Lesson Notes By Weeks and Term v4 - SHS 3
INTRODUCTION TO VEHICLE TECHNOLOGY
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INTRODUCTION TO VEHICLE TECHNOLOGY
Download the Lessonotes Mobile Ghana app for faster lesson access on Android and iPhone.
Subject: Applied Technology
Class: SHS 3
Term: 1st Term
Week: 6
Grade code: 3.1.2.LI.5
Strand code: 1
Sub-strand code: 2
Content standard code: 3.1.2.CS.1
Indicator code: 3.1.2.LI.5
Theme: AUTOMOTIVE TECHNOLOGY
Subtheme: INTRODUCTION TO VEHICLE TECHNOLOGY
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This lesson introduces students to the exciting and rapidly growing field of Electric Vehicle (EV) technology. As Ghana faces challenges with fluctuating fuel prices and increasing environmental awareness, understanding alternatives to traditional petrol and diesel cars is crucial. EVs represent the future of transportation, offering a cleaner, quieter, and potentially cheaper way to travel. This lesson will demystify how these modern vehicles work by breaking down their main components and explaining the flow of energy from the charging point to the moving wheels. This knowledge is essential for future technicians, engineers, and informed citizens.
A. What is an Electric Vehicle (EV)?
An Electric Vehicle (EV) is a vehicle that is powered by one or more electric motors, using electrical energy stored in a rechargeable battery pack. Unlike conventional vehicles that use an Internal Combustion Engine (ICE) to burn fuel (petrol or diesel), EVs produce no tailpipe emissions, making them environmentally friendly.
Key Difference: ICE Vehicle: Burns fuel -> Creates controlled explosions -> Pushes pistons -> Turns crankshaft -> Turns wheels. (Chemical Energy -> Heat Energy -> Mechanical Energy) EV: Stores electricity -> Powers a motor -> Motor spins -> Turns wheels. (Electrical Energy -> Magnetic Energy -> Mechanical Energy) B. Main Components of an Electric Vehicle
Here are the essential parts of an EV. We will use analogies to a regular car to make it easier to understand. Traction Battery Pack: Analogy: The "Fuel Tank" of the EV. Explanation: This is a large, high-voltage battery pack (usually lithium-ion) that stores the electrical energy needed to power the vehicle. It provides Direct Current (DC) power to the electric motor via a controller. Its capacity, measured in kilowatt-hours (kWh), determines the vehicle's range (how far it can go on a single charge). Electric Traction Motor: Analogy: The "Engine" of the EV. Explanation: This device converts electrical energy from the battery into mechanical energy to turn the wheels. When the driver accelerates, the motor spins. Importantly, the same motor can also act as a generator during braking to recharge the battery (this is called regenerative braking). Most modern EVs use Alternating Current (AC) motors for their efficiency and power. Power Electronics Controller (Inverter): Analogy: The "Brain" and "Fuel Injector" combined. Explanation: This is a critical component that manages the flow of electrical power from the battery to the motor. Its main job is to act as an inverter, converting the battery's Direct Current (DC) into the Alternating Current (AC) that the motor needs to operate. It also controls the speed of the motor by varying the frequency of the AC power, based on how hard the driver presses the accelerator pedal. On-board Charger: Analogy: The "Funnel" for filling the fuel tank. Explanation: This component is built into the car. Its function is to convert the AC electricity from a charging station or a wall socket into DC electricity that can be stored in the traction battery pack. It manages the charging process to ensure the battery is charged safely and efficiently. Charging Port: Analogy: The "Fuel Cap". Explanation: This is the external port on the vehicle where the charging cable is plugged in. It allows the car to connect to an external power source for recharging the traction battery. Drivetrain (Transmission): Analogy: A much simpler "Gearbox". Explanation: EVs have a much simpler transmission than ICE cars. Because electric motors can generate high torque from a standstill and operate efficiently over a wide range of speeds, most EVs use a simple, single-speed transmission to transmit power from the motor to the wheels. DC-DC Converter: Analogy: A "Step-down Transformer" for the car's accessories. Explanation: The high-voltage traction battery cannot directly power the car's regular accessories like the headlights, radio, and wipers, which run on a lower voltage (typically 12V). The DC-DC converter steps down the high-voltage DC power from the traction battery to low-voltage DC power to recharge the 12V auxiliary battery and run these accessories. C. How an EV Operates: A Step-by-Step Guide