Tuesday, November 12, 2013

THE MOST POWERFUL ENGINE IN THE WORLD

THE MOST POWERFUL ENGINE IN THE WORLD: The Wartsila-Sulzer RTA96-C turbocharged two-stroke diesel engine


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.)

Length: 89 feet

Height: 44 feet

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.

Sunday, November 10, 2013

Ships Main Engine Thrust Block

In a marine engine the function of the thrust block, propeller shaft, and stern tube are closely related, being responsible for the efficient transmission of the engine’s power to the propeller and ensuring the control of torque and propeller shaft alignment from the thrust block to the stern tube.

The "Tilting Pad Bearing" or often the "Michell Bearing" is used for thrust bearing which was invented by Michell, an Australian mining engineer.

The purpose of a thrust block on a large marine engine is to transmit the torque produced by the rotating propeller through the housing hold-down bolts into the ship’s structure. 

The pads are prevented from overheating and premature wear by a fluid film of oil between them and the collar, with the oil supply being hydrodynamic due to the rotation of the drive shaft.

Saturday, November 9, 2013

Scavenge Fire

What would you do in the event of a Scavenge Fire?

If a Scavenge Fire were to start, the two main objectives are to confine the Scavenge Fire to the Scavenge Space and to minimise damage to the Engine.
In the event of the Fire breaking out, inform Bridge that the Engine is to be brought to Dead Slow Ahead and also inform the Chief Engineer.

The Fuel should be cut off to that particular Cylinder.  The Cylinder Lub Oil should be increased to prevent seizure and wear.
If Fixed Fire Fighting Equipment is attached to the Scavenge Trunking, this can be brought into operation, depending on severity of situation.  But in most cases the Fire will generally subside within 5-15 minutes.
Once the Fire is out and Navigational Circumstances allow it, the Engine must be Stopped.

Do not open Scavenge Space Doors or Crankcase Doors before Site of Fire has cooled down.  When opening up, care must be taken to keep clear of any flame.
After opening up, all scavenge spaces must be thoroughly cleaned and all debris removed.  The Piston Rods and Cylinder Liner should be examined for surface blemishes, straightness, etc., and the Diaphragm Glands (Stuffing Box) examined to ensure that they are operational and not damaged.

Also Piston Rings should be checked, as Blow By may have been the Ignition Source of the Fire.  If possible the Piston Head in question should be renewed at the earliest possible moment and the damaged Unit overhauled.

On Engines fitted with Tie Bolts, it may be necessary to re-tighten the Bolts adjacent to the Fire.
When starting the Engine again, care must be taken after switching on the Fuel to the Cylinder in question, and that also the Cylinder Lub Oil quantities are reduced to normal

Heavy Oil Fuel System from Bunker Tanks to Engine.

Heavy Oil Fuel System from Bunker Tanks to Engine.

Fuel is pumped from the Fuel Oil Double Bottoms via a Transfer Pump to a Fuel Oil Settling Tank where it is heated.
  The Fuel Oil Purifiers/Centrifuges take suction from the Settling Tank via Purifier Heaters, pass through the Purifiers, where any water and impurities are removed and passed on to the Service Tank which also has a set of Heating Coils.

From the Service Tank the Fuel then passes via a Flowmeter to the Mixing Tank, from where the Booster Pumps take suction, discharging to the Fuel Oil Heaters, where the correct Fuel Oil Temperature/Viscosity is achieved for correct Fuel Combustion in the Engine. 
  The Fuel then passes through the Viscosity Regulator which controls the Heater Temperature, then on to the Fuel Oil Filters (which are heated), to the Fuel Pumps, then to the Fuel Injectors via Double Skin/Wall High Pressure Pipe.
Any surplus Fuel returns via a Regulating Valve from the Fuel Pumps back to the Mixing Tank.
Diesel Oil can also be used in the System and is fed to the System via a three-way valve.

 When Diesel is used, no heating is required

Main Engine Oil Sump Level Rising?

What Action would you take in the event of the Main Engine Oil Sump Level Rising? 
  What could be the Problem and how would you fix it?

The action to be taken would depend on how fast the level was rising and what was causing it to rise.
It could be due to the Lub Oil Filling Valve being left open.

But, if it were due to Water or Fuel entering the Sump, the Engine would have to be Stopped as soon as it was Safe to do so.

Tests would be carried out to tell if it were Water or Fuel.
If it were Fuel, you can normally smell this in the Oil, but a Flow Stick Test can be done.

Water has a tendency to form the colour of the Oil, depending on extent of contamination.
If it were Fuel, the most likely cause would be a faulty Injector; therefore it would be changed.

If it were Water, it could be coming from a Cracked Liner or Liner 'O' Rings, therefore possible Liner change to solve the Problem.

The Oil may have to be changed, depending on extent of Contamination, but the Lub Oil Purifier may be able to cope with it. 
GENERAL SAFETY HINTS ON BOARD 

DO NOT DEVIATE FROM ANY WRITTEN PROCEDURE OR INSTRUCTION
AS THEY ARE IN ORDER TO IMPROVE SAFETY AND PROTECT
ENVIRONMENT FROM RISK OF POLLUTION.

THE MAJORITY OF ACCIDENTS ARISE BECAUSE RECOGNIZED SAFE WORKING PRACTICES OR COMPANY PROCEDURE ARE IGNORED.