD20s that go thru Middleton.[;)]
The link worked for me: perhaps you should try it again.
The EMD engine draws air in through “ports” (holes in the cylinder wall, just above the piston at bottom dead centre) but unlike small petrol engines, the gas is exhausted through four valves located in the clynder head, like those in four stroke engines (except there are no intake valves).
The EMD 567, 645 and 710 engines have normal lubricating oil systems with oil held in a sump under the crankshaft, but do have one different feature: lubricating oil is sprayed from a pipe to the underside of the piston (when at bottom dead centre) to cool the piston.
The crankcase of the EMD diesel engines is not pressurised as it is in a small petrol engine, which allows conventional lubrication.
yes the sound difrece is very noticeble, GE’s have a really cool chugging sound,
When we took the City Of New Orleans last summer and I stood in the doorway of the first supliner right behind the engine and just listened to the chugging sound of the exhaust and the whoop of the air compressors, I could have stood there all night but some exhaust fumes started to come through the door so I left
[#offtopic]but when ever I flushed the toiled(alot), within 2 seconds I would hear the whoop sound of the air compressors, but since the toilet uses a vacum i dont see how these are related
I am not familiar with the EMD prime movers in particular, but the air/fuel mixture in a diesel engine does not happen outside the cylinder. A Diesel engine receives a charge of fresh air into the cylinder, and then compresses nothing but fresh air on the compression stroke of the cycle. the compression of the air increases the temp to a high level, then at the appropriate time for ignition, the injectors, inject the fuel into the cylinder, which is then ignited. A Diesel engine has no spark plugs (not to be confused with glow plugs) the air/fuel mixture ratio is not critical in a Diesel engine as it is in a gasoline engine. With a diesel the more air that can be compressed into the cylinder the more power it can produce. the same amount of air in the cylinder will effectively burn any amount of fuel, from a small amount to as large an amount as there is adequate oxygen to combust properly.
I guess that depends on your definition of “cool”. Personally, I think they sound like a rock crusher gone bad. Give me the old non-turbo EMD’s any day. Get 'em in the middle of a rock cut in the 8th notch, now that is the “cool” sound of power!
