(SEM VI) THEORY EXAMINATION 2024-25 AUTOMOTIVE ELECTRICAL & ELECTRONICS

Automotive Electrical & Electronics (BAU061)

Section-Wise Important Questions & Study Notes

SECTION–A

(Attempt all questions | 2 × 7 = 14)
This section checks basic definitions and fundamentals.
Write 2–3 lines only for each answer.

(a) Ohm’s Law & Kirchhoff’s Law

Ohm’s Law: Current is directly proportional to voltage at constant temperature (V = IR).

Kirchhoff’s Laws: KCL deals with current at a junction; KVL deals with voltage in a closed loop.

(b) Types of Automotive Batteries (Any Four)

Lead-acid battery

AGM (Absorbent Glass Mat) battery

Gel battery

Lithium-ion battery

(c) Main Function of Starter Motor

The starter motor converts electrical energy from the battery into mechanical energy to crank the engine for starting.

(d) Difference Between DC and AC Generator

(e) Spark Plug and Its Role

A spark plug produces an electric spark to ignite the air-fuel mixture in petrol engines.

(f) Advantages of CAN Bus System (Any Two)

Reduces wiring complexity

Faster and reliable data communication between ECUs

(g) Types of Automotive Sensors (Any Two)

Oxygen (O₂) sensor                                           Temperature sensor

Speed sensor                                                     Pressure sensor

SECTION–B

(Attempt any THREE | 7 × 3 = 21)
 Write descriptive answers with headings and neat diagrams.

(a) Lead Acid Battery – Construction & Working

Explain:                                                              Plates (positive PbO₂, negative Pb)

Electrolyte (H₂SO₄)                                            Container and separators
Working during charging and discharging reactions.

(b) Starter Motors – Construction & Types

Explain:                                                              DC series motor construction

Types: inertia starter, pre-engaged starter        Mention advantages of pre-engaged starters.

(c) Alternator in Charging System

Explain:                                                              Rotor, stator, diode rectifier

Voltage regulation                                             Why alternators replaced generators in modern vehicles

(d) Distributor-Less Ignition System (DIS)

Explain:                                                              Elimination of distributor

Use of crankshaft position sensor                     ECU-controlled ignition timing
Advantages: better efficiency, low maintenance

(e) Automotive Electronic Systems – Architecture & Functions

Explain:                                                              Sensors → ECU → Actuators

Role of microcontrollers                                    Applications: engine control, safety, comfort systems

SECTION–C

(Attempt any ONE | 7 × 1 = 7)

(a) Battery Charging Techniques & Tests

Explain:                                                                Constant current charging

Constant voltage charging                                  Trickle charging
Battery tests:                                                        Hydrometer test

Load test                                                              Voltage test

OR

(b) Maintenance of Automotive Batteries

Explain:                                                                Electrolyte level checking

Terminal cleaning                                                Specific gravity checking

Safety precautions