THE WORLD'S BIGGEST COMBUSTION ENGINE
The above image is of one of the world's biggest engines. 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-Sulzer is manufactured by the Aioi Works in Japan and is part of Japans Diesel United Limited engine manufacturers. The Sulzer 9RTA84C is the companies newest, most efficient engine.
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 2,000 ton engine out of the factory? 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.
Indeed these engines are a big as an office block if not bigger. Three flights of stairs are needed for the mechanics to ascend to inspect the top of the engine. Hand rails are essential, as a worker could sustain injury or even death from falling off the engine. Imagine getting killed and somebody had to explain " Yeah, he fell off an 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, 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.
However, when 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.
Ship owners usually request an engine construction of a single engine unit and a single propeller design for ease of maintenance, and not surprisingly, any later troubleshooting. Below is seen a modern, big single, six bladed propeller of a super tanker. These are also some of the worlds largest propellers and weigh several tons each.
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.
When we consider the amount of weight that these engines and their respective components have to haul through the ocean, its not surprising that everything is on such a massive scale. Below, the worlds largest container ship at 170,794 tons the Emma Maersk, fully loaded and no doubt on its way from China to Europe.
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 three foot, two inches with a stroke of eight foot two inches. The twelve cylinder version weighs in at two thousand metric tons and delivers 90,000 horse power at 100 revolutions per minute, with best fuel economy at 53,244 horse power at 90 rpm.
Of course all of this power is not created just by burning oil, the engine is also turbo charged. The main turbo unit is so huge a person could live inside it, the Wartsila-Sulzer RTA96-C turbo unit is shown below, with two guys standing on it for scale.
When we mention economy, the fourteen 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's what I cynically call good economy!
Mathematical calculations relate that 1,660 gallons are used every hour, this equals 39½ barrels of Brent Crude oil used every hour, this also equates as $4261.76 every hour the engine runs. These figures are worked out from the basis of Brent Crude @ $107.88 per barrel*
Below, every barrel of oil you can see in this image, including the ones in the background, would just about run the Wartsila-Sulzer RTA96-C engine for two weeks! With thousands of these ships working all round the clock, that's a lot of oil burned up, its amazing the world hasn't run dry by now!
Expensive?...you bet! It costs $4261.76 every hour the engine runs or 27.6 gallons every minute, which equates as $71.00 every minute or $1.18 every 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 three day trip or 72 hours, would cost the owners a cool $306,846.72 This also now helps us to see why we pay so much for our gasoline, as gasoline is a by-product of oil.
(* Price of oil at time of publishing this webpage: edited October 24th 2012)
If any big container ships have to use the Panama Canal or Suez Canal then they can add between $50,000 to $250,000 to the wayfarers bill! That is how much they would be charged just for a one way passage.
Cruise ships pay more, between $80,000 to $300,000. The most expensive Panama Canal toll fee ever paid was for a Disney World cruise ship, they were hit with a bill for $331,200 for one passage on May 16th 2008. If you were to pass through the Panama Canal in your little 20 foot yacht, then prepare to part with about two grand!
In the image below a worker at the factory is finalising work on the ten cylinder engine block. This image shows the piston sleeves, the worker could quite easily have a nap inside one of the cylinder bores and nobody would notice! The engine studs are more like telegraph poles! Everything is on a grand scale.
Below are shown the pistons that will soon be fitted into the engine. Unlike normal car pistons these three 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.
If I could just explain that the pistons are assembled in two halves, these are the lower halves that are shown above. More conventional flat head piston heads make up the other half and are slightly concave. They are bolted to these lower halves to make a complete piston and are shown further down the page.
Despite the colossal amounts of power output produced by these behemoth engines, surprisingly low wear rates have actually been recorded. Below, a worker inspects one of the cylinders sleeves, where the pistons will eventually go. Like most of the other engine components, they are all highly polished.
The cylinder's liner wear for example is practically negligible at only about 0.03mm down for every one thousand hours of engine use...proving that the lubrication system these engines employ work very well. Below, the fully assembled piston rods, these are all highly polished to reduce friction and wear even more. These pistons weigh five tons each and produce about eight thousand horse power each.
It must be remembered here that these engines work about twenty times slower than a normal two liter car engine for example. Very low engine revolutions are a major contributor to the life of these super massive engines.
The image below depicts the three hundred ton crankshaft of the ten cylinder engine. There are also steps built onto the side wall of the casing to enable mechanics to climb down into the engines sump!
When a crankshaft weighs four hundred tons, then quality control needs to walk around to inspect it thoroughly before its lowered into the engine block. Admittedly, this crankshaft will not be too easy to take back out again if its faulty.
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.
You may also 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 fourteen cylinder model, running the engine flat out at just under 102 rpm. Indeed 102 rpm may be 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 fantastic power output.
Page created February 7th 2006. Updated January 9th 2013