New large ship engine

[Turbineguy]

Here's some news on ship propulsion achieving greater efficiency and reduced fuel consumption.
In its ideal configuration this system looks to be over 65% efficient. That's nearly three times that of a ship with boilers and steam turbines.

These are large engines with a bore of about 3 ft, stroke of about 8 feet and running at around 100 rpm. They are two-stroke engines. Air comes into the cylinder through ports exposed by the piston reaching the bottom of the stroke and they utilize a single hydraulically operated exhaust valve in the cylinder head. There is no mechanical valve spring, air pressure is used to close the valve.

The engine will run stable down to 15 rpm. The common rail fuel system is a throw-back to an older technology, made new because of electronic control. This and the hydraulically operated valves allow for a short camshaft. The engine is reversible and is started by supplying high pressure air directly into the cylinder.

http://www.newsletterscience.com/marex/readmore.cgi?issue_id=175&article_id=1578&l=1&s=16239

some pictures:

http://people.bath.ac.uk/ccsshb/12cyl/ This is the older model with a different fuel injection system. The DU stands for Diesel United, a consortium of Japanese engine builders.

[madrchsod]

1. cool---- a really really big

turbo charged saab three cylinder 2 stroke engine.....still only 65% --1665 heavy crude an hour.

[midnight armadillo]

3. Not to be picky...

...but Saab's first turbocharged engine was in the 4-cylinger, 4-stroke Saab 99, in 1977. To my knowledge, they never turbo'd any of the two-strokes.

[Kolesar]

2. Hoist mains'l !!