Lesson Notes By Weeks and Term v4 - SHS 3

Lesson Video

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Performance objectives

• Describe the principles of superchargers and turbochargers.
• Explain how they increase engine performance.
• Identify their key components.
• Compare and contrast their operation.
• Discuss their advantages and disadvantages.

Lesson summary

Welcome, students! Today, we are moving beyond the basic internal combustion engine to explore how we can make engines more powerful and efficient. Have you ever wondered why some small cars feel surprisingly fast, or how large trucks and buses manage to climb steep hills like the ones on the Aburi or Kwahu mountains with heavy loads? The answer often lies in two special devices: the supercharger and the turbocharger. This lesson is very important for you as future technicians, engineers, or even just knowledgeable drivers in Ghana.

Lesson notes

Part 1: The Basic Engine - Naturally Aspirated

Before we discuss superchargers and turbochargers, we must first understand a standard engine. Most basic car engines are naturally aspirated. Definition: A naturally aspirated engine draws air into its cylinders using only the atmospheric pressure created by the downward stroke of the piston. Analogy: Think of breathing normally. Your lungs create a vacuum, and air flows in naturally. The engine does the same thing. It just "breathes" in the air that's around it. Limitation: The amount of power an engine can make is limited by the amount of air it can breathe in. At higher altitudes, like parts of the Eastern Region, the air is less dense, and a naturally aspirated engine will produce even less power. Part 2: The Solution - Forced Induction

To overcome the limitation of natural aspiration, engineers developed forced induction. Definition: Forced induction is the process of using a compressor (an air pump) to force more air into the engine's cylinders than would be possible with atmospheric pressure alone. The Core Principle: More Air + More Fuel = More Power. Analogy: Think of fanning a coal pot fire. When you fan it, you are forcing more air (oxygen) onto the coals. This makes the fire burn much hotter and stronger. Forced induction does the same thing for an engine.

The two main types of forced induction systems are the Supercharger and the Turbocharger. Part 3: The Supercharger (Mechanically Driven Power)

Evaluation guide

• Describe the principle of supercharger and turbocharger.
• Problem based Learning:
• Learners work independently or in a group to identify and brainstorm the principle of
• understanding