COOLING

Explain the terms ( Kinetic energy) Conduction,convection and radiation? Conduction is heat energy moving through a solid e.g. steel. Convection is the cycle ov heat through a liquid as the hot liquid rises the cold falls. Radiation is heat being transfered to the air from a hot object e.g. the engine

Indirect cooling? The coolant is in a closed cycle but still uses the raw water to cool the coolant further, this is a effective way of heat control because it works the same way as a car engine on a thermostat which means less corrosion and a faster warm up.

Direct cooling? The direct cooling method is to pump raw water up and through the water jacket then back out with the exhause fumes, this isnt as effective or practicle as indirect because of the corrosion and how long it takes for the engine to heat up - costing you more fuel.

What are the the problems you get with indect and direct cooling? Corrosion is the biggest problem because the raw water is so destructive, maintanance on the indirect cooling can be a mission - depending on how easy it is to get to the heat exchanger. You also have to regularly check the inlet valves because the can get blocked - causing over heating.

What is the puppose of a thermostat? To allow the engine to heat up to optimum running temp before letting the coolant pass through to be kept constant so the engine is always at the right temp.

Pressure cap? The pressure cap is a release valve for when/if the pressure in the radiator becomes to high for the specifications, it is also the way to top up the coolant.

Why is engines fitted with a core plug, and what is the purpose of a core plug? The manufacturors put them in so when they are moulded the can shake out all the core moulding sand. another reason for the core plugs is so if the water in the water jacket freezes it won't crack the block or head it will push out the frost plug instead.

What is the purpose of a heat exchanger? A heat exchanger is the equivelant to a radiator on a car except instead of cooling the coolant with air you cool it with raw water from the ocean which is also cycled to keep cold. It works by raw water circulating through pipes next to the circulating hot coolant the heat is transfered to the raw water leaving the coolant colder.

What is the core of the heat exchanger made of? Aluminium or copper because they are light weight and dont corrode very easily. 

How does the centrifugal circulating water pump work?

How does a raw water pump work?

Why is it important to lubicate the impellor when fitting from new?

When fitting a impellor what should you check before refitting the housing and why?

What is the purpose of a oil cooler and how does it work?

What is the process of a intercooler/aftercooler how does it work?

Why do we have Inhibitors & antifreeze?

How do you test Antifreeze?

What is cavitation corrosion?

What is galvanic corrosion?

Describle the terms

Stray corrosion?

Stress corrosion?

Corrosion Fatigue?

Crevice corrosion?

What is Electrolysis?

How do you prevent corrosion?

Why and what is bonding in the marine industry?

What are sacrifical anode made off?

Where would you place them in the marine industry?

10.06.11

What is the purpose of a water muffle?