Why Water is the Preferred Coolant for Car Engines: 3 Reasons Explained

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SUMMARY

Water is the preferred coolant for car engines due to its higher heat capacity, higher boiling point, and lower evaporation rate compared to alcohol. These properties allow water to absorb and dissipate heat more effectively, maintaining optimal engine temperatures. Alcohol, while it has some cooling properties, is less effective because it boils and evaporates at lower temperatures, leading to potential cooling inefficiencies in the radiator system.

PREREQUISITES
  • Understanding of heat capacity and its significance in cooling systems
  • Knowledge of boiling points and evaporation rates of different liquids
  • Basic principles of car engine operation and cooling systems
  • Familiarity with the properties of common coolants, specifically water and alcohol
NEXT STEPS
  • Research the thermal properties of various coolants, including ethylene glycol and propylene glycol
  • Learn about the design and function of car radiators and cooling systems
  • Investigate the impact of coolant choice on engine performance and efficiency
  • Explore safety considerations regarding flammable liquids in automotive applications
USEFUL FOR

Automotive enthusiasts, engineering students, and anyone interested in understanding the science behind car engine cooling systems.

jacklwk
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why we use water, but not alcohol as a coolant in the car engine?can you give me three reasons?
 
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Alcohol has a lower heat capcity than water
It boils at a lower temperature than water
It evaporates at a lower temperatuer than water


Why would we use alcohol as a coolant?
 
Thx A Lot~
 
Np. All 3 reasons are related. Because it has a higher heat capacity, it takes more engergy to boil, which also means more engergy to evaporate. Was this a homework question, or were you just wondering?
 
actually this is a homework question.
i am just a secondary 3 student.
can i say water is cheaper and alcohol is flamable?
 
I'm not sure those would be better reasons than the ones I listed above. The fact that alcohol is flammable shouldn't be a factor because it is never exposed to a spark, only the gasoline is. If the water was ever present where the combustion took place, the engine wouldn't run. Also, inside the radior, some of the water does boil; that's why you don't open a radior cap on a hot engine. Not all of the water boils because it's under pressure. If alcohol were used, more of it would boil and you wouldn't have the same volume of cooling liquid inside the radior; more would exist in a vaporous form than with water.
 
THX for your detailed explanation!You are really a enthusiast!
 
Haha. I do love cars, and the test I'm studying for right now deals with heat capacity. Good thing you asked when you did.
 

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