COXSWAIN ENGINEERING. Marine Engines -Basic Operation 4 Stroke & 2 Stroke.

COXSWAINENGINEERING

Marine Engines -Basic Operation4 Stroke & 2 Stroke

4 Stroke Engine

2-Stroke Engine

*IgnitionPower stroke drives piston downwards

Downward piston movement compresses air/fuel mixture in crankcase.As exhaust port is uncovered, pressure from ignition drives out exhaust gases

At bottom of stroke, inlet port opens allowing pressurised air/fuel mixture to rush into cylinder (also displaces remaining exhaust gases)

As air/fuel mix is compressed, vacuum in crankcase is created and sucks more air/fuel mixture from carburetor

Power Power(incl Exhaust)

Power(incl Induction)

Compression

4 Stroke 2 Stroke(Fires once every 2 revolutions of crankshaft, or once every 4th piston stroke)

(Fires once every revolution of crankshaft, or once every 2nd piston stroke)

DIRECT INJECTION

INDIRECTINJECTION

Petrol, Diesel & OutboardEngines

OUTBOARD AND INBOARD PROPULSION UNITS

Outboard

OUTBOARD AND INBOARD PROPULSION UNITS

Shaft Drive

OUTBOARD AND INBOARD PROPULSION UNITS

V Drive

OUTBOARD AND INBOARD PROPULSION UNITS

Stern Drive(Inboard / Outboard

OUTBOARD AND INBOARD PROPULSION UNITS

Z Drive

KORT NOZZLE

OUTBOARD AND INBOARD PROPULSION UNITS

Sail Drive

OUTBOARD AND INBOARD PROPULSION UNITS

Sail Drive

OUTBOARD AND INBOARD PROPULSION UNITS

Hydraulic Drive

Drive Train Assembly

Stern Tube Arrangements

PropellerEngine

As seen aboard larger vessels

Typical Stern Tube arrangement on smaller vessel

Mechanical Shaft Seals(Packless, Non-Drip)

“Duramax”

“PSS”

Steering Gear

• Wire and Pulley

• Push/Pull

• Chain and Steering Box

• Hydraulic

SteeringWire & Pulley

SteeringPush/Pull

SteeringChain and Steering Box

SteeringHydraulic

SteeringHydraulic

Cooling, Lubricating & Fuel Systems

Direct Cooling System

Indirect Cooling System

Shell and Tube Heat Exchangers

Keel Cooling

Keel Cooling

Lubrication System

Diesel Fuel System

Bleeding the fuel system

Typical Fuel Tank Arrangement

Typical Fuel Arrangement

Bilge & Pumping Arrangements

Bilge Pumping Manifold

Valves andPipework

BACK FLOODING

Q. WHAT IS BACK FLOODING?

Ans. Water entering vessel through existing pipework

BACKFLOODING

Prevention?

•Screw Down Non-Return Valves

•L-Ported Cocks

•Non-Return Valves

•Isolating Valves

O/B D/Wash

Open – from Sea Cock to Deck Wash

O/B D/Wash

Open – from Sea Cock/Bilge to Overboard Discharge

O/B D/Wash

CLOSED

L-Ported Cock

Non-Return Valve

Screw Down Non-Return Valve

Isolating Valves

Ball Valve

Globe Valve

Gate Valve

Butterfly Valve

BILGE PUMPING

2. Select Seawater suction

3. Select Over Board discharge

4. Start pump and ensure seawater is being

pumped over board

5. Select Bilge suction - ensure bilge water

discharge over board

6. As soon as over board discharge flow lessens, select

Seawater suction and ensure water is being pumped over board

7. Shut down pump

1. Ensure Sea Water isolating valve is OPEN

BILGE PUMPING

PROBLEM SOLUTION

Not pumping Bilge compartment not selected

Not pumping Bilge suction blocked

Not pumping Bilge pump not operating

Not pumping Broken pipe/hole in suction line

Monitoring machinery

Pre-start Checks

• Fuel – Sufficient amount for journey, Fuel cock on, Water drained from sedimenter

• Oil – At correct level, top up if necessary

• Water – At correct level, top up if necessary

• Batteries – Electrolyte level OK, Correct Battery Bank selected

• Drive belts, Hoses in good condition & adjusted correctly

• Sea Water Cock open (strainer clean)

• Bilge pump valves set correctly

Operating Checks• Engine gauges (Coolant Temperature, Oil Pressure,

Oil Temperature, Exhaust Temperature, Gearbox Oil Pressure, Gearbox Oil Temperature……..)

