250+ TOP MCQs on Engine Electronics and Answers

Automobile Engineering Multiple Choice Questions on “Engine Electronics”.

1. Which of the following is the knock sensor?
a) Flap type sensor
b) Thermocouples
c) Thermistors
d) Piezoelectric pickup
Answer: d
Clarification: Piezoelectric pickup is the knock sensor. This sensor is mounted on the cylinder block. Knock sensor system uses a sensor, which is piezoelectric vibration pickup.

2. What is the use of the lambda sensors in the catalytic converter?
a) To keep excess air ratio within a range
b) To keep the flow rate of constant air
c) To keep the exhaust pressure constant
d) To keep the exhaust temperature constant
Answer: a
Clarification: In catalytic convertor, the lambda sensors are used to keep excess air ratio within a range. The catalytic converter is the emission control device.

3. Where are the electro-optical sensors used?
a) Position and speed measurement
b) Piston temperature measurement
c) Cooling water flow measurement
d) Lubricating oil flow measurement
Answer: a
Clarification: The electro-optical sensors can be used for position and speed measurement. These devices can operate on high frequencies. Also, it can detect fast-moving objects.

4. What is the main use of the strain gauge?
a) To measure viscosity
b) To measure velocity
c) To measure temperature
d) To measure pressure
Answer: d
Clarification: The main use of the strain gauge is to measure pressure. In this sensor, the conductor changes the dimension along with the member whose strain is to be measured.

5. What is the use of the hot-wire sensor?
a) To measure temperature
b) To measure the smoke intensity
c) To measure the mass flow rate
d) To measure pressure
Answer: c
Clarification: The hot-wire sensor is used to measure the mass flow rate. This sensor is positioned between the air filter and the throttle valve.

6. What is the disadvantage of the piezoelectric pressure sensor?
a) It has too much sensitivity
b) It can measure only low pressure
c) It is not suitable for dynamic measurement
d) It can only give pressure difference
Answer: d
Clarification: The disadvantage of the piezoelectric pressure sensor is that it can only give the pressure difference. The advantages of the piezoelectric pressure sensor are quick frequency response and they are of small size.

7. What is LVDT used to measure?
a) Gas temperature
b) Engine speed
c) Crank angle
d) Large displacement
Answer: d
Clarification: LVDT is used to measure the large displacement. These are only used for the low-frequency measurements. These sensors are used to measure the parameters like valve lift etc.

8. In which of the following See beck effect is used?
a) Hot-wire sensors
b) Resistance temperature detectors
c) Thermocouples
d) Thermistors
Answer: c
Clarification: Thermocouples use the Seebeck effect to measure the temperature. Thermocouples can be used for high-temperature measurement.

9. Which of the following is used by the Hall Effect pickup?
a) Thermistors
b) Potentiometers
c) Inductive transducers
d) Semiconductors
Answer: d
Clarification: In Hall Effect pickup, semiconductors are used. This sensor used for detecting the position of the shaft and speed. This sensor can be used to detect motion.

10. Vortex sensor is used for measurement of the temperature.
a) True
b) False
Answer: b
Clarification: Vortex sensor is used for measurement of the intake airflow. In this sensor, as the air passes the bluff body creates the vortex. Due to which pressure disturbances are created which can be sensed by the microphone.

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