Auxiliary Engine

Question. What Do You Mean By Auxiliary Engines?
Answer: Auxiliary Engines Are Those Engines Which Are Not Used For Propulsion, Rather The Power Produced By These Engines Is Used In Generation Of Electricity.

Q. How Do Auxiliary Engines Provide Electricity?
Ans: Actually These Auxiliary Engines Onboard Are Coupled With Alternators Which Convert The Mechanical Power/energy Produced By Auxiliary Engines Into Electrical Power/energy.

Q. Define The Various Parts Of An Auxiliary Engine?
Ans: An Auxiliary Engine Consists Of Various Parts: 
A) Cylinder Head: Cylinder Head Consist Of Exhaust Valve, Inlet Valve, Indicator Cock, Fuel Injector, Starting Air Valve Etc. 
A) Cylinder Liner 
B) Piston Assembly : It Consists Of A Piston, Made In Two Parts Upper Part Is Piston Crown And The Lower Is Piston Skirt , Two To Three Compression Rings Are Fitted In The Ring Grooves Of Piston Crown Where As An Oil Scraper Ring Is Fitted In Ring Groove Of Piston Skirt. 
C) Gudgeon Pin Bearing Assembly: At The Mating Point Of The Connecting Rod And Piston Skirt, This Gudgeon Pin Bearing Assembly Connects Both Of Them. 
D) Bottom End Bearing Assembly: Bottom End Or Crank Pin Bearing Assembly Joins The Connecting Rod To The Crank Journal Vis-a-vis Crankshaft. 
E) Crankshaft: Generally Semi Built Type Crankshafts Are Used These Days Which Are Lighter And Durable. There Are Drilled Passages Through The Crankshaft For Lubrication.

Q. Explain The Lub Oil Diagram For An Auxiliary Engine?
Ans: The Lub Oil Diagram For Auxiliary Engine Is As Follows: Description: There Is Only One Type Of Oil Used For Both Cylinder And System Lubrication In Auxiliary Engines Where As In Main Engine Separate Cylinder And System Oils Are Used . When The Auxiliary Engine Is Not Running Then A Motor Driven Priming Pump, Pumps Lub Oil From Sump To Different Parts Such That Seizure Of Parts Doesn't Take Place. When Auxiliary Engine Is Started, The Shaft Driven Gear Pump Comes Into Action And Draws Oil From Sump Via A Strainer. The Lub Oil Further Moves Under The Pressure Generated By The Gear Pump To The Lub Oil Cooler, There Is A Separate By-pass Line For Centrifugal Filter Which Cleans The Oil From Sump To Sump. From Cooler, The Oil Moves To The Main Gallery For Distribution Through A Notch Wire Filter. In The Main Gallery This Lub Oil Is Transferred To Various Parts Like Turbocharger For Bearing Lubrication, Camshaft Gears, Main Bearing, Fuel Injection Pump Tappet Roller, Suction And Exhaust Valve Rocker Arm Lubrication Etc. After Lubrication This Lub Oil Drains From All These Parts To The Sump.

Q. List Various Properties Of The Lub Oil Used In Auxiliary Engines And How Is It Different From The Lub Oil Used In Main Engine?
Ans:
Viscosity: It Is A Measure Of Internal Resistance To Flow Of Fluids. Higher The Viscosity, The Greater Will Be Internal Resistance To Flow. If The Viscosity Of Lub Oil Is Too Low It May Not Be Possible To Maintain Sufficient Fluid Film Thickness For Avoiding Metal To Metal Contact. In Commercial Marine Applications, Viscosity Of Lubricating Oil Is Specified In SAE(Society Of Automotive Engineers)units. Typical Values Are SAE 30 For Crosshead Type Engine Bearings (equivalent To 9.3 To 12.5cst At 100 Deg Celsius) And SAE 40 For Trunk Piston Bearings (equivalent To 12.5 To 16.3 Cst). For Cylinder Lubrication, SAE 50 (equivalent To 16.3 To 21.9 Cst) Is Normally Specified. 

Demulsification: Demulsification Is The Opposite Of Emulsification I.eit Is The Separation Of Water From Oil. More The Demulsibility, The More Easily The Water Separates Out From Oil.


TBN(Total Base Number): It Is Expressed In Terms Of Number Of Mg Of KOH Required To Neutralize The Acid Present In One Gram Of The Lub Oil It Is One Of The Most Important Properties For Cylinder Lubrication. The TBN Value Of Lub Oil For Auxiliary Engines Is 15 To 30. 

Anti Oxidation: Oxidation Is A Common Form Of Deterioration Of Lub Oil In Service. Oxidation Takes Place At High Temperature In The Presence Of Air And Certain Contaminants Such As Rust, Sludge, Metal Wear Particles Such As Iron, Copper And Lead All Of Which Act As Catalysts. Oxidation Gives Rise To Sludge Formation And If Allowed To Continue Unchecked, It May Proceed At An Increasing Rate Eventually Causing Blockage Of Filters, Purifiers Etc. Stability Is The Property Of Oil That Resists Oxidation. To Ensure Oxidation, Good Base Stock Oil With Suitable Anti-oxidation Additives Should Be Used. 

Dispersancy: It Is The Ability Of The Oil To Maintain Insoluble Particles In Such A Finely Divided Condition That They Do Not Settle Out And Deposit As Sludge On The Colder Engine Surfaces. Dispersancy Is Ensured By Adding Dispersant Additives To The Oil. 

Detergency: Detergency Of The Lub Oil Is Its Property Of Being Able To Keep Interior Parts Of The Engine Clean And Free Of Deposits. Detergent Additives Include Metallo-organic Compounds Of Sodium, Calcium, And Magnesium, Phenolates, Phosphonates And Sulfonates. These React Chemically With Sludge To Neutralize And Keep Them Oil Soluble.