USCG Aftercoolers

9. c) higher torque and higher brake horsepower

Aftercooling of a turbocharged diesel engine will result in ______. a) higher torque but lower brake horsepower b) lower torque but higher brake horsepower c) higher torque and higher brake horsepower d) lower torque and lower brake horsepower

8. a) increases the density of the air

An aftercooler installed between the turbocharger and the cylinder air inlet ______. a) increases the density of the air b) decreases the density of the air c) increases the specific heat of the air d) decreases the specific heat of the exhaust

12. b) density of the air charge will decrease

If cooling water flow through the aftercooler is interrupted, the power output of a turbocharged diesel engine will drop because the ______. a) turbocharger will stall b) density of the air charge will decrease c) scavenge effect will increase d) exhaust pressure will increase

c) aftercooling the intake air

Performance of a turbocharged engine can be improved by ______. a) decreasing the amount of valve overlap b) preheating the air intake c) aftercooling the intake air d) preheating light fuels

4. c) aftercooler

The air supplied to the cylinders by a turbocharger is often reduced in volume by a/an ______. a) air compressor b) diffuser c) aftercooler d) venturi

6. a) increase the density of the intake air

The function of the aftercooler installed between the turbocharger and intake manifold on some diesel engines, is to ______. a) increase the density of the intake air b) decrease turbocharger power usage c) reduce exhaust gas temperature d) compensate for turbocharger RPM fluctuations

11. c) air charge density decreases

The power output of a turbocharged diesel engine will drop if the cooling water flow through the aftercooler is interrupted because the ______. a) turbocharger stalls b) exhaust pressure increases c) air charge density decreases d) scavenge effect increases

c) increase the density of the inlet air

The purpose of an aftercooler is to ______. a) reduce the turbocharger operating temperature b) increase the pressure of the inlet air c) increase the density of the inlet air d) reduce the blower operating temperature

10. a) B

The section of the turbocharger which would be connected to the aftercooler inlet is labeled ______. See illustration MO-0080. a) B b) C c) H d) K

7. a) increase the density of the cylinder air charge

When used in conjunction with a turbocharger, the main function of an aftercooler is to ______. a) increase the density of the cylinder air charge b) prevent turbocharger overheating c) eliminate the need for a precooler d) remove moisture from air compressed by the turbocharger

14. d) A decrease in the air temperature differential between the cooler inlet and outlet.

Which condition indicates the air side fouling of an aftercooler on a turbocharged diesel engine? a) An increased air temperature differential between the cooler inlet and outlet. b) A decrease in the air pressure differential across the cooler. c) Excessive condensate forming in the air box. d) A decrease in the air temperature differential between the cooler inlet and outlet.

1. c) Aftercooler

Which of the diesel engine components listed increases air density and helps to improve engine operating efficiency? a) Impeller b) Compressor c) Aftercooler d) Exhaust diffuser

5. c) Aftercooler

Which of the engine components listed increases air charge density and helps to improve engine operating efficiency? a) Intake manifold b) Water-cooled exhaust system c) Aftercooler d) Exhaust diffuser

13. b) Blank off the cooling water lines and run at reduced speed.

Which of the following procedures should be carried out to permit the continued operation of a crosshead engine with a leaky aftercooler? a) Bypass the aftercooler to operate at sea speed. b) Blank off the cooling water lines and run at reduced speed. c) Switch to diesel fuel and run at reduced speed. d) Nothing needs to be done due to the low heating value of heavy fuel.