Marine Motor Engineering Knowledge

Marine Motor Engineering Knowledge

           soon will update all the materials guys.preparing the notes and need to justify some answers before posting on blog.kindly share your materials and knowledge.       please wait few days......       thank you.                       

        

    MARINE DIESEL ENGINES:  

      MAN B&w:

                       

       MAN – Germany – Maschinenfabrik Augsburg Nurnberg

        B&W – Denmark – Burmeister &Wain

              

         

The merger of above two Giants is now known as MAN B&W.

         

      DETAILED TIMELINE OF MAN IS 

           http://www.corporate.man.eu/en/company/history/man-timeline/MAN-Timeline.html

      sulzer and man b&w engines series:

     
                          Sulzer engine series: RD, RND , RTA, RT -flex

                        MAN B&w  : KEF , KGF , MC,ME

      
                                COMPARISON BETWEEN SULZER AND MAN

Technology/ System	Wartsila SULZER	MAN Diesel Turbo	Who gets the EDGE?
Intelligent Engine	RT Flex- A complete electronically controlled engine with common rail system	ME Engine- Complete electronically controlled engine integrated with hydraulic control.	Wartsila- For installing an Intelligent engine technology in 2001. Prior to MAN (2003).
Fuel Injection System	Common rail Electronic control with Delta Injection System	Hydraulic actuated Electronic Control Injection system	Wartsila- For integrating Delta control with 3 injectors controlled independently for different load.
Exhaust Valve Control	Electronically controlled variable exhaust valve timing	Camshaft operated Exhaust valve for reliable operation	MAN- For integrating a smart mechanical exhaust valve operation in Intelligent engine for reliable operation.
Fuel Injectors	Conventional fuel injectors	Zero Sac Volume type fuel injectors with slide valve	MAN- Slide type fuel injector reduces after burning and hence NOx emission
Fuel Pump	Spill, suction valve controlled pump with VIT	Jerk type plunger barrel controlled pump with Super VIT	MAN- Super VIT with independent injection timing control w.r.t fuel index.
Starting Air system	Starting air valve opened by 30 bar air and a closing supply for positive shut along with spring. A relief valve in air manifold to avoid overpressure during starting airline explosion.	Starting air valve open by 30 bar air and shut by spring. Bursting disc provided to avoid overpressure during explosion	Wartsila- Additional safety provided in positive closing and relief valve for reliability during manoeuvring.
Piston and Rings	Convex shaped piston with Jet Shaker cooling. Chromium coated Piston ring.	OROS type Piston for better combustion area and reduction in piston temperature. Controlled Pressure Relief type top piston ring.	MAN-With OROS piston, the Maximum piston temperature reduces by 90°C. With CPR ring, better pressure distribution on liner and lower ring.
Cylinder Liner	Fine honed and bore cooled Liner with mid layer insulation.	Bore cooled liner.	Wartsila- Better cooling and insulation increases Cylinder liner Life
Main Bearing	White metal bearing lined on thin back.	Tri metal bearing with high load carrying capacity.	MAN-Tri metal bearing with long life and better embed ability.
Crosshead	12-15 bar pressure from separate pump supplied to bigger size plain bearing.	Small size bearing with oil wedges to retain oil which is supplied by normal system pressure.	Wartsila-Elevated pressure ensures better lubrication at high load. A back up line is provided in case of failure of crosshead pump.
Cylinder Lubrication	Electronically controlled Pulse Lubrication System with metered quantity injection	Alpha Adaptive Cylinder Lubrication control system allowing blending of cylinder oil for different grade of sulphur in fuel	MAN- ACC with different inputs like sulphur content and load index provide better neutralizing features.
Drive	Gear driven with timing gear driving the camshaft	Chain driven with 2 chains driving a camshaft	MAN- Chain drives are cheaper, lighter and easier to maintain and duplication provides backup.
Turbocharging	Prefers Axial turbocharger with constant pulse system.	Variable Turbine Angle turbocharger provides better operation at all load range	MAN-VTA allows engine to run without auxiliary blower at low load operation.
Exhaust Valve	Cobentional Valve seat with Nimonic and Stellite coating	W seat for better operation and increased time between overhaul. Dura spindle with better heat resistant property.	MAN- W seat allows cooling of exhaust valve during combustion stroke
Miscellaneous	Tribo pack allows increased time between overhaul of cylinder component up to 3 years. Electronic monitoring system for safe operation	Electronic monitoring system for safe operation.	Wartsila- With Tribo pack which is a package of design measures increases the TBO to 3 years.

       

   Governor is a device which controls the speed of engine automatically in the prescribed

limits.governor does its job by  measuring the speed and control the a amount of fuel supply to the engine.

Types of governors.

a.    Mechanical governor.           b.    Hydraulic governor

c.    Inertia governor [fitted on older slow speed engine]    d.  Electronic governor

Hydraulic governor is widely used because of their   sensitivity,having grater power to move the fuel control mechanism of the engine

 G/E governor is a droop speed governor with over speed trip.

 M/E governor is a constant speed governor with over speed trip



isochronous governor 

It is a constant speed governor .It is able to maintain exactly constant speed without hunting. This type of governor that has proportional and reset is called isochronous governor

speed droop governor is used at G/E - It is fitted to get load sharing ability isochronous governor gives constant speed, thus can not sharing the load.

AVR is fitted at alternator


governor droop -  When considering the engine and governor combination, the difference between the no load speed and full load speed is called governor droop.

Small droop causes rapid swing

Large drop causes slower response to change in speed

The use of temporary speed droop to prevent over correction of the fuel supply is called

compensation
It required two actions-
	Droop application	- as the fuel supply is changed
	Droop removal	- as the engine response to the fuel change and returns to original
	speed .

Why Inertia type Governor is not used nowadays 

1)        Although very simple type, it requires an engine speed increase of 5% or more to make it operate

2)        In some cases, increase of engine speed will bring into or near to critical speed that can cause severe vibration.

Governor Maintenance

Periodically check oil level,Change the governor oil,Grease the linkage and joint