Scavenging,Turbocharging & Aircooling (Set 1)

1. Which of the two events listed occurs simultaneously in a two-stroke/cycle diesel engine?

Exhaust and scavenging

Scavenging and compression

Ignition and expansion

Exhaust and compression

2. Scavenging in a turbocharged, four-stroke/cycle diesel engine is accomplished _____________.

during the valve overlap period

with only the exhaust valve open

at a pressure below atmospheric

without cooling the cylinders or pistons

3. Air scavenging of a diesel engine cylinder ____________.

blows out the exhaust gases

supplies oxygen for combustion

cools the valves and cylinder walls

all of the above

4. A diesel engine is supercharged in order to ____________.

lower the no-load RPMs

provide more air for combining with the fuel

increase the no-load RPMs

provide more fuel for combining with the air

5. One characteristic of a pulse type turbocharging system is ________________.

high average exhaust manifold pressure

greatly fluctuating inlet manifold pressure

constant exhaust manifold pressure

multiple exhaust pipes to the turbocharger

6. Which of the listed types of superchargers will NOT have a volumetric capacity proportional to engine speed?

Exhaust gas turbocharger

Roots blower

Piston type blower

Vane type blower

7. Which of the following turbocharging systems channels the exhaust gases of each individual cylinder directly into the turbine rotor blades?

Reaction

Pulse

Constant Pressure

Variable pressure

8. A turbocharged, four-stroke/cycle diesel engine has a larger valve overlap than a naturally aspirated four-stroke/cycle diesel engine, in order to increase the _____________.

temperature of the exhaust gases

energy supplied to the turbocharger

air pressure to the intake manifold

purge of exhausted gases from the cylinders

9. Which of the following statements is correct regarding a turbocharged four-stroke/cycle diesel generator?

At zero load the intake manifold pressure is greater than the exhaust manifold pressure.

At full load the intake manifold pressure and exhaust manifold pressure are equal.

At full load the intake manifold pressure is less than the exhaust manifold pressure.

At full load the intake manifold pressure is greater than the exhaust manifold pressure.

10. Why will a turbocharged diesel engine produce black smoke if excessive additional load is applied too quickly?

Exhaust energy would draw excess air.

The inertia of the turbocharger rotor causes a time lag which delays the turbocharger speed increase.

Exhaust gas pumping losses are increased due to turbine windage.

Exhaust gas back pressure falls slightly due to increased nozzle action.

Scavenging,Turbocharging & Aircooling (Set 1)

Multiple Choice Questions