Mechanical Engineering Mcqs
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

A hmh flame speed is obtained in diesel engine when air fuel ratio is_______________?

A. Uniform throughout the mixture
B. Chemically correct mixture
C. About 3-5% rich mixture
D. About 10% rich mixture

A diesel engine has_________________?

A. 1 valve
B. 2 valves
C. 3 valves
D. 4 valves

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

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

Scavenging air in diesel engine means___________________?

A. Air used for combustion sent under pres-sure
B. Forced air for cooling cylinder
C. Burnt air containing products of combustion
D. Air used for forcing burnt gases out of engine’s cylinder during the exhaust period