Lesson Notes By Weeks and Term v4 - SHS 3

Lesson Video

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Performance objectives

• Describe the principles of superchargers and turbochargers.
• Compare the functions of both systems.
• Explain how they improve engine performance.
• Identify their applications in Ghana.

Lesson summary

This lesson introduces the concept of forced induction—a technology used to significantly increase the power and efficiency of an internal combustion engine without increasing its size. We see vehicles every day on Ghanaian roads, from powerful cargo trucks climbing the Kwahu mountains to fast private cars in Accra. Many of these vehicles use either a supercharger or a turbocharger to achieve their performance. Understanding how these components work is fundamental for any student of automotive technology, as it explains how modern engineers achieve a balance of power, efficiency, and lower emissions.

Lesson notes

A. The Foundation: Why More Air Equals More Power?

To understand superchargers and turbochargers, we must first remember the basics of combustion. For an engine to create power, it needs to burn fuel. The "fire triangle" in an engine consists of: Fuel (e.g., petrol, diesel) Air (specifically, the oxygen in the air) Heat/Ignition (from a spark plug or compression)

The amount of power an engine can produce is limited by how much fuel and air it can burn in each combustion cycle. A Naturally Aspirated (N/A) engine works like a human breathing. On its intake stroke, the piston moves down, creating a vacuum that sucks air from the atmosphere into the cylinder. It can only take in air at atmospheric pressure (around 14.7 psi at sea level). Forced Induction is the process of using a compressor (an air pump) to force more air into the engine's cylinders than it could normally suck in on its own. By packing more air (more oxygen molecules) into the same space, the engine can also burn a larger quantity of fuel. This results in a much more powerful explosion in the cylinder, pushing the piston down with greater force and generating significantly more power.

Think of it like building a fire. If you blow gently on the embers, the fire grows much bigger and hotter because you are supplying it with more oxygen. Superchargers and turbochargers are sophisticated ways of "blowing" on the engine's fire. B. The Supercharger: Direct, Instant 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