Lesson Notes By Weeks and Term - Senior Secondary 2

Automobile: A diesel engine II

Get it on Google Play
Get it on the Apple App Store
  1. Home
  2. Lesson Notes By Weeks and Term
  3. Senior Secondary 2
  4. Automobile: A diesel engine II

TERM – 1ST TERM

WEEK FIVE

Class: Senior Secondary School 2

Age: 16 years

Duration: 40 minutes of 5 periods each

Date:

Subject: AUTO MECHANICAL

Topic: AUTOMOBILE: A DIESEL ENGINE II

SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to

I.) Define detonation

II.) Identify the causes of detonation

III.) State the effects of detonation

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 detonation and state the causes

Students listens attentively to the teacher                                                                          

STEP 2

EXPLANATION

Teacher explain the effects of detonation

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 DIESEL ENGINE II

Detonation

Detonation, also known as engine knocking or pinging, is an abnormal combustion phenomenon that occurs when the air-fuel mixture in the combustion chamber ignites spontaneously and simultaneously at multiple points instead of a controlled, uniform ignition. This uncontrolled combustion creates shock waves and rapid pressure spikes within the cylinder, leading to a characteristic knocking sound.

Causes of Detonation

  1. Low Octane Fuel: Using gasoline with an octane rating lower than required for the engine's compression ratio can cause detonation.
  2. High Engine Load: Operating the engine under heavy loads, such as towing heavy loads or driving uphill, can increase cylinder pressures and temperatures, leading to detonation.
  3. Carbon Deposits: Carbon deposits in the combustion chamber can create hot spots that promote premature ignition of the air-fuel mixture.
  4. Incorrect Ignition Timing: Incorrect ignition timing can cause the air-fuel mixture to ignite either too early or too late, leading to detonation.
  5. Overheating: Engine overheating, whether due to insufficient cooling or excessive combustion temperatures, can increase the likelihood of detonation.

Effects of Detonation

  1. Detonation can cause significant damage to engine components, including pistons, cylinder walls, piston rings, and cylinder head components.
  2. Detonation can lead to reduced engine performance, including decreased power output and acceleration.
  3. The inefficient combustion associated with detonation can increase fuel consumption, reducing fuel efficiency and increasing operating costs.
  4. Detonation can lead to increased emissions of harmful pollutants such as nitrogen oxides (NOx) and unburned hydrocarbons (HC).
  5. The characteristic knocking or pinging noise associated with detonation can be disturbing and indicative of engine stress and potential damage.

EVALUATION: 1. Define detonation

  1. Mention 4 cause of detonation
  2. State 4 effects of detonation

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively