Air Cooled Engine Technology. Roth 9 th Ch 11 Cooling Systems Pages

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1 Roth 9 th Ch 11 Cooling Systems Pages

2 1. The and span of an engine depend on how well it is. Efficiency, Life, Cooled Efficiency, Life, Stored Efficiency, Life, Manufactured

3 2. The average temperature of burned gases in an air cooled engine is about Fahrenheit. Peak combustion temperatures must remain below 2400 F to prevent formation of NOx pollution F 2400 F 1200 F

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7 3. About of the heat is carried away by the cooling system, of the heat is exhausted, and the remaining 1/3 is used to produce engine power. (call it the thermal efficiency rule of thirds) 1/3 1/3 1/3

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9 4. The five basic parts of an air cooling system are (S, B, S, CF & F): Screen, Shroud, Baffles, Cooling Fins, Fan

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11 5. is the process of heat transfer through solid or liquid materials in contact. Conduction Convection Radiation

12 6. is the process of heat transfer through movement of gases, such as air. Conduction Convection Radiation

13 7. Exhaust in any way will overheat any engine. cooling fins cause hot spots. Restricted, Clogged Exhausted, Open Restricted, Clean

14 Cooling fins, cast on to the outside of the cylinder & engine block, increase the surface area of the engine exposed to the cooling air. This aids the convection process of cooling. Hotter parts = longer fins

15 8. are the hollow passages surrounding the cylinders in liquid cooled engines through which coolant flows to conduct heat away from hot parts. Water Jackets Coolant Sweaters Water Circuits

16 9. Liquid cooling systems are 4 times more than air cooling systems. The operating temperatures of these engines are more closely controlled for lower emissions & better performance. Audible Quiet Efficient

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19 10. Self contained liquid cooling systems circulate an solution (ethylene or propylene glycol) through water jackets. This lubricates, prevents corrosion, raises the boil point & lowers the freeze point. (50/50 is the recommended mixture concentration) Anti Freeze Anti Coagulant Anti Aircraft

20 11. Outboards often have water pumps, which use a synthetic rubber impeller to change the volume of water moving through the jackets in relation to engine speed. Vari Volume Constant Volume Semi Volume

21 12. Some outboards use a water flow system where the water flow from the propeller action and the forward motion of the boat provide water circulation. Pressure Vacuum Hoover Vacuum Dyson Vacuum

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23 For use in super shallow water

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29 13.Outboards use a valve to stop water from leaving the jackets until the engine reaches its proper (most efficient) operating temperature. Lake water can overcool or under cool without a t stat. Thermostat Thermometer Thermal Element

30 14. are the main heat exchangers used in self contained, liquid cooling systems.

31 15. The tube & fin assembly of a radiator is known as the radiator. (copper/aluminum/brass) Store Core Chore

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33 16. Wax pellet are coolant flow control valves use to maintain the proper (most efficient) operating temperatures in selfcontained liquid cooling systems. Coolant flow out of the block and into the radiator is not allowed until the thermostat opens. (over cooling & under cooling ) Thermostats Thermometers Thermal Elements

34 17. A is often used to increase air flow through the fins of a radiator or through cooling fins. They can be either belt driven, operated by an electric motor, or can be made as a part of the flywheel. Baffle Fan Valance

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36 18. circulating through the engine acts as a lubricant as well as a coolant in 2 & 4 cycle engines. Oil Electrolyte Coolant

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43 No Shroud Not Efficient Shroud = Efficient Cooling

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