About this previous year paper
SECTION A – Very Short Answer Type
(2 × 10 = 20 Marks)
a) Situations where Condition Monitoring is more suitable
Condition monitoring is suitable for critical, costly, and continuously operating machines, where unexpected failure can cause heavy loss, such as engines, gearboxes, and industrial machines.
b) Trip sheets
Trip sheets are records maintained for vehicles showing distance traveled, fuel consumed, route taken, and time, used to monitor vehicle performance and efficiency.
c) Types of maintenance cost
Preventive maintenance cost
Breakdown maintenance cost
Corrective maintenance cost
d) Lubrication oil topping up
Lubrication oil topping up means adding oil to the engine to maintain the required oil level between scheduled oil changes.
e) FIP adjustment and testing
Fuel Injection Pump (FIP) adjustment ensures correct fuel quantity and timing, while testing checks pump performance using calibration equipment.
f) Emergency maintenance vs general maintenance
Emergency maintenance is unplanned and immediate, done after sudden failure, whereas general maintenance is planned and preventive.
g) Wiring harness testing
Wiring harness testing checks continuity, insulation, and proper connections to ensure reliable electrical power flow in the vehicle.
h) Voltage of a fully charged battery cell
Each fully charged lead-acid battery cell contributes approximately 2.1 volts.
i) Fuel feed system
The fuel feed system supplies fuel from the tank to the engine at the required pressure and quantity.
j) Window glass actuation
Window glass actuation is the mechanism that raises or lowers window glass, either manually or electrically.
SECTION B – Long Answer Type
(Attempt any three – 10 Marks each)
2(a) “Engine tuning is a life-extending activity” – Justification
Engine tuning involves adjusting ignition timing, fuel supply, valve clearance, and idle speed to ensure optimal performance.
Justification:
Reduces engine wear
Improves fuel efficiency
Prevents knocking and overheating
Enhances power output
Example:
Correct ignition timing prevents detonation, protecting pistons and valves, thus extending engine life.
2(b) Short notes
(a) Overcharging of battery
Overcharging occurs when excessive voltage is supplied, causing:
Water loss
Plate damage
Overheating
It reduces battery life.
(b) Ignition timing light
An ignition timing light is used to check and adjust ignition timing by flashing light synchronized with spark plug firing.
2(c) Method of setting ignition timing using timing light
Steps:
Connect timing light to battery and spark plug wire
Start engine and aim light at timing marks
Observe mark alignment
Adjust distributor until correct timing is achieved
This ensures smooth engine operation.
2(d) Capacitor Discharge Ignition (CDI) testing method
CDI stores electrical energy in a capacitor and releases it quickly to the ignition coil.
Testing procedure:
Check capacitor voltage
Inspect ignition coil resistance
Test triggering circuit
Verify spark strength
CDI ensures strong spark at high speeds.
2(e) Minor body panel beating, tinkering, and shouldering
Panel beating: Straightening dented panels
Tinkering: Minor body repairs using tools
Shouldering: Smoothing repaired surfaces before painting
These restore vehicle appearance.
SECTION C – Descriptive Answer Type
3(a) Servicing and its types
Servicing is the routine inspection, adjustment, and replacement of vehicle parts to maintain performance.
Types: Free servicing
Paid servicing Preventive servicing
Periodic servicing
Servicing prevents breakdowns and improves safety.
3(b) Types of service stations
Authorized service station Independent service station
Specialized service station Mobile service station
Each type differs in equipment, expertise, and service scope.
4(a) Reconditioning and repairing of engine components
Reconditioning:
Restoring worn components using: Grinding
Honing Reboring
Repairing: Replacing or fixing damaged parts like:
Pistons Valves
Bearings These processes reduce replacement cost.
4(b) Cleaning and inspection
Cleaning: Removal of dirt, grease, and deposits.
Techniques: Solvent cleaning
Steam cleaning Ultrasonic cleaning
Inspection:
Visual, dimensional, and non-destructive testing to detect wear and cracks.
5(a) Objectives of transmission and related troubles
Objectives: Transmit power
Vary speed and torque Allow reverse motion
Troubles: Gear slipping
Noise Hard shifting
Maintenance: Lubrication
Proper adjustment Periodic inspection
5(b) Tire rotation
Need: Uniform tire wear
Longer tire life Better handling
Arrangements: Front-to-rear
Cross rotation Five-tire rotation
(Tire rotation diagrams are usually drawn in exams.)
6(a) Need for regular electrical maintenance
Electrical maintenance ensures: Reliable starting
Proper lighting Efficient charging
Battery troubles: Sulphation
Low electrolyte level Overcharging
Loose terminals
6(b) Ignition system and comparison
Ignition system:
Produces spark to ignite air-fuel mixture.
| Feature | Coil Ignition | Transistor Assisted |
|---|---|---|
| Control | Mechanical | Electronic |
| Spark strength | Moderate | Strong |
| Reliability | Lower | Higher |
7(a) Corrosion and anti-corrosion methods
Corrosion: Gradual deterioration of metal due to chemical reaction.
Types: Uniform corrosion
Galvanic corrosion Pitting corrosion
Prevention: Painting
Galvanization Cathodic protection
Use of coatings
7(b) Regular body maintenance & window winding mechanism
Body maintenance steps: Washing and waxing
Rust inspection Paint touch-ups
Lubrication of hinges Window winding mechanism:
Consists of: Handle or motor
Regulator mechanism Glass channel
It converts rotational motion into vertical movement of glass.