Exam 16: Variable Geometry and Series Turbochargers

A "woofing" sound from the air intake when the engine is rapidly accelerated and decelerated is one symptom of a slow-responding actuator and this condition, known as turbocharger surge, produces a sound referred to as:

Also known as aftercooling and intercooling, what system removes excess heat from the air, thereby charging the cylinders?

What can enable higher turbine speeds?

Which VGT sensor is primarily responsible for preventing turbocharger overspeed?

When replacing motors and modules in the actuator, the ECM (Engine Control Module) is required to ________ to accurately adjust vane or the sliding nozzle's new position.

Single-sequential turbocharger (SST) claims to have reduced the mass of the turbine wheel and accompanying inertia by up to:

What continuously monitors the VGT (variable-geometry turbocharger) to detect any condition that could lead to potential increases in exhaust emissions?

Which of the following strategies best explains how the VGT operates as an engine brake?

Two technicians are discussing VGT's (variable-geometry turbochargers') variable-nozzle opening. Technician A says when less exhaust gas flow takes place across the turbine, the turbine speed drops because exhaust backpressure increases. Technician B says that by varying the width of the nozzle opening with an actuator, the turbine speed power is adjusted to provide just enough energy to drive the compressor wheel at the desired boost level for any engine speed and load condition. Who is right?

Which of the following allow more turbocharger exhaust flow in high horsepower engines?

Ford used this DualBoost Turbo turbocharger from 2011 until 2014, when it replaced it with a:

Which of the following use a mechanism to hold the intake valve open longer under high boost conditions so that the engine does not need to work as hard to compress air?

The position of the VGT (variable-geometry turbochargers) vanes can be varied to produce the desired boost pressure. At idle and during shutdown, the vanes are ----_____ closed?

Technician A says that a late-model engine equipped with a VGT will close the vanes to increase intake boost and exhaust backpressure during braking. Technician B says the vanes will open to reduce intake airflow during engine braking. Who is correct?

Technician A says that a late-model engine equipped with a VGT will close the vanes to increase intake boost and exhaust backpressure during braking. Technician B says the vanes will open to reduce intake airflow during engine braking. Who is correct?

High boost pressures produced by which of the following enable the use of late intake valve closing?

Technician A says that driving the turbine wheel at higher speeds enables very high compressor wheel speeds. Technician B says that pairing low inertia rotating components with electronic turbocharger controls provides adequate air and exhaust gas flow over an extended operational range. Who is right?

What characteristic of VGTs requires the use of titanium alloys for compressor wheels?

Under which of the following operating conditions does the low-pressure turbocharger of a series turbocharger arrangement produce maximum boost?

Technician A says that coolant passageways through the turbocharger housing are used to keep the turbocharger bearings and other parts cooled when the engine is running. Technician B says that coolant passageways are used primarily to circulate coolant after the engine has been shut off. Who is correct?