# Thermal Engineering 16

Objective Questions and Answer: Thermal Engineering 16

Subject: Thermal Engineering 16

Part 16: Objective questions and answers of Thermal Engineering

Q1. The theoretically correct air fuel ratio for petrol engine is of the order of

a) 6:01

b) 9:01

c) 12:01

d) 15:01

Q2. Air fuel ratio for idling speed of a petrol engine is approximately

a) 1:01

b) 5:01

c) 10:01

d) 15:01

Q3. Air fuel ratio at which a petrol engine cannot work is

a) 8:01

b) 10:01

c) 15:01

d) 20 : 1 and less

Q4. For maximum power generation, the air fuel ratio for a petrol engine for vehicles, is of the order of

a) 9:01

b) 12:01

c) 15:01

d) 18:01

Q5. The following volume of air is required for consuming 1 liter of fuel by a four stroke engine

a) 1 m^3

b) 5 m^3

c) 5-6 m^3

d) 9-10 m^3

Q6. Pour point of fuel oil is the

a) Minimum temperature to which oil is heated in order to give off inflammable vapours in sufficient quantity to ignite momentarily when brought in contact with a flame

b) Temperature at which it solidifies or congeals

c) It catches fire without external aid

d) Indicated by 90% distillation temperature i.e., when 90% of sample oil has distilled off

Q7. A 5 BHP engine running at full load would consume diesel of the order of

a) 0.3 kg/hr

b) 1 kg/hr

c) 3 kg/hr

d) 5 kg/hr

Q8. Diesel engine can work on very lean air fuel ratio of the order of 30 : 1. A petrol engine can also work on such a lean ratio provided

a) It is properly designed

b) Best quality fuel is used

c) Can not work as it is impossible

d) Flywheel size is proper

Q9. A diesel engine has

a) 1 valve

b) 2 valves

c) 3 valves

d) 4 valves

Q10. A hmh flame speed is obtained in diesel engine when air fuel ratio is

a) Uniform throughout the mixture

b) Chemically correct mixture

Q11. The knock in diesel engine occurs due to

a) Instantaneous and rapid burning of the first part of the charge

b) Instantaneous atuo iginition of last part of charge

c) Delayed burning of the first part of the charge

d) Reduction of delay period

Q12. The air-fuel ratio in petrol engines-is controlled by

a) Controlling valve opening/closing

b) Governing

c) Injection

d) Carburettion

Q13. Volatility of diesel fuel oil is

a) Minimum temperature to which oil is heated in order to give off inflammable vapours in sufficient quantity to ignite momentarily when brought in contact with a flame

b) Temperature at which it solidifies or congeals

c) It catches fire without external aid

d) Indicated by 90% distillation temperature, i.e., when 90% of sample oil has distilled off

Q14. Which is more viscous lub oil

a) SEA 30

b) SAE 80

c) SAE 50

d) SAE 70

Q15. In the opposed piston diesel engine, the combustion chamber is located

a) Above the piston

b) Below the piston

c) Between the pistons

d) Any where

Q16. A stoichiometric air-fuel ratio is

a) Chemically correct mixture

b) Lean mixture

c) Rich mixture for idling

d) Rich mixture for over loads

Q17. In a naturally aspirated diesel engine, the air is supplied by

a) A supercharger

b) A centrifugal blower

c) A vacuum chamber

d) An injection tube

Q18. In loop scavenging, the top of the piston is

a) Flat

b) Contoured

c) Slanted

d) Depressed

Q19. In the crankcase method of scavenging, the air pressure is produced by

a) Supercharger

b) Centrifugal pump

c) Natural aspirator

d) Movement of engine piston

Q20. If the compression ratio of an engine working on Otto cycle is increased from 5 to 7, the %age increase in efficiency will be

a) 2%

b) 4%

c) 8%

d) 14%

Part 16: Objective questions and answers of Thermal Engineering