Important Quiz questions about engine, quiz questions about engine technical terms

Important quiz questions about engine:-

1. Which of the following is correct?

a) Thermal efficiency varies directly as specific fuel consumption

B) Thermal efficiency varies as specific fuel consumption

C) Thermal efficiency varies as inertial as specific fuel consumption

D) Thermal efficiency varies as square as specific fuel consumption

Answer: B

Explanation: Specific fuel consumption is the ratio of the fuel consumption rate of the electricity produced. Thermal efficiency is the ratio of power produced to the fuel consumption rate. Hence both are inversely proportional to each other.

2. What is mechanical efficiency?

a) Brake power to brake power ratio

b) The ratio of the indicated power to the brake power

c) The ratio of the strength indicated to the friction power

d) The ratio of friction strength to the indicated strength

Answer: D

Explanation: Mechanical efficiency is the ratio of friction strength to the indicated strength. Mechanical efficiency takes into account mechanical losses. Mechanical losses are divided into friction losses; Absorbing power, ventilating action, and cylinder charging work.

3. What is volumetric efficiency?

a) A measure of engine power

b) a measurement of engine speed

C) a measure of pressure increase in the cylinder

d) A measure of the breathing capacity of the engine

Answer: D

Explanation: Volumetric efficiency is the ratio of the volume displaced by the fluid to the volume flowing by the piston. It is the ratio of the actual mass of air drawn by the engine to the theoretical mass that must be drawn by the engine.

4. What does the Sankey diagram represent?

a) Torque vs Speed

b) Heat balance of the engine

c) Air consumption vs. speed

d)) bth vs brake power

Answer: B

Explanation: The Sankey diagram represents the heat balance sheet of the engine. In this diagram, the width of the stream is assumed to be the amount of heat.

5. The Otto engine consumes 9 liters of petrol per hour and develops 30 kW. The specific gravity of petrol is 0.8 and its calorific value is 45000 kJ / kg. What is the indicated thermal efficiency of the engine?

A) 33.33%

B) 25%

C) 30%

d) 32%

Answer: D

Explanation: thermal efficiency = equivalent power / heat input equivalent = (30 * 60 * 60 * 100) / (9 * 10-3 * 800) * 45000 = 33.33%.

6. Which of the following signals is the correlation between effective pressure (imep), brake mean effective pressure (bmep) and friction mean effective power (fmep)?

a) imep = fmep + bmep

b) imep = fmep * bmep

c) imep = fmep - bmep

d) imep = fmep / bmep

Answer: A

Explanation: The induced mean effective pressure (imep) is assumed in which the break means the effective pressure (bmep) and the friction means the effective pressure (fmep).

7. The indicated power of a single-cylinder engine is 1.9 kW. It develops a torque of 10 Nm at 1600 rpm. What is the friction power as a percentage of brake power?

A) 12.43%

B) 13.83%

C) 14.83%

d) 15.43%

Answer: B

Explanation: Brake power = BP, Indicated power = IP = 1.6KW, Friction power = FP, Speed = N = 1800 rpm, and Torque = T = 10 Nm. Brake power = BP = 2πNT / 60000 = 2 1600 * 1600 * 10/60000 = 1.675 kW. Frictional power = fp = ip - bp = 1.9 - 1.675 = 0.225 kW. Percent Loss = (fp / bp) * 100 = (0.225 / 1.675) * 100 = 13.43%.

8. The bore and stroke of a single-cylinder four-stroke engine are 90 mm and 120 mm respectively. The torque is 24 Nm. What is the brake mean effective pressure of the engine?

a) 3.9 times

b) 4.9 times

c) 5.9 times

d) 6.9 times

Answer: A

Explanation: Brake mean effective pressure = pbm, torque = T = 24 Nm, stroke = L = 120 mm, bore = D = 90 mm. pbm = 16T / D2L = (16 * 24) / (0.09 * 0.09 * 0.12) = 3.9 * 105 Pa = 3.9 times.

9. What is the brake specific fuel consumption of an engine whose fuel consumption is 6 grams per second and power output is 90 kW?

a) 0.24 kg / kWh

b) 0.0667 kg / kWh

c) 0.54 kg / kWh

d) 0.44 kg / kWh

Important quiz questions about engine

Answer: A

Explanation: Brake specific fuel consumption = bf / bp where bp = brake power and = f = brake specific fuel consumption. Brake specific fuel consumption = 6/90 = 0.0667 g / kW-s = (0.0667 * 3600) / 1000 = 0.24 kg / kWh.

10. If IP = 2.62 kW and bp = 2.4 kW to fp = 5.04 kW

A) truth

B) false

Answer: B

11. Which of the following Morse test is applicable?

a) Single-cylinder SI engine

B) single-cylinder CI engine

c) Multi-cylinder CI engine

d) Single and multi-cylinder SI and CI engines

Answer: C

Explanation: Morse test is used to measure the indicated power (IP) from a multi-cylinder CI engine. Testing involves obtaining the indicated power (IP) of a CI engine without any equipment.

12. Which of the following is a chemiluminescence analyzer used to measure?

An ox

b) CO

c) H.C.

d) CO2

Answer: A

Explanation: Chemiluminescence analyzer is used to measure NOx in exhaust gases from the engine. The principle of measurement is based on the chemiluminescence reaction between ozone and NO. This results in the formation of excited NO2.

13. Which of the following is the best method for measuring speed?

a) Mechanical tachometer

b) Electrical tachometer

c) Magnetic Pick

d) Mechanical Counter

Answer: C

Explanation: Magnetic pickup is the best tool for measuring speed. Mechanical and electrical tachometers are affected by temperature variations and are not precise.

14. Which of the following is the most accurate method of determining frictional strength?

A) Morse test

B) Willian's line

C) motoring test

D) Measurement of brakes and indicated power

Answer: D

Explanation: Frictional strength can be obtained by measurement of brake and indicated strength. The indicated power can be obtained by the signal diagram and brake power obtained by the dynamometer.

15. What is the need of an air box in the airbox method of measuring airflow?

a) to flush out the pulsation

B) to provide a constant velocity of flow

C) is a continuous flow

d) keep a constant temperature

Answer: A

Explanation: The air box is used to eject the pulsation when measuring airflow. In IC engines, satisfactory measurement of air consumption is difficult because the flow is pulsating due to the cyclic nature of the engine and because the air is a compressed fluid.

16. Which of the following is used for measuring flame Ionization detector (FID)?

A) CO

b) H.C.

c) CO2

d) NOx

Answer: B

Explanation: Flame ionization detector (FID) is used to measure hydrocarbon concentration. Ionization is a characteristic of the HC compound.

17. Which of the following is the most accurate dynamometer?

A) eddy current dynamometer

B) Prony brake dynamometer

C) hydraulic type dynamometer

D) Swinging Area Type Dynamometer

Answer: D

Explanation: The swinging field type dynamometer is the most accurate dynamometer. It consists of an electric machine that can be run by a motor or generator.

18. Which of the following non-dispersive infra-red (NDIR) analyzer is used to measure?

a) CO2

b) CO

c) H.C.

d) NOx

Answer: B

Explanation: Non-dispersive infra-red (NDIR) analyzer is used to measure CO. The detection method is based on the principle of selective absorption of infrared energy of particular wavelength for a certain gas that will be absorbed by that gas.

19. What can be obtained from the engine indicator diagram?

a) induced means effective pressure

b) Brake means effective pressure

C) relative efficiency

D) mechanical efficiency

Answer: A

Explanation: The engine indicator diagram is used to obtain the indicated mean effective pressure. Pressure-volume, P-V, and pressure-crank angle, P-the are two types of indicator diagrams that can be obtained from an engine. Both these indicator diagrams are mutually variable.

20. Which of the following depends on the effective brake pressure (BMEP) in the engine?

a) Speed and torque

b) speed and power

c) Torque

D) speed

Answer: B

Explanation: Brake power = 2πNT / 60000 where N = engine speed in RPM and T = torque in Nm. The dynamometer gives engine torque from which brake power can be calculated. Thus the mean effective pressure of the brake in an engine depends only on the torque. Also, brake power = Pmb * L * A * n / 60000. Therefore, Pmb = kT where k = 2 A / L * A and k = 4π / L * A where L = stroke length, A = cross-sectional area of cylinder, n = no. Work stroke per minute and, Pmb = mean effective pressure of brake.

21. What is dual fuel engine?

a) Engine that uses gaseous and liquid fuel

b) engine that uses two liquid fuels

c) Engine that uses two gaseous fuels

d) engine that uses a liquid and any other fuel

Answer: A

Explanation: The duel fuel engine uses gaseous and liquid fuel. The dual-fuel engine operates on a diesel cycle. Gaseous fuel is called primary fuel. A mixture of air and gaseous fuel is compressed into the cylinder.

22. Which of the following has combustion similar to HCCI (homogeneous charge compression ignition) engine?

a) SI Engine

b) CI engine

c) Hybrid of both SI and CI engines

d) Wankel Engine

Answer: C

Explanation: The HCCI engine has combustion similar to the hybrids of both the SI and CI engines. HCCI is a form of IC engine in which mixed fuel and air are compressed to the auto-ignition temperature of the fuel.

23. Which of the following is correct for HCCI engine?

a) emits high NOx and soot

B) has a large power range

C) efficiency is comparatively low

D) pre-catalytic hydrocarbon emissions are high

Answer: D

Explanation: Pre-catalytic hydrocarbon emissions are high, which is one of the disadvantages of HCCI engines. The advantages of HCCI engines are NOx and soot emissions are almost negligible.

24. The Lean-Burn concept is ideal for which of the following engines?

a) CI engine

b) SI engine

c) Free piston engine

d) Wankel Engine

Answer: B

Explanation: SI engines are more ideal for the Lean-Burn concept. A lean-burn mode is a way to reduce throttling losses. In SI engines, power is partially reduced by closing a throttle.

25. By which technique can charge stratification be achieved?

A) injection

B) carbocation

C) Lean Burn Technology

D) injection as well as carbureation

Answer: D

Explanation: Charge stratification can be achieved by injection as well as carboregulation. Charge stratification means providing different fuel – air mixing strengths at different locations in the combustion chamber.

26. Which of the following is true for stratified charge engines?

A) more prone to knocking

B) multi-fuel capacity

C) more throttling losses

D) overall rich mixture

Answer: B

Explanation: Multi-fuel efficiencies are one of the benefits of stratified charge engines. Stratified engines have been developed to combine the benefits of diesel and petrol engines.

27. What is true about the Wankel engine?

a) It is a rotary external combustion engine

b) it is more expensive

C) It has a long operating cycle

d) there is less time to complete combustion

Answer: C

Explanation: The Wankel engine is a type of internal combustion engine that converts pressure to rotational speed using a rotary design. It does not use reciprocating pistons.

28. Where is the variable compression ratio used?

a) SI Engine

b) CI engine

c) Wankel Engine

D) HCCI engine

Answer: A

Explanation: Variable compression is used in SI engines. There are several ways to change both geometric and effective compression ratios.

29. Which one of the following is true for stratified charge engines?

A) more prone to knocking

B) It uses an overall rich mixture

c) It has a lot of throttling loss

d) It has multi fuel efficiency

Answer: D

Explanation: The stratified charge engine has multi-fuel capacity. The benefits of stratified charge engines are high thermodynamic efficiency and low air pollution.

30. Which of the following is true about the Stirling engine?

a) high efficiency

B) quiet operation

C) compatible with alternative and renewable energy

D) High efficiency, quiet operation and compatible with renewable energy

Answer: D

Explanation: The Stirling engine has high efficiency. The Stirling engine is a heat engine that works on cyclic compression and expansion of air or any other fluid.