Exam 15: Fixed Geometry and Wastegated Turbochargers

Consider an on-highway diesel engine that has a precisely matched turbocharger. Under which of the following conditions should turbine speeds be greatest to achieve maximum engine output?

Which of the following can prevent exhaust gas from expanding?

Technician A says waste-gated turbochargers enable smaller displacement diesel engines to produce more power at low engine speeds. Technician B says waste gates prevent turbochargers from overspeeding at high speed and load conditions. Who is correct?

Which of the following conditions is likely caused by the failure of the waste gate to open on a waste-gated turbocharger?

Power decreases 1% for every _____ above 90°F.

Smaller displacement engines will not need to turn as fast to produce what is known as:

Which of the following conditions is likely caused by the waste gate failing to close on a waste-gated turbocharger?

After a turbocharger failure or after a CAC (charge-air-cooler) core has become internally restricted, which of the following is done?

What causes the pressure to drive the turbine wheel of the turbocharger?

Technician A says that turbocharger lag is caused by the inertia of heavy compressor and turbine wheel assemblies. Technician B says turbocharger lag is caused by the slow buildup of fuel rate by the high-pressure injection system. Who is correct?

The inlet to the turbine is located on the outside radius of the turbine housing and attaches to the:

What is shaped like the turbine housing but with the opposite direction of gas flow?

Which of the following is NOT a benefit of charge air cooling?

To measure center support bearing wear, push down on the compressor wheel with moderate finger pressure while inserting the thickest feeler blade that will fit between the compressor wheel and the:

Exhaust gas energy would normally vent directly to the atmosphere. Instead, which of the following can recover some of that energy to improve engine efficiency?

A CAC (charge-air-cooler) system pressure drop is measured with a:

Technician A says that if a turbocharger is disassembled and a new compressor wheel is installed, then the turbocharger will need to be balanced. Technician B says that a compressor wheel's light weight will not affect turbocharger operation one way or another. Who is correct?

If you find a worn compressor/turbine wheel shaft or bearings, which of the following should be done?

Two technicians are describing pressure testing a CAC (charge-air-cooler). Technician A says that you connect an air pressure regulator to the test adapter plug, and pressurize the cooler to 30 psi. Technician B says that you shut off the air pressure supply to the regulator, and count the number of seconds it takes for the cooler to drop 15 psi. Who is right?

Technician A says waste-gated turbochargers enable smaller displacement diesel engines to produce more power at low engine speeds. Technician B says waste gates prevent turbochargers from overspeeding at high speed and load conditions. Who is correct?