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?
A)A only"
B)B only"
C)Both A and B
D)Neither A nor B"

Question

Quizplus · Accepted Answer

Technician B is correct. By varying the width of the nozzle opening with an actuator, the VGT adjusts the turbine speed to provide the necessary energy to drive the compressor wheel at the desired boost level for any engine speed and load condition. Technician A's statement is incorrect because less exhaust gas flow does not necessarily increase exhaust backpressure; it depends on the nozzle position.

Two Technicians Are Discussing VGT's (Variable-Geometry Turbochargers') Variable-Nozzle Opening