• Visual checks for oil/water leaks, unusual vibration

• Pumps operational (o/board cooling discharge, wet exhaust discharge)

• Genset charging

• Sterntube not overheating/leaking excessively

• Colour of exhaust gases not abnormal– Black smoke = injector problems– Blue smoke = faulty piston rings– White smoke = poor compression

Checks on Shut-down

• Let engine idle for some time to cool down (especially if turbocharged)

• Shut down as per manufacturer’s instructions

• Turn off Fuel cock

• Turn off Sea Water Suction

• Turn off Battery Master Switch

• Check bilge pump is off and ensure no backflooding

Troubleshoothing

• Starting problems– Battery, Connections, Starter motor, Water in cylinder…

• Cooling system problems– Strainer, Seawater pump, Engine water pump,

Thermostat, Coolant, Header tank cap, Sender unit

• Lubrication problems– Oil level, Fuel in oil, Oil pump, Blocked Filter,

• Fuel Problems– Low fuel level, Air in system, Blocked Filter, Fuel lift

Pump, Injector Pump, Injectors

• Engine stops– Check Fuel, Cooling, Lubrication systems

Electrical Systems

Direct Current (DC)&

Alternating Current (AC)

Care and Maintenance of Lead Acid Batteries

Series & Parallel connection

Batteries may be connected in series for increased voltage, or in parallel for increased capacity

Series = positive to negative connection

Parallel = positive to positive & negative to negative connection

+ _+ _

Batteries - Series

+ _

12 V50 AH

12 V50 AH

24 V50 AH

(Increased Voltage, same Capacity)

+ _

+ _

Batteries - Parallel

12 V50 AH

12 V50 AH

+ _12 V100 AH

(Same Voltage, increased Capacity)

Care and Maintenance of Lead Acid Batteries

For best performance:

Keep Battery clean, dry and free from terminal corrosion

Electrolyte at correct level

Correctly charged

Battery Cleanliness

A dirty battery or spilt electrolyte may provide a path for electrical current to leak away

Corrosion on battery terminals (green-white powder) may seriously affect or prevent battery from supplying current

Electrolyte Level

Keep topped up with Distilled or Demineralised water only

(Chemical action inside battery causes water loss)

Maintain water level at approximately 10mm above plates inside battery

Correct Charging

To provide the best service, a battery must be correctly charged

Both overcharging and undercharging can seriously affect a battery’s performance

CONSTRUCTION OF LEAD ACID BATTERIES

Chemical combination of lead and lead peroxide plates,in a solution of sulphuric acid produces a voltage between the plates

Essential Battery Maintenance

•Keep clean & dry

•Electrolyte at correct level

•Correctly charged

GENERAL MAINTENANCE

• Check battery fluid level and state of charge w/- hydrometer

• Remove battery connections and clean

• Ensure battery is correctly stowed & secured

• Check cables for cracks / damage

• Check operation of charging system (voltmeter if fitted)

Electrical System

Care and Maintenance of Lead Acid Batteries

Battery condition may be determined by:

Measuring the Specific Gravity

Measuring On-Load Terminal Voltage

Specific Gravity Specific Gravity of electrolyte varies

proportionally with amount of charge in battery

SG is highest when fully charged, and lowest when discharged

SG measured with Hydrometer

Fully charged = 1.250Discharged = 1.150

How to Measure Specific Gravity

1.250 = Fully Charged1.150 = Discharged

HYDROMETER

Measuring ON-Line Terminal Voltage

Must be measured when battery is supplying current to a load (i.e. radio, spot light etc)

Should not drop below 11.4 Volts

(Measuring Off-load voltage does NOT indicate true condition of battery)

Use Voltmeter

Battery HazardsRisk of Explosion Hydrogen gas is given off during charging Any spark may ignite when mixed with air Use metal tools with care when working on

battery connections to avoid short circuits

Chemical Burns Electrolyte contains Sulphuric Acid Most concentrated after charging Ensure eye protection Dilute spills with running water

Shore Power Connection

3 Phase – 415V AC3 Phase – 415V AC--Common Ship’s Power

Single Phase – 240V ACSingle Phase – 240V AC--Domestic Power Supply

SINGLE and THREE PHASE

Shore Power Connection

When connecting shore power, ensure correct phase rotation prior to engaging switch on distribution panel (otherwise pumps will rotate in opposite direction)

Connecting Shore Power

•Check Shore Power lead is correctly connected to vessel shore supply inlet

•Ensure shore supply facility is “Off”

•Connect vessel shore power lead to shore

facility

•Turn “ON” power at shore facility

•Check vessel electrical distribution board to ensure correct phase rotation (3-phase)

•If phase rotation is incorrect, use “Reverse Polarity” switch to ensure correct phasing

•Engage switch to select “Shore Power”

•Shut down ship supply genset

Disconnecting Shore Power

• Start Ship Genset (allow to warm up)

• Select “Ship Power” on electrical distribution board

• Ensure correct power supply

• Turn “OFF” shore supply facility

• Remove shore power lead and store on vessel

LPG

LPG

•Keep cylinder upright (otherwise liquid will enter the regulator/piping and expand 250 times causing failure/explosion and a major leak)

•A gas smell is an indication of a leak

•Gas is heavier than air and will settle in the lowest part (bilge) of the vessel

•Check joins/connections with soapy water

•Store cylinder above decks, well secured and ventilated

•Check test date on cylinder (10 years)

BLEVEBoiling Liquid Expanding Vapour Explosion

END COXSWAIN

ENGINEERING