Well, the main difference between the Baldwin engine and those of other builders is really in the whole approach to engine design. The De La Vergne Co., who was bought by Baldwin in 1931 and who's engines were the predicesor of the BLW 600, developed an engine that ran with a high combustion temperature and a constant ignition charactoristic with a very large cylinder. Fuel is continuously injected over the length of the power stroke, but it is injected smoothly at a constant rate with the same pressure from the begining to the end of injection. With this style of ignition the fuel burns like a fire, it doesn't explode like a bomb. Because of that you can use virtually anything the burns, it doesn't have to have the "explosive" charactoristics of diesel fuel to keep the engine going. The large cylinder and low but very broad RPM range means the Baldwin 600 can absorbe a large amount of excess energy, which occurs when the engine is accelorated. With this reserve capacity, fuels of widely different volitilities and energys can be used without damaging the engine. Infact a safety margine of about 11% over the stated rated capacity is built into the engine. Another factor which allows for such a variety of fuels is the very large fuel injector equipment, made possible by the size of the massive cylinders. The injectors themselves have 9 nozzle ports, spraying fuel in a 160 degree vertical and 360 degree horizontal arc. In effect the whole cylinder is filled with atomized fuel from the very beginning of ignition, resulting in a smooth and uniformly steady burn. The nozzle ports are quite a bit larger than those found on other comparative engines, which accounts for the ease in which the BLW 600 can burn the tar-like Bunker "C" oil. I also know for a fact that this engine can run on Petrolium Jelly (aka Vasoline), as I have seen the inside of the fuel filters of the engine. The original filters, which where in place when we started the engine for the first time ourselves, were coated inside and out with a solid mass of jelled diesel fuel. Inspite of this, we had no trouble in starting the engine after it had sit idle for 8 years.
EMDs and other two strokes however are forced to use a more explosive ignition style, which dumps a large amount of fuel in the beginning of the power stroke, which tapers off sharply. They have to use a fuel with enough force to kick the piston around the whole stroke after burning for just a fraction of it. This means the engine is subjected to a severe strain at the beginning and loses pressure thereafter. You don't get to use the effect of that very high pressure over the whole stroke; infact you hardly have any benifit of it because the high pressure of the beginning is making up for the lack of pressure at the end. Fuels other than diesel can be very dangerous in these engines. If they have too much power, the pressure can become much too great upon ignition, resulting the the cylinder head being shot right off the engine. If they burn to hot, the piston and valves can be burned, even melted. If they burn too cold or do not generate enough power, the piston might not have enough pressure to carry it around the full stroke. Then if you have fuels which are too thick, they won't flow properly through the smaller injection equipment EMD uses. If they are too thin, too much fuel might be injected before the govener can compensate. Worse yet, the fuel might vaporize or fail to carry away the excess temperature of the injector nozzles, as EMD uses excess fuel to cool the injectors.
Then you have Alcos, which are four strokes like Baldwins, but have a much lower combustin temperature and much smaller cylinders and run from two to 6 times the RPMs. The reason why they smoke so much is partly because they have an ignition temperature that is too low for their performance profile. They don't have a reserve of extra pressure or temperature capacity to absorbe the amount of fuel injected in all cases, especially when accelorating. This is compounded by the speed at which the engine operates. The fuel can't burn completely before the cycle ends, which means it's blown out the exhaust in all that smoke. What this all adds up to is you cannot substitue a fuel that has any less energy than Diesel fuel, or the engine can stall before enough fuel is burn to push the piston all the way around. You are also restricted in fuels which have more power than diesel oil. With the engine's limited capacity to absorbe the energy of the fuel, the engine would have to be accelorated very slowly to avoid putting too much energy in the engine, resulting in more pressure than the engine can handle, and ending in the cylinder head flying off to land half a mile away. The engine would become far too sensitive for practical use.
Now that doesn't mean that you can't run an EMD or Alco on fuels such as LNG or Bunker "C" oil. It just means you can't use them in their original configuration. Adjustments will need to be made in timing and compression ratios, resulting in the need of slightly different parts. Vegetable oil and Bio-diesel, provided the mix approximates the performance of regular diesel oil, could be used without significant modification.
When it comes down to it, the main difference between a Baldwin and an EMD or ALCO or GE or another similar engine is the fundimental paradim on which the engine is designed. Baldwin used a large, slow and efficient engine, while the others focused more on slightly smaller designs which run quite a bit faster, and have less of a margin.
BLW 600 cylinder dimensions:
Diameter: 12 3/4"
Stroke: 15 1/2"
Total Cylinder Displacement: 1978cu inches
RPM: 125 - 625
Average estimate of comparative engines (EMD, ALCO, etc..)
Diameter: between 9" - 9 3/4"
Stroke Between 9" and 10"
Total Cylinder Displacement: Between 570cu inches - 650cu inches
RPM: 300 - 1000
Now there are some newer engines in developmentment and early use such as the GEVO, which are starting to approximate the performance of the BLW 600. Someday they may become as flexible as the BLW 600, but I find it dissapointing to see that it has taken almost 75 years for the current industry to catch up to the basic design principles that Baldwin had known until they left the locomotive market in 1956. You may be wondering, "If the technology is so great, why didn't other companys pick it up after Baldwin ceased production?" Well the answer is that although they didn't make locomotives anymore, BLH has still a corperate entity until 1970, and they held all the patent rights and design specifics up until the very end. Anyone trying to copy the designs would have to pay royalties to them. Also, by the 1950s, other builder's had become so entrenched in engines of their own development, they were not interested in even the slightest suggestion that they should stray from them. They felt that they had too much invested in their own products to make any significant fundemental changes.
Matthew Imbrogno
Mechanical vollenteer, Arizona Railway Museum.
-One of the few today who gets to experiance the wonders of a Baldwin diesel, and I'll be happy to share them wth you!
(Disclaimer: I am not trying to advertise either one of those establishments.)