Diesel MPG

[Deggesty]

MILW-RODR

2. The 567 series engine was a 2-stroke diesel, I do believe the 645 was a 4-stroke. At any rate 4 strokes are way more fuel effiecent. A major part of the reason why the governent started saying everything from a car to 10cc weed eater should be a 4-stroke design engine.

I may be mistaken, but as I recall the article in Trains about the 645 engine when it was new, the only real difference from the 567 was the bore, and almost everything that was not changed in increasing the bore could be used on either a 567 or 645. When I learned that a newer engine is four stroke, I was surprised.

Johnny

[creepycrank]

Yes superficially the 645 is a 567 with a larger bore. 9-1/16 vs 8 1/2 inches with same stroke and its definently a 2 stroke engine. The E crankcase is different in detail from the D crankcase, heavier overall and a different design in the seal plate area. The oil and water pumps are a little bigger and the turbo is a little different and so on. The out side diameter of the cylinder liner is the same so it has been possible to up grade some engines (particularly the over-stressed D4 engines) to use more durable lazer hardened 645 power assemblies but it requires some conversion work in replacing the counterweights at the ends of the camshafts with the heavier 645 version and using 645 type "p" pipes as the old ones will not bolt up to the 645 liner and wouldn't be aimed correctly. Converting older 567 C engines works too if an operator only wants to stock one size part but that's gone out the window with all the upgrade kits available. EMD engine designations 567 C 567 CI per cylinder, blower engine, C crankcase 567D4 567 CI per cylinder, turbo engine, D crankcase and 4 is for industrial generator engine 645 E3 645 CI per cylinder, turbo engine, E crankcase and 3 is locomotive, 4 is generator, 5 is marine application

[silicon212]

MILW-RODR

...

2. The 567 series engine was a 2-stroke diesel, I do believe the 645 was a 4-stroke. At any rate 4 strokes are way more fuel effiecent. A major part of the reason why the governent started saying everything from a car to 10cc weed eater should be a 4-stroke design engine.

...

 The 567, 645 and 710 engines are all two stroke.  The 12v265H and 16v265H are EMD's only 4-stroke engines.  Of those, 68 of the latter went into North American locomotives and only one of the former was built for an SD89 demonstrator.  More of the 265s are being built for China and there are a number in service in the marine industry.

Another point about fuel economy:  When it comes to gasoline two stroke engines such as your weed eater or chain saw, that holds true that they're pretty horrible for economy.  Diesel engines or direct injected engines do not share that feature - it comes down to power density and with a two stroke, there is more power density because there's an ignition cycle with each rotation of the crank vs. one every other rotation as in a four stroke. 

The typical two stroke 3000 HP engine (i.e. 16-645E3) has a smaller per-cylinder displacement and runs at lower top RPMs than a competing 3000 HP four stroke design (such as a 16FDL7).  It works out to be about the same, a given volume of fuel has a certain BTU rating (think: HP production) no matter whether the engine fires once per revolution or once every other revolution.

[oltmannd]

creepycrank

HHV is High Heating Value but shouldn't be 19350 btu per pound. I think no.2 diesel is about 7.04 pounds per gallon.

Yes.  (too many years have passed since I was messing with this stuff! )