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The Worlds Biggest Combustion Engine
The above image is of one of the worlds biggest engine's. It is not a photo-shopped joke, but the real thing...amazing isn't it ! The worlds biggest engine however is the Wartsila-Sulzer RTA96-C. It is a turbo charged two stroke diesel engine and it is the most powerful and efficient low revolution engine in the world today. The Wartsila-Sulser is manufactured by the Aioi Works in Japan and is part of Japans Diesel United Ltd engine manufacturers. Below is an 89 foot long 44 foot wide 12 cylinder engine and I would not be far off to state that this engine is as big as an office block ! What I find confusing is why they haven't actually built the ship around the engine ? How they actually get the 2000 ton engine out of the factory? and moreover install an engine of this size into a ship?
Well in actual fact, that is exactly what happens, the ship is indeed built around the engine. In the marine construction trade, all boats and ships including harbor tugs and fishing trawlers have the superstructure of the ship built around the engine. The only exceptions are small modest boats. Shipping companies and large vessel owners do not want to lose valuable space by having to allow access hatches for the installation and removal of the engine. More recently, ship building has changed with modern techniques, in that many ships today are built in individual modules, these manageable sections are then welded together as one unit. The engine-beds, along with the hull below it, are built and the engine is lifted into place, then the remainder of the engine component is constructed around the now 'in-situ' engine. With modern cranes that can now lift over a thousand tons, reasonably large marine engines can be lifted and positioned into a hull with comparative ease. Below for example, a 25 meter long, 400 ton crankshaft is manoeuvred by crane, ready to be placed into an engine. A 400 ton crankshaft is about as serious as you want to get in the world of engineering.
After many thousands of nautical miles, actually calculated by engine/hours, these colossal engines need to be completely overhauled. When overhauling something of this size then its time to get the equally colossal equipment out. The ship will be dry docked and the portion of the hull that supports the engine-bed is cut away so that the engine-bed can be lowered and extracted. The new engine is fitted in reverse procedure to the method stated for removal. When however we are talking about the Wartsila-Sulzer RTA96-C, this super massive engine and its ultra low engine revolutions will invariably last the lifetime of the ship and will never need to be overhauled. If you were to hear one of these engines running flat out, you would believe that it was in reality, just ticking over.
These large, everlasting, highly durable engines are designed to power the worlds super oil tankers and large container ships. The Company that will eventually own these engines, will have them made to their own preferences. They usually request an engine construction of a single unit and single propeller design for ease of maintenance, and not surprisingly, any later troubleshooting. A single unit and single screw design has also proved over time to have a longer life span than double or even quad screws. Longevity of this engine design is based on less moving parts equals less stuff to wear out, which makes sense when you think about it. These engines are built in 6, 8, 10, 12 and 14 cylinder configurations. All the engines are straight or "inline". The diameter of each cylinder is 3 foot 2 inches with a stroke of 8 foot 2 inches. The 12 cylinder version weighs in at 2000 metric tons and delivers 90,000 hp at 100 revs per minute, with best fuel economy at 53,244 hp at 90 rpm. When I mention economy, the 14 cylinder engine for example with a displacement of 25,480 liters ( 1.56 million cubic inches ) burns up 1,660 gallons of crude oil every hour, now that is what I cynically call good economy ! Please Note: For higher resolution images, please see the external link at bottom of page.
----------------------------------------------------------- RUNNING COSTS Mathematical calculations show us that 1,660 gallons are used every hour, this equals 39½ whole barrels of oil used every hour, this also equates as $3610 every hour the engine runs. These figures are worked out from the basis of crude oil @ $91.38 a barrel* $3610 every hour the engine runs or 27.6 gallons which equates as $60.00 every minute or 1 dollar a second ! That is of course if the ship owners buy oil at trade price...if not then these figures are the absolute cheapest. An average 3 day trip or 72 hours, would cost the owners a cool $260,000. This also now helps us to see why we pay so much for our petrol, as petrol is a by-product of oil. (* price at time of publishing this webpage: edited 31st December 2010) ----------------------------------------------------------- In the image below a worker at the factory is finalising work on the cylinder block. This image shows the piston sleeves, the worker could quite easily have a nap inside one of the cylinder bores and no-one would notice ! The engine studs are more like telegraph poles !
Below is shown the pistons that will soon be fitted into the engine. Unlike normal car pistons these 3 foot diameter pistons incorporate lots of holes and it is through these holes that oil is injected through valves to keep all the working parts at a maximum low wear tolerance. Massive amounts of constant lubrication is absolutely necessary or these big engines would seize up rather quickly. Despite the colossal amounts of power output produced by these behemoth engines, surprisingly low wear rates have actually been recorded. The cylinder's liner wear for example is practically negligible at only about 0.03mm down for every 1000 hours of engine use...proving that the lubrication system these engines employ work very well. It must be remembered here that these engines work at about 20 times slower than a normal 2.0 litre car engine for example, and this is a major contributor to the life of the engine.
The image below depicts the 300 ton crankshaft of the 10 cylinder engine. There are also steps on the wall of the casing to enable mechanics to climb down into the engines sump !
In the image below the pistons shell bearings are being fitted into the engine block. They are lowered into place by a crane and guided in by two workers and a supervisor. They keep all surfaces of the engine clean at this stage as any grit or dirt could later add wear to the engine or worse destroy it. So the workers are wearing special cloth overshoes so as not to leave any abrasions on the fine working surfaces. Also you may notice that sheeting is covering the rest of the engines crankcase bearing housing to keep the dust off. These engines cost many millions upon millions of dollars in fact more than the ship itself that they are installed into. This money is made back after one trip ( plus profit ) that the tanker will make though, so its not all bad news for the companies that purchase them.
100,000 horse power was actually achieved on a test bed in the workshop with the 14 cylinder model, running the engine flat out at just under 102 rpm. 102 rpm may sound slow compared to a normal sized car engine that operates at about 2500 rpm but with an engine is as big as this, then fast engine revolutions are made obsolete by the shear power output.
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