Lesson Notes By Weeks and Term - Senior Secondary 2
Automobile: A petrol engine II
Automobile: A petrol engine II
TERM – 1ST TERM
WEEK TWO
Class: Senior Secondary School 2
Age: 16 years
Duration: 40 minutes of 5 periods each
Date:
Subject: AUTO MECHANICAL
Topic: AUTOMOBILE: A PETROL ENGINE II
SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to
I.) Describe a four-stroke cycle operation
II.) Discuss the working sequence of a four-stroke cycle operation
INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers, demonstration, videos from source
INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures,
INSTRUCTIONAL PROCEDURES
PERIOD 1-2
|
PRESENTATION |
TEACHER’S ACTIVITY |
STUDENT’S ACTIVITY |
|
STEP 1 INTRODUCTION |
The teacher explains the meaning of the four stroke cycle operation |
Students listens attentively to the teacher |
|
STEP 2 EXPLANATION |
Teacher discusses the working sequence of a four stroke cycle operation |
Students exhibit attentiveness and active engagement |
|
STEP 3 NOTE TAKING |
The teacher writes a summarized note on the board |
The students copy the note in their books |
NOTE
AUTOMOBILE: A PETROL ENGINE II
The four stroke cycle operation
The four-stroke cycle operation, also known as the Otto cycle, is a type of internal combustion engine operation that completes the four strokes of intake, compression, power, and exhaust within four strokes of the piston.
The working sequence of a four-stroke cycle operation
- The piston moves downward from the top of the cylinder, creating a vacuum in the combustion chamber.
- The intake valve opens, allowing a mixture of air and fuel to enter the combustion chamber from the intake manifold.
- As the piston reaches the bottom of the stroke, the intake valve closes.
- With both the intake and exhaust valves closed, the piston moves upward, compressing the air-fuel mixture in the combustion chamber.
- The compression raises the temperature and pressure of the mixture, preparing it for combustion.
- When the piston reaches the top of the compression stroke, the spark plug ignites the compressed air-fuel mixture.
- The combustion rapidly expands the gases, generating high pressure that forces the piston downward.
- As the piston descends, it transfers the energy of the expanding gases to the crankshaft via the connecting rod, producing useful work.
- As the piston approaches the bottom of the power stroke, the exhaust valve opens, and the intake valve remains closed.
- The piston moves upward, pushing the burned gases out of the combustion chamber and into the exhaust manifold.
- Once the piston reaches the top of the exhaust stroke, the exhaust valve closes, and the intake valve begins to open, starting the next intake stroke.
EVALUATION: 1. What is a four stroke cycle operation?
CLASSWORK: As in evaluation
CONCLUSION: The teacher commends the students positively