Share this on Facebook
download .zip with all pictures
Having Sailed with these engines (they come even larger), i’d though I would answer some of the questions;
1. how much oil goes into one of those? Answer : These engines have two separate lubricating oil systems. One is the system lubricating oil which is lubricating the crank, piston, crosshead, bearings etc. About 35.000 liters in a small engine (bore of about 600 mm) and 60.000 liters in a big engine (bore of more dan 800 mm). The second system is the cylinder lubricating oil system. This oil is injected directly into the cylinder(liner) is is used to lubricate the motion of the piston in the cylinder. This oil is consumed with each stroke (a kind of engine KY jelly)
2. What kind of RPM does this run? Answer : Minimum RPM is usually about 22 rpm (dead slow ahead) then upwards to about 80 rpm which is full ahead. After that there is a automated program to slowly increase the rpm to a maximum of about 100 to 105. These engines do not run at the maximum rating (MCR : Maximum Continuous Rating) but at about 90% of this.
3. The engines reverse? Answer : Yes… they do. Point of interest is that these engines are air-started. High pressure air is used (at 30 bars) to put the rotating components (pistons, rods and cranck) into motion by “injecting” air through a special valve in the cylinderhead. Once the engine achives a certain RPM, the fuelvalves are actuated and fuel oil is injected. due to the large mass of the rotating components, enough kinetic energy is present to start combustion. Reversing the engine takes some time; first the engine rpm has to come down to 0 rpm after which the cams on the camshaft are rotated such that the cams are now in a “mirrored” position in relation to the “ahead” position. Then the starting of the engine is commenced and the engine is running in reverse. During an emergency stop, starting air is used to brake the engine down from 100 rpm down to 0 rpm. When this is used….. all hell brakes loose in the engine room. 600 tons of engine is shaking and trying to break loose from its foundation…
4. Any guess what those main caps torque to? Answer : Nuts are hydraulically tightened to about 1000 bars of hydraulic pressure.
5. Is that rust on the crankshaft, or assembly oil? Answer : It’s conservation oil. Engines are assembled in the factory with individual component made usually in different plant.
More Questions … Happy to answer them – Former Chief Engineer Maersk Lines.