lost my job three weeks ago in Ontario. So hoped on a plane after making arrangements and just finished my first week on a huge job here in Alberta. One of my taks took me into a “generator building”. So this building is a fair size from the outside with a huge exhaust stack and muffler on the outside. Now mind you I have worked on 3000 hp Cat diesel generators which were 16 cylingers and quite large. This took the cake though. It is massive, counted 10 cylinders per side, then seen the Electro-Motive plaq on the side. You guessed it, it is a L20-710G4B Diesel. How did they ever manage to shoe-horn this thing into a SD80MAC? Sure the locomotives are quite large but this thing puts the Cats to shame. The crank shaft has to be 11 inch diameter on this 5000 hp engine, to say the least it left an impression.
That 20 cyl 710GB engine is impressive isn’t it? I love it, and I think that is one of the main reasons why I love the SD80MAC so much. That 9 1/16" x 11" bore/stroke is just massive. Yes it does put other marine diesels to shame. lol I would put this engine up against that of the SD90MAC any day even the SD70ACe today! Unfortunately, there were only 30 built.
EMD didn’t have much trouble stuffing a 20 cylinder 645 engine in the SD-45 series and the external dimensions of the 710 are similar to the 645. My recollection was that the crank on the 20 cylinder engines was made of two sections, though my dad said that the 24 cylinder Winton diesel he worked on at Diesel Engineering school during WW2 had a single piece crank.
Grande Motor Trieste made some diesels with about a cubic meter displacement per cylinder (~60,000 cu in), good for 1,000 kW per cylinder. Largest engine was 20 cylinders. Some of the ship diesels make that GMT engine look puny by comparison.
The biggest engines I’ve had the “pleasure” or working on were some Pielsticks(PC2.5), they are roughly 2x the size of an EMD, and they are baby’s compared to many marine and industrial engines. I had a hard time just lifting the injector nozzle on a PC4.2 pielstick. The injector test stand for that engine had 4 stairs leading up to it. EMD makes a big engine, but no where near the biggest.
Monster engine indeed. With all the cid and dead weight of componets,how is this beast started up?? Is there a pony engine and the compression released or what? Something has to have a great amount of torque to build required rpm s to start engine.
According to Wikipedia, 1820 liters… (thats 111,000 CI).
I’ve been on the Lake Champlain ferry, which, IIRC, has a two cylinder Diesel. You can hear the individual cylinders - foomp foomp foomp foomp…
The Navy harbor tugs I saw working in Pearl Harbor were very much the same.
A 14 cylinder version at 102 RPM would be generating about 25 compressions per second, a 12 cylinder loco prime mover at 600 RPM would be generating about 120, and the 6 cylinder in your car at 2500 RPM about 250.
Most marine engines of any size, both propulsion and generators, are started with compressed air. The smaller generator sets, and some propulsion engines, use an air driven starter motor, whereas larger generator sets, and propulsion engines use direct injection air starting. That is, compressed air at approximately 300 psig is injected into each cylinder, in cylinder firing order, to get the engine rolling and up to the speed necessary for compression ignition to take over. There is no need for the cylinder compression to be released.
Emergency generator sets may have an air starting system but they are usually fitted with an electric starter which is supplied from a battery bank. Sometimes two starters are fitted and may be wired up to operate together, but normally only one will be connected to the starting circuit. The second starter is there as a back-up in case of failure of the first starter. In some cases an emergency hydraulic system may be fitted as back-up. Electric starting of these engines is practical since they are generally rated at under 1000 kW.
Since all engines need to be well balanced in order to reduce vibration when running, it does not take a lot of effort to overcome inertia and friction of bearing surfaces during start-up. For engines that are larger than truck engines, a pre-lube pump, separate from the engine, is usually fitted and a minimum lube oil pressure has to be present at the engine before the starting system will allow a start to be initiated. Once the engine starts and exceeds a set RPM, the engine driven lube oil pump takes over and a pressure switch shuts down the pre-lube.
Of course there are always exceptions to the foregoing.
Mike; thank you for the information about starting the " monster" diesel or other huge engines. Those engines are an engineering feat and design . I would not want to be close to one when something went ( BANG ) Respectfully, Jim
From my old Shop foreman they can Cut out Cylinders if needed one at a time to reduce power. There are some that they can actually remove the piston and keep that engine running at speed. That would be a feat. Sorry I would not want to be that mechnic who has to torque those rod bolts.
I have heard this story about reducing power by cutting out cylinders before but I don’t know why anyone would do such a thing as engines are not normally designed to run with less than the full complement of cylinders working. Fairbanks Morse engines could be fitted with a “locomotive” type fuel rack system which would cut out one of the two fuel injectors fitted to each cylinder when the engine was running at idle speed, but this was more to do with conserving fuel and reducing carbon build up within the exhaust manifold than reducing power.
Some of the newer high speed marine engines, such as the German built MTU (with up to 20 cylinders in a V arrangement), which are fitted with four or more turbochargers, have electronic control systems which will cut out one or more of the turbochargers, in sequence, as power (speed) is reduced.
In an emergency, it might be possible to take one cylinder out of service and run the engine at reduced speed in order to get the ship into a port, depending upon what has happened to the damaged cylinder / piston. But this is not done on a regular basis, and depends again on what the engine manufacturer will allow. In order for the engine to run in this condition usually requires the bottom end bearing and connection rod to be removed and the piston secured in the top dead center position or removed from the cylinder. Not a task to be undertaken in heavy seas! The foregoing applies to low speed diesels only. Medium and high speed diesels would probably vibrate themselves to pieces if one cylinder was taken out of service. You might be able to get away with taking a pair of cylinders out of service on a medium speed Vee engine in an emergency, but again it depends upon what the engine manufacturer will allow you to do.
As an aside, all current low speed diesels are two stroke, most medium speed engines are four stroke with a few makes which are two stroke, and all high speed engines are four stroke. Low speed diesels operate at up to 300 rpm, med
As far a medium speed diesels are concerned the manufacturer says “fix it”. All ABS (American Bureau of Shipping) require each vessel to carry a comprehensive supply of spare parts such as power assembles, fuel injectors, water pumps and fortunently for me in one case extra valve bridges. Its hot work changing a power assembly in the middle of the Atlantic but a Crowley engineer said he managed it in 2 hours.
Larry, is Wikipedia using a new math? This morning, I calculated the displacement from the dimensions given by Wartsila (& pi = 3.1416), and came up with a displacement of 1809.5615 liters, or, 110,426.21 in3 (taking 1 stere = 61,023.74 in3)