Cooling Systems Flashcards
Learn about cooling systems
Why must an internal combustion engine have a cooling system?
To remove excess heat from the engine and to maintain a constant “safe”
operating temperature. The engine would be seriously damaged if the
excess heat was not removed.
When heat energy moves
along a solid object and
into another solid object
that is touching it.
Conduction
When heat energy is
transferred by a moving
liquid or gas. From hot to cold.
Convection
When heat energy is transferred in wave form, with no physical contact between the heat source and the heated object.
Radiation.
True or false? When heat is removed it can cause an object to become
smaller.
True.
True or false? When enough heat is added to water it will begin to boil and
turn to vapour. This is called a “change of state”.
True.
True or false? Heat will always move from a cooler region to a warmer region
False!
True or false? Heat can change the colour of metals
True.
A cooling system that uses only air to remove excess heat from the engine and take it directly to the atmosphere. The air can be forced past the engine
by a fan and guided by shrouds and ducts. Or simply by a draught type air flow.
Direct cooling system.
A cooling system that uses liquid coolant to remove heat from the engine. The coolant is pumped through chambers inside the engine, called water-jackets. The liquid coolant absorbs heat from the engine and is
then pumped to a radiator mounted outside the engine where the heat is exposed to cooler air. The coolant then re-enters the engine to absorb more
heat and continue the cycle.
Indirect cooling system
ON a DIRECT cooling system what is meant by the term “draught air flow”?
Draught air flow is when the air near the engine becomes hotter and begins to rise. The air rises because the molecules become less dense and thus lighter.
This allows denser cooler air to come in underneath where the hot air vacated and continue the cycle.
Three types of cooling system fans that are used on
indirect cooling systems.
Flex fan
Thermostatic fan (variable speed fan)
Electric fan
True or false? Both direct and indirect cooling systems can use a thermostat to control engine temperature.
True
True or false? An indirect cooling system uses cooling fins.
False, most of the time.
True or false? An Indirect cooling system uses a water pump
True
True or false? A direct cooling system will have frost plugs.
False!
Receives an electronic signal from the
temperature sender unit to show the
engine temperature to the driver
Temperature gauge
Pumps coolant around the engine and
through the radiator
Water pump
To seal holes in the engine left over from the casting process.
They pop out if the coolant freezes.
Frost plug / Welsh plug
Stores excess coolant from the radiator
and allows it to be drawn back to the
radiator as it cools.
Coolant reservoir
Controls the engine temperature. It remains
closed at start-up forcing the coolant to
cycle inside the engine until operating
temperature is reached. It then opens and
allows the coolant to flow through the
radiator. It then maintains a constant
engine temperature.
Thermostat
Used to connect the engine and the water pump to the
radiator.
Radiator hose
Mixture of water and ethylene glycol
Coolant / anti freeze.
Allows hot coolant to be exposed to a cooler air flow
Radiator
What is the name of the act that deals with the proper methods of
disposing of workshop waste such as coolant?
Resource management act
Describe how old coolant should be properly disposed of.
Coolant must be stored for collection. So as that it can be properly disposed by the quallified waste management service. We use ExOil.
What does testing the specific gravity of coolant tell you about the
composition of the coolant?
It measures the density of the coolant which will indicate how much antifreeze is in the coolant and whether it needs to be topped
up or replaced.
