Lesson Notes By Weeks and Term v4 - SHS 2

Lesson Video

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Performance objectives

• Describe the purpose of engine cooling systems.
• Explain the construction and operation of a thermosyphon system.
• Describe the construction and operation of a pump-assisted system.
• Compare and contrast the two systems.

Lesson summary

In Ghana, we see cars, trotros, and buses every day. Have you ever seen a vehicle stopped by the roadside with steam pouring from the engine? This is often due to a problem with the cooling system. An engine is like a powerful athlete; when it works hard, it generates a lot of heat. If this heat isn't controlled, the engine can be severely damaged, leading to expensive repairs. This lesson introduces the two main types of water-cooling systems designed to prevent this: the older Thermosyphon system and the modern Pump-Assisted system used in virtually all cars today. Understanding how they work is a fundamental skill for any aspiring technician, engineer, or even a knowledgeable driver.

Lesson notes

A. The Purpose of the Engine Cooling System

An internal combustion engine creates power by burning a mixture of fuel and air inside its cylinders. This process of combustion generates extremely high temperatures (over 2000°C). While some of this heat is used to create power and some exits through the exhaust, a significant amount (about 30-35%) is absorbed by the engine's metal parts (pistons, cylinders, cylinder head).

The Problem: If this excess heat is not removed: The engine oil will break down and lose its ability to lubricate. Metal parts will expand, potentially causing pistons to seize in the cylinders. The cylinder head can warp or crack. The engine will fail catastrophically.

The Solution: The cooling system's job is to remove this excess heat and maintain the engine at its optimal operating temperature (typically between 85°C and 105°C). This ensures the engine runs efficiently, lasts longer, and produces fewer harmful emissions. B. The Thermosyphon Water-Cooling System

Evaluation guide

• Describe the construction and operation of the thermosyphon and pump
• assisted water- cooling systems
• Problem based Learning:
• Learners brainstorm in groups with views tolerated from others, to discuss the exactpurpose of cooling system, and also examine the layout of thermosyphon and pump assisted water- cooling systems on a motor vehicle and present a report for discussions.