automotive electrical and electronics two marks

7/22/2019 Automotive Electrical and Electronics Two Marks

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DEPARTMENT OF MECHANICAL ENGINEERING

TWO MARK QUESTIONS

Sub. Code : AT 2302 Year/ Class : III - Auto

Sub. Name: Automotive Electrical And Electronics Sem.: V

1. Draw the voltage curves of a lead-acid battery? (2)

2. Draw the curves of Internal resistance & Voltage. (2)

3. Write short notes on Battery Efficiency (1)

The efficiency of a battery is generally defined in terms of ampere hours or watt

hours. It may be noted that a battery is far more efficient when discharged at a slow rate

than when it is discharged rapidly.

Battery efficiency = W1/W2 in terms of watt hours (1)

= A1/A2 in terms of ampere hours

Where,



W1 is watt hour output for full discharge

W2 is watt hour input for full discharge

A1 is ampere hour output for full discharge

A2 is ampere hour input for full discharge

4. Write short notes on Cold rate battery. (2)It is also termed as short time rate. This rating is the number of minutes that a

battery will deliver 300A of current at a starting temperature of -18°C befor the cell

voltage falls below 1.0V. It indicates the ability of battery during cold weather starting.

5. What are the effects of temperature on electrolyte gravity? (2)

The specific gravity of the electrolyte varies with the temperature the liquid

expense and becomes thinner when heated and it losses its specific gravity. It is there for

essential to take into account the temperature while taking specific gravity reading to

know the state of change of the battery accurately.

6. Make a teble and write specific gravity readings and state of charge of battery. (2)

Approxiamte Specific

Gravity

State of Charge of Battery

1.260-1.280 Fully Charged

1.230-1.260 3/4t

Charged

1.200-1.230 Half Charged

1.170-1.200 1/4t

Charged

1.140-1.170 About Rundown

1.110-1.140 Discharged

7. Write short notes on the following:Internal resistance (2)

The internal resistance depends upon the size of plates. The electro motive

force is greater than the terminal voltage. When the cell is being

discharged the emf is less than the applied voltage when the cell is being

charge

8. Write the types of Battery failures (2)

Various types of battery failures are over charging failure, cycling failure,

Sulphation failure and Internal Short circuit.

9. Write few points on maintainance of batteries. (2)

(i) Battery may be charged at low charging rate

(ii) Avoid overfilling

(iii)Check generator regulator system



(iv) Reduce the setting of voltage regulator. Also reduce Specific gravity of

electrolyte

10. How are the following defects caused in lead acid batteries

Sulphation: A badly dulphated battery has got injured plat grids and separators becauseof swelling of the plate as the sulphate occupies more space than the active materials. A badly

sulphated battery may be restored to a usable condition, nut, its original life expectancy can

never be restored as it has already lost part of its life due to sulphation

11. What is the function of ignition system? (2)

The main function of the ignition system to ignite the mixture of fuel and air that

is drawn into the cylinder.

12. Define Dwell angle? (2)

The dwell angle is the angle moved by the cam during contact closed period.

(Or)

The dwell angle or cam angle is the number of degrees travelled by the distributor

cam while the contact points are closed.

13. What is the function of Ballast resistor& Ignition coil? (2)

The main function of the ballast resistors is to regulate the current flowing in the

primary winding. It also limits the rate of battery discharge if the ignition switch itself on

when the engine has stopped. The ignition coils are used to wind the core. Now a days

the primary coils are wound over the secondary coil. It gives the stronger magnetic field.

14. What are the functions of Contact breaker? (2)

The contact breaker is a cam actuated switch which triggers the signal when an

high tension impulse is required for the spark plug.

15. What are functions of distributor? (2)

It opens and close the primary circuit of the ignition coil and it distributes the

resulting high voltage surges from the secondary winding of the ignition coil to various

spark plug of the engine.

16. What are classifications of ignition system? (1+1)

i. Conventional Ignition System

ii. Electronic Ignition System

a. Programmed Ignition System

b. Distributorless Ignition System

c. Direct Ignition System.



17. What are factors to be considered for the design of an ignition system? (1+1)

Air Fuel Ratio

Combustion Chamber design

Engine Speed Ragge

Combustion Temperature

Load

Emission Regulation

18. On what factors does the ideal ignition timing depend? (1+1)

Engine Temperature

Valve Timing

The fuel ability to vaporize quickly

The engine design characteristics such as cylinder bore, combustion chamber, spark

plug to action etc.,

19. Under what condition are the ignition delay and ignition advance necessary? (2)

The engine has an ignition timing of 8° before TDC. The spark occur when the

crank shaft is positioned at 8° of rotation before a cylinder TDC point changing the

ignition timing so that the spark plug fires earlier.

20. What is coil ignition? (2)

In the coil ignition system the ignition coil transforms the low tension 12V supply

given by the battery to the high tension with voltage needed to produce a spark at the

spark plug.

The coil has primary and secondary windings forming two complete circuits thatmake up the complete systems.

21. What are the types of triggering devices? (2) Optical triggering device

Magnetic pick up triggering device Hall effect triggering device

22. What are advantages of electronic ignition system? In this system the components can leak higher voltage than contact points It can produce much more secondary voltage than conventional ignition system It can handle much more current

23. What is the function of crank shaft position sensor?

(2)The main function of the crank shaft position sensor is to sense the crank shaft position in

an engine



24. What is the function of cam shaft position sensor?

(2)

The function of this sensor is to send a signal to the computer to indicate that a particular cylinder is ready to be fired.

25. What are types of trigger wheel? (2) Trigger wheel Reluctor Interpreter ring Pulse ring

26. What is function of pulse shaping stage? (2)

A pulse generator is connected to a control module once the AC signal is fed from the

generator to the trigger circuit stage, the pulse is shaped in to a DC rectangular form. Thetriangular pulse width depends on the duration of the pulse output from the generator

27. What is the function of a spark plug(2)The main function of a spark plug is to provide the spark at the end of compression stroke

for the ignition fuels

28. What is the heat range of Spark Plug

(2)

The ideal operating heat range of spark plug is between 673K & 1173K.

29. What are the advantages of an ESA system

(2) The ignition timing can be accurately matched to the individual application under

a range of various operating conditions

The number of wearing components is considerably reduced in this system.

30. How the percentage dwell set to suit engine speed (2)

At low speed the percentage dwell is kept relatively small, which is increased

progressively with increase of speed.

31. What are the basic requirements of a starting system? (2)

The internal combustion engine requires

A combustible mixture

Compression stroke

A form of ignition

Minimum initial starting speed



32. What are solenoids? (2)

The solenoids are the magnetically operated switches. In this solenoids a core

element is wounded with wires to perform as a magnet

33. Define alternators? (2)

Alternator or AC generator is the generator which produces alternating current.

Instead of the direct current as produced by commutator type generator.

34. What are regulators& its types? (2)

The regulators are the device which regulates the current produced by the

generator. The various types of regulators are

Voltage regulators

Current regulator

35. Define Cranking motor Efficiency (2)

The efficiency is defined as the ratio between mechanical output to the electrical

input. The efficiency of the motor is

η = Mechanical output in watt / Electrical input in watt

36. What do you meant by sensors? (2)

The sensors are a device which is used to record data for measurement and or

control. There are so many types of sensors are used in automobile.

Examples

Oil level and quality sensors

Pressure sensors

Knock sensors

Temperature sensors

37. What are the types of sensors used in automobile? (2)

Oil level sensor

Cam shaft sensor

Crank shaft sensors

Temperature sensor

Air mass flow sensor

Knock sensor

Pressure sensor

Exhaust gas sensor



38. What is the purpose of fuel level indicators? (2)

Fuel level indicators are used to indicate the measurement of fuel in the tank.

39. What are the types of speedometer? (2)

Centrifugal type

Magnetic type

Electric type

40. What you mean by speedometer & odometer? (2)

The Speedometer indicates the speed at which the automobile is running.

The Odometer is a device for measuring and registering the kilometres a vehicle

has been driven. The short distance odometer is usually called as tripmeter and the

Odometer is a part of the Speedometer.

41. Write short notes on the Battery Efficiency.

The efficiency of a battery is generally defined in terms of ampere hours or watt hours. It

may be noted that a battery is far more efficient when discharged at a slow rate than when it

is discharged rapidly.

Battery efficiency = W1/W2 in terms of watt hours (1)

= A1/A2 in terms of ampere hours

Where,

W1 is watt hour output for full discharge

W2 is watt hour input for full discharge

A1 is ampere hour output for full discharge

A2 is ampere hour input for full discharge

42. What are the effects of temperature on electrolyte gravity?

The specific gravity of the electrolyte varies with the temperature the liquid

expense and becomes thinner when heated and it loses its specific gravity. It is there for

essential to take into account the temperature while taking specific gravity reading to

know the state of change of the battery accurately.

43. What is the function of Ballast resistor& Ignition coil?

The main function of the ballast resistors is to regulate the current flowing in the

primary winding. It also limits the rate of battery discharge if the ignitions switch it self

on when the engine has stopped. The ignition coils are used to wind the core. Now a day

the primary coils are wound over the secondary coil. It gives the stronger magnetic field.



44. What are the functions of Contact breaker?

The contact breaker is a cam actuated switch which triggers the signal when an

high tension impulse is required for the spark plug.

45. What is function of pulse shaping stage?

A pulse generator is connected to a control module once the AC signal is fed fromthe generator to the trigger circuit stage, the pulse is shaped in to a DC rectangular form.The triangular pulse width depends on the duration of the pulse output from the

generator.

46. What is the function of crank shaft position sensor & cam shaft position sensor?The main function of the crank shaft position sensor is to sense the crank shaft

position in an engine

The function of cam shaft position sensor is to send a signal to the computer toindicate that a particular cylinder is ready to be fired.

47. What are solenoids?The solenoids are the magnetically operated switches. In this solenoids a core

element is wounded with wires to perform as a magnet

48. Define alternators?

Alternator or AC generator is the generator which produces alternating current.

Instead of the direct current as produced by commutator type generator.

49. What do you meant by sensors? What are the types of sensors used in automobile?

The sensors are a device which is used to record data for measurement and or control. There are so many types of sensors are used in automobile.

Examples

Oil level and quality sensors

Pressure sensors

Knock sensors

Temperature sensors

50. What you mean by speedometer & odometer?

The Speedometer indicates the speed at which the automobile is running.The Odometer is a device for measuring and registering the kilometres a vehicle

has been driven. The short distance odometer is usually called as trip meter and the

Odometer is a part of the Speedometer.

automotive electrical and electronics two marks

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