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This is one of the best hacks that I have ever seen. So subtle, so perfect…. until you
see it. Then it jumps out at you every time you scan the page… heh.
The Wartsila-Sulzer RTA96-C turbocharged two-stroke diesel engine is the most powerful and most efficient prime-mover in the world today. The Aioi Works of Japan’s Diesel United, Ltd built the first engines and is where some of these pictures were taken. It is available in 6 through 14 cylinder versions, all are inline engines. These engines were designed primarily for very large container ships. Ship owners like a single engine/single propeller design and the new generation of larger container ships needed a bigger engine to propel them.
The cylinder bore is just under 38″ and the stroke is just over 98″. Each cylinder displaces 111,143 cubic inches (1820 liters) and produces 7780 horsepower. Total displacement comes out to 1,556,002 cubic inches (25,480 liters) for the fourteen cylinder version.
|Some facts on the 14 cylinder version:|
|Total engine weight:||2300 tons (The crankshaft alone weighs 300 tons.)|
|Maximum power:||108,920 hp at 102 rpm|
|Maximum torque:||5,608,312 lb/ft at 102rpm|
Fuel consumption at maximum power is 0.278 lbs per hp per hour (Brake Specific Fuel Consumption). Fuel consumption at maximum economy is 0.260 lbs/hp/hour. At maximum economy the engine exceeds 50% thermal efficiency. That is, more than 50% of the energy in the fuel in converted to motion.
For comparison, most automotive and small aircraft engines have BSFC figures in the 0.40-0.60 lbs/hp/hr range and 25-30% thermal efficiency range.
Even at its most efficient power setting, the big 14 consumes 1,660 gallons of heavy fuel oil per hour.
The internals of this engine are a bit different than most automotive engines.
The top of the connecting rod is not attached directly to the piston. The top of the connecting rod attaches to a “crosshead” which rides in guide channels. A long piston rod then connects the crosshead to the piston.
I assume this is done so the the sideways forces produced by the connecting rod are absorbed by the crosshead and not by the piston. Those sideways forces are what makes the cylinders in an auto engine get oval-shaped over time.
Installing the “thin-shell” bearings. Crank & rod journals are 38″ in diameter and 16″ wide:
The crank sitting in the block (also known as a “gondola-style” bedplate). This is a 10 cylinder version.Note the steps by each crank throw that lead down into the crankcase:
A piston & piston rod assembly. The piston is at the top. The large square plate at the bottom is where the whole assembly attaches to the crosshead:
Some piston rods:
The “spikes” on the piston rods are hollow tubes that go into the holes you can see on the bottom of the pistons (left picture) and inject oil into the inside of the piston which keeps the top of the piston from overheating. Some high-performance auto engines have a similar feature where an oil squirter nozzle squirts oil onto the bottom of the piston.
The cylinder deck (10 cylinder version). Cylinder liners are die-cast ductile cast iron. Look at the size of those head studs!:
A completed 12 cylinder engine:
Biologists have linked a mysterious, underwater farting sound to bubbles coming out of a herring’s anus. No fish had been known to emit sound from its anus nor to be capable of producing such a high-pitched noise.
“It sounds just like a high-pitched raspberry,” says Ben Wilson of the University of British Columbia in Vancouver, Canada. Wilson and his colleagues cannot be sure why herring make this sound, but initial research suggests that it might explain the puzzle of how shoals keep together after dark.
“Surprising and interesting” is how aquatic acoustic specialist Dennis Higgs, of the University of Windsor in Ontario, describes the discovery. It is the first case of a fish potentially using high frequency for communication, he believes.
Arthur Popper, an aquatic bio-acoustic specialist at the University of Maryland, US, is also intrigued. “I’d not have thought of it, but fish do very strange and diverse things,” he says
Grunts and buzzes
Fish are known to call out to potential mates with low “grunts and buzzes”, produced by wobbling a balloon of air called the swim bladder located in the abdomen. The swim bladder inflates and deflates to adjust the fish’s buoyancy.
The biologists initially assumed that the swim bladder was also producing the high-pitched sound they had detected. But then they noticed that a stream of bubbles expelled from the fish’s anus corresponded exactly with the timing of the noise. So a more likely cause was air escaping from the swim bladder through the anus.
It was at this point that the team named the noise Fast Repetitive Tick (FRT). But Wilson points that, unlike a human fart, the sounds are probably not caused by digestive gases because the number of sounds does not change when the fish are fed.
The researchers also tested whether the fish were farting from fear, perhaps to sound an alarm. But when they exposed fish to a shark scent, there was again no change in the number of FRTs.
Finally, three observations persuaded the researchers that the FRT is most likely produced for communication. Firstly, when more herring are in a tank, the researchers record more FRTs per fish.
Secondly, the herring are only noisy after dark, indicating that the sounds might allow the fish to locate one another when they cannot be seen. Thirdly, the biologists know that herrings can hear sounds of this frequency, while most fish cannot. This would allow them to communicate by FRT without alerting predators to their presence.
Wilson emphasises that at present this idea is just a theory. But the discovery is still useful, he says. Herring might be tracked by their FRTs, in the same way that whales and dolphins are monitored by their high-pitched squeals. Fishermen might even exploit this to locate shoals.
There may even be a conservation issue. Some experts believe human-generated sounds can damage underwater mammals. Now it seems underwater noise might disrupt fish too